two tests still fail:
main.innodb_icp and main.range_vs_index_merge_innodb
call records_in_range() with both range ends being open
(which triggers an assert)
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().
ORDER BY COUNT(*) LIMIT.
PROBLEM:
With respect to problem in the bug description, we
exhibit different behaviors for the two tables
presented, because innodb statistics (rec_per_key
in this case) are updated for the first table
and not so for the second one. As a result the
query plan gets changed in test_if_skip_sort_order
to use 'index' scan. Hence the difference in the
explain output. (NOTE: We can reproduce the problem
with first table by reducing the number of tuples
and changing the table structure)
The varied output w.r.t the query on the second table
is because of the result in the query plan change.
When a query plan is changed to use 'index' scan,
after the call to test_if_skip_sort_order, we set
keyread to TRUE immedietly. If for some reason
we drop this index scan for a filesort later on,
we fetch only the keys not the entire tuple.
As a result we would see junk values in the result set.
Following is the code flow:
Call test_if_skip_sort_order
-Choose an index to give sorted output
-If this is a covering index, set_keyread to TRUE
-Set the scan to INDEX scan
Call test_if_skip_sort_order second time
-Index is not chosen (note that we do not pass the
actual limit value second time. Hence we do not choose
index scan second time which in itself is a bug fixed
in 5.6 with WL#5558)
-goto filesort
Call filesort
-Create quick range on a different index
-Since keyread is set to TRUE, we fetch only the columns of
the index
-results in the required columns are not fetched
FIX:
Remove the call to set_keyread(TRUE) from
test_if_skip_sort_order. The access function which is
'join_read_first' or 'join_read_last' calls set_keyread anyways.
mysql-test/r/func_group_innodb.result:
Added test result for Bug#12713907
mysql-test/t/func_group_innodb.test:
Added test case for Bug#12713907
sql/sql_select.cc:
Remove the call to set_keyread as we do it from access
functions 'join_read_first' and 'join_read_last'
- 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''
