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Fixed bug #28188: performance degradation for outer join queries to which

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'not exists' optimization is applied.

In fact 'not exists' optimization did not work anymore after the patch
introducing the evaluate_join_record function had been applied.

Corrected the evaluate_join_record function to respect the 'not_exists'
optimization.
This commit is contained in:
igor@olga.mysql.com
2007-05-01 23:34:14 -07:00
parent 2cf753a1e8
commit 1a0cf6db7c
3 changed files with 47 additions and 3 deletions
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5
sql/sql_select.cc
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@ -10526,7 +10526,6 @@ static enum_nested_loop_state
evaluate_join_record(JOIN *join, JOIN_TAB *join_tab,
int error, my_bool *report_error)
{
bool not_exists_optimize= join_tab->table->reginfo.not_exists_optimize;
bool not_used_in_distinct=join_tab->not_used_in_distinct;
ha_rows found_records=join->found_records;
COND *select_cond= join_tab->select_cond;
@ -10563,6 +10562,8 @@ evaluate_join_record(JOIN *join, JOIN_TAB *join_tab,
first_unmatched->found= 1;
for (JOIN_TAB *tab= first_unmatched; tab <= join_tab; tab++)
{
if (tab->table->reginfo.not_exists_optimize)
return NESTED_LOOP_NO_MORE_ROWS;
/* Check all predicates that has just been activated. */
/*
Actually all predicates non-guarded by first_unmatched->found
@ -10608,8 +10609,6 @@ evaluate_join_record(JOIN *join, JOIN_TAB *join_tab,
if (found)
{
enum enum_nested_loop_state rc;
if (not_exists_optimize)
return NESTED_LOOP_NO_MORE_ROWS;
/* A match from join_tab is found for the current partial join. */
rc= (*join_tab->next_select)(join, join_tab+1, 0);
if (rc != NESTED_LOOP_OK && rc != NESTED_LOOP_NO_MORE_ROWS)