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EXPLAIN DELETE for MariaDB

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- Backported the code to 10.0-base
- Removed incorrect assert
This commit is contained in:
Sergey Petrunya 2013-02-12 08:20:14 +04:00
parent a555ceb2fb
commit 18fec5128b
13 changed files with 550 additions and 83 deletions
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14
mysql-test/r/show_explain.result
View File

@ -192,16 +192,24 @@ ERROR HY000: Target is not running an EXPLAINable command
drop table t2;
set debug_dbug=@old_debug;
#
# Attempt SHOW EXPLAIN for a DELETE
# Attempt SHOW EXPLAIN for a DELETE (UPD: now works)
#
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: Target is not running an EXPLAINable command
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 2 Using where
2 DEPENDENT SUBQUERY t0 ALL NULL NULL NULL NULL 10 Using where
Warnings:
Note 1003 delete from t2 where (select max(a) from t0 where t2.a + t0.a <3) >3
show explain for $thr2;
ERROR HY000: Target is not running an EXPLAINable command
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 2 Using where
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Query plan already deleted
Warnings:
Note 1003 delete from t2 where (select max(a) from t0 where t2.a + t0.a <3) >3
drop table t2;
set debug_dbug=@old_debug;
#

6
mysql-test/t/show_explain.test
View File

@ -249,7 +249,7 @@ drop table t2;
set debug_dbug=@old_debug;
--echo #
--echo # Attempt SHOW EXPLAIN for a DELETE
--echo # Attempt SHOW EXPLAIN for a DELETE (UPD: now works)
--echo #
create table t2 as select a as a, a as dummy from t0 limit 2;
set @show_explain_probe_select_id=2;
@ -257,10 +257,10 @@ 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_TARGET_NOT_EXPLAINABLE
#--error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr2;
--source include/wait_condition.inc
--error ER_TARGET_NOT_EXPLAINABLE
#--error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr2;
connection con1;
reap;

2
sql/my_apc.h
View File

@ -64,6 +64,8 @@ public:
{
return test(apc_calls);
}
inline bool is_enabled() { return enabled; }
/* Functor class for calls you can schedule */
class Apc_call

221
sql/sql_delete.cc
View File

@ -40,6 +40,129 @@
#include "records.h" // init_read_record,
#include "sql_derived.h" // mysql_handle_list_of_derived
// end_read_record
/*
@brief
Print query plan of a single-table DELETE command
@detail
This function is used by EXPLAIN DELETE and by SHOW EXPLAIN when it is
invoked on a running DELETE statement.
*/
int Delete_plan::print_explain(select_result_sink *output, uint8 explain_flags,
bool *printed_anything)
{
if (deleting_all_rows || impossible_where)
{
const char *msg= deleting_all_rows? "Deleting all rows": "Impossible where";
if (print_explain_message_line(output, explain_flags, 1/*select number*/,
"SIMPLE", msg))
{
return 1;
}
*printed_anything= true;
return 0;
}
select_lex->set_explain_type(FALSE);
/*
Print an EXPLAIN line. We dont have join, so we can't directly use
JOIN::print_explain.
We do have a SELECT_LEX (TODO but how is it useful? it has select_type..
and that's it?)
*/
enum join_type jtype;
if (select && select->quick)
{
int quick_type= 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))
jtype= JT_INDEX_MERGE;
else
jtype= JT_RANGE;
}
else
{
if (index == MAX_KEY)
jtype= JT_ALL;
else
jtype= JT_NEXT;
}
StringBuffer<128> possible_keys_line;
make_possible_keys_line(table, possible_keys, &possible_keys_line);
const char *key_name;
const char *key_len;
StringBuffer<128> key_str;
StringBuffer<128> key_len_str;
StringBuffer<128> extra_str;
/* Calculate key_len */
if (select && select->quick)
{
select->quick->add_keys_and_lengths(&key_str, &key_len_str);
key_name= key_str.c_ptr();
key_len= key_len_str.c_ptr();
}
else
{
key_name= (index == MAX_KEY)? NULL : table->key_info[index].name;
key_len= NULL;
}
if (select && select->cond)
extra_str.append(STRING_WITH_LEN("Using where"));
if (select && select->quick &&
select->quick->get_type() == QUICK_SELECT_I::QS_TYPE_RANGE)
{
explain_append_mrr_info((QUICK_RANGE_SELECT*)select->quick, &extra_str);
}
if (using_filesort)
{
if (extra_str.length() !=0)
extra_str.append(STRING_WITH_LEN("; "));
extra_str.append(STRING_WITH_LEN("Using filesort"));
}
/*
Single-table DELETE commands do not do "Using temporary".
"Using index condition" is also not possible (which is an unjustified limitation)
*/
print_explain_row(output, explain_flags,
1, /* id */
select_lex->type,
table->pos_in_table_list->alias,
// partitions,
jtype,
possible_keys_line.length()? possible_keys_line.c_ptr(): NULL,
key_name,
key_len,
NULL, /* 'ref' is always NULL in single-table EXPLAIN DELETE */
select ? select->records : table_rows,
extra_str.c_ptr());
*printed_anything= true;
for (SELECT_LEX_UNIT *unit= select_lex->first_inner_unit();
unit;
unit= unit->next_unit())
{
if (unit->print_explain(output, explain_flags, printed_anything))
return 1;
}
return 0;
}
/**
Implement DELETE SQL word.
@ -61,12 +184,16 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
bool const_cond_result;
ha_rows deleted= 0;
bool reverse= FALSE;
bool err= true;
ORDER *order= (ORDER *) ((order_list && order_list->elements) ?
order_list->first : NULL);
uint usable_index= MAX_KEY;
SELECT_LEX *select_lex= &thd->lex->select_lex;
killed_state killed_status= NOT_KILLED;
THD::enum_binlog_query_type query_type= THD::ROW_QUERY_TYPE;
Delete_plan query_plan;
query_plan.index= MAX_KEY;
query_plan.using_filesort= FALSE;
DBUG_ENTER("mysql_delete");
if (open_and_lock_tables(thd, table_list, TRUE, 0))
@ -90,6 +217,8 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
}
thd_proc_info(thd, "init");
table->map=1;
query_plan.select_lex= &thd->lex->select_lex;
query_plan.table= table;
if (mysql_prepare_delete(thd, table_list, &conds))
DBUG_RETURN(TRUE);
@ -163,6 +292,11 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
ha_rows const maybe_deleted= table->file->stats.records;
DBUG_PRINT("debug", ("Trying to use delete_all_rows()"));
query_plan.set_delete_all_rows(maybe_deleted);
if (thd->lex->describe)
goto exit_without_my_ok;
if (!(error=table->file->ha_delete_all_rows()))
{
/*
@ -187,7 +321,12 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
Item::cond_result result;
conds= remove_eq_conds(thd, conds, &result);
if (result == Item::COND_FALSE) // Impossible where
{
limit= 0;
query_plan.set_impossible_where();
if (thd->lex->describe)
goto exit_without_my_ok;
}
}
#ifdef WITH_PARTITION_STORAGE_ENGINE
@ -195,6 +334,7 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
{
free_underlaid_joins(thd, select_lex);
// No matching record
//psergey-explain-todo: No-partitions used EXPLAIN here..
my_ok(thd, 0);
DBUG_RETURN(0);
}
@ -211,6 +351,10 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
DBUG_RETURN(TRUE);
if ((select && select->check_quick(thd, safe_update, limit)) || !limit)
{
query_plan.set_impossible_where();
if (thd->lex->describe)
goto exit_without_my_ok;
delete select;
free_underlaid_joins(thd, select_lex);
/*
@ -243,26 +387,46 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
if (order)
{
uint length= 0;
SORT_FIELD *sortorder;
ha_rows examined_rows;
ha_rows found_rows;
table->update_const_key_parts(conds);
order= simple_remove_const(order, conds);
bool need_sort;
if (select && select->quick && select->quick->unique_key_range())
{ // Single row select (always "ordered")
need_sort= FALSE;
usable_index= MAX_KEY;
query_plan.using_filesort= FALSE;
query_plan.index= MAX_KEY;
}
else
usable_index= get_index_for_order(order, table, select, limit,
&need_sort, &reverse);
if (need_sort)
query_plan.index= get_index_for_order(order, table, select, limit,
&query_plan.using_filesort,
&reverse);
}
query_plan.select= select;
query_plan.possible_keys= table->quick_keys;
query_plan.table_rows= table->file->stats.records;
thd->lex->delete_plan= &query_plan;
/*
Ok, we have generated a query plan for the DELETE.
- if we're running EXPLAIN DELETE, goto produce explain output
- otherwise, execute the query plan
*/
if (thd->lex->describe)
goto exit_without_my_ok;
thd->apc_target.enable();
DBUG_EXECUTE_IF("show_explain_probe_delete_exec_start",
dbug_serve_apcs(thd, 1););
if (query_plan.using_filesort)
{
ha_rows examined_rows;
ha_rows found_rows;
uint length= 0;
SORT_FIELD *sortorder;
{
DBUG_ASSERT(usable_index == MAX_KEY);
DBUG_ASSERT(query_plan.index == MAX_KEY);
table->sort.io_cache= (IO_CACHE *) my_malloc(sizeof(IO_CACHE),
MYF(MY_FAE | MY_ZEROFILL |
MY_THREAD_SPECIFIC));
@ -276,6 +440,7 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
{
delete select;
free_underlaid_joins(thd, &thd->lex->select_lex);
thd->apc_target.disable();
DBUG_RETURN(TRUE);
}
thd->examined_row_count+= examined_rows;
@ -294,19 +459,21 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
{
delete select;
free_underlaid_joins(thd, select_lex);
thd->apc_target.disable();
DBUG_RETURN(TRUE);
}
if (usable_index == MAX_KEY || (select && select->quick))
if (query_plan.index == MAX_KEY || (select && select->quick))
{
if (init_read_record(&info, thd, table, select, 1, 1, FALSE))
{
delete select;
free_underlaid_joins(thd, select_lex);
thd->apc_target.disable();
DBUG_RETURN(TRUE);
}
}
else
init_read_record_idx(&info, thd, table, 1, usable_index, reverse);
init_read_record_idx(&info, thd, table, 1, query_plan.index, reverse);
init_ftfuncs(thd, select_lex, 1);
thd_proc_info(thd, "updating");
@ -398,6 +565,7 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
if (options & OPTION_QUICK)
(void) table->file->extra(HA_EXTRA_NORMAL);
thd->apc_target.disable();
cleanup:
/*
Invalidate the table in the query cache if something changed. This must
@ -458,6 +626,29 @@ cleanup:
DBUG_PRINT("info",("%ld records deleted",(long) deleted));
}
DBUG_RETURN(error >= 0 || thd->is_error());
/* Special exits */
exit_without_my_ok:
thd->lex->delete_plan= &query_plan;
select_send *result;
bool printed_anything;
if (!(result= new select_send()))
return 1; /* purecov: inspected */
List<Item> dummy; /* note: looked in 5.6 and they too use a dummy list like this */
result->prepare(dummy, &thd->lex->unit);
thd->send_explain_fields(result);
int err2= thd->lex->print_explain(result, 0 /* explain flags*/, &printed_anything);
if (err2)
result->abort_result_set();
else
result->send_eof();
delete select;
free_underlaid_joins(thd, select_lex);
//table->set_keyread(false);
DBUG_RETURN((err || thd->is_error() || thd->killed) ? 1 : 0);
}

31
sql/sql_lex.cc
View File

@ -448,6 +448,7 @@ void lex_start(THD *thd)
lex->thd= lex->unit.thd= thd;
lex->delete_plan= NULL;
lex->context_stack.empty();
lex->unit.init_query();
lex->unit.init_select();
@ -2557,6 +2558,7 @@ LEX::LEX()
INITIAL_LEX_PLUGIN_LIST_SIZE, 0);
reset_query_tables_list(TRUE);
mi.init();
delete_plan= NULL;
}
@ -4166,12 +4168,17 @@ bool st_select_lex::is_merged_child_of(st_select_lex *ancestor)
return all_merged;
}
int print_explain_message_line(select_result_sink *result,
SELECT_LEX *select_lex,
bool on_the_fly,
uint8 options,
const char *message);
int LEX::print_explain(select_result_sink *output, uint8 explain_flags,
bool *printed_anything)
{
if (delete_plan)
{
delete_plan->print_explain(output, explain_flags, printed_anything);
return 0;
}
int res= unit.print_explain(output, explain_flags, printed_anything);
return res;
}
int st_select_lex::print_explain(select_result_sink *output,
@ -4235,8 +4242,9 @@ int st_select_lex::print_explain(select_result_sink *output,
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);
set_explain_type(TRUE/* on_the_fly */);
res= print_explain_message_line(output, 0/*options*/, select_number, type,
msg);
}
err:
return res;
@ -4256,9 +4264,10 @@ int st_select_lex_unit::print_explain(select_result_sink *output,
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;
first->set_explain_type(TRUE/* on_the_fly */);
res= print_explain_message_line(output, 0/*options*/, first->select_number,
first->type, msg);
return res;
}
for (SELECT_LEX *sl= first; sl; sl= sl->next_select())

48
sql/sql_lex.h
View File

@ -2344,6 +2344,48 @@ protected:
LEX *m_lex;
};
class Delete_plan;
class SQL_SELECT;
/* Query plan of a single-table DELETE */
class Delete_plan
{
bool deleting_all_rows;
bool impossible_where;
public:
TABLE *table;
SQL_SELECT *select;
uint index;
ha_rows table_rows; /* Use if select==NULL */
bool using_filesort;
key_map possible_keys;
/*
Top-level select_lex. Most of its fields are not used, we need it only to
get to the subqueries.
*/
SELECT_LEX *select_lex;
/* Construction functions */
Delete_plan() :
deleting_all_rows(false), impossible_where(false), using_filesort(false) {}
/* Set this query plan to be a plan to make a call to h->delete_all_rows() */
void set_delete_all_rows(ha_rows rows_arg)
{
deleting_all_rows= true;
table_rows= rows_arg;
}
/* Set this plan to be a plan to do nothing because of impossible WHRE*/
void set_impossible_where() { impossible_where= true; }
int print_explain(select_result_sink *output, uint8 explain_flags,
bool *printed_anything);
};
/* The state of the lex parsing. This is saved in the THD struct */
struct LEX: public Query_tables_list
@ -2355,6 +2397,9 @@ struct LEX: public Query_tables_list
/* list of all SELECT_LEX */
SELECT_LEX *all_selects_list;
/* For single-table DELETE: its query plan */
Delete_plan *delete_plan;
char *length,*dec,*change;
LEX_STRING name;
char *help_arg;
@ -2769,6 +2814,9 @@ struct LEX: public Query_tables_list
}
return FALSE;
}
int print_explain(select_result_sink *output, uint8 explain_flags,
bool *printed_anything);
};

80
sql/sql_parse.cc
View File

@ -3212,7 +3212,8 @@ end_with_restore_list:
{
DBUG_ASSERT(first_table == all_tables && first_table != 0);
TABLE_LIST *aux_tables= thd->lex->auxiliary_table_list.first;
multi_delete *del_result;
bool explain= test(lex->describe);
select_result *result;
if ((res= multi_delete_precheck(thd, all_tables)))
break;
@ -3227,37 +3228,72 @@ end_with_restore_list:
if ((res= open_and_lock_tables(thd, all_tables, TRUE, 0)))
break;
MYSQL_MULTI_DELETE_START(thd->query());
if (!explain)
{
MYSQL_MULTI_DELETE_START(thd->query());
}
if ((res= mysql_multi_delete_prepare(thd)))
{
MYSQL_MULTI_DELETE_DONE(1, 0);
if (!explain)
{
MYSQL_MULTI_DELETE_DONE(1, 0);
}
goto error;
}
if (!thd->is_fatal_error &&
(del_result= new multi_delete(aux_tables, lex->table_count)))
if (!thd->is_fatal_error)
{
res= mysql_select(thd, &select_lex->ref_pointer_array,
select_lex->get_table_list(),
select_lex->with_wild,
select_lex->item_list,
select_lex->where,
0, (ORDER *)NULL, (ORDER *)NULL, (Item *)NULL,
(ORDER *)NULL,
(select_lex->options | thd->variables.option_bits |
SELECT_NO_JOIN_CACHE | SELECT_NO_UNLOCK |
OPTION_SETUP_TABLES_DONE) & ~OPTION_BUFFER_RESULT,
del_result, unit, select_lex);
res|= thd->is_error();
MYSQL_MULTI_DELETE_DONE(res, del_result->num_deleted());
if (res)
del_result->abort_result_set();
delete del_result;
if (explain)
{
result= new select_send();
if (thd->send_explain_fields(result))
{
delete result;
result= NULL;
}
select_lex->set_explain_type(FALSE);
}
else
result= new multi_delete(aux_tables, lex->table_count);
if (result)
{
res= mysql_select(thd, &select_lex->ref_pointer_array,
select_lex->get_table_list(),
select_lex->with_wild,
select_lex->item_list,
select_lex->where,
0, (ORDER *)NULL, (ORDER *)NULL, (Item *)NULL,
(ORDER *)NULL,
(select_lex->options | thd->variables.option_bits |
SELECT_NO_JOIN_CACHE | SELECT_NO_UNLOCK |
OPTION_SETUP_TABLES_DONE) & ~OPTION_BUFFER_RESULT,
result, unit, select_lex);
res|= thd->is_error();
if (!explain)
{
MYSQL_MULTI_DELETE_DONE(res, del_result->num_deleted());
}
if (res)
result->abort_result_set(); /* for both DELETE and EXPLAIN DELETE */
else
{
if (explain)
result->send_eof();
}
delete result;
}
}
else
{
res= TRUE; // Error
MYSQL_MULTI_DELETE_DONE(1, 0);
if (!explain)
{
MYSQL_MULTI_DELETE_DONE(1, 0);
}
}
break;
}

158
sql/sql_select.cc
View File

@ -21594,23 +21594,20 @@ 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,
uint select_number,
const char *select_type,
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));
item_list.push_back(new Item_int((int32) select_number));
item_list.push_back(new Item_string(select_type,
strlen(select_type), cs));
for (uint i=0 ; i < 7; i++)
item_list.push_back(item_null);
if (options & DESCRIBE_PARTITIONS)
@ -21626,6 +21623,104 @@ int print_explain_message_line(select_result_sink *result,
}
/*
Make a comma-separated list of possible_keys names and add it into the string
*/
void make_possible_keys_line(TABLE *table, key_map possible_keys, String *line)
{
if (!possible_keys.is_clear_all())
{
uint j;
for (j=0 ; j < table->s->keys ; j++)
{
if (possible_keys.is_set(j))
{
if (line->length())
line->append(',');
line->append(table->key_info[j].name,
strlen(table->key_info[j].name),
system_charset_info);
}
}
}
}
/*
Print an EXPLAIN output row, based on information provided in the parameters
@note
Parameters that may have NULL value in EXPLAIN output, should be passed
(char*)NULL.
@return
0 - OK
1 - OOM Error
*/
int print_explain_row(select_result_sink *result,
uint8 options,
uint select_number,
const char *select_type,
const char *table_name,
//const char *partitions, (todo)
enum join_type jtype,
const char *possible_keys,
const char *index,
const char *key_len,
const char *ref,
ha_rows rows,
const char *extra)
{
const CHARSET_INFO *cs= system_charset_info;
Item *item_null= new Item_null();
List<Item> item_list;
Item *item;
item_list.push_back(new Item_int((int32) select_number));
item_list.push_back(new Item_string(select_type,
strlen(select_type), cs));
item_list.push_back(new Item_string(table_name,
strlen(table_name), cs));
if (options & DESCRIBE_PARTITIONS)
item_list.push_back(item_null); // psergey-todo: produce proper value
const char *jtype_str= join_type_str[jtype];
item_list.push_back(new Item_string(jtype_str,
strlen(jtype_str), cs));
item= possible_keys? new Item_string(possible_keys, strlen(possible_keys),
cs) : item_null;
item_list.push_back(item);
/* 'index */
item= index ? new Item_string(index, strlen(index), cs) : item_null;
item_list.push_back(item);
/* 'key_len */
item= key_len ? new Item_string(key_len, strlen(key_len), cs) : item_null;
item_list.push_back(item);
/* 'ref' */
item= ref ? new Item_string(ref, strlen(ref), cs) : item_null;
item_list.push_back(item);
/* 'rows' */
item_list.push_back(new Item_int(rows,
MY_INT64_NUM_DECIMAL_DIGITS));
/* 'filtered' */
if (options & DESCRIBE_EXTENDED)
item_list.push_back(item_null);
/* 'Extra' */
item_list.push_back(new Item_string(extra, strlen(extra), 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)
{
@ -21705,6 +21800,26 @@ int print_fake_select_lex_join(select_result_sink *result, bool on_the_fly,
}
/*
Append MRR information from quick select to the given string
*/
void explain_append_mrr_info(QUICK_RANGE_SELECT *quick, String *res)
{
char mrr_str_buf[128];
mrr_str_buf[0]=0;
int len;
handler *h= quick->head->file;
len= h->multi_range_read_explain_info(quick->mrr_flags, mrr_str_buf,
sizeof(mrr_str_buf));
if (len > 0)
{
res->append(STRING_WITH_LEN("; "));
res->append(mrr_str_buf, len);
}
}
/**
EXPLAIN handling.
@ -21746,8 +21861,12 @@ int JOIN::print_explain(select_result_sink *result, uint8 explain_flags,
*/
if (message)
{
if (print_explain_message_line(result, join->select_lex, on_the_fly,
explain_flags, message))
if (on_the_fly)
join->select_lex->set_explain_type(on_the_fly);
if (print_explain_message_line(result, explain_flags,
join->select_lex->select_number,
join->select_lex->type, message))
error= 1;
}
@ -21762,7 +21881,7 @@ int JOIN::print_explain(select_result_sink *result, uint8 explain_flags,
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);
@ -22171,19 +22290,8 @@ int JOIN::print_explain(select_result_sink *result, uint8 explain_flags,
*/
if (quick_type == QUICK_SELECT_I::QS_TYPE_RANGE)
{
char mrr_str_buf[128];
mrr_str_buf[0]=0;
int len;
uint mrr_flags=
((QUICK_RANGE_SELECT*)(tab->select->quick))->mrr_flags;
len= table->file->multi_range_read_explain_info(mrr_flags,
mrr_str_buf,
sizeof(mrr_str_buf));
if (len > 0)
{
extra.append(STRING_WITH_LEN("; "));
extra.append(mrr_str_buf, len);
}
explain_append_mrr_info((QUICK_RANGE_SELECT*)(tab->select->quick),
&extra);
}
if (need_tmp_table)

22
sql/sql_select.h
View File

@ -1804,6 +1804,28 @@ void eliminate_tables(JOIN *join);
/* Index Condition Pushdown entry point function */
void push_index_cond(JOIN_TAB *tab, uint keyno);
/* EXPLAIN-related utility functions */
int print_explain_message_line(select_result_sink *result,
uint8 options,
uint select_number,
const char *select_type,
const char *message);
void explain_append_mrr_info(QUICK_RANGE_SELECT *quick, String *res);
int print_explain_row(select_result_sink *result,
uint8 options,
uint select_number,
const char *select_type,
const char *table_name,
//const char *partitions, (todo)
enum join_type jtype,
const char *possible_keys,
const char *index,
const char *key_len,
const char *ref,
ha_rows rows,
const char *extra);
void make_possible_keys_line(TABLE *table, key_map possible_keys, String *line);
/****************************************************************************
Temporary table support for SQL Runtime
***************************************************************************/

4
sql/sql_show.cc
View File

@ -2337,8 +2337,8 @@ void Show_explain_request::call_in_target_thread()
DBUG_ASSERT(current_thd == target_thd);
set_current_thd(request_thd);
if (target_thd->lex->unit.print_explain(explain_buf, 0 /* explain flags*/,
&printed_anything))
if (target_thd->lex->print_explain(explain_buf, 0 /* explain flags*/,
&printed_anything))
{
failed_to_produce= TRUE;
}

32
sql/sql_string.h
View File

@ -500,6 +500,38 @@ public:
}
};
// The following class is a backport from MySQL 5.6:
/**
String class wrapper with a preallocated buffer of size buff_sz
This class allows to replace sequences of:
char buff[12345];
String str(buff, sizeof(buff));
str.length(0);
with a simple equivalent declaration:
StringBuffer<12345> str;
*/
template<size_t buff_sz>
class StringBuffer : public String
{
char buff[buff_sz];
public:
StringBuffer() : String(buff, buff_sz, &my_charset_bin) { length(0); }
explicit StringBuffer(const CHARSET_INFO *cs) : String(buff, buff_sz, cs)
{
length(0);
}
StringBuffer(const char *str, size_t length, const CHARSET_INFO *cs)
: String(buff, buff_sz, cs)
{
set(str, length, cs);
}
};
static inline bool check_if_only_end_space(CHARSET_INFO *cs,
const char *str,
const char *end)

5
sql/sql_update.cc
View File

@ -1394,7 +1394,10 @@ bool mysql_multi_update(THD *thd,
thd->abort_on_warning= test(thd->variables.sql_mode &
(MODE_STRICT_TRANS_TABLES |
MODE_STRICT_ALL_TABLES));
/*
psergey-explain-todo:
This is the place where EXPLAIN <multi-table-update> should be handled.
*/
List<Item> total_list;
res= mysql_select(thd, &select_lex->ref_pointer_array,

10
sql/sql_yacc.yy
View File

@ -11881,13 +11881,21 @@ describe:
opt_describe_column {}
| describe_command opt_extended_describe
{ Lex->describe|= DESCRIBE_NORMAL; }
select
explanable_command
{
LEX *lex=Lex;
lex->select_lex.options|= SELECT_DESCRIBE;
}
;
explanable_command:
select
| insert
| replace
| update
| delete
;
describe_command:
DESC
| DESCRIBE