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Fixed bug mdev-4367.

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When calculating selectivity of conditions one should take into account
the cases when some tables to be joined are empty.
This commit is contained in:
Igor Babaev
2013-04-03 23:50:14 -07:00
parent d62ee4e970
commit 50d4d1ca18
5 changed files with 57 additions and 7 deletions
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12
sql/opt_range.cc
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@@ -3324,6 +3324,12 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
DBUG_ENTER("calculate_cond_selectivity_for_table");
table->cond_selectivity= 1.0;
#if 0
#else
if (table_records == 0)
DBUG_RETURN(FALSE);
#endif
if (thd->variables.optimizer_use_condition_selectivity > 2 &&
!bitmap_is_clear_all(used_fields))
@@ -3363,11 +3369,6 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
double rows;
if (*key)
{
#if 0
rows= records_in_column_ranges(&param, idx, *key);
if (rows != HA_POS_ERROR)
(*key)->field->cond_selectivity= rows/table_records;
#else
table->reginfo.impossible_range= 0;
if ((*key)->type == SEL_ARG::IMPOSSIBLE)
{
@@ -3381,7 +3382,6 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
if (rows != HA_POS_ERROR)
(*key)->field->cond_selectivity= rows/table_records;
}
#endif
}
}