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MWL#182: Explain running statements

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- Merge with current 5.5-main
This commit is contained in:
Sergey Petrunya 2012-06-15 00:50:17 +04:00
commit fb33db5608
31 changed files with 2869 additions and 176 deletions
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1
.bzrignore
View File

@ -1137,6 +1137,7 @@ plugin/handler_socket/perl-Net-HandlerSocket/Makefile.PL
libmysqld/libmysqld_exports_file.cc
libmysqld/gcalc_slicescan.cc
libmysqld/gcalc_tools.cc
libmysqld/my_apc.cc
sql/share/errmsg.sys
sql/share/mysql
install_manifest.txt

25
client/mysqltest.cc
View File

@ -84,6 +84,8 @@ static my_bool non_blocking_api_enabled= 0;
#define QUERY_SEND_FLAG 1
#define QUERY_REAP_FLAG 2
#define QUERY_PRINT_ORIGINAL_FLAG 4
#ifndef HAVE_SETENV
static int setenv(const char *name, const char *value, int overwrite);
#endif
@ -342,7 +344,8 @@ enum enum_commands {
Q_ERROR,
Q_SEND, Q_REAP,
Q_DIRTY_CLOSE, Q_REPLACE, Q_REPLACE_COLUMN,
Q_PING, Q_EVAL,
Q_PING, Q_EVAL,
Q_EVALP,
Q_EVAL_RESULT,
Q_ENABLE_QUERY_LOG, Q_DISABLE_QUERY_LOG,
Q_ENABLE_RESULT_LOG, Q_DISABLE_RESULT_LOG,
@ -408,6 +411,7 @@ const char *command_names[]=
"replace_column",
"ping",
"eval",
"evalp",
"eval_result",
/* Enable/disable that the _query_ is logged to result file */
"enable_query_log",
@ -8269,7 +8273,8 @@ void run_query(struct st_connection *cn, struct st_command *command, int flags)
/*
Evaluate query if this is an eval command
*/
if (command->type == Q_EVAL || command->type == Q_SEND_EVAL)
if (command->type == Q_EVAL || command->type == Q_SEND_EVAL ||
command->type == Q_EVALP)
{
init_dynamic_string(&eval_query, "", command->query_len+256, 1024);
do_eval(&eval_query, command->query, command->end, FALSE);
@ -8301,10 +8306,20 @@ void run_query(struct st_connection *cn, struct st_command *command, int flags)
*/
if (!disable_query_log && (flags & QUERY_SEND_FLAG))
{
replace_dynstr_append_mem(ds, query, query_len);
char *print_query= query;
int print_len= query_len;
if (flags & QUERY_PRINT_ORIGINAL_FLAG)
{
print_query= command->query;
print_len= command->end - command->query;
}
replace_dynstr_append_mem(ds, print_query, print_len);
dynstr_append_mem(ds, delimiter, delimiter_length);
dynstr_append_mem(ds, "\n", 1);
}
/* We're done with this flag */
flags &= ~QUERY_PRINT_ORIGINAL_FLAG;
/*
Write the command to the result file before we execute the query
@ -9162,6 +9177,7 @@ int main(int argc, char **argv)
case Q_EVAL_RESULT:
die("'eval_result' command is deprecated");
case Q_EVAL:
case Q_EVALP:
case Q_QUERY_VERTICAL:
case Q_QUERY_HORIZONTAL:
if (command->query == command->query_buf)
@ -9189,6 +9205,9 @@ int main(int argc, char **argv)
flags= QUERY_REAP_FLAG;
}
if (command->type == Q_EVALP)
flags |= QUERY_PRINT_ORIGINAL_FLAG;
/* Check for special property for this query */
display_result_vertically|= (command->type == Q_QUERY_VERTICAL);

1
libmysqld/CMakeLists.txt
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@ -95,6 +95,7 @@ SET(SQL_EMBEDDED_SOURCES emb_qcache.cc libmysqld.c lib_sql.cc
../sql/create_options.cc ../sql/rpl_utility.cc
../sql/rpl_reporting.cc
../sql/sql_expression_cache.cc
../sql/my_apc.cc ../sql/my_apc.h
${GEN_SOURCES}
${MYSYS_LIBWRAP_SOURCE}
)

1
mysql-test/include/index_merge2.inc
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@ -343,6 +343,7 @@ alter table t1 add index i3(key3);
update t1 set key2=key1,key3=key1;
# to test the bug, the following must use "sort_union":
--replace_column 9 ROWS
explain select * from t1 where (key3 > 30 and key3<35) or (key2 >32 and key2 < 40);
select * from t1 where (key3 > 30 and key3<35) or (key2 >32 and key2 < 40);
drop table t1;

2
mysql-test/r/index_merge_innodb.result
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@ -313,7 +313,7 @@ alter table t1 add index i3(key3);
update t1 set key2=key1,key3=key1;
explain select * from t1 where (key3 > 30 and key3<35) or (key2 >32 and key2 < 40);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index_merge i2,i3 i3,i2 4,4 NULL 9 Using sort_union(i3,i2); Using where
1 SIMPLE t1 index_merge i2,i3 i3,i2 4,4 NULL ROWS Using sort_union(i3,i2); Using where
select * from t1 where (key3 > 30 and key3<35) or (key2 >32 and key2 < 40);
key1 key2 key3
31 31 31

2
mysql-test/r/index_merge_myisam.result
View File

@ -1146,7 +1146,7 @@ alter table t1 add index i3(key3);
update t1 set key2=key1,key3=key1;
explain select * from t1 where (key3 > 30 and key3<35) or (key2 >32 and key2 < 40);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index_merge i2,i3 i3,i2 4,4 NULL 11 Using sort_union(i3,i2); Using where
1 SIMPLE t1 index_merge i2,i3 i3,i2 4,4 NULL ROWS Using sort_union(i3,i2); Using where
select * from t1 where (key3 > 30 and key3<35) or (key2 >32 and key2 < 40);
key1 key2 key3
31 31 31

662
mysql-test/r/show_explain.result Normal file
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@ -0,0 +1,662 @@
drop table if exists t0, t1, t2, t3, t4;
drop view if exists v1;
create table t0 (a int);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1 (a int);
insert into t1 select A.a + 10*B.a + 100*C.a from t0 A, t0 B, t0 C;
alter table t1 add b int, add c int, add filler char(32);
update t1 set b=a, c=a, filler='fooo';
alter table t1 add key(a), add key(b);
show explain for 2*1000*1000*1000;
ERROR HY000: Unknown thread id: 2000000000
show explain for (select max(a) from t0);
ERROR 42000: This version of MariaDB doesn't yet support 'Usage of subqueries or stored function calls as part of this statement'
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
show explain for $thr1;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
select count(*) from t1 where a < 100000;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index a a 5 NULL 1000 Using where; Using index
Warnings:
Note 1003 select count(*) from t1 where a < 100000
count(*)
1000
select max(c) from t1 where a < 10;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 10 Using index condition
Warnings:
Note 1003 select max(c) from t1 where a < 10
max(c)
9
# We can catch EXPLAIN, too.
set @show_expl_tmp= @@optimizer_switch;
set optimizer_switch='index_condition_pushdown=on,mrr=on,mrr_sort_keys=on';
explain select max(c) from t1 where a < 10;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 10 Using index condition; Rowid-ordered scan
Warnings:
Note 1003 explain select max(c) from t1 where a < 10
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 10 Using index condition; Rowid-ordered scan
set optimizer_switch= @show_expl_tmp;
# UNION, first branch
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
explain select a from t0 A union select a+1 from t0 B;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY A ALL NULL NULL NULL NULL 10
2 UNION B ALL NULL NULL NULL NULL 10
NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL
Warnings:
Note 1003 explain select a from t0 A union select a+1 from t0 B
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY A ALL NULL NULL NULL NULL 10
2 UNION B ALL NULL NULL NULL NULL 10
NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL
# UNION, second branch
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
explain select a from t0 A union select a+1 from t0 B;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY A ALL NULL NULL NULL NULL 10
2 UNION B ALL NULL NULL NULL NULL 10
NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL
Warnings:
Note 1003 explain select a from t0 A union select a+1 from t0 B
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY A ALL NULL NULL NULL NULL 10
2 UNION B ALL NULL NULL NULL NULL 10
NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL
# Uncorrelated subquery, select
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 B) from t0 A where a<1;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY A ALL NULL NULL NULL NULL 10 Using where
2 SUBQUERY B ALL NULL NULL NULL NULL 10
Warnings:
Note 1003 select a, (select max(a) from t0 B) from t0 A where a<1
a (select max(a) from t0 B)
0 9
# Uncorrelated subquery, explain
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
explain select a, (select max(a) from t0 B) from t0 A where a<1;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY A ALL NULL NULL NULL NULL 10 Using where
2 SUBQUERY B ALL NULL NULL NULL NULL 10
Warnings:
Note 1003 explain select a, (select max(a) from t0 B) from t0 A where a<1
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY A ALL NULL NULL NULL NULL 10 Using where
2 SUBQUERY B ALL NULL NULL NULL NULL 10
# correlated subquery, select
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY a ALL NULL NULL NULL NULL 10 Using where
2 DEPENDENT SUBQUERY b ALL NULL NULL NULL NULL 10 Using where
Warnings:
Note 1003 select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1
a (select max(a) from t0 b where b.a+a.a<10)
0 9
# correlated subquery, explain
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY a ALL NULL NULL NULL NULL 10 Using where
2 DEPENDENT SUBQUERY b ALL NULL NULL NULL NULL 10 Using where
Warnings:
Note 1003 select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1
a (select max(a) from t0 b where b.a+a.a<10)
0 9
# correlated subquery, select, while inside the subquery
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY a ALL NULL NULL NULL NULL 10 Using where
2 DEPENDENT SUBQUERY b ALL NULL NULL NULL NULL 10 Using where
Warnings:
Note 1003 select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1
a (select max(a) from t0 b where b.a+a.a<10)
0 9
# correlated subquery, explain, while inside the subquery
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY a ALL NULL NULL NULL NULL 10 Using where
2 DEPENDENT SUBQUERY b ALL NULL NULL NULL NULL 10 Using where
Warnings:
Note 1003 select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1
a (select max(a) from t0 b where b.a+a.a<10)
0 9
# correlated subquery, explain, while inside the subquery
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
a (select max(a) from t0 b where b.a+a.a<10)
0 9
# Try to do SHOW EXPLAIN for a query that runs a SET command:
# I've found experimentally that select_id==2 here...
#
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
set @foo= (select max(a) from t0 where sin(a) >0);
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
#
# Attempt SHOW EXPLAIN for an UPDATE
#
create table t2 as select a as a, a as dummy from t0 limit 2;
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
update t2 set dummy=0 where (select max(a) from t0 where t2.a + t0.a <3) >3 ;
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
drop table t2;
#
# Attempt SHOW EXPLAIN for a DELETE
#
create table t2 as select a as a, a as dummy from t0 limit 2;
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
delete from t2 where (select max(a) from t0 where t2.a + t0.a <3) >3 ;
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
drop table t2;
#
# Multiple SHOW EXPLAIN calls for one select
#
create table t2 as select a as a, a as dummy from t0 limit 3;
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
select t2.a, ((select max(a) from t0 where t2.a + t0.a <3) >3) as SUBQ from t2;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 3
2 DEPENDENT SUBQUERY t0 ALL NULL NULL NULL NULL 10 Using where
Warnings:
Note 1003 select t2.a, ((select max(a) from t0 where t2.a + t0.a <3) >3) as SUBQ from t2
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 3
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Query plan already deleted
Warnings:
Note 1003 select t2.a, ((select max(a) from t0 where t2.a + t0.a <3) >3) as SUBQ from t2
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 3
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Query plan already deleted
Warnings:
Note 1003 select t2.a, ((select max(a) from t0 where t2.a + t0.a <3) >3) as SUBQ from t2
a SUBQ
0 0
1 0
2 0
drop table t2;
#
# SHOW EXPLAIN for SELECT ... ORDER BY with "Using filesort"
#
explain select * from t0 order by a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 Using filesort
set debug_dbug='d,show_explain_probe_join_exec_start';
set @show_explain_probe_select_id=1;
select * from t0 order by a;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 Using filesort
Warnings:
Note 1003 select * from t0 order by a
a
0
1
2
3
4
5
6
7
8
9
#
# SHOW EXPLAIN for SELECT ... with "Using temporary"
#
explain select distinct a from t0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 Using temporary
set debug_dbug='d,show_explain_probe_join_exec_start';
set @show_explain_probe_select_id=1;
select distinct a from t0;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 Using temporary
Warnings:
Note 1003 select distinct a from t0
a
0
1
2
3
4
5
6
7
8
9
#
# SHOW EXPLAIN for SELECT ... with "Using temporary; Using filesort"
#
explain select distinct a from t0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 Using temporary
set debug_dbug='d,show_explain_probe_join_exec_start';
set @show_explain_probe_select_id=1;
select distinct a from t0;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 Using temporary
Warnings:
Note 1003 select distinct a from t0
a
0
1
2
3
4
5
6
7
8
9
set debug_dbug='';
#
# MDEV-238: SHOW EXPLAIN: Server crashes in JOIN::print_explain with FROM subquery and GROUP BY
#
CREATE TABLE t2 ( a INT );
INSERT INTO t2 VALUES (1),(2),(1),(4),(2);
explain SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 5 Using temporary; Using filesort
1 SIMPLE t2 ALL NULL NULL NULL NULL 5 Using join buffer (flat, BNL join)
set debug_dbug='d,show_explain_in_find_all_keys';
SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a;
# FIXED by "conservative assumptions about when QEP is available" fix:
# NOTE: current code will not show "Using join buffer":
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
a
1
2
4
set debug_dbug='';
DROP TABLE t2;
#
# MDEV-239: Assertion `field_types == 0 ... ' failed in Protocol_text::store(double, uint32, String*) with
# SHOW EXPLAIN over EXPLAIN EXTENDED
#
CREATE TABLE t2 (a INT);
INSERT INTO t2 VALUES (1),(2),(1),(4),(2);
EXPLAIN EXTENDED SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a ;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 5 100.00 Using temporary; Using filesort
1 SIMPLE t2 ALL NULL NULL NULL NULL 5 100.00 Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` join `test`.`t2` group by `test`.`t2`.`a`
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
EXPLAIN EXTENDED SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a ;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 5 Using temporary; Using filesort
1 SIMPLE t2 ALL NULL NULL NULL NULL 5 Using join buffer (flat, BNL join)
Warnings:
Note 1003 EXPLAIN EXTENDED SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 5 100.00 Using temporary; Using filesort
1 SIMPLE t2 ALL NULL NULL NULL NULL 5 100.00 Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` join `test`.`t2` group by `test`.`t2`.`a`
set debug_dbug='';
DROP TABLE t2;
#
# MDEV-240: SHOW EXPLAIN: Assertion `this->optimized == 2' failed in
# JOIN::print_explain on query with a JOIN, TEMPTABLE view,
#
CREATE TABLE t3 (a INT);
CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t3;
INSERT INTO t3 VALUES (8);
CREATE TABLE t2 (b INT);
INSERT INTO t2 VALUES (4),(5),(6),(7),(8),(9);
explain SELECT * FROM v1, t2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> system NULL NULL NULL NULL 1
1 PRIMARY t2 ALL NULL NULL NULL NULL 6
2 DERIVED t3 system NULL NULL NULL NULL 1
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_end';
SELECT * FROM v1, t2;
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
a b
8 4
8 5
8 6
8 7
8 8
8 9
set debug_dbug='';
DROP VIEW v1;
DROP TABLE t2, t3;
#
# MDEV-267: SHOW EXPLAIN: Server crashes in JOIN::print_explain on most of queries
#
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
select sleep(1);
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select sleep(1)
sleep(1)
0
set debug_dbug='';
#
# Same as above, but try another reason for JOIN to be degenerate
#
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
select * from t0 where 1>10;
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
a
set debug_dbug='';
#
# Same as above, but try another reason for JOIN to be degenerate (2)
#
create table t3(a int primary key);
insert into t3 select a from t0;
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
select * from t0,t3 where t3.a=112233;
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
a a
set debug_dbug='';
drop table t3;
#
# MDEV-270: SHOW EXPLAIN: server crashes in JOIN::print_explain on a query with
# select tables optimized away
#
CREATE TABLE t2 (pk INT PRIMARY KEY, a INT ) ENGINE=MyISAM;
INSERT INTO t2 VALUES
(1,4),(2,62),(3,7),(4,1),(5,0),(6,7),(7,7),(8,1),(9,7),(10,1),
(11,5),(12,2),(13,0),(14,1),(15,8),(16,1),(17,1),(18,9),(19,1),(20,5) ;
explain SELECT * FROM t2 WHERE a =
(SELECT MAX(a) FROM t2
WHERE pk= (SELECT MAX(pk) FROM t2 WHERE pk = 3)
);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 20 Using where
2 SUBQUERY t2 const PRIMARY PRIMARY 4 const 1 Using where
3 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_do_select';
SELECT * FROM t2 WHERE a =
(SELECT MAX(a) FROM t2
WHERE pk= (SELECT MAX(pk) FROM t2 WHERE pk = 3)
);
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 20 Using where
2 SUBQUERY t2 const PRIMARY PRIMARY 4 const 1 Using where
3 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
Warnings:
Note 1003 SELECT * FROM t2 WHERE a =
(SELECT MAX(a) FROM t2
WHERE pk= (SELECT MAX(pk) FROM t2 WHERE pk = 3)
)
pk a
3 7
6 7
7 7
9 7
set debug_dbug='';
drop table t2;
#
# MDEV-273: SHOW EXPLAIN: server crashes in JOIN::print_explain on a query with impossible WHERE
#
CREATE TABLE t2 (a1 INT, KEY(a1)) ENGINE=MyISAM;
INSERT INTO t2 VALUES
(4),(6),(7),(1),(0),(7),(7),(1),(7),(1),
(5),(2),(0),(1),(8),(1),(1),(9),(1),(5);
CREATE TABLE t3 (b1 INT) ENGINE=MyISAM;
INSERT INTO t3 VALUES
(4),(5),(8),(4),(8),(2),(9),(6),(4),(8),
(3),(5),(9),(6),(8),(3),(2),(6),(3),(1),
(4),(3),(1),(7),(0),(0),(9),(5),(9),(0),
(2),(2),(5),(9),(1),(4),(8),(6),(5),(5),
(1),(7),(2),(8),(9),(3),(2),(6),(6),(5),
(4),(3),(2),(7),(4),(6),(0),(8),(5),(8),
(2),(9),(7),(5),(7),(0),(4),(3),(1),(0),
(6),(2),(8),(3),(7),(3),(5),(5),(1),(2),
(1),(7),(1),(9),(9),(8),(3);
CREATE TABLE t4 (c1 INT) ENGINE=MyISAM;
EXPLAIN
SELECT count(*) FROM t2, t3
WHERE a1 < ALL (
SELECT a1 FROM t2
WHERE a1 IN ( SELECT a1 FROM t2, t4 )
);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 index NULL a1 5 NULL 20 Using where; Using index
1 PRIMARY t3 ALL NULL NULL NULL NULL 87 Using join buffer (flat, BNL join)
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_do_select';
SELECT count(*) FROM t2, t3
WHERE a1 < ALL (
SELECT a1 FROM t2
WHERE a1 IN ( SELECT a1 FROM t2, t4 )
);
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 index NULL a1 5 NULL 20 Using where; Using index
1 PRIMARY t3 ALL NULL NULL NULL NULL 87 Using join buffer (flat, BNL join)
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL no matching row in const table
Warnings:
Note 1003 SELECT count(*) FROM t2, t3
WHERE a1 < ALL (
SELECT a1 FROM t2
WHERE a1 IN ( SELECT a1 FROM t2, t4 )
)
count(*)
1740
set debug_dbug='';
drop table t2, t3, t4;
#
# MDEV-275: SHOW EXPLAIN: server crashes in JOIN::print_explain with IN subquery and aggregate function
#
CREATE TABLE t2 ( `pk` INT NOT NULL PRIMARY KEY, `a1` INT NOT NULL, KEY(`a1`)) ENGINE=MyISAM;
INSERT INTO t2 VALUES
(1,5),(2,4),(3,6),(4,9),(5,2),(6,8),(7,4),(8,8),(9,0),(10,43),
(11,23),(12,3),(13,45),(14,16),(15,2),(16,33),(17,2),(18,5),(19,9),(20,2);
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
SELECT * FROM t2 WHERE (5, 78) IN (SELECT `a1`, MAX(`a1`) FROM t2 GROUP BY `a1`);
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
pk a1
set debug_dbug='';
DROP TABLE t2;
DROP TABLE t1;
#
# MDEV-305: SHOW EXPLAIN: ref returned by SHOW EXPLAIN is different from the normal EXPLAIN ('const' vs empty string)
#
CREATE TABLE t1(a INT, KEY(a));
INSERT INTO t1 VALUES (3),(1),(5),(1);
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
SELECT 'test' FROM t1 WHERE a=1;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 5 const 1 Using index
Warnings:
Note 1003 SELECT 'test' FROM t1 WHERE a=1
test
test
test
set debug_dbug='';
DROP TABLE t1;
#
# MDEV-299: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN changes back and forth during query execution
#
create table t1 (key1 int, col1 int, col2 int, filler char(100), key(key1));
insert into t1 select A.a+ 10 * B.a, 10, 10, 'filler-data' from t0 A, t0 B;
update t1 set col1=3, col2=10 where key1=1;
update t1 set col1=3, col2=1000 where key1=2;
update t1 set col1=3, col2=10 where key1=3;
update t1 set col1=3, col2=1000 where key1=4;
set @tmp_mdev299_jcl= @@join_cache_level;
set join_cache_level=0;
explain select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE A ALL NULL NULL NULL NULL 100 Using where
1 SIMPLE B ALL key1 NULL NULL NULL 100 Range checked for each record (index map: 0x1)
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_test_if_quick_select';
select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE A ALL NULL NULL NULL NULL 100 Using where
1 SIMPLE B ALL key1 NULL NULL NULL 100 Range checked for each record (index map: 0x1)
Warnings:
Note 1003 select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE A ALL NULL NULL NULL NULL 100 Using where
1 SIMPLE B ALL key1 NULL NULL NULL 100 Range checked for each record (index map: 0x1)
Warnings:
Note 1003 select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE A ALL NULL NULL NULL NULL 100 Using where
1 SIMPLE B ALL key1 NULL NULL NULL 100 Range checked for each record (index map: 0x1)
Warnings:
Note 1003 select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE A ALL NULL NULL NULL NULL 100 Using where
1 SIMPLE B ALL key1 NULL NULL NULL 100 Range checked for each record (index map: 0x1)
Warnings:
Note 1003 select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100
count(*)
212
set debug_dbug='';
drop table t1;
#
# MDEV-297: SHOW EXPLAIN: Server gets stuck until timeout occurs while
# executing SHOW INDEX and SHOW EXPLAIN in parallel
#
CREATE TABLE t1(a INT, b INT, c INT, KEY(a), KEY(b), KEY(c));
INSERT INTO t1 (a) VALUES (3),(1),(5),(1);
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
SHOW INDEX FROM t1;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE STATISTICS ALL NULL NULL NULL NULL NULL Skip_open_table; Scanned all databases
Warnings:
Note 1003 SHOW INDEX FROM t1
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
t1 1 a 1 a A NULL NULL NULL YES BTREE
t1 1 b 1 b A NULL NULL NULL YES BTREE
t1 1 c 1 c A NULL NULL NULL YES BTREE
set debug_dbug='';
DROP TABLE t1;
#
# MDEV-324: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN for a query with TEMPTABLE view
# loses 'DERIVED' line on the way without saying that the plan was already deleted
#
CREATE TABLE t1 (a INT);
INSERT INTO t1 VALUES (1),(2);
CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t1;
EXPLAIN SELECT a + 1 FROM v1;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2
2 DERIVED t1 ALL NULL NULL NULL NULL 2
set debug_dbug='d,show_explain_probe_join_tab_preread';
set @show_explain_probe_select_id=1;
SELECT a + 1 FROM v1;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2
2 DERIVED NULL NULL NULL NULL NULL NULL NULL Query plan already deleted
Warnings:
Note 1003 SELECT a + 1 FROM v1
a + 1
2
3
set debug_dbug='';
DROP VIEW v1;
DROP TABLE t1;
#
# MDEV-323: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN loses
# 'UNION RESULT' line on the way without saying that the plan was already deleted
#
CREATE TABLE t1 (a INT);
INSERT INTO t1 VALUES (4),(6);
EXPLAIN
SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 );
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 Using where
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
set debug_dbug='d,show_explain_probe_union_read';
SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 );
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 Using where
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
Warnings:
Note 1003 SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 )
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 Using where
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
Warnings:
Note 1003 SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 )
a
set debug_dbug='';
DROP TABLE t1;
drop table t0;

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@ -0,0 +1,671 @@
#
# Tests for SHOW EXPLAIN FOR functionality
#
--source include/have_debug.inc
--disable_warnings
drop table if exists t0, t1, t2, t3, t4;
drop view if exists v1;
--enable_warnings
#
# Testcases in this file do not work with embedded server. The reason for this
# is that we use the following commands for synchronization:
#
# set @show_explain_probe_select_id=1;
# set debug_dbug='d,show_explain_probe_join_exec_start';
# send select count(*) from t1 where a < 100000;
#
# When ran with mysqltest_embedded, this translates into:
#
# Thread1> DBUG_PUSH("d,show_explain_probe_join_exec_start");
# Thread1> create another thread for doing "send ... reap"
# Thread2> mysql_parse("select count(*) from t1 where a < 100000");
#
# That is, "select count(*) ..." is ran in a thread for which DBUG_PUSH(...)
# has not been called. As a result, show_explain_probe_join_exec_start does not fire, and
# "select count(*) ..." does not wait till its SHOW EXPLAIN command, and the
# test fails.
#
-- source include/not_embedded.inc
create table t0 (a int);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1 (a int);
insert into t1 select A.a + 10*B.a + 100*C.a from t0 A, t0 B, t0 C;
alter table t1 add b int, add c int, add filler char(32);
update t1 set b=a, c=a, filler='fooo';
alter table t1 add key(a), add key(b);
#
# Try killing a non-existent thread
#
--error ER_NO_SUCH_THREAD
show explain for 2*1000*1000*1000;
--error ER_NOT_SUPPORTED_YET
show explain for (select max(a) from t0);
#
# Setup two threads and their ids
#
let $thr1=`select connection_id()`;
connect (con1, localhost, root,,);
connection con1;
let $thr2=`select connection_id()`;
connection default;
# SHOW EXPLAIN FOR <idle thread>
--error ER_ERROR_WHEN_EXECUTING_COMMAND
evalp show explain for $thr2;
# SHOW EXPLAIN FOR <ourselves>
--error ER_ERROR_WHEN_EXECUTING_COMMAND
evalp show explain for $thr1;
let $wait_condition= select State='show_explain_trap' from information_schema.processlist where id=$thr2;
#
# Test SHOW EXPLAIN for simple queries
#
connection con1;
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
send select count(*) from t1 where a < 100000;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
send select max(c) from t1 where a < 10;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
--echo # We can catch EXPLAIN, too.
set @show_expl_tmp= @@optimizer_switch;
set optimizer_switch='index_condition_pushdown=on,mrr=on,mrr_sort_keys=on';
send explain select max(c) from t1 where a < 10;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set optimizer_switch= @show_expl_tmp;
--echo # UNION, first branch
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
send explain select a from t0 A union select a+1 from t0 B;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
--echo # UNION, second branch
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
send explain select a from t0 A union select a+1 from t0 B;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
--echo # Uncorrelated subquery, select
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 B) from t0 A where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
--echo # Uncorrelated subquery, explain
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
send explain select a, (select max(a) from t0 B) from t0 A where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
--echo # correlated subquery, select
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
--echo # correlated subquery, explain
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
--echo # correlated subquery, select, while inside the subquery
set @show_explain_probe_select_id=2; # <---
set debug_dbug='d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
--echo # correlated subquery, explain, while inside the subquery
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
--echo # correlated subquery, explain, while inside the subquery
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default;
--source include/wait_condition.inc
--error ER_ERROR_WHEN_EXECUTING_COMMAND
evalp show explain for $thr2;
connection con1;
reap;
# TODO: explain in the parent subuqery when the un-correlated child has been
# run (and have done irreversible cleanups)
# ^^ Is this at all possible after 5.3?
# Maybe, for 5.3 try this:
# - run before/after the parent has invoked child's optimization
# - run after materialization
--echo # Try to do SHOW EXPLAIN for a query that runs a SET command:
--echo # I've found experimentally that select_id==2 here...
--echo #
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
send set @foo= (select max(a) from t0 where sin(a) >0);
connection default;
--source include/wait_condition.inc
--error ER_ERROR_WHEN_EXECUTING_COMMAND
evalp show explain for $thr2;
connection con1;
reap;
--echo #
--echo # Attempt SHOW EXPLAIN for an UPDATE
--echo #
create table t2 as select a as a, a as dummy from t0 limit 2;
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
send update t2 set dummy=0 where (select max(a) from t0 where t2.a + t0.a <3) >3 ;
connection default;
--source include/wait_condition.inc
--error ER_ERROR_WHEN_EXECUTING_COMMAND
evalp show explain for $thr2;
--error ER_ERROR_WHEN_EXECUTING_COMMAND
evalp show explain for $thr2;
connection con1;
reap;
drop table t2;
--echo #
--echo # Attempt SHOW EXPLAIN for a DELETE
--echo #
create table t2 as select a as a, a as dummy from t0 limit 2;
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
send delete from t2 where (select max(a) from t0 where t2.a + t0.a <3) >3 ;
connection default;
--source include/wait_condition.inc
--error ER_ERROR_WHEN_EXECUTING_COMMAND
evalp show explain for $thr2;
--error ER_ERROR_WHEN_EXECUTING_COMMAND
evalp show explain for $thr2;
connection con1;
reap;
drop table t2;
--echo #
--echo # Multiple SHOW EXPLAIN calls for one select
--echo #
create table t2 as select a as a, a as dummy from t0 limit 3;
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
send select t2.a, ((select max(a) from t0 where t2.a + t0.a <3) >3) as SUBQ from t2;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
evalp show explain for $thr2;
evalp show explain for $thr2;
connection con1;
reap;
drop table t2;
--echo #
--echo # SHOW EXPLAIN for SELECT ... ORDER BY with "Using filesort"
--echo #
explain select * from t0 order by a;
set debug_dbug='d,show_explain_probe_join_exec_start';
set @show_explain_probe_select_id=1;
send select * from t0 order by a;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
--echo #
--echo # SHOW EXPLAIN for SELECT ... with "Using temporary"
--echo #
connection default;
explain select distinct a from t0;
connection con1;
set debug_dbug='d,show_explain_probe_join_exec_start';
set @show_explain_probe_select_id=1;
send select distinct a from t0;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
--echo #
--echo # SHOW EXPLAIN for SELECT ... with "Using temporary; Using filesort"
--echo #
connection default;
explain select distinct a from t0;
connection con1;
set debug_dbug='d,show_explain_probe_join_exec_start';
set @show_explain_probe_select_id=1;
send select distinct a from t0;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
--echo #
--echo # MDEV-238: SHOW EXPLAIN: Server crashes in JOIN::print_explain with FROM subquery and GROUP BY
--echo #
CREATE TABLE t2 ( a INT );
INSERT INTO t2 VALUES (1),(2),(1),(4),(2);
explain SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a;
set debug_dbug='d,show_explain_in_find_all_keys';
send SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a;
connection default;
--source include/wait_condition.inc
--echo # FIXED by "conservative assumptions about when QEP is available" fix:
--echo # NOTE: current code will not show "Using join buffer":
--error ER_ERROR_WHEN_EXECUTING_COMMAND
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
DROP TABLE t2;
--echo #
--echo # MDEV-239: Assertion `field_types == 0 ... ' failed in Protocol_text::store(double, uint32, String*) with
--echo # SHOW EXPLAIN over EXPLAIN EXTENDED
--echo #
CREATE TABLE t2 (a INT);
INSERT INTO t2 VALUES (1),(2),(1),(4),(2);
EXPLAIN EXTENDED SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a ;
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
send EXPLAIN EXTENDED SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a ;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
DROP TABLE t2;
--echo #
--echo # MDEV-240: SHOW EXPLAIN: Assertion `this->optimized == 2' failed in
--echo # JOIN::print_explain on query with a JOIN, TEMPTABLE view,
--echo #
CREATE TABLE t3 (a INT);
CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t3;
INSERT INTO t3 VALUES (8);
CREATE TABLE t2 (b INT);
INSERT INTO t2 VALUES (4),(5),(6),(7),(8),(9);
explain SELECT * FROM v1, t2;
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_end';
send SELECT * FROM v1, t2;
connection default;
--source include/wait_condition.inc
--error ER_ERROR_WHEN_EXECUTING_COMMAND
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
DROP VIEW v1;
DROP TABLE t2, t3;
--echo #
--echo # MDEV-267: SHOW EXPLAIN: Server crashes in JOIN::print_explain on most of queries
--echo #
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
send select sleep(1);
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
--echo #
--echo # Same as above, but try another reason for JOIN to be degenerate
--echo #
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
send select * from t0 where 1>10;
connection default;
--source include/wait_condition.inc
--error ER_ERROR_WHEN_EXECUTING_COMMAND
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
--echo #
--echo # Same as above, but try another reason for JOIN to be degenerate (2)
--echo #
create table t3(a int primary key);
insert into t3 select a from t0;
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
send select * from t0,t3 where t3.a=112233;
connection default;
--source include/wait_condition.inc
--error ER_ERROR_WHEN_EXECUTING_COMMAND
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
drop table t3;
--echo #
--echo # MDEV-270: SHOW EXPLAIN: server crashes in JOIN::print_explain on a query with
--echo # select tables optimized away
--echo #
CREATE TABLE t2 (pk INT PRIMARY KEY, a INT ) ENGINE=MyISAM;
INSERT INTO t2 VALUES
(1,4),(2,62),(3,7),(4,1),(5,0),(6,7),(7,7),(8,1),(9,7),(10,1),
(11,5),(12,2),(13,0),(14,1),(15,8),(16,1),(17,1),(18,9),(19,1),(20,5) ;
explain SELECT * FROM t2 WHERE a =
(SELECT MAX(a) FROM t2
WHERE pk= (SELECT MAX(pk) FROM t2 WHERE pk = 3)
);
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_do_select';
send SELECT * FROM t2 WHERE a =
(SELECT MAX(a) FROM t2
WHERE pk= (SELECT MAX(pk) FROM t2 WHERE pk = 3)
);
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
drop table t2;
--echo #
--echo # MDEV-273: SHOW EXPLAIN: server crashes in JOIN::print_explain on a query with impossible WHERE
--echo #
CREATE TABLE t2 (a1 INT, KEY(a1)) ENGINE=MyISAM;
INSERT INTO t2 VALUES
(4),(6),(7),(1),(0),(7),(7),(1),(7),(1),
(5),(2),(0),(1),(8),(1),(1),(9),(1),(5);
CREATE TABLE t3 (b1 INT) ENGINE=MyISAM;
INSERT INTO t3 VALUES
(4),(5),(8),(4),(8),(2),(9),(6),(4),(8),
(3),(5),(9),(6),(8),(3),(2),(6),(3),(1),
(4),(3),(1),(7),(0),(0),(9),(5),(9),(0),
(2),(2),(5),(9),(1),(4),(8),(6),(5),(5),
(1),(7),(2),(8),(9),(3),(2),(6),(6),(5),
(4),(3),(2),(7),(4),(6),(0),(8),(5),(8),
(2),(9),(7),(5),(7),(0),(4),(3),(1),(0),
(6),(2),(8),(3),(7),(3),(5),(5),(1),(2),
(1),(7),(1),(9),(9),(8),(3);
CREATE TABLE t4 (c1 INT) ENGINE=MyISAM;
EXPLAIN
SELECT count(*) FROM t2, t3
WHERE a1 < ALL (
SELECT a1 FROM t2
WHERE a1 IN ( SELECT a1 FROM t2, t4 )
);
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_do_select';
send
SELECT count(*) FROM t2, t3
WHERE a1 < ALL (
SELECT a1 FROM t2
WHERE a1 IN ( SELECT a1 FROM t2, t4 )
);
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
drop table t2, t3, t4;
--echo #
--echo # MDEV-275: SHOW EXPLAIN: server crashes in JOIN::print_explain with IN subquery and aggregate function
--echo #
CREATE TABLE t2 ( `pk` INT NOT NULL PRIMARY KEY, `a1` INT NOT NULL, KEY(`a1`)) ENGINE=MyISAM;
INSERT INTO t2 VALUES
(1,5),(2,4),(3,6),(4,9),(5,2),(6,8),(7,4),(8,8),(9,0),(10,43),
(11,23),(12,3),(13,45),(14,16),(15,2),(16,33),(17,2),(18,5),(19,9),(20,2);
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
send
SELECT * FROM t2 WHERE (5, 78) IN (SELECT `a1`, MAX(`a1`) FROM t2 GROUP BY `a1`);
connection default;
--source include/wait_condition.inc
--error ER_ERROR_WHEN_EXECUTING_COMMAND
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
DROP TABLE t2;
DROP TABLE t1;
--echo #
--echo # MDEV-305: SHOW EXPLAIN: ref returned by SHOW EXPLAIN is different from the normal EXPLAIN ('const' vs empty string)
--echo #
CREATE TABLE t1(a INT, KEY(a));
INSERT INTO t1 VALUES (3),(1),(5),(1);
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
send SELECT 'test' FROM t1 WHERE a=1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
DROP TABLE t1;
--echo #
--echo # MDEV-299: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN changes back and forth during query execution
--echo #
create table t1 (key1 int, col1 int, col2 int, filler char(100), key(key1));
insert into t1 select A.a+ 10 * B.a, 10, 10, 'filler-data' from t0 A, t0 B;
# Make matches 3 records
update t1 set col1=3, col2=10 where key1=1; # small range
update t1 set col1=3, col2=1000 where key1=2; # big range
update t1 set col1=3, col2=10 where key1=3; # small range again
update t1 set col1=3, col2=1000 where key1=4; # big range
set @tmp_mdev299_jcl= @@join_cache_level;
set join_cache_level=0;
explain select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100;
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_test_if_quick_select';
send
select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
--source include/wait_condition.inc
evalp show explain for $thr2;
--source include/wait_condition.inc
evalp show explain for $thr2;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
drop table t1;
--echo #
--echo # MDEV-297: SHOW EXPLAIN: Server gets stuck until timeout occurs while
--echo # executing SHOW INDEX and SHOW EXPLAIN in parallel
--echo #
CREATE TABLE t1(a INT, b INT, c INT, KEY(a), KEY(b), KEY(c));
INSERT INTO t1 (a) VALUES (3),(1),(5),(1);
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
send SHOW INDEX FROM t1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
DROP TABLE t1;
--echo #
--echo # MDEV-324: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN for a query with TEMPTABLE view
--echo # loses 'DERIVED' line on the way without saying that the plan was already deleted
--echo #
CREATE TABLE t1 (a INT);
INSERT INTO t1 VALUES (1),(2);
CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t1;
EXPLAIN SELECT a + 1 FROM v1;
set debug_dbug='d,show_explain_probe_join_tab_preread';
set @show_explain_probe_select_id=1;
send
SELECT a + 1 FROM v1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
DROP VIEW v1;
DROP TABLE t1;
--echo #
--echo # MDEV-323: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN loses
--echo # 'UNION RESULT' line on the way without saying that the plan was already deleted
--echo #
CREATE TABLE t1 (a INT);
INSERT INTO t1 VALUES (4),(6);
EXPLAIN
SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 );
set debug_dbug='d,show_explain_probe_union_read';
send
SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 );
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
DROP TABLE t1;
## TODO: Test this: have several SHOW EXPLAIN requests be queued up for a
## thread and served together.
## TODO: SHOW EXPLAIN while the primary query is running EXPLAIN EXTENDED/PARTITIONS
##
drop table t0;

1
sql/CMakeLists.txt
View File

@ -85,6 +85,7 @@ SET (SQL_SOURCE
gcalc_slicescan.cc gcalc_tools.cc
threadpool_common.cc
../sql-common/mysql_async.c
my_apc.cc my_apc.h
${GEN_SOURCES}
${MYSYS_LIBWRAP_SOURCE}
)

22
sql/filesort.cc
View File

@ -502,7 +502,6 @@ static ha_rows find_all_keys(SORTPARAM *param, SQL_SELECT *select,
my_off_t record;
TABLE *sort_form;
THD *thd= current_thd;
volatile killed_state *killed= &thd->killed;
handler *file;
MY_BITMAP *save_read_set, *save_write_set, *save_vcol_set;
uchar *next_sort_key= sort_keys_buf;
@ -523,6 +522,11 @@ static ha_rows find_all_keys(SORTPARAM *param, SQL_SELECT *select,
if (flag)
ref_pos= &file->ref[0];
next_pos=ref_pos;
DBUG_EXECUTE_IF("show_explain_in_find_all_keys",
dbug_serve_apcs(thd, 1);
);
if (!quick_select)
{
next_pos=(uchar*) 0; /* Find records in sequence */
@ -586,7 +590,7 @@ static ha_rows find_all_keys(SORTPARAM *param, SQL_SELECT *select,
break;
}
if (*killed)
if (thd->check_killed())
{
DBUG_PRINT("info",("Sort killed by user"));
if (!quick_select)
@ -1231,18 +1235,18 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
void *first_cmp_arg;
element_count dupl_count= 0;
uchar *src;
killed_state not_killable;
uchar *unique_buff= param->unique_buff;
volatile killed_state *killed= &current_thd->killed;
const bool killable= !param->not_killable;
THD* const thd=current_thd;
DBUG_ENTER("merge_buffers");
status_var_increment(current_thd->status_var.filesort_merge_passes);
current_thd->query_plan_fsort_passes++;
if (param->not_killable)
status_var_increment(thd->status_var.filesort_merge_passes);
thd->query_plan_fsort_passes++;
/*if (param->not_killable)
{
killed= &not_killable;
not_killable= NOT_KILLED;
}
}*/
error=0;
rec_length= param->rec_length;
@ -1320,7 +1324,7 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
while (queue.elements > 1)
{
if (*killed)
if (killable && thd->check_killed())
{
error= 1; goto err; /* purecov: inspected */
}

2
sql/item_func.cc
View File

@ -4298,7 +4298,7 @@ longlong Item_func_sleep::val_int()
#define extra_size sizeof(double)
static user_var_entry *get_variable(HASH *hash, LEX_STRING &name,
user_var_entry *get_variable(HASH *hash, LEX_STRING &name,
bool create_if_not_exists)
{
user_var_entry *entry;

377
sql/my_apc.cc Normal file
View File

@ -0,0 +1,377 @@
/*
TODO: MP AB Copyright
*/
#ifdef MY_APC_STANDALONE
#include <my_global.h>
#include <my_pthread.h>
#include <my_sys.h>
#include "my_apc.h"
#else
#include "sql_priv.h"
#include "sql_class.h"
#endif
/*
Standalone testing:
g++ -c -DMY_APC_STANDALONE -g -I.. -I../include -o my_apc.o my_apc.cc
g++ -L../mysys -L../dbug -L../strings my_apc.o -lmysys -ldbug -lmystrings -lpthread -lrt
*/
/*
Initialize the target.
@note
Initialization must be done prior to enabling/disabling the target, or making
any call requests to it.
Initial state after initialization is 'disabled'.
*/
void Apc_target::init(mysql_mutex_t *target_mutex)
{
DBUG_ASSERT(!enabled);
LOCK_thd_data_ptr= target_mutex;
#ifndef DBUG_OFF
n_calls_processed= 0;
#endif
}
/*
Destroy the target. The target must be disabled when this call is made.
*/
void Apc_target::destroy()
{
DBUG_ASSERT(!enabled);
}
/*
Enter ther state where the target is available for serving APC requests
*/
void Apc_target::enable()
{
/* Ok to do without getting/releasing the mutex: */
enabled++;
}
/*
Make the target unavailable for serving APC requests.
@note
This call will serve all requests that were already enqueued
*/
void Apc_target::disable()
{
bool process= FALSE;
mysql_mutex_lock(LOCK_thd_data_ptr);
if (!(--enabled))
process= TRUE;
mysql_mutex_unlock(LOCK_thd_data_ptr);
if (process)
process_apc_requests();
}
/* [internal] Put request qe into the request list */
void Apc_target::enqueue_request(Call_request *qe)
{
//call_queue_size++;
if (apc_calls)
{
Call_request *after= apc_calls->prev;
qe->next= apc_calls;
apc_calls->prev= qe;
qe->prev= after;
after->next= qe;
}
else
{
apc_calls= qe;
qe->next= qe->prev= qe;
}
}
/*
[internal] Remove request qe from the request queue.
The request is not necessarily first in the queue.
*/
void Apc_target::dequeue_request(Call_request *qe)
{
//call_queue_size--;
if (apc_calls == qe)
{
if ((apc_calls= apc_calls->next) == qe)
{
//DBUG_ASSERT(!call_queue_size);
apc_calls= NULL;
}
}
qe->prev->next= qe->next;
qe->next->prev= qe->prev;
}
/*
Make an APC (Async Procedure Call) to another thread.
- The caller is responsible for making sure he's not calling to the same
thread.
- The caller should have locked target_thread_mutex.
psergey-todo: Should waits here be KILLable? (it seems one needs
to use thd->enter_cond() calls to be killable)
*/
bool Apc_target::make_apc_call(apc_func_t func, void *func_arg,
int timeout_sec, bool *timed_out)
{
bool res= TRUE;
*timed_out= FALSE;
if (enabled)
{
/* Create and post the request */
Call_request apc_request;
apc_request.func= func;
apc_request.func_arg= func_arg;
apc_request.processed= FALSE;
mysql_cond_init(0 /* do not track in PS */, &apc_request.COND_request, NULL);
enqueue_request(&apc_request);
apc_request.what="enqueued by make_apc_call";
struct timespec abstime;
const int timeout= timeout_sec;
set_timespec(abstime, timeout);
int wait_res= 0;
/* todo: how about processing other errors here? */
while (!apc_request.processed && (wait_res != ETIMEDOUT))
{
/* We own LOCK_thd_data_ptr */
wait_res= mysql_cond_timedwait(&apc_request.COND_request,
LOCK_thd_data_ptr, &abstime);
// &apc_request.LOCK_request, &abstime);
}
if (!apc_request.processed)
{
/*
The wait has timed out. Remove the request from the queue (ok to do
because we own LOCK_thd_data_ptr.
*/
apc_request.processed= TRUE;
dequeue_request(&apc_request);
*timed_out= TRUE;
res= TRUE;
}
else
{
/* Request was successfully executed and dequeued by the target thread */
res= FALSE;
}
mysql_mutex_unlock(LOCK_thd_data_ptr);
/* Destroy all APC request data */
mysql_cond_destroy(&apc_request.COND_request);
}
else
{
mysql_mutex_unlock(LOCK_thd_data_ptr);
}
return res;
}
/*
Process all APC requests.
This should be called periodically by the APC target thread.
*/
void Apc_target::process_apc_requests()
{
if (!get_first_in_queue())
return;
while (1)
{
Call_request *request;
mysql_mutex_lock(LOCK_thd_data_ptr);
if (!(request= get_first_in_queue()))
{
/* No requests in the queue */
mysql_mutex_unlock(LOCK_thd_data_ptr);
break;
}
/*
Remove the request from the queue (we're holding queue lock so we can be
sure that request owner won't try to remove it)
*/
request->what="dequeued by process_apc_requests";
dequeue_request(request);
request->processed= TRUE;
request->func(request->func_arg);
request->what="func called by process_apc_requests";
#ifndef DBUG_OFF
n_calls_processed++;
#endif
mysql_cond_signal(&request->COND_request);
mysql_mutex_unlock(LOCK_thd_data_ptr);
}
}
/*****************************************************************************
* Testing
*****************************************************************************/
#ifdef MY_APC_STANDALONE
volatile bool started= FALSE;
volatile bool service_should_exit= FALSE;
volatile bool requestors_should_exit=FALSE;
volatile int apcs_served= 0;
volatile int apcs_missed=0;
volatile int apcs_timed_out=0;
Apc_target apc_target;
mysql_mutex_t target_mutex;
int int_rand(int size)
{
return round (((double)rand() / RAND_MAX) * size);
}
/* An APC-serving thread */
void *test_apc_service_thread(void *ptr)
{
my_thread_init();
mysql_mutex_init(0, &target_mutex, MY_MUTEX_INIT_FAST);
apc_target.init(&target_mutex);
apc_target.enable();
started= TRUE;
fprintf(stderr, "# test_apc_service_thread started\n");
while (!service_should_exit)
{
//apc_target.disable();
usleep(10000);
//apc_target.enable();
for (int i = 0; i < 10 && !service_should_exit; i++)
{
apc_target.process_apc_requests();
usleep(int_rand(30));
}
}
apc_target.disable();
apc_target.destroy();
my_thread_end();
pthread_exit(0);
}
class Apc_order
{
public:
int value; // The value
int *where_to; // Where to write it
Apc_order(int a, int *b) : value(a), where_to(b) {}
};
void test_apc_func(void *arg)
{
Apc_order *order=(Apc_order*)arg;
usleep(int_rand(1000));
*(order->where_to) = order->value;
__sync_fetch_and_add(&apcs_served, 1);
}
void *test_apc_requestor_thread(void *ptr)
{
my_thread_init();
fprintf(stderr, "# test_apc_requestor_thread started\n");
while (!requestors_should_exit)
{
int dst_value= 0;
int src_value= int_rand(4*1000*100);
/* Create APC to do dst_value= src_value */
Apc_order apc_order(src_value, &dst_value);
bool timed_out;
bool res= apc_target.make_apc_call(test_apc_func, (void*)&apc_order, 60, &timed_out);
if (res)
{
if (timed_out)
__sync_fetch_and_add(&apcs_timed_out, 1);
else
__sync_fetch_and_add(&apcs_missed, 1);
if (dst_value != 0)
fprintf(stderr, "APC was done even though return value says it wasnt!\n");
}
else
{
if (dst_value != src_value)
fprintf(stderr, "APC was not done even though return value says it was!\n");
}
//usleep(300);
}
fprintf(stderr, "# test_apc_requestor_thread exiting\n");
my_thread_end();
}
const int N_THREADS=23;
int main(int args, char **argv)
{
pthread_t service_thr;
pthread_t request_thr[N_THREADS];
int i, j;
my_thread_global_init();
pthread_create(&service_thr, NULL, test_apc_service_thread, (void*)NULL);
while (!started)
usleep(1000);
for (i = 0; i < N_THREADS; i++)
pthread_create(&request_thr[i], NULL, test_apc_requestor_thread, (void*)NULL);
for (i = 0; i < 15; i++)
{
usleep(500*1000);
fprintf(stderr, "# %d APCs served %d missed\n", apcs_served, apcs_missed);
}
fprintf(stderr, "# Shutting down requestors\n");
requestors_should_exit= TRUE;
for (i = 0; i < N_THREADS; i++)
pthread_join(request_thr[i], NULL);
fprintf(stderr, "# Shutting down service\n");
service_should_exit= TRUE;
pthread_join(service_thr, NULL);
fprintf(stderr, "# Done.\n");
my_thread_end();
my_thread_global_end();
return 0;
}
#endif // MY_APC_STANDALONE

127
sql/my_apc.h Normal file
View File

@ -0,0 +1,127 @@
/*
TODO: MP AB Copyright
*/
/*
Interface
~~~~~~~~~
(
- This is an APC request queue
- We assume there is a particular owner thread which periodically calls
process_apc_requests() to serve the call requests.
- Other threads can post call requests, and block until they are exectued.
)
Implementation
~~~~~~~~~~~~~~
- The target has a mutex-guarded request queue.
- After the request has been put into queue, the requestor waits for request
to be satisfied. The worker satisifes the request and signals the
requestor.
*/
/*
Target for asynchronous procedue calls (APCs).
*/
class Apc_target
{
mysql_mutex_t *LOCK_thd_data_ptr;
public:
Apc_target() : enabled(0), apc_calls(NULL) /*, call_queue_size(0)*/ {}
~Apc_target() { DBUG_ASSERT(!enabled && !apc_calls);}
void init(mysql_mutex_t *target_mutex);
void destroy();
void enable();
void disable();
void process_apc_requests();
typedef void (*apc_func_t)(void *arg);
/*
Make an APC call: schedule it for execution and wait until the target
thread has executed it. This function must not be called from a thread
that's different from the target thread.
@retval FALSE - Ok, the call has been made
@retval TRUE - Call wasnt made (either the target is in disabled state or
timeout occured)
*/
bool make_apc_call(apc_func_t func, void *func_arg,
int timeout_sec, bool *timed_out);
#ifndef DBUG_OFF
int n_calls_processed; /* Number of calls served by this target */
#endif
private:
class Call_request;
/*
Non-zero value means we're enabled. It's an int, not bool, because one can
call enable() N times (and then needs to call disable() N times before the
target is really disabled)
*/
int enabled;
/*
Circular, double-linked list of all enqueued call requests.
We use this structure, because we
- process requests sequentially (i.e. they are removed from the front)
- a thread that has posted a request may time out (or be KILLed) and
cancel the request, which means we need a fast request-removal
operation.
*/
Call_request *apc_calls;
/*
This mutex is used to
- make queue put/remove operations atomic (one must be in posession of the
mutex when putting/removing something from the queue)
- make sure that nobody enqueues a request onto an Apc_target which has
disabled==TRUE. The idea is:
= requestor must be in possession of the mutex and check that
disabled==FALSE when he is putting his request into the queue.
= When the owner (ie. service) thread changes the Apc_target from
enabled to disabled, it will acquire the mutex, disable the
Apc_target (preventing any new requests), and then serve all pending
requests.
That way, we will never have the situation where the Apc_target is
disabled, but there are some un-served requests.
*/
//pthread_mutex_t LOCK_apc_queue;
class Call_request
{
public:
apc_func_t func; /* Function to call */
void *func_arg; /* Argument to pass it */
bool processed;
//pthread_mutex_t LOCK_request;
//pthread_cond_t COND_request;
/* Condition that will be signalled when the request has been served */
mysql_cond_t COND_request;
Call_request *next;
Call_request *prev;
const char *what; /* (debug) state of the request */
};
void enqueue_request(Call_request *qe);
void dequeue_request(Call_request *qe);
/* return the first call request in queue, or NULL if there are none enqueued */
Call_request *get_first_in_queue()
{
return apc_calls;
}
};
///////////////////////////////////////////////////////////////////////

1
sql/mysqld.cc
View File

@ -3339,6 +3339,7 @@ SHOW_VAR com_status_vars[]= {
{"show_engine_status", (char*) offsetof(STATUS_VAR, com_stat[(uint) SQLCOM_SHOW_ENGINE_STATUS]), SHOW_LONG_STATUS},
{"show_events", (char*) offsetof(STATUS_VAR, com_stat[(uint) SQLCOM_SHOW_EVENTS]), SHOW_LONG_STATUS},
{"show_errors", (char*) offsetof(STATUS_VAR, com_stat[(uint) SQLCOM_SHOW_ERRORS]), SHOW_LONG_STATUS},
{"show_explain", (char*) offsetof(STATUS_VAR, com_stat[(uint) SQLCOM_SHOW_EXPLAIN]), SHOW_LONG_STATUS},
{"show_fields", (char*) offsetof(STATUS_VAR, com_stat[(uint) SQLCOM_SHOW_FIELDS]), SHOW_LONG_STATUS},
#ifndef DBUG_OFF
{"show_function_code", (char*) offsetof(STATUS_VAR, com_stat[(uint) SQLCOM_SHOW_FUNC_CODE]), SHOW_LONG_STATUS},

3
sql/opt_subselect.cc
View File

@ -1657,6 +1657,7 @@ static bool convert_subq_to_sj(JOIN *parent_join, Item_in_subselect *subq_pred)
parent_lex->ftfunc_list->push_front(ifm);
}
parent_lex->have_merged_subqueries= TRUE;
DBUG_RETURN(FALSE);
}
@ -1767,6 +1768,8 @@ static bool convert_subq_to_jtbm(JOIN *parent_join,
create_subquery_temptable_name(tbl_alias, hash_sj_engine->materialize_join->
select_lex->select_number);
jtbm->alias= tbl_alias;
parent_lex->have_merged_subqueries= TRUE;
#if 0
/* Inject sj_on_expr into the parent's WHERE or ON */
if (emb_tbl_nest)

19
sql/protocol.h
View File

@ -35,6 +35,7 @@ class Protocol
protected:
THD *thd;
String *packet;
/* Used by net_store_data() for charset conversions */
String *convert;
uint field_pos;
#ifndef DBUG_OFF
@ -49,6 +50,10 @@ protected:
MYSQL_FIELD *next_mysql_field;
MEM_ROOT *alloc;
#endif
/*
The following two are low-level functions that are invoked from
higher-level store_xxx() funcs. The data is stored into this->packet.
*/
bool net_store_data(const uchar *from, size_t length,
CHARSET_INFO *fromcs, CHARSET_INFO *tocs);
bool store_string_aux(const char *from, size_t length,
@ -73,6 +78,20 @@ public:
virtual bool send_result_set_metadata(List<Item> *list, uint flags);
bool send_result_set_row(List<Item> *row_items);
void get_packet(const char **start, size_t *length)
{
*start= packet->ptr();
*length= packet->length();
}
void set_packet(const char *start, size_t len)
{
packet->length(0);
packet->append(start, len);
#ifndef DBUG_OFF
field_pos= field_count - 1;
#endif
}
bool store(I_List<i_string> *str_list);
bool store(const char *from, CHARSET_INFO *cs);
String *storage_packet() { return packet; }

1
sql/sp_head.cc
View File

@ -218,6 +218,7 @@ sp_get_flags_for_command(LEX *lex)
case SQLCOM_SHOW_CREATE_TRIGGER:
case SQLCOM_SHOW_DATABASES:
case SQLCOM_SHOW_ERRORS:
case SQLCOM_SHOW_EXPLAIN:
case SQLCOM_SHOW_FIELDS:
case SQLCOM_SHOW_FUNC_CODE:
case SQLCOM_SHOW_GRANTS:

160
sql/sql_class.cc
View File

@ -1196,6 +1196,7 @@ void THD::init(void)
/* Initialize the Debug Sync Facility. See debug_sync.cc. */
debug_sync_init_thread(this);
#endif /* defined(ENABLED_DEBUG_SYNC) */
apc_target.init(&LOCK_thd_data);
}
@ -1361,6 +1362,7 @@ void THD::cleanup(void)
ull= NULL;
}
apc_target.destroy();
cleanup_done=1;
DBUG_VOID_RETURN;
}
@ -2006,6 +2008,20 @@ CHANGED_TABLE_LIST* THD::changed_table_dup(const char *key, long key_length)
int THD::send_explain_fields(select_result *result)
{
List<Item> field_list;
make_explain_field_list(field_list);
return (result->send_result_set_metadata(field_list,
Protocol::SEND_NUM_ROWS |
Protocol::SEND_EOF));
}
/*
Populate the provided field_list with EXPLAIN output columns.
this->lex->describe has the EXPLAIN flags
*/
void THD::make_explain_field_list(List<Item> &field_list)
{
Item *item;
CHARSET_INFO *cs= system_charset_info;
field_list.push_back(item= new Item_return_int("id",3, MYSQL_TYPE_LONGLONG));
@ -2044,10 +2060,9 @@ int THD::send_explain_fields(select_result *result)
}
item->maybe_null= 1;
field_list.push_back(new Item_empty_string("Extra", 255, cs));
return (result->send_result_set_metadata(field_list,
Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF));
}
#ifdef SIGNAL_WITH_VIO_CLOSE
void THD::close_active_vio()
{
@ -2151,6 +2166,21 @@ void THD::rollback_item_tree_changes()
}
/*
Check if the thread has been killed, and also process "APC requests"
@retval true The thread is killed, execution should be interrupted
@retval false Not killed, continue execution
*/
bool THD::check_killed()
{
if (killed)
return TRUE;
apc_target.process_apc_requests();
return FALSE;
}
/*****************************************************************************
** Functions to provide a interface to select results
*****************************************************************************/
@ -2279,6 +2309,86 @@ int select_send::send_data(List<Item> &items)
DBUG_RETURN(0);
}
//////////////////////////////////////////////////////////////////////////////
int select_result_explain_buffer::send_data(List<Item> &items)
{
List_iterator_fast<Item> li(items);
char buff[MAX_FIELD_WIDTH];
String buffer(buff, sizeof(buff), &my_charset_bin);
DBUG_ENTER("select_send::send_data");
protocol->prepare_for_resend();
Item *item;
while ((item=li++))
{
if (item->send(protocol, &buffer))
{
protocol->free(); // Free used buffer
my_message(ER_OUT_OF_RESOURCES, ER(ER_OUT_OF_RESOURCES), MYF(0));
break;
}
/*
Reset buffer to its original state, as it may have been altered in
Item::send().
*/
buffer.set(buff, sizeof(buff), &my_charset_bin);
}
if (thd->is_error())
{
protocol->remove_last_row();
DBUG_RETURN(1);
}
/*
Instead of calling protocol->write(), steal the packed and put it to our
buffer
*/
const char *packet_data;
size_t len;
protocol->get_packet(&packet_data, &len);
String *s= new (thd->mem_root) String;
s->append(packet_data, len);
data_rows.push_back(s);
protocol->remove_last_row(); // <-- this does nothing. Do we need it?
// prepare_for_resend() will wipe out the packet
DBUG_RETURN(0);
}
/* Write all strings out to the output, and free them. */
void select_result_explain_buffer::flush_data()
{
List_iterator<String> it(data_rows);
String *str;
while ((str= it++))
{
protocol->set_packet(str->ptr(), str->length());
protocol->write();
delete str;
}
data_rows.empty();
}
/* Just free all of the accumulated strings */
void select_result_explain_buffer::discard_data()
{
List_iterator<String> it(data_rows);
String *str;
while ((str= it++))
{
delete str;
}
data_rows.empty();
}
//////////////////////////////////////////////////////////////////////////////
bool select_send::send_eof()
{
/*
@ -3172,6 +3282,10 @@ void THD::end_statement()
}
/*
Start using arena specified by @set. Current arena data will be saved to
*backup.
*/
void THD::set_n_backup_active_arena(Query_arena *set, Query_arena *backup)
{
DBUG_ENTER("THD::set_n_backup_active_arena");
@ -3186,6 +3300,12 @@ void THD::set_n_backup_active_arena(Query_arena *set, Query_arena *backup)
}
/*
Stop using the temporary arena, and start again using the arena that is
specified in *backup.
The temporary arena is returned back into *set.
*/
void THD::restore_active_arena(Query_arena *set, Query_arena *backup)
{
DBUG_ENTER("THD::restore_active_arena");
@ -3198,6 +3318,42 @@ void THD::restore_active_arena(Query_arena *set, Query_arena *backup)
DBUG_VOID_RETURN;
}
/*
Produce EXPLAIN data.
This function is APC-scheduled to be run in the context of the thread that
we're producing EXPLAIN for.
*/
void Show_explain_request::get_explain_data(void *arg)
{
Show_explain_request *req= (Show_explain_request*)arg;
//TODO: change mem_root to point to request_thd->mem_root.
// Actually, change the ARENA, because we're going to allocate items!
Query_arena backup_arena;
THD *target_thd= req->target_thd;
bool printed_anything= FALSE;
target_thd->set_n_backup_active_arena((Query_arena*)req->request_thd,
&backup_arena);
req->query_str.copy(target_thd->query(),
target_thd->query_length(),
&my_charset_bin);
if (target_thd->lex->unit.print_explain(req->explain_buf, 0 /* explain flags*/,
&printed_anything))
req->failed_to_produce= TRUE;
if (!printed_anything)
req->failed_to_produce= TRUE;
target_thd->restore_active_arena((Query_arena*)req->request_thd,
&backup_arena);
}
Statement::~Statement()
{
}

113
sql/sql_class.h
View File

@ -43,7 +43,7 @@
#include "violite.h" /* vio_is_connected */
#include "thr_lock.h" /* thr_lock_type, THR_LOCK_DATA,
THR_LOCK_INFO */
#include "my_apc.h"
class Reprepare_observer;
class Relay_log_info;
@ -1520,6 +1520,29 @@ private:
extern "C" void my_message_sql(uint error, const char *str, myf MyFlags);
class select_result_explain_buffer;
class Show_explain_request
{
public:
THD *target_thd;
THD *request_thd;
bool failed_to_produce;
select_result_explain_buffer *explain_buf;
String query_str;
static void get_explain_data(void *arg);
};
class THD;
void mysqld_show_explain(THD *thd, ulong thread_id);
#ifndef DBUG_OFF
void dbug_serve_apcs(THD *thd, int n_calls);
#endif
/**
@class THD
For each client connection we create a separate thread with THD serving as
@ -2185,6 +2208,8 @@ public:
*/
killed_state volatile killed;
bool check_killed();
/* scramble - random string sent to client on handshake */
char scramble[SCRAMBLE_LENGTH+1];
@ -2383,10 +2408,20 @@ public:
void close_active_vio();
#endif
void awake(killed_state state_to_set);
/** Disconnect the associated communication endpoint. */
void disconnect();
/*
This is what allows this thread to serve as a target for others to
schedule Async Procedure Calls on.
It's possible to schedule arbitrary C function call but currently this
facility is used only by SHOW EXPLAIN code (See Show_explain_request)
*/
Apc_target apc_target;
#ifndef MYSQL_CLIENT
enum enum_binlog_query_type {
/* The query can be logged in row format or in statement format. */
@ -2580,7 +2615,7 @@ public:
void add_changed_table(const char *key, long key_length);
CHANGED_TABLE_LIST * changed_table_dup(const char *key, long key_length);
int send_explain_fields(select_result *result);
void make_explain_field_list(List<Item> &field_list);
/**
Clear the current error, if any.
We do not clear is_fatal_error or is_fatal_sub_stmt_error since we
@ -3190,10 +3225,42 @@ public:
class JOIN;
class select_result :public Sql_alloc {
/* Pure interface for sending tabular data */
class select_result_sink: public Sql_alloc
{
public:
/*
send_data returns 0 on ok, 1 on error and -1 if data was ignored, for
example for a duplicate row entry written to a temp table.
*/
virtual int send_data(List<Item> &items)=0;
virtual ~select_result_sink() {};
};
/*
Interface for sending tabular data, together with some other stuff:
- Primary purpose seems to be seding typed tabular data:
= the DDL is sent with send_fields()
= the rows are sent with send_data()
Besides that,
- there seems to be an assumption that the sent data is a result of
SELECT_LEX_UNIT *unit,
- nest_level is used by SQL parser
*/
class select_result :public select_result_sink
{
protected:
THD *thd;
/*
All descendant classes have their send_data() skip the first
unit->offset_limit_cnt rows sent. Select_materialize
also uses unit->get_unit_column_types().
*/
SELECT_LEX_UNIT *unit;
/* Something used only by the parser: */
public:
select_result();
virtual ~select_result() {};
@ -3211,11 +3278,6 @@ public:
virtual uint field_count(List<Item> &fields) const
{ return fields.elements; }
virtual bool send_result_set_metadata(List<Item> &list, uint flags)=0;
/*
send_data returns 0 on ok, 1 on error and -1 if data was ignored, for
example for a duplicate row entry written to a temp table.
*/
virtual int send_data(List<Item> &items)=0;
virtual bool initialize_tables (JOIN *join=0) { return 0; }
virtual void send_error(uint errcode,const char *err);
virtual bool send_eof()=0;
@ -3242,6 +3304,37 @@ public:
};
/*
A select result sink that collects the sent data and then can flush it to
network when requested.
This class is targeted at collecting EXPLAIN output:
- Unoptimized data storage (can't handle big datasets)
- Unlike select_result class, we don't assume that the sent data is an
output of a SELECT_LEX_UNIT (and so we dont apply "LIMIT x,y" from the
unit)
*/
class select_result_explain_buffer : public select_result_sink
{
public:
THD *thd;
Protocol *protocol;
select_result_explain_buffer(){};
/* The following is called in the child thread: */
int send_data(List<Item> &items);
/* this will be called in the parent thread: */
void flush_data();
void discard_data();
List<String> data_rows;
};
/*
Base class for select_result descendands which intercept and
transform result set rows. As the rows are not sent to the client,
@ -3812,6 +3905,8 @@ class user_var_entry
DTCollation collation;
};
user_var_entry *get_variable(HASH *hash, LEX_STRING &name,
bool create_if_not_exists);
/*
Unique -- class for unique (removing of duplicates).

6
sql/sql_join_cache.cc
View File

@ -2236,7 +2236,7 @@ enum_nested_loop_state JOIN_CACHE::join_matching_records(bool skip_last)
while (!(error= join_tab_scan->next()))
{
if (join->thd->killed)
if (join->thd->check_killed())
{
/* The user has aborted the execution of the query */
join->thd->send_kill_message();
@ -2506,7 +2506,7 @@ enum_nested_loop_state JOIN_CACHE::join_null_complements(bool skip_last)
for ( ; cnt; cnt--)
{
if (join->thd->killed)
if (join->thd->check_killed())
{
/* The user has aborted the execution of the query */
join->thd->send_kill_message();
@ -3356,7 +3356,7 @@ int JOIN_TAB_SCAN::next()
update_virtual_fields(thd, table);
while (!err && select && (skip_rc= select->skip_record(thd)) <= 0)
{
if (thd->killed || skip_rc < 0)
if (thd->check_killed() || skip_rc < 0)
return 1;
/*
Move to the next record if the last retrieved record does not

125
sql/sql_lex.cc
View File

@ -1873,6 +1873,7 @@ void st_select_lex::init_query()
nest_level= 0;
link_next= 0;
is_prep_leaf_list_saved= FALSE;
have_merged_subqueries= FALSE;
bzero((char*) expr_cache_may_be_used, sizeof(expr_cache_may_be_used));
m_non_agg_field_used= false;
m_agg_func_used= false;
@ -3441,7 +3442,7 @@ bool st_select_lex::optimize_unflattened_subqueries()
if (options & SELECT_DESCRIBE)
{
/* Optimize the subquery in the context of EXPLAIN. */
sl->set_explain_type();
sl->set_explain_type(FALSE);
sl->options|= SELECT_DESCRIBE;
inner_join->select_options|= SELECT_DESCRIBE;
}
@ -3831,9 +3832,10 @@ void SELECT_LEX::update_used_tables()
/**
Set the EXPLAIN type for this subquery.
psergey-todo: comments about
*/
void st_select_lex::set_explain_type()
void st_select_lex::set_explain_type(bool on_the_fly)
{
bool is_primary= FALSE;
if (next_select())
@ -3855,6 +3857,9 @@ void st_select_lex::set_explain_type()
}
}
if (on_the_fly && !is_primary && have_merged_subqueries)
is_primary= TRUE;
SELECT_LEX *first= master_unit()->first_select();
/* drop UNCACHEABLE_EXPLAIN, because it is for internal usage only */
uint8 is_uncacheable= (uncacheable & ~UNCACHEABLE_EXPLAIN);
@ -3907,10 +3912,15 @@ void st_select_lex::set_explain_type()
else
{
type= is_uncacheable ? "UNCACHEABLE UNION": "UNION";
if (this == master_unit()->fake_select_lex)
type= "UNION RESULT";
}
}
}
options|= SELECT_DESCRIBE;
if (!on_the_fly)
options|= SELECT_DESCRIBE;
}
@ -4057,6 +4067,115 @@ bool st_select_lex::is_merged_child_of(st_select_lex *ancestor)
}
int print_explain_message_line(select_result_sink *result,
SELECT_LEX *select_lex,
bool on_the_fly,
uint8 options,
const char *message);
int st_select_lex::print_explain(select_result_sink *output,
uint8 explain_flags,
bool *printed_anything)
{
int res;
if (join && join->have_query_plan == JOIN::QEP_AVAILABLE)
{
/*
There is a number of reasons join can be marked as degenerate, so all
three conditions below can happen simultaneously, or individually:
*/
*printed_anything= TRUE;
if (!join->table_count || !join->tables_list || join->zero_result_cause)
{
/* It's a degenerate join */
const char *cause= join->zero_result_cause ? join-> zero_result_cause :
"No tables used";
res= join->print_explain(output, explain_flags, TRUE, FALSE, FALSE,
FALSE, cause);
}
else
{
res= join->print_explain(output, explain_flags, TRUE,
join->need_tmp, // need_tmp_table
(join->order != 0 && !join->skip_sort_order), // bool need_order
join->select_distinct, // bool distinct
NULL); //const char *message
}
if (res)
goto err;
for (SELECT_LEX_UNIT *unit= join->select_lex->first_inner_unit();
unit;
unit= unit->next_unit())
{
/*
Display subqueries only if they are not parts of eliminated WHERE/ON
clauses.
*/
if (!(unit->item && unit->item->eliminated))
{
if ((res= unit->print_explain(output, explain_flags, printed_anything)))
goto err;
}
}
}
else
{
const char *msg;
if (!join)
DBUG_ASSERT(0); /* Seems not to be possible */
/* Not printing anything useful, don't touch *printed_anything here */
if (join->have_query_plan == JOIN::QEP_NOT_PRESENT_YET)
msg= "Not yet optimized";
else
{
DBUG_ASSERT(join->have_query_plan == JOIN::QEP_DELETED);
msg= "Query plan already deleted";
}
res= print_explain_message_line(output, this, TRUE /* on_the_fly */,
0, msg);
}
err:
return res;
}
int st_select_lex_unit::print_explain(select_result_sink *output,
uint8 explain_flags, bool *printed_anything)
{
int res= 0;
SELECT_LEX *first= first_select();
if (first && !first->next_select() && !first->join)
{
/*
If there is only one child, 'first', and it has join==NULL, emit "not in
EXPLAIN state" error.
*/
const char *msg="Query plan already deleted";
res= print_explain_message_line(output, first, TRUE /* on_the_fly */,
0, msg);
return 0;
}
for (SELECT_LEX *sl= first; sl; sl= sl->next_select())
{
if ((res= sl->print_explain(output, explain_flags, printed_anything)))
break;
}
/* Note: fake_select_lex->join may be NULL or non-NULL at this point */
if (fake_select_lex)
{
res= print_fake_select_lex_join(output, TRUE /* on the fly */,
fake_select_lex, explain_flags);
}
return res;
}
/**
A routine used by the parser to decide whether we are specifying a full
partitioning or if only partitions to add or to split.

17
sql/sql_lex.h
View File

@ -193,6 +193,7 @@ enum enum_sql_command {
SQLCOM_SHOW_RELAYLOG_EVENTS,
SQLCOM_SHOW_USER_STATS, SQLCOM_SHOW_TABLE_STATS, SQLCOM_SHOW_INDEX_STATS,
SQLCOM_SHOW_CLIENT_STATS,
SQLCOM_SHOW_EXPLAIN,
/*
When a command is added here, be sure it's also added in mysqld.cc
@ -355,6 +356,8 @@ typedef uchar index_clause_map;
#define INDEX_HINT_MASK_ALL (INDEX_HINT_MASK_JOIN | INDEX_HINT_MASK_GROUP | \
INDEX_HINT_MASK_ORDER)
class select_result_sink;
/* Single element of an USE/FORCE/IGNORE INDEX list specified as a SQL hint */
class Index_hint : public Sql_alloc
{
@ -715,6 +718,8 @@ public:
friend int subselect_union_engine::exec();
List<Item> *get_unit_column_types();
int print_explain(select_result_sink *output, uint8 explain_flags,
bool *printed_anything);
};
typedef class st_select_lex_unit SELECT_LEX_UNIT;
@ -775,6 +780,12 @@ public:
those converted to jtbm nests. The list is emptied when conversion is done.
*/
List<Item_in_subselect> sj_subselects;
/*
Needed to correctly generate 'PRIMARY' or 'SIMPLE' for select_type column
of EXPLAIN
*/
bool have_merged_subqueries;
List<TABLE_LIST> leaf_tables;
List<TABLE_LIST> leaf_tables_exec;
@ -1004,7 +1015,7 @@ public:
*/
bool optimize_unflattened_subqueries();
/* Set the EXPLAIN type for this subquery. */
void set_explain_type();
void set_explain_type(bool on_the_fly);
bool handle_derived(LEX *lex, uint phases);
void append_table_to_list(TABLE_LIST *TABLE_LIST::*link, TABLE_LIST *table);
bool get_free_table_map(table_map *map, uint *tablenr);
@ -1027,8 +1038,10 @@ public:
bool save_leaf_tables(THD *thd);
bool save_prep_leaf_tables(THD *thd);
bool is_merged_child_of(st_select_lex *ancestor);
bool is_merged_child_of(st_select_lex *ancestor);
int print_explain(select_result_sink *output, uint8 explain_flags,
bool *printed_anything);
/*
For MODE_ONLY_FULL_GROUP_BY we need to maintain two flags:
- Non-aggregated fields are used in this select.

27
sql/sql_parse.cc
View File

@ -335,6 +335,7 @@ void init_update_queries(void)
sql_command_flags[SQLCOM_SHOW_ENGINE_STATUS]= CF_STATUS_COMMAND;
sql_command_flags[SQLCOM_SHOW_ENGINE_MUTEX]= CF_STATUS_COMMAND;
sql_command_flags[SQLCOM_SHOW_ENGINE_LOGS]= CF_STATUS_COMMAND;
sql_command_flags[SQLCOM_SHOW_EXPLAIN]= CF_STATUS_COMMAND;
sql_command_flags[SQLCOM_SHOW_PROCESSLIST]= CF_STATUS_COMMAND;
sql_command_flags[SQLCOM_SHOW_GRANTS]= CF_STATUS_COMMAND;
sql_command_flags[SQLCOM_SHOW_CREATE_DB]= CF_STATUS_COMMAND;
@ -3127,6 +3128,32 @@ end_with_restore_list:
thd->security_ctx->priv_user),
lex->verbose);
break;
case SQLCOM_SHOW_EXPLAIN:
{
/* Same security as SHOW PROCESSLIST (TODO check this) */
if (!thd->security_ctx->priv_user[0] &&
check_global_access(thd,PROCESS_ACL))
break;
Item *it= (Item *)lex->value_list.head();
if (lex->table_or_sp_used())
{
my_error(ER_NOT_SUPPORTED_YET, MYF(0), "Usage of subqueries or stored "
"function calls as part of this statement");
break;
}
if ((!it->fixed && it->fix_fields(lex->thd, &it)) || it->check_cols(1))
{
my_message(ER_SET_CONSTANTS_ONLY, ER(ER_SET_CONSTANTS_ONLY),
MYF(0));
goto error;
}
mysqld_show_explain(thd, (ulong)it->val_int());
break;
}
case SQLCOM_SHOW_AUTHORS:
res= mysqld_show_authors(thd);
break;

1
sql/sql_prepare.cc
View File

@ -2134,6 +2134,7 @@ static bool check_prepared_statement(Prepared_statement *stmt)
Note that we don't need to have cases in this list if they are
marked with CF_STATUS_COMMAND in sql_command_flags
*/
case SQLCOM_SHOW_EXPLAIN:
case SQLCOM_DROP_TABLE:
case SQLCOM_RENAME_TABLE:
case SQLCOM_ALTER_TABLE:

1
sql/sql_priv.h
View File

@ -331,6 +331,7 @@ enum enum_yes_no_unknown
External variables
*/
/* sql_yacc.cc */
#ifndef DBUG_OFF
extern void turn_parser_debug_on();

514
sql/sql_select.cc
View File

@ -272,6 +272,53 @@ Item_equal *find_item_equal(COND_EQUAL *cond_equal, Field *field,
JOIN_TAB *first_depth_first_tab(JOIN* join);
JOIN_TAB *next_depth_first_tab(JOIN* join, JOIN_TAB* tab);
#ifndef DBUG_OFF
// psergey:
void dbug_serve_apcs(THD *thd, int n_calls)
{
// TODO how do we signal that we're SHOW-EXPLAIN-READY?
const char *save_proc_info= thd->proc_info;
thd_proc_info(thd, "show_explain_trap");
int n_apcs= thd->apc_target.n_calls_processed + n_calls;
while (thd->apc_target.n_calls_processed < n_apcs)
{
my_sleep(300);
if (thd->check_killed())
break;
}
thd_proc_info(thd, save_proc_info);
}
/*
Debugging: check if @name=value, comparing as integer
Intended usage:
DBUG_EXECUTE_IF("show_explain_probe_2",
if (dbug_user_var_equals_int(thd, "select_id", select_id))
dbug_serve_apcs(thd, 1);
);
*/
bool dbug_user_var_equals_int(THD *thd, const char *name, int value)
{
user_var_entry *var;
LEX_STRING varname= {(char*)name, strlen(name)};
if ((var= get_variable(&thd->user_vars, varname, FALSE)))
{
bool null_value;
longlong var_value= var->val_int(&null_value);
if (!null_value && var_value == value)
return TRUE;
}
return FALSE;
}
#endif
/**
This handles SELECT with and without UNION.
*/
@ -928,6 +975,13 @@ err:
}
int JOIN::optimize()
{
int res= optimize_inner();
if (!res)
have_query_plan= QEP_AVAILABLE;
return res;
}
/**
global select optimisation.
@ -941,7 +995,7 @@ err:
*/
int
JOIN::optimize()
JOIN::optimize_inner()
{
ulonglong select_opts_for_readinfo;
uint no_jbuf_after;
@ -2142,6 +2196,32 @@ JOIN::save_join_tab()
}
void JOIN::exec()
{
/*
Enable SHOW EXPLAIN only if we're in the top-level query.
*/
thd->apc_target.enable();
DBUG_EXECUTE_IF("show_explain_probe_join_exec_start",
if (dbug_user_var_equals_int(thd,
"show_explain_probe_select_id",
select_lex->select_number))
dbug_serve_apcs(thd, 1);
);
exec_inner();
DBUG_EXECUTE_IF("show_explain_probe_join_exec_end",
if (dbug_user_var_equals_int(thd,
"show_explain_probe_select_id",
select_lex->select_number))
dbug_serve_apcs(thd, 1);
);
thd->apc_target.disable();
}
/**
Exec select.
@ -2153,8 +2233,8 @@ JOIN::save_join_tab()
@todo
When can we have here thd->net.report_error not zero?
*/
void
JOIN::exec()
void JOIN::exec_inner()
{
List<Item> *columns_list= &fields_list;
int tmp_error;
@ -2458,6 +2538,10 @@ JOIN::exec()
DBUG_PRINT("info",("Creating group table"));
/* Free first data from old join */
/*
psergey-todo: this is the place of pre-mature JOIN::free call.
*/
curr_join->join_free();
if (curr_join->make_simple_join(this, curr_tmp_table))
DBUG_VOID_RETURN;
@ -3695,7 +3779,7 @@ make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list,
goto error;
/* Generate an execution plan from the found optimal join order. */
DBUG_RETURN(join->thd->killed || get_best_combination(join));
DBUG_RETURN(join->thd->check_killed() || get_best_combination(join));
error:
/*
@ -6743,7 +6827,7 @@ best_extension_by_limited_search(JOIN *join,
DBUG_ENTER("best_extension_by_limited_search");
THD *thd= join->thd;
if (thd->killed) // Abort
if (thd->check_killed()) // Abort
DBUG_RETURN(TRUE);
DBUG_EXECUTE("opt", print_plan(join, idx, read_time, record_count, idx,
@ -6900,7 +6984,7 @@ find_best(JOIN *join,table_map rest_tables,uint idx,double record_count,
{
DBUG_ENTER("find_best");
THD *thd= join->thd;
if (thd->killed)
if (thd->check_killed())
DBUG_RETURN(TRUE);
if (!rest_tables)
{
@ -7214,28 +7298,36 @@ prev_record_reads(POSITION *positions, uint idx, table_map found_ref)
return found;
}
enum enum_exec_or_opt {WALK_OPTIMIZATION_TABS , WALK_EXECUTION_TABS};
/*
Enumerate join tabs in breadth-first fashion, including const tables.
*/
JOIN_TAB *first_breadth_first_tab(JOIN *join)
JOIN_TAB *first_breadth_first_tab(JOIN *join, enum enum_exec_or_opt tabs_kind)
{
return join->join_tab; /* There's always one (i.e. first) table */
/* There's always one (i.e. first) table */
return (tabs_kind == WALK_EXECUTION_TABS)? join->join_tab:
join->table_access_tabs;
}
JOIN_TAB *next_breadth_first_tab(JOIN *join, JOIN_TAB *tab)
JOIN_TAB *next_breadth_first_tab(JOIN *join, enum enum_exec_or_opt tabs_kind,
JOIN_TAB *tab)
{
JOIN_TAB* const first_top_tab= first_breadth_first_tab(join, tabs_kind);
const uint n_top_tabs_count= (tabs_kind == WALK_EXECUTION_TABS)?
join->top_join_tab_count:
join->top_table_access_tabs_count;
if (!tab->bush_root_tab)
{
/* We're at top level. Get the next top-level tab */
tab++;
if (tab < join->join_tab + join->top_join_tab_count)
if (tab < first_top_tab + n_top_tabs_count)
return tab;
/* No more top-level tabs. Switch to enumerating SJM nest children */
tab= join->join_tab;
tab= first_top_tab;
}
else
{
@ -7259,7 +7351,7 @@ JOIN_TAB *next_breadth_first_tab(JOIN *join, JOIN_TAB *tab)
Ok, "tab" points to a top-level table, and we need to find the next SJM
nest and enter it.
*/
for (; tab < join->join_tab + join->top_join_tab_count; tab++)
for (; tab < first_top_tab + n_top_tabs_count; tab++)
{
if (tab->bush_children)
return tab->bush_children->start;
@ -7283,7 +7375,7 @@ JOIN_TAB *first_top_level_tab(JOIN *join, enum enum_with_const_tables with_const
JOIN_TAB *next_top_level_tab(JOIN *join, JOIN_TAB *tab)
{
tab= next_breadth_first_tab(join, tab);
tab= next_breadth_first_tab(join, WALK_EXECUTION_TABS, tab);
if (tab && tab->bush_root_tab)
tab= NULL;
return tab;
@ -7583,6 +7675,13 @@ get_best_combination(JOIN *join)
join->top_join_tab_count= join->join_tab_ranges.head()->end -
join->join_tab_ranges.head()->start;
/*
Save pointers to select join tabs for SHOW EXPLAIN
*/
join->table_access_tabs= join->join_tab;
join->top_table_access_tabs_count= join->top_join_tab_count;
update_depend_map(join);
DBUG_RETURN(0);
}
@ -7826,6 +7925,7 @@ static bool create_ref_for_key(JOIN *join, JOIN_TAB *j,
j->ref.null_rejecting= 0;
j->ref.disable_cache= FALSE;
j->ref.null_ref_part= NO_REF_PART;
j->ref.const_ref_part_map= 0;
keyuse=org_keyuse;
store_key **ref_key= j->ref.key_copy;
@ -7861,6 +7961,13 @@ static bool create_ref_for_key(JOIN *join, JOIN_TAB *j,
if (keyuse->null_rejecting)
j->ref.null_rejecting |= 1 << i;
keyuse_uses_no_tables= keyuse_uses_no_tables && !keyuse->used_tables;
/*
Todo: we should remove this check for thd->lex->describe on the next
line. With SHOW EXPLAIN code, EXPLAIN printout code no longer depends
on it. However, removing the check caused change in lots of query
plans! Does the optimizer depend on the contents of
table_ref->key_copy ? If yes, do we produce incorrect EXPLAINs?
*/
if (!keyuse->val->used_tables() && !thd->lex->describe)
{ // Compare against constant
store_key_item tmp(thd,
@ -7873,6 +7980,7 @@ static bool create_ref_for_key(JOIN *join, JOIN_TAB *j,
if (thd->is_fatal_error)
DBUG_RETURN(TRUE);
tmp.copy();
j->ref.const_ref_part_map |= key_part_map(1) << i ;
}
else
*ref_key++= get_store_key(thd,
@ -8015,6 +8123,7 @@ JOIN::make_simple_join(JOIN *parent, TABLE *temp_table)
!(parent->join_tab_reexec= (JOIN_TAB*) thd->alloc(sizeof(JOIN_TAB))))
DBUG_RETURN(TRUE); /* purecov: inspected */
// psergey-todo: here, save the pointer for original join_tabs.
join_tab= parent->join_tab_reexec;
table= &parent->table_reexec[0]; parent->table_reexec[0]= temp_table;
table_count= top_join_tab_count= 1;
@ -10212,7 +10321,12 @@ void JOIN_TAB::cleanup()
if (cache)
{
cache->free();
cache= 0;
cache= 0; // psergey: this is why we don't see "Using join cache" in SHOW EXPLAIN
// when it is run for "Using temporary+filesort" queries while they
// are at reading-from-tmp-table phase.
//
// TODO ask igor if this can be just moved to later phase
// (JOIN_CACHE objects themselves are not big, arent they)
}
limit= 0;
if (table)
@ -10308,9 +10422,18 @@ bool JOIN_TAB::preread_init()
mysql_handle_single_derived(join->thd->lex,
derived, DT_CREATE | DT_FILL))
return TRUE;
preread_init_done= TRUE;
if (select && select->quick)
select->quick->replace_handler(table->file);
DBUG_EXECUTE_IF("show_explain_probe_join_tab_preread",
if (dbug_user_var_equals_int(join->thd,
"show_explain_probe_select_id",
join->select_lex->select_number))
dbug_serve_apcs(join->thd, 1);
);
return FALSE;
}
@ -10518,6 +10641,11 @@ void JOIN::cleanup(bool full)
{
DBUG_ENTER("JOIN::cleanup");
DBUG_PRINT("enter", ("full %u", (uint) full));
/*
psergey: let's try without this first:
*/
have_query_plan= QEP_DELETED;
if (table)
{
@ -15421,7 +15549,7 @@ create_internal_tmp_table_from_heap2(THD *thd, TABLE *table,
DBUG_EXECUTE_IF("raise_error", write_err= HA_ERR_FOUND_DUPP_KEY ;);
if (write_err)
goto err;
if (thd->killed)
if (thd->check_killed())
{
thd->send_kill_message();
goto err_killed;
@ -15680,6 +15808,15 @@ do_select(JOIN *join,List<Item> *fields,TABLE *table,Procedure *procedure)
else
{
DBUG_ASSERT(join->table_count);
THD *thd= join->thd;
DBUG_EXECUTE_IF("show_explain_probe_do_select",
if (dbug_user_var_equals_int(thd,
"show_explain_probe_select_id",
join->select_lex->select_number))
dbug_serve_apcs(thd, 1);
);
if (join->outer_ref_cond && !join->outer_ref_cond->val_int())
error= NESTED_LOOP_NO_MORE_ROWS;
else
@ -15810,7 +15947,7 @@ sub_select_cache(JOIN *join, JOIN_TAB *join_tab, bool end_of_records)
rc= sub_select(join, join_tab, end_of_records);
DBUG_RETURN(rc);
}
if (join->thd->killed)
if (join->thd->check_killed())
{
/* The user has aborted the execution of the query */
join->thd->send_kill_message();
@ -16097,7 +16234,7 @@ evaluate_join_record(JOIN *join, JOIN_TAB *join_tab,
DBUG_RETURN(NESTED_LOOP_ERROR);
if (error < 0)
DBUG_RETURN(NESTED_LOOP_NO_MORE_ROWS);
if (join->thd->killed) // Aborted by user
if (join->thd->check_killed()) // Aborted by user
{
join->thd->send_kill_message();
DBUG_RETURN(NESTED_LOOP_KILLED); /* purecov: inspected */
@ -16841,6 +16978,14 @@ int read_first_record_seq(JOIN_TAB *tab)
static int
test_if_quick_select(JOIN_TAB *tab)
{
DBUG_EXECUTE_IF("show_explain_probe_test_if_quick_select",
if (dbug_user_var_equals_int(tab->join->thd,
"show_explain_probe_select_id",
tab->join->select_lex->select_number))
dbug_serve_apcs(tab->join->thd, 1);
);
delete tab->select->quick;
tab->select->quick=0;
return tab->select->test_quick_select(tab->join->thd, tab->keys,
@ -17301,7 +17446,7 @@ end_write(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
}
}
end:
if (join->thd->killed)
if (join->thd->check_killed())
{
join->thd->send_kill_message();
DBUG_RETURN(NESTED_LOOP_KILLED); /* purecov: inspected */
@ -17384,7 +17529,7 @@ end_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
}
join->send_records++;
end:
if (join->thd->killed)
if (join->thd->check_killed())
{
join->thd->send_kill_message();
DBUG_RETURN(NESTED_LOOP_KILLED); /* purecov: inspected */
@ -17434,7 +17579,7 @@ end_unique_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
DBUG_RETURN(NESTED_LOOP_ERROR); /* purecov: inspected */
}
}
if (join->thd->killed)
if (join->thd->check_killed())
{
join->thd->send_kill_message();
DBUG_RETURN(NESTED_LOOP_KILLED); /* purecov: inspected */
@ -17512,7 +17657,7 @@ end_write_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
if (join->procedure)
join->procedure->add();
end:
if (join->thd->killed)
if (join->thd->check_killed())
{
join->thd->send_kill_message();
DBUG_RETURN(NESTED_LOOP_KILLED); /* purecov: inspected */
@ -18997,7 +19142,7 @@ static int remove_dup_with_compare(THD *thd, TABLE *table, Field **first_field,
error= file->ha_rnd_next(record);
for (;;)
{
if (thd->killed)
if (thd->check_killed())
{
thd->send_kill_message();
error=0;
@ -19129,7 +19274,7 @@ static int remove_dup_with_hash_index(THD *thd, TABLE *table,
for (;;)
{
uchar *org_key_pos;
if (thd->killed)
if (thd->check_killed())
{
thd->send_kill_message();
error=0;
@ -21148,29 +21293,155 @@ void JOIN::clear()
}
}
/*
Print an EXPLAIN line with all NULLs and given message in the 'Extra' column
*/
int print_explain_message_line(select_result_sink *result,
SELECT_LEX *select_lex,
bool on_the_fly,
uint8 options,
const char *message)
{
const CHARSET_INFO *cs= system_charset_info;
Item *item_null= new Item_null();
List<Item> item_list;
if (on_the_fly)
select_lex->set_explain_type(on_the_fly);
item_list.push_back(new Item_int((int32)
select_lex->select_number));
item_list.push_back(new Item_string(select_lex->type,
strlen(select_lex->type), cs));
for (uint i=0 ; i < 7; i++)
item_list.push_back(item_null);
if (options & DESCRIBE_PARTITIONS)
item_list.push_back(item_null);
if (options & DESCRIBE_EXTENDED)
item_list.push_back(item_null);
item_list.push_back(new Item_string(message,strlen(message),cs));
if (result->send_data(item_list))
return 1;
return 0;
}
int print_fake_select_lex_join(select_result_sink *result, bool on_the_fly,
SELECT_LEX *select_lex, uint8 explain_flags)
{
const CHARSET_INFO *cs= system_charset_info;
Item *item_null= new Item_null();
List<Item> item_list;
if (on_the_fly)
select_lex->set_explain_type(on_the_fly); //psergey
/*
here we assume that the query will return at least two rows, so we
show "filesort" in EXPLAIN. Of course, sometimes we'll be wrong
and no filesort will be actually done, but executing all selects in
the UNION to provide precise EXPLAIN information will hardly be
appreciated :)
*/
char table_name_buffer[SAFE_NAME_LEN];
item_list.empty();
/* id */
item_list.push_back(new Item_null);
/* select_type */
item_list.push_back(new Item_string(select_lex->type,
strlen(select_lex->type),
cs));
/* table */
{
SELECT_LEX *sl= select_lex->master_unit()->first_select();
uint len= 6, lastop= 0;
memcpy(table_name_buffer, STRING_WITH_LEN("<union"));
for (; sl && len + lastop + 5 < NAME_LEN; sl= sl->next_select())
{
len+= lastop;
lastop= my_snprintf(table_name_buffer + len, NAME_LEN - len,
"%u,", sl->select_number);
}
if (sl || len + lastop >= NAME_LEN)
{
memcpy(table_name_buffer + len, STRING_WITH_LEN("...>") + 1);
len+= 4;
}
else
{
len+= lastop;
table_name_buffer[len - 1]= '>'; // change ',' to '>'
}
item_list.push_back(new Item_string(table_name_buffer, len, cs));
}
/* partitions */
if (explain_flags & DESCRIBE_PARTITIONS)
item_list.push_back(item_null);
/* type */
item_list.push_back(new Item_string(join_type_str[JT_ALL],
strlen(join_type_str[JT_ALL]),
cs));
/* possible_keys */
item_list.push_back(item_null);
/* key*/
item_list.push_back(item_null);
/* key_len */
item_list.push_back(item_null);
/* ref */
item_list.push_back(item_null);
/* in_rows */
if (explain_flags & DESCRIBE_EXTENDED)
item_list.push_back(item_null);
/* rows */
item_list.push_back(item_null);
/* extra */
if (select_lex->master_unit()->global_parameters->order_list.first)
item_list.push_back(new Item_string("Using filesort",
14, cs));
else
item_list.push_back(new Item_string("", 0, cs));
if (result->send_data(item_list))
return 1;
return 0;
}
/**
EXPLAIN handling.
Send a description about what how the select will be done to stdout.
Produce lines explaining execution of *this* select (not including children
selects)
@param on_the_fly TRUE <=> we're being executed on-the-fly, so don't make
modifications to any select's data structures
*/
static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
bool distinct,const char *message)
int JOIN::print_explain(select_result_sink *result, uint8 explain_flags,
bool on_the_fly,
bool need_tmp_table, bool need_order,
bool distinct, const char *message)
{
List<Item> field_list;
List<Item> item_list;
JOIN *join= this; /* Legacy: this code used to be a non-member function */
THD *thd=join->thd;
select_result *result=join->result;
Item *item_null= new Item_null();
CHARSET_INFO *cs= system_charset_info;
int quick_type;
DBUG_ENTER("select_describe");
int error= 0;
DBUG_ENTER("JOIN::print_explain");
DBUG_PRINT("info", ("Select 0x%lx, type %s, message %s",
(ulong)join->select_lex, join->select_lex->type,
message ? message : "NULL"));
DBUG_ASSERT(have_query_plan == QEP_AVAILABLE);
/* Don't log this into the slow query log */
thd->server_status&= ~(SERVER_QUERY_NO_INDEX_USED | SERVER_QUERY_NO_GOOD_INDEX_USED);
join->unit->offset_limit_cnt= 0;
if (!on_the_fly)
{
thd->server_status&= ~(SERVER_QUERY_NO_INDEX_USED | SERVER_QUERY_NO_GOOD_INDEX_USED);
join->unit->offset_limit_cnt= 0;
}
/*
NOTE: the number/types of items pushed into item_list must be in sync with
@ -21178,101 +21449,32 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
*/
if (message)
{
item_list.push_back(new Item_int((int32)
join->select_lex->select_number));
item_list.push_back(new Item_string(join->select_lex->type,
strlen(join->select_lex->type), cs));
for (uint i=0 ; i < 7; i++)
item_list.push_back(item_null);
if (join->thd->lex->describe & DESCRIBE_PARTITIONS)
item_list.push_back(item_null);
if (join->thd->lex->describe & DESCRIBE_EXTENDED)
item_list.push_back(item_null);
item_list.push_back(new Item_string(message,strlen(message),cs));
if (result->send_data(item_list))
join->error= 1;
if (print_explain_message_line(result, join->select_lex, on_the_fly,
explain_flags, message))
error= 1;
}
else if (join->select_lex == join->unit->fake_select_lex)
{
/*
here we assume that the query will return at least two rows, so we
show "filesort" in EXPLAIN. Of course, sometimes we'll be wrong
and no filesort will be actually done, but executing all selects in
the UNION to provide precise EXPLAIN information will hardly be
appreciated :)
*/
char table_name_buffer[SAFE_NAME_LEN];
item_list.empty();
/* id */
item_list.push_back(new Item_null);
/* select_type */
item_list.push_back(new Item_string(join->select_lex->type,
strlen(join->select_lex->type),
cs));
/* table */
{
SELECT_LEX *sl= join->unit->first_select();
uint len= 6, lastop= 0;
memcpy(table_name_buffer, STRING_WITH_LEN("<union"));
for (; sl && len + lastop + 5 < NAME_LEN; sl= sl->next_select())
{
len+= lastop;
lastop= my_snprintf(table_name_buffer + len, NAME_LEN - len,
"%u,", sl->select_number);
}
if (sl || len + lastop >= NAME_LEN)
{
memcpy(table_name_buffer + len, STRING_WITH_LEN("...>") + 1);
len+= 4;
}
else
{
len+= lastop;
table_name_buffer[len - 1]= '>'; // change ',' to '>'
}
item_list.push_back(new Item_string(table_name_buffer, len, cs));
}
/* partitions */
if (join->thd->lex->describe & DESCRIBE_PARTITIONS)
item_list.push_back(item_null);
/* type */
item_list.push_back(new Item_string(join_type_str[JT_ALL],
strlen(join_type_str[JT_ALL]),
cs));
/* possible_keys */
item_list.push_back(item_null);
/* key*/
item_list.push_back(item_null);
/* key_len */
item_list.push_back(item_null);
/* ref */
item_list.push_back(item_null);
/* in_rows */
if (join->thd->lex->describe & DESCRIBE_EXTENDED)
item_list.push_back(item_null);
/* rows */
item_list.push_back(item_null);
/* extra */
if (join->unit->global_parameters->order_list.first)
item_list.push_back(new Item_string("Using filesort",
14, cs));
else
item_list.push_back(new Item_string("", 0, cs));
if (result->send_data(item_list))
join->error= 1;
if (print_fake_select_lex_join(result, on_the_fly,
join->select_lex,
explain_flags))
error= 1;
}
else if (!join->select_lex->master_unit()->derived ||
join->select_lex->master_unit()->derived->is_materialized_derived())
{
table_map used_tables=0;
//if (!join->select_lex->type)
if (on_the_fly)
join->select_lex->set_explain_type(on_the_fly);
bool printing_materialize_nest= FALSE;
uint select_id= join->select_lex->select_number;
JOIN_TAB* const first_top_tab= first_breadth_first_tab(join, WALK_OPTIMIZATION_TABS);
for (JOIN_TAB *tab= first_breadth_first_tab(join); tab;
tab= next_breadth_first_tab(join, tab))
for (JOIN_TAB *tab= first_breadth_first_tab(join, WALK_OPTIMIZATION_TABS); tab;
tab= next_breadth_first_tab(join, WALK_OPTIMIZATION_TABS, tab))
{
if (tab->bush_root_tab)
{
@ -21304,6 +21506,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
tmp3.length(0);
tmp4.length(0);
quick_type= -1;
QUICK_SELECT_I *quick= NULL;
/* Don't show eliminated tables */
if (table->map & join->eliminated_tables)
@ -21320,17 +21523,19 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
join->select_lex->type;
item_list.push_back(new Item_string(stype, strlen(stype), cs));
enum join_type tab_type= tab->type;
if ((tab->type == JT_ALL || tab->type == JT_HASH) &&
tab->select && tab->select->quick)
tab->select && tab->select->quick && tab->use_quick != 2)
{
quick= tab->select->quick;
quick_type= tab->select->quick->get_type();
if ((quick_type == QUICK_SELECT_I::QS_TYPE_INDEX_MERGE) ||
(quick_type == QUICK_SELECT_I::QS_TYPE_INDEX_INTERSECT) ||
(quick_type == QUICK_SELECT_I::QS_TYPE_ROR_INTERSECT) ||
(quick_type == QUICK_SELECT_I::QS_TYPE_ROR_UNION))
tab->type= tab->type == JT_ALL ? JT_INDEX_MERGE : JT_HASH_INDEX_MERGE;
tab_type= tab->type == JT_ALL ? JT_INDEX_MERGE : JT_HASH_INDEX_MERGE;
else
tab->type= tab->type == JT_ALL ? JT_RANGE : JT_HASH_RANGE;
tab_type= tab->type == JT_ALL ? JT_RANGE : JT_HASH_RANGE;
}
/* table */
@ -21360,7 +21565,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
cs));
}
/* "partitions" column */
if (join->thd->lex->describe & DESCRIBE_PARTITIONS)
if (explain_flags & DESCRIBE_PARTITIONS)
{
#ifdef WITH_PARTITION_STORAGE_ENGINE
partition_info *part_info;
@ -21379,8 +21584,8 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
#endif
}
/* "type" column */
item_list.push_back(new Item_string(join_type_str[tab->type],
strlen(join_type_str[tab->type]),
item_list.push_back(new Item_string(join_type_str[tab_type],
strlen(join_type_str[tab_type]),
cs));
/* Build "possible_keys" value and add it to item_list */
if (!tab->keys.is_clear_all())
@ -21404,7 +21609,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
item_list.push_back(item_null);
/* Build "key", "key_len", and "ref" values and add them to item_list */
if (tab->type == JT_NEXT)
if (tab_type == JT_NEXT)
{
key_info= table->key_info+tab->index;
key_len= key_info->key_length;
@ -21423,22 +21628,30 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
length= (longlong10_to_str(key_len, keylen_str_buf, 10) -
keylen_str_buf);
tmp3.append(keylen_str_buf, length, cs);
if (tab->ref.key_parts)
if (tab->ref.key_parts && tab_type != JT_FT)
{
for (store_key **ref=tab->ref.key_copy ; *ref ; ref++)
store_key **ref=tab->ref.key_copy;
for (uint kp= 0; kp < tab->ref.key_parts; kp++)
{
if (tmp4.length())
tmp4.append(',');
tmp4.append((*ref)->name(), strlen((*ref)->name()), cs);
if ((key_part_map(1) << kp) & tab->ref.const_ref_part_map)
tmp4.append("const");
else
{
tmp4.append((*ref)->name(), strlen((*ref)->name()), cs);
ref++;
}
}
}
}
if (is_hj && tab->type != JT_HASH)
if (is_hj && tab_type != JT_HASH)
{
tmp2.append(':');
tmp3.append(':');
}
if (tab->type == JT_HASH_NEXT)
if (tab_type == JT_HASH_NEXT)
{
register uint length;
key_info= table->key_info+tab->index;
@ -21453,9 +21666,9 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
tab->select && tab->select->quick)
=======*/
}
if (tab->type != JT_CONST && tab->select && tab->select->quick)
if (tab->type != JT_CONST && tab->select && quick)
tab->select->quick->add_keys_and_lengths(&tmp2, &tmp3);
if (key_info || (tab->select && tab->select->quick))
if (key_info || (tab->select && quick))
{
if (tmp2.length())
item_list.push_back(new Item_string(tmp2.ptr(),tmp2.length(),cs));
@ -21465,7 +21678,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
item_list.push_back(new Item_string(tmp3.ptr(),tmp3.length(),cs));
else
item_list.push_back(item_null);
if (key_info && tab->type != JT_NEXT)
if (key_info && tab_type != JT_NEXT)
item_list.push_back(new Item_string(tmp4.ptr(),tmp4.length(),cs));
else
item_list.push_back(item_null);
@ -21508,7 +21721,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
table_list->schema_table)
{
/* in_rows */
if (join->thd->lex->describe & DESCRIBE_EXTENDED)
if (explain_flags & DESCRIBE_EXTENDED)
item_list.push_back(item_null);
/* rows */
item_list.push_back(item_null);
@ -21516,9 +21729,9 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
else
{
ha_rows examined_rows;
if (tab->select && tab->select->quick)
examined_rows= tab->select->quick->records;
else if (tab->type == JT_NEXT || tab->type == JT_ALL || is_hj)
if (tab->select && quick)
examined_rows= quick->records;
else if (tab_type == JT_NEXT || tab_type == JT_ALL || is_hj)
{
if (tab->limit)
examined_rows= tab->limit;
@ -21545,7 +21758,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
MY_INT64_NUM_DECIMAL_DIGITS));
/* Add "filtered" field to item_list. */
if (join->thd->lex->describe & DESCRIBE_EXTENDED)
if (explain_flags & DESCRIBE_EXTENDED)
{
float f= 0.0;
if (examined_rows)
@ -21557,11 +21770,11 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
/* Build "Extra" field and add it to item_list. */
key_read=table->key_read;
if ((tab->type == JT_NEXT || tab->type == JT_CONST) &&
if ((tab_type == JT_NEXT || tab_type == JT_CONST) &&
table->covering_keys.is_set(tab->index))
key_read=1;
if (quick_type == QUICK_SELECT_I::QS_TYPE_ROR_INTERSECT &&
!((QUICK_ROR_INTERSECT_SELECT*)tab->select->quick)->need_to_fetch_row)
!((QUICK_ROR_INTERSECT_SELECT*)quick)->need_to_fetch_row)
key_read=1;
if (tab->info)
@ -21589,8 +21802,8 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
uint keyno= MAX_KEY;
if (tab->ref.key_parts)
keyno= tab->ref.key;
else if (tab->select && tab->select->quick)
keyno = tab->select->quick->index;
else if (tab->select && quick)
keyno = quick->index;
if (keyno != MAX_KEY && keyno == table->file->pushed_idx_cond_keyno &&
table->file->pushed_idx_cond)
@ -21629,7 +21842,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
{
extra.append(STRING_WITH_LEN("; Using where with pushed "
"condition"));
if (thd->lex->describe & DESCRIBE_EXTENDED)
if (explain_flags & DESCRIBE_EXTENDED)
{
extra.append(STRING_WITH_LEN(": "));
((COND *)pushed_cond)->print(&extra, QT_ORDINARY);
@ -21722,7 +21935,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
extra.append(STRING_WITH_LEN("; End temporary"));
else if (tab->do_firstmatch)
{
if (tab->do_firstmatch == join->join_tab - 1)
if (tab->do_firstmatch == /*join->join_tab*/ first_top_tab - 1)
extra.append(STRING_WITH_LEN("; FirstMatch"));
else
{
@ -21772,9 +21985,28 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
// For next iteration
used_tables|=table->map;
if (result->send_data(item_list))
join->error= 1;
error= 1;
}
}
DBUG_RETURN(error);
}
/*
See st_select_lex::print_explain() for the SHOW EXPLAIN counterpart
*/
static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
bool distinct,const char *message)
{
THD *thd=join->thd;
select_result *result=join->result;
DBUG_ENTER("select_describe");
join->error= join->print_explain(result, thd->lex->describe,
FALSE, /* Not on-the-fly */
need_tmp_table, need_order, distinct,
message);
for (SELECT_LEX_UNIT *unit= join->select_lex->first_inner_unit();
unit;
unit= unit->next_unit())
@ -21817,7 +22049,7 @@ bool mysql_explain_union(THD *thd, SELECT_LEX_UNIT *unit, select_result *result)
for (SELECT_LEX *sl= first; sl; sl= sl->next_select())
{
sl->set_explain_type();
sl->set_explain_type(FALSE); //psergey-todo: maybe remove this from here?
sl->options|= SELECT_DESCRIBE;
}

38
sql/sql_select.h
View File

@ -101,6 +101,13 @@ typedef struct st_table_ref
uchar *key_buff; ///< value to look for with key
uchar *key_buff2; ///< key_buff+key_length
store_key **key_copy; //
/*
Bitmap of key parts which refer to constants. key_copy only has copiers for
non-const key parts.
*/
key_part_map const_ref_part_map;
Item **items; ///< val()'s for each keypart
/*
Array of pointers to trigger variables. Some/all of the pointers may be
@ -896,6 +903,20 @@ protected:
public:
JOIN_TAB *join_tab, **best_ref;
/*
For "Using temporary+Using filesort" queries, JOIN::join_tab can point to
either:
1. array of join tabs describing how to run the select, or
2. array of single join tab describing read from the temporary table.
SHOW EXPLAIN code needs to read/show #1. This is why two next members are
there for saving it.
*/
JOIN_TAB *table_access_tabs;
uint top_table_access_tabs_count;
JOIN_TAB **map2table; ///< mapping between table indexes and JOIN_TABs
JOIN_TAB *join_tab_save; ///< saved join_tab for subquery reexecution
@ -1161,8 +1182,14 @@ public:
const char *zero_result_cause; ///< not 0 if exec must return zero result
bool union_part; ///< this subselect is part of union
enum join_optimization_state { NOT_OPTIMIZED=0,
OPTIMIZATION_IN_PROGRESS=1,
OPTIMIZATION_DONE=2};
bool optimized; ///< flag to avoid double optimization in EXPLAIN
bool initialized; ///< flag to avoid double init_execution calls
enum { QEP_NOT_PRESENT_YET, QEP_AVAILABLE, QEP_DELETED} have_query_plan;
/*
Additional WHERE and HAVING predicates to be considered for IN=>EXISTS
@ -1245,6 +1272,7 @@ public:
ref_pointer_array_size= 0;
zero_result_cause= 0;
optimized= 0;
have_query_plan= QEP_NOT_PRESENT_YET;
initialized= 0;
cond_equal= 0;
having_equal= 0;
@ -1273,9 +1301,11 @@ public:
SELECT_LEX_UNIT *unit);
bool prepare_stage2();
int optimize();
int optimize_inner();
int reinit();
int init_execution();
void exec();
void exec_inner();
int destroy();
void restore_tmp();
bool alloc_func_list();
@ -1387,6 +1417,11 @@ public:
{
return (unit->item && unit->item->is_in_predicate());
}
int print_explain(select_result_sink *result, uint8 explain_flags,
bool on_the_fly,
bool need_tmp_table, bool need_order,
bool distinct,const char *message);
private:
/**
TRUE if the query contains an aggregate function but has no GROUP
@ -1738,6 +1773,9 @@ inline bool optimizer_flag(THD *thd, uint flag)
return (thd->variables.optimizer_switch & flag);
}
int print_fake_select_lex_join(select_result_sink *result, bool on_the_fly,
SELECT_LEX *select_lex, uint8 select_options);
uint get_index_for_order(ORDER *order, TABLE *table, SQL_SELECT *select,
ha_rows limit, bool *need_sort, bool *reverse);
ORDER *simple_remove_const(ORDER *order, COND *where);

110
sql/sql_show.cc
View File

@ -1998,6 +1998,116 @@ void mysqld_list_processes(THD *thd,const char *user, bool verbose)
DBUG_VOID_RETURN;
}
/*
SHOW EXPLAIN FOR command handler
@param thd Current thread's thd
@param thread_id Thread whose explain we need
@notes
- Attempt to do "SHOW EXPLAIN FOR <myself>" will properly produce "target not
running EXPLAINable command".
- todo: check how all this can/will work when using thread pools
*/
void mysqld_show_explain(THD *thd, ulong thread_id)
{
THD *tmp;
Protocol *protocol= thd->protocol;
List<Item> field_list;
DBUG_ENTER("mysqld_show_explain");
thd->make_explain_field_list(field_list);
if (protocol->send_result_set_metadata(&field_list, Protocol::SEND_NUM_ROWS |
Protocol::SEND_EOF))
DBUG_VOID_RETURN;
/*
Find the thread we need EXPLAIN for. Thread search code was copied from
kill_one_thread()
*/
mysql_mutex_lock(&LOCK_thread_count); // For unlink from list
I_List_iterator<THD> it(threads);
while ((tmp=it++))
{
if (tmp->command == COM_DAEMON)
continue;
if (tmp->thread_id == thread_id)
{
mysql_mutex_lock(&tmp->LOCK_thd_data); // Lock from delete
break;
}
}
mysql_mutex_unlock(&LOCK_thread_count);
if (tmp)
{
bool bres;
/*
Ok we've found the thread of interest and it won't go away because
we're holding its LOCK_thd data.
Post it an EXPLAIN request.
todo: where to get timeout from?
*/
bool timed_out;
int timeout_sec= 30;
Show_explain_request explain_req;
select_result_explain_buffer *explain_buf;
explain_buf= new select_result_explain_buffer;
explain_buf->thd=thd;
explain_buf->protocol= thd->protocol;
explain_req.explain_buf= explain_buf;
explain_req.target_thd= tmp;
explain_req.request_thd= thd;
explain_req.failed_to_produce= FALSE;
/* Ok, we have a lock on target->LOCK_thd_data, can call: */
bres= tmp->apc_target.make_apc_call(Show_explain_request::get_explain_data,
(void*)&explain_req,
timeout_sec, &timed_out);
if (bres || explain_req.failed_to_produce)
{
/* TODO not enabled or time out */
if (timed_out)
{
my_error(ER_ERROR_WHEN_EXECUTING_COMMAND, MYF(0),
"SHOW EXPLAIN",
"Timeout");
}
else
{
my_error(ER_ERROR_WHEN_EXECUTING_COMMAND, MYF(0),
"SHOW EXPLAIN",
"Target is not running EXPLAINable command");
}
bres= TRUE;
explain_buf->discard_data();
}
else
{
push_warning(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
ER_YES, explain_req.query_str.c_ptr_safe());
}
//mysql_mutex_unlock(&tmp->LOCK_thd_data);
if (!bres)
{
explain_buf->flush_data();
my_eof(thd);
}
}
else
{
my_error(ER_NO_SUCH_THREAD, MYF(0), thread_id);
}
DBUG_VOID_RETURN;
}
int fill_schema_processlist(THD* thd, TABLE_LIST* tables, COND* cond)
{
TABLE *table= tables->table;

2
sql/sql_union.cc
View File

@ -720,6 +720,8 @@ bool st_select_lex_unit::exec()
}
}
DBUG_EXECUTE_IF("show_explain_probe_union_read",
dbug_serve_apcs(thd, 1););
/* Send result to 'result' */
saved_error= TRUE;
{

6
sql/sql_yacc.yy
View File

@ -11614,6 +11614,12 @@ show_param:
Lex->spname= $3;
Lex->sql_command = SQLCOM_SHOW_CREATE_EVENT;
}
| describe_command FOR_SYM expr
{
Lex->sql_command= SQLCOM_SHOW_EXPLAIN;
Lex->value_list.empty();
Lex->value_list.push_front($3);
}
;
show_engine_param:

7
sql/table.h
View File

@ -1106,7 +1106,12 @@ public:
See TABLE_LIST::process_index_hints().
*/
bool force_index_group;
bool distinct,const_table,no_rows, used_for_duplicate_elimination;
/*
TRUE<=> this table was created with create_tmp_table(... distinct=TRUE..)
call
*/
bool distinct;
bool const_table,no_rows, used_for_duplicate_elimination;
/**
If set, the optimizer has found that row retrieval should access index