summaryrefslogtreecommitdiff
path: root/sql/item_subselect.cc
diff options
context:
space:
mode:
authorIgor Babaev <igor@askmonty.org>2022-01-07 11:52:25 -0800
committerIgor Babaev <igor@askmonty.org>2022-01-07 11:52:25 -0800
commit8265d6d9f632add97f0d13cdfca7188164ba8f2c (patch)
treed8e1a1034fef783dd0e1475fbb73c637790a9d7f /sql/item_subselect.cc
parentc18896f9c1ce6e4b9a8519a2d5155698d82ae45a (diff)
downloadmariadb-git-8265d6d9f632add97f0d13cdfca7188164ba8f2c.tar.gz
MDEV-22846 Server crashes in handler_index_cond_check on SELECT
If the optimizer decides to rewrites a NOT IN predicand of the form outer_expr IN (SELECT inner_col FROM ... WHERE subquery_where) into the EXISTS subquery EXISTS (SELECT 1 FROM ... WHERE subquery_where AND (outer_expr=inner_col OR inner_col IS NULL)) then the pushed equality predicate outer_expr=inner_col can be used for ref[or_null] access if inner_col is a reference to an indexed column. In this case if there is a selective range condition over this column then a Rowid filter may be employed coupled the with ref[or_null] access. The filter is 'pushed' into the engine and in InnoDB currently it cannot be used with index look-ups by primary key. The ref[or_null] access can be used only when outer_expr is not NULL. Otherwise the original predicand is evaluated to TRUE only if the result set returned by the query SELECT 1 FROM ... WHERE subquery_where is empty. When performing this evaluation the executor switches to the table scan by primary key. Before this patch the pushed filter still remained marked as active and the engine tried to apply the filter. This was incorrect and in InnoDB this attempt to use the filter led to an assertion failure. This patch fixes the problem by disabling usage of the filter when outer_expr is evaluated to NULL.
Diffstat (limited to 'sql/item_subselect.cc')
-rw-r--r--sql/item_subselect.cc4
1 files changed, 4 insertions, 0 deletions
diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index 82b40966e4f..56ab0f648ee 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -4026,6 +4026,8 @@ int subselect_single_select_engine::exec()
tab->save_read_record= tab->read_record.read_record_func;
tab->read_record.read_record_func= rr_sequential;
tab->read_first_record= read_first_record_seq;
+ if (tab->rowid_filter)
+ tab->table->file->disable_pushed_rowid_filter();
tab->read_record.thd= join->thd;
tab->read_record.ref_length= tab->table->file->ref_length;
tab->read_record.unlock_row= rr_unlock_row;
@@ -4046,6 +4048,8 @@ int subselect_single_select_engine::exec()
tab->read_record.ref_length= 0;
tab->read_first_record= tab->save_read_first_record;
tab->read_record.read_record_func= tab->save_read_record;
+ if (tab->rowid_filter)
+ tab->table->file->enable_pushed_rowid_filter();
}
executed= 1;
if (!(uncacheable() & ~UNCACHEABLE_EXPLAIN) &&