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Bug#51494 crash with join, explain and 'sounds like' operator

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The crash happens because of discrepancy between values of
conts_tables and join->const_table_map(make_join_statisctics).
Calculation of conts_tables used condition with
HA_STATS_RECORDS_IS_EXACT flag check. Calculation of
join->const_table_map does not use this flag check.
In case of MERGE table without union with index
the table does not become const table and
thus join_read_const_table() is not called
for the table. join->const_table_map supposes
this table is const and later in make_join_select
this table is used for making&calculation const
condition. As table record buffer is not populated
it leads to crash.
The fix is adding a check if an engine supports
HA_STATS_RECORDS_IS_EXACT flag before updating
join->const_table_map.
This commit is contained in:
Sergey Glukhov
2010-03-19 10:01:02 +04:00
parent 0d608d5b11
commit bed0948145
3 changed files with 29 additions and 1 deletions
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3
sql/sql_select.cc
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@@ -2943,7 +2943,8 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables_arg, COND *conds,
s->quick=select->quick;
s->needed_reg=select->needed_reg;
select->quick=0;
if (records == 0 && s->table->reginfo.impossible_range)
if (records == 0 && s->table->reginfo.impossible_range &&
(s->table->file->ha_table_flags() & HA_STATS_RECORDS_IS_EXACT))
{
/*
Impossible WHERE or ON expression