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MDEV-7370: Server deadlocks on renaming a table for which persistent statistics exists

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RENAME TABLE code tries to update EITS statistics. It hung, because
it used an index on (db_name,table_name) to find the table, and attempted
to update these values at the same time. The fix is do what SQL UPDATE
statement does when updating index that it's used for scanning:
- First, buffer the rowids of rows to be updated,
- then make the second pass to actually update the rows

Also fixed the call to rename_table_in_stat_tables() in sql_rename.cc
to pass the correct new database (before, it passed old db_name so cross-
database renames were not handled correctly).

Variant #2, with review feedback addressed.
This commit is contained in:
Sergei Petrunia 2015-11-18 21:31:45 +03:00
parent c2ec897745
commit f91798dd1c
5 changed files with 389 additions and 3 deletions
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95
mysql-test/r/stat_tables.result
View File

@ -421,4 +421,99 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1 Using index
1 SIMPLE t2 ALL NULL NULL NULL NULL 2 Using where
DROP TABLE t1,t2;
#
# MDEV-7370: Server deadlocks on renaming a table for which persistent statistics exists
#
drop database if exists db1;
drop database if exists db1;
create database db1;
create database db2;
use db1;
#
# First, run the original testcase:
#
create table t1 (i int);
insert into t1 values (10),(20);
analyze table t1 persistent for all;
Table Op Msg_type Msg_text
db1.t1 analyze status Engine-independent statistics collected
db1.t1 analyze status OK
rename table t1 to db2.t1;
# Verify that stats in the old database are gone:
select * from mysql.column_stats where db_name='db1' and table_name='t1';
db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram
select * from mysql.table_stats where db_name='db1' and table_name='t1';
db_name table_name cardinality
# Verify that stats are present in the new database:
select * from mysql.column_stats where db_name='db2' and table_name='t1';
db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram
db2 t1 i 10 20 0.0000 4.0000 1.0000 0 NULL NULL
select * from mysql.table_stats where db_name='db2' and table_name='t1';
db_name table_name cardinality
db2 t1 2
#
# Now, try with more than one column and with indexes:
#
use test;
create table t1(a int primary key);
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
use db1;
create table t2 (a int, b int, c int, key IDX1(a), key IDX2(a,b));
insert into t2 select a/10, a/2, a from test.t1;
analyze table t2 persistent for all;
Table Op Msg_type Msg_text
db1.t2 analyze status Engine-independent statistics collected
db1.t2 analyze status Table is already up to date
alter table t2 rename db2.t2;
# Verify that stats in the old database are gone:
select * from mysql.table_stats where db_name='db1' and table_name='t2';
db_name table_name cardinality
select * from mysql.column_stats where db_name='db1' and table_name='t2';
db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram
select * from mysql.index_stats where db_name='db1' and table_name='t2';
db_name table_name index_name prefix_arity avg_frequency
# Verify that stats are present in the new database:
select * from mysql.table_stats where db_name='db2' and table_name='t2';
db_name table_name cardinality
db2 t2 10
select * from mysql.column_stats where db_name='db2' and table_name='t2';
db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram
db2 t2 a 0 1 0.0000 4.0000 5.0000 0 NULL NULL
db2 t2 b 0 5 0.0000 4.0000 1.6667 0 NULL NULL
db2 t2 c 0 9 0.0000 4.0000 1.0000 0 NULL NULL
select * from mysql.index_stats where db_name='db2' and table_name='t2';
db_name table_name index_name prefix_arity avg_frequency
db2 t2 IDX1 1 5.0000
db2 t2 IDX2 1 5.0000
db2 t2 IDX2 2 1.6667
use db2;
#
# Now, rename within the same database and verify:
#
rename table t2 to t3;
# No stats under old name:
select * from mysql.table_stats where db_name='db2' and table_name='t2';
db_name table_name cardinality
select * from mysql.column_stats where db_name='db2' and table_name='t2';
db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram
select * from mysql.index_stats where db_name='db2' and table_name='t2';
db_name table_name index_name prefix_arity avg_frequency
# Stats under the new name:
select * from mysql.table_stats where db_name='db2' and table_name='t3';
db_name table_name cardinality
db2 t3 10
select * from mysql.column_stats where db_name='db2' and table_name='t3';
db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram
db2 t3 a 0 1 0.0000 4.0000 5.0000 0 NULL NULL
db2 t3 b 0 5 0.0000 4.0000 1.6667 0 NULL NULL
db2 t3 c 0 9 0.0000 4.0000 1.0000 0 NULL NULL
select * from mysql.index_stats where db_name='db2' and table_name='t3';
db_name table_name index_name prefix_arity avg_frequency
db2 t3 IDX1 1 5.0000
db2 t3 IDX2 1 5.0000
db2 t3 IDX2 2 1.6667
use test;
drop database db1;
drop database db2;
drop table t1;
set use_stat_tables=@save_use_stat_tables;

95
mysql-test/r/stat_tables_innodb.result
View File

@ -448,6 +448,101 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1 Using index
1 SIMPLE t2 ALL NULL NULL NULL NULL 2 Using where
DROP TABLE t1,t2;
#
# MDEV-7370: Server deadlocks on renaming a table for which persistent statistics exists
#
drop database if exists db1;
drop database if exists db1;
create database db1;
create database db2;
use db1;
#
# First, run the original testcase:
#
create table t1 (i int);
insert into t1 values (10),(20);
analyze table t1 persistent for all;
Table Op Msg_type Msg_text
db1.t1 analyze status Engine-independent statistics collected
db1.t1 analyze status OK
rename table t1 to db2.t1;
# Verify that stats in the old database are gone:
select * from mysql.column_stats where db_name='db1' and table_name='t1';
db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram
select * from mysql.table_stats where db_name='db1' and table_name='t1';
db_name table_name cardinality
# Verify that stats are present in the new database:
select * from mysql.column_stats where db_name='db2' and table_name='t1';
db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram
db2 t1 i 10 20 0.0000 4.0000 1.0000 0 NULL NULL
select * from mysql.table_stats where db_name='db2' and table_name='t1';
db_name table_name cardinality
db2 t1 2
#
# Now, try with more than one column and with indexes:
#
use test;
create table t1(a int primary key);
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
use db1;
create table t2 (a int, b int, c int, key IDX1(a), key IDX2(a,b));
insert into t2 select a/10, a/2, a from test.t1;
analyze table t2 persistent for all;
Table Op Msg_type Msg_text
db1.t2 analyze status Engine-independent statistics collected
db1.t2 analyze status OK
alter table t2 rename db2.t2;
# Verify that stats in the old database are gone:
select * from mysql.table_stats where db_name='db1' and table_name='t2';
db_name table_name cardinality
select * from mysql.column_stats where db_name='db1' and table_name='t2';
db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram
select * from mysql.index_stats where db_name='db1' and table_name='t2';
db_name table_name index_name prefix_arity avg_frequency
# Verify that stats are present in the new database:
select * from mysql.table_stats where db_name='db2' and table_name='t2';
db_name table_name cardinality
db2 t2 10
select * from mysql.column_stats where db_name='db2' and table_name='t2';
db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram
db2 t2 a 0 1 0.0000 4.0000 5.0000 0 NULL NULL
db2 t2 b 0 5 0.0000 4.0000 1.6667 0 NULL NULL
db2 t2 c 0 9 0.0000 4.0000 1.0000 0 NULL NULL
select * from mysql.index_stats where db_name='db2' and table_name='t2';
db_name table_name index_name prefix_arity avg_frequency
db2 t2 IDX1 1 5.0000
db2 t2 IDX2 1 5.0000
db2 t2 IDX2 2 1.6667
use db2;
#
# Now, rename within the same database and verify:
#
rename table t2 to t3;
# No stats under old name:
select * from mysql.table_stats where db_name='db2' and table_name='t2';
db_name table_name cardinality
select * from mysql.column_stats where db_name='db2' and table_name='t2';
db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram
select * from mysql.index_stats where db_name='db2' and table_name='t2';
db_name table_name index_name prefix_arity avg_frequency
# Stats under the new name:
select * from mysql.table_stats where db_name='db2' and table_name='t3';
db_name table_name cardinality
db2 t3 10
select * from mysql.column_stats where db_name='db2' and table_name='t3';
db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram
db2 t3 a 0 1 0.0000 4.0000 5.0000 0 NULL NULL
db2 t3 b 0 5 0.0000 4.0000 1.6667 0 NULL NULL
db2 t3 c 0 9 0.0000 4.0000 1.0000 0 NULL NULL
select * from mysql.index_stats where db_name='db2' and table_name='t3';
db_name table_name index_name prefix_arity avg_frequency
db2 t3 IDX1 1 5.0000
db2 t3 IDX2 1 5.0000
db2 t3 IDX2 2 1.6667
use test;
drop database db1;
drop database db2;
drop table t1;
set use_stat_tables=@save_use_stat_tables;
set optimizer_switch=@save_optimizer_switch_for_stat_tables_test;
SET SESSION STORAGE_ENGINE=DEFAULT;

73
mysql-test/t/stat_tables.test
View File

@ -232,4 +232,77 @@ SELECT * FROM t1 STRAIGHT_JOIN t2 WHERE name IN ( 'AUS','YEM' ) AND id = 1;
DROP TABLE t1,t2;
--echo #
--echo # MDEV-7370: Server deadlocks on renaming a table for which persistent statistics exists
--echo #
--disable_warnings
drop database if exists db1;
drop database if exists db1;
--enable_warnings
create database db1;
create database db2;
use db1;
--echo #
--echo # First, run the original testcase:
--echo #
create table t1 (i int);
insert into t1 values (10),(20);
analyze table t1 persistent for all;
rename table t1 to db2.t1;
--echo # Verify that stats in the old database are gone:
select * from mysql.column_stats where db_name='db1' and table_name='t1';
select * from mysql.table_stats where db_name='db1' and table_name='t1';
--echo # Verify that stats are present in the new database:
select * from mysql.column_stats where db_name='db2' and table_name='t1';
select * from mysql.table_stats where db_name='db2' and table_name='t1';
--echo #
--echo # Now, try with more than one column and with indexes:
--echo #
use test;
create table t1(a int primary key);
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
use db1;
create table t2 (a int, b int, c int, key IDX1(a), key IDX2(a,b));
insert into t2 select a/10, a/2, a from test.t1;
analyze table t2 persistent for all;
alter table t2 rename db2.t2;
--echo # Verify that stats in the old database are gone:
select * from mysql.table_stats where db_name='db1' and table_name='t2';
select * from mysql.column_stats where db_name='db1' and table_name='t2';
select * from mysql.index_stats where db_name='db1' and table_name='t2';
--echo # Verify that stats are present in the new database:
select * from mysql.table_stats where db_name='db2' and table_name='t2';
select * from mysql.column_stats where db_name='db2' and table_name='t2';
select * from mysql.index_stats where db_name='db2' and table_name='t2';
use db2;
--echo #
--echo # Now, rename within the same database and verify:
--echo #
rename table t2 to t3;
--echo # No stats under old name:
select * from mysql.table_stats where db_name='db2' and table_name='t2';
select * from mysql.column_stats where db_name='db2' and table_name='t2';
select * from mysql.index_stats where db_name='db2' and table_name='t2';
--echo # Stats under the new name:
select * from mysql.table_stats where db_name='db2' and table_name='t3';
select * from mysql.column_stats where db_name='db2' and table_name='t3';
select * from mysql.index_stats where db_name='db2' and table_name='t3';
use test;
drop database db1;
drop database db2;
drop table t1;
set use_stat_tables=@save_use_stat_tables;

3
sql/sql_rename.cc
View File

@ -274,8 +274,9 @@ do_rename(THD *thd, TABLE_LIST *ren_table, char *new_db, char *new_table_name,
LEX_STRING table_name= { ren_table->table_name,
ren_table->table_name_length };
LEX_STRING new_table= { (char *) new_alias, strlen(new_alias) };
LEX_STRING new_db_name= { (char*)new_db, strlen(new_db)};
(void) rename_table_in_stat_tables(thd, &db_name, &table_name,
&db_name, &new_table);
&new_db_name, &new_table);
if ((rc= Table_triggers_list::change_table_name(thd, ren_table->db,
old_alias,
ren_table->table_name,

126
sql/sql_statistics.cc
View File

@ -592,6 +592,8 @@ public:
stat_file->extra(HA_EXTRA_FLUSH);
return FALSE;
}
friend class Stat_table_write_iter;
};
@ -1264,6 +1266,117 @@ public:
};
/*
An iterator to enumerate statistics table rows which allows to modify
the rows while reading them.
Used by RENAME TABLE handling to assign new dbname.tablename to statistic
rows.
*/
class Stat_table_write_iter
{
Stat_table *owner;
IO_CACHE io_cache;
uchar *rowid_buf;
uint rowid_size;
public:
Stat_table_write_iter(Stat_table *stat_table_arg)
: owner(stat_table_arg), rowid_buf(NULL),
rowid_size(owner->stat_file->ref_length)
{
my_b_clear(&io_cache);
}
/*
Initialize the iterator. It will return rows with n_keyparts matching the
curernt values.
@return false - OK
true - Error
*/
bool init(uint n_keyparts)
{
if (!(rowid_buf= (uchar*)my_malloc(rowid_size, MYF(0))))
return true;
if (open_cached_file(&io_cache, mysql_tmpdir, TEMP_PREFIX,
1024, MYF(MY_WME)))
return true;
handler *h= owner->stat_file;
uchar key[MAX_KEY_LENGTH];
uint prefix_len= 0;
for (uint i= 0; i < n_keyparts; i++)
prefix_len += owner->stat_key_info->key_part[i].store_length;
key_copy(key, owner->record[0], owner->stat_key_info,
prefix_len);
key_part_map prefix_map= (key_part_map) ((1 << n_keyparts) - 1);
h->ha_index_init(owner->stat_key_idx, false);
int res= h->ha_index_read_map(owner->record[0], key, prefix_map,
HA_READ_KEY_EXACT);
if (res)
{
reinit_io_cache(&io_cache, READ_CACHE, 0L, 0, 0);
/* "Key not found" is not considered an error */
return (res == HA_ERR_KEY_NOT_FOUND)? false: true;
}
do {
h->position(owner->record[0]);
my_b_write(&io_cache, h->ref, rowid_size);
} while (!h->ha_index_next_same(owner->record[0], key, prefix_len));
/* Prepare for reading */
reinit_io_cache(&io_cache, READ_CACHE, 0L, 0, 0);
h->ha_index_or_rnd_end();
if (h->ha_rnd_init(false))
return true;
return false;
}
/*
Read the next row.
@return
false OK
true No more rows or error.
*/
bool get_next_row()
{
if (!my_b_inited(&io_cache) || my_b_read(&io_cache, rowid_buf, rowid_size))
return true; /* No more data */
handler *h= owner->stat_file;
/*
We should normally be able to find the row that we have rowid for. If we
don't, let's consider this an error.
*/
int res= h->ha_rnd_pos(owner->record[0], rowid_buf);
return (res==0)? false : true;
}
void cleanup()
{
if (rowid_buf)
my_free(rowid_buf);
rowid_buf= NULL;
owner->stat_file->ha_index_or_rnd_end();
close_cached_file(&io_cache);
my_b_clear(&io_cache);
}
~Stat_table_write_iter()
{
cleanup();
}
};
/*
Histogram_builder is a helper class that is used to build histograms
for columns
@ -3285,25 +3398,34 @@ int rename_table_in_stat_tables(THD *thd, LEX_STRING *db, LEX_STRING *tab,
stat_table= tables[INDEX_STAT].table;
Index_stat index_stat(stat_table, db, tab);
index_stat.set_full_table_name();
while (index_stat.find_next_stat_for_prefix(2))
Stat_table_write_iter index_iter(&index_stat);
if (index_iter.init(2))
rc= 1;
while (!index_iter.get_next_row())
{
err= index_stat.update_table_name_key_parts(new_db, new_tab);
if (err & !rc)
rc= 1;
index_stat.set_full_table_name();
}
index_iter.cleanup();
/* Rename table in the statistical table column_stats */
stat_table= tables[COLUMN_STAT].table;
Column_stat column_stat(stat_table, db, tab);
column_stat.set_full_table_name();
while (column_stat.find_next_stat_for_prefix(2))
Stat_table_write_iter column_iter(&column_stat);
if (column_iter.init(2))
rc= 1;
while (!column_iter.get_next_row())
{
err= column_stat.update_table_name_key_parts(new_db, new_tab);
if (err & !rc)
rc= 1;
column_stat.set_full_table_name();
}
column_iter.cleanup();
/* Rename table in the statistical table table_stats */
stat_table= tables[TABLE_STAT].table;