This is a backport of the fix for MySQL bug #13723054 in 5.6.
Original comment:
The crash is caused by arbitrary memory area owerwriting in case of
BLOB fields during attempt to copy BLOB field key image into record
buffer(record buffer is too small to get BLOB key part image).
note:
QUICK_GROUP_MIN_MAX_SELECT can not work with BLOB fields
because it uses record buffer as temporary buffer for key values
however this case is filtered out by covering_keys() check
in get_best_group_min_max() as BLOBs always require key length
modificator in the key declaration and if the key has a BLOB
then it can not be covered key.
The fix is to use 'max_used_key_length' key length instead of 0.
Analysis:
Spcifically the crash in this bug was a result of the call to key_copy()
that copied the whole key, inlcuding the BLOB field which is not used
for index access. Copying the blob field overwrote memory as far as the
function parameter 'key_info'. As a result the contents of key_info was
all 0, which resulted in a crash when this key_info was accessed few
lines below in key_cmp().
sql/sql_insert.cc:
CREATE ... IF NOT EXISTS may do nothing, but
it is still not a failure. don't forget to my_ok it.
******
CREATE ... IF NOT EXISTS may do nothing, but
it is still not a failure. don't forget to my_ok it.
sql/sql_table.cc:
small cleanup
******
small cleanup
when semijoin=on
When setting the aggregate function as having no rows to report
the function no_rows_in_result() was calling Item_sum::reset().
However this function in addition to cleaning up the aggregate
value by calling aggregator_clear() was also adding the current
value to the aggregate value by calling aggregator_add().
Fixed by making no_rows_in_result() to call aggregator_clear()
directly.
Renamed Item_sum::reset to Item_sum::reset_and_add() to
and added a comment to avoid misinterpretation of what the
function does.
- Renamed "Using join cache" to "Using join buffer".
- "Using join buffer" is now printed on the last
table that "reads" from the join buffer cache.
mysql-test/r/archive_gis.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/compress.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/ctype_utf8.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/derived.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/distinct.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/func_group.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/func_group_innodb.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/gis.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/greedy_optimizer.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/group_by.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/group_min_max.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/index_merge_myisam.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/information_schema.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/innodb_gis.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/innodb_mysql.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/join.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/join_nested.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/key_diff.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/myisam.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/ndb_condition_pushdown.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/ndb_gis.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/range.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/row.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/select.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/ssl.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/ssl_compress.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/subselect.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/subselect3.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/union.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/view.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
sql/sql_select.cc:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
- added join cache indication in EXPLAIN (Extra column).
- prefer filesort over full scan over
index for ORDER BY (because it's faster).
- when switching from REF to RANGE because
RANGE uses longer key turn off sort on
the head table only as the resulting
RANGE access is a candidate for join cache
and we don't want to disable it by sorting
on the first table only.
mysql-test/r/archive_gis.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/compress.result:
bug #27531:
- join cache in EXPLAIN.
- prefer filesort over full scan over index for ORDER BY.
mysql-test/r/ctype_utf8.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/derived.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/distinct.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/func_group.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/func_group_innodb.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/gis.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/greedy_optimizer.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/group_by.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/group_min_max.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/index_merge_myisam.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/information_schema.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/innodb_gis.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/innodb_mysql.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/join.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/join_nested.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/key_diff.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/myisam.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/ndb_condition_pushdown.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/ndb_gis.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/range.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/row.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/select.result:
bug #27531:
- join cache in EXPLAIN.
- prefer filesort over full scan over index for ORDER BY.
mysql-test/r/ssl.result:
bug #27531:
- join cache in EXPLAIN.
- prefer filesort over full scan over index for ORDER BY.
mysql-test/r/ssl_compress.result:
bug #27531:
- join cache in EXPLAIN.
- prefer filesort over full scan over index for ORDER BY.
mysql-test/r/subselect.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/subselect3.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/union.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/view.result:
bug #27531: join cache in EXPLAIN
sql/sql_select.cc:
bug #27531:
- join cache in EXPLAIN.
- prefer filesort over full scan over
index for ORDER BY.
- disable sorting on the first table only
when switching from REF to RANGE.
mysql-test/r/func_group_innodb.result:
New BitKeeper file ``mysql-test/r/func_group_innodb.result''
mysql-test/t/func_group_innodb.test:
New BitKeeper file ``mysql-test/t/func_group_innodb.test''
