- If missing: add "disconnect <session>"
- If physical disconnect of non "default" sessions is not finished
at test end: add routine which waits till this happened
+ additional improvements
- remove superfluous files created by the test
- replace error numbers by error names
- remove trailing spaces, replace tabs by spaces
- unify writing of bugs within comments
- correct comments
- minor changes of formatting
Fixed tests:
backup
check
compress
grant
information_schema
multi_update
overflow
packet
query_cache_not_embedded
sp-threads
subselect
synchronization
timezone_grant
Item_in_optimizer::is_null() evaluated "NULL IN (SELECT ...)" to NULL regardless of
whether subquery produced any records, this was a documented limitation.
The limitation has been removed (see bugs 8804, 24085, 24127) now
Item_in_optimizer::val_int() correctly handles all cases with NULLs. Make
Item_in_optimizer::is_null() invoke val_int() to return correct values for
"NULL IN (SELECT ...)".
enable uncacheable flag if we update a view with check option
and check option has a subselect, otherwise, the check option
can be evaluated after the subselect was freed as independent
(See full_local in JOIN::join_free())
manually resolved conflicts:
Text conflict in client/mysqltest.c
Contents conflict in mysql-test/include/have_bug25714.inc
Text conflict in mysql-test/include/have_ndbapi_examples.inc
Text conflict in mysql-test/mysql-test-run.pl
Text conflict in mysql-test/suite/parts/inc/partition_check_drop.inc
Text conflict in mysql-test/suite/parts/inc/partition_layout.inc
Text conflict in mysql-test/suite/parts/inc/partition_layout_check1.inc
Text conflict in mysql-test/suite/parts/inc/partition_layout_check2.inc
Text conflict in mysql-test/suite/parts/r/partition_alter1_1_2_myisam.result
Text conflict in mysql-test/suite/parts/r/partition_alter1_1_myisam.result
Text conflict in mysql-test/suite/parts/r/partition_alter1_2_myisam.result
Text conflict in mysql-test/suite/parts/r/partition_alter2_myisam.result
Text conflict in mysql-test/suite/parts/r/partition_alter3_innodb.result
Text conflict in mysql-test/suite/parts/r/partition_alter3_myisam.result
Text conflict in mysql-test/suite/parts/r/partition_basic_innodb.result
Text conflict in mysql-test/suite/parts/r/partition_basic_myisam.result
Text conflict in mysql-test/suite/parts/r/partition_basic_symlink_myisam.result
Text conflict in mysql-test/suite/parts/r/partition_engine_myisam.result
Text conflict in mysql-test/suite/parts/r/partition_syntax_myisam.result
Text conflict in mysql-test/suite/rpl_ndb/t/disabled.def
Text conflict in mysql-test/t/disabled.def
Calling List<Cached_item>::delete_elements for the same list twice
caused a crash of the server in the function JOIN::cleaunup.
Ensured that delete_elements() in JOIN::cleanup would be called only once.
When there is an error executing EXISTS predicates they return NULL as their string
or decimal value but don't set the NULL value flag.
Fixed by returning 0 (as a decimal or a string) on error exectuting the subquery.
Note that we can't return NULL as EXISTS is not supposed to return NULL.
with dependent subqueries
An IN subquery is executed on EXPLAIN when it's not correlated.
If the subquery required a temporary table for its execution
not all the internal structures were restored from pointing to
the items of the temporary table to point back to the items of
the subquery.
Fixed by restoring the ref array when a temp tables were used in
executing the IN subquery during EXPLAIN EXTENDED.
The test case for the bug#31048 checks that there is no crash on stack
overrun. But due to different stack sizes on different platforms it failed
on some of them.
The new test case check that a query with at least 4 level subquery nesting
works without the stack overrun nesting and other levels of nesting doesn't
cause a crash.
The problem occurred when one had a subquery that had an equality X=Y where
Y referred to a named select list expression from the parent select. MySQL
crashed when trying to use the X=Y equality for ref-based access.
Fixed by allowing non-Item_field items in the described case.
server crash.
The filesort implementation has an optimization for subquery execution which
consists of reusing previously allocated buffers. In particular the call to
the read_buffpek_from_file function might be skipped when a big enough buffer
for buffer descriptors (buffpeks) is already allocated. Beside allocating
memory for buffpeks this function fills allocated buffer with data read from
disk. Skipping it might led to using an arbitrary memory as fields' data and
finally to a crash.
Now the read_buffpek_from_file function is always called. It allocates
new buffer only when necessary, but always fill it with correct data.
crashes MySQL 5.122
There was a difference in how UNIONs are handled
on top level and when in sub-query.
Because the rules for sub-queries were syntactically
allowing cases that are not currently supported by
the server we had crashes (this bug) or wrong results
(bug 32051).
Fixed by making the syntax rules for UNIONs match the
ones at top level.
These rules however do not support nesting UNIONs, e.g.
(SELECT a FROM t1 UNION ALL SELECT b FROM t2)
UNION
(SELECT c FROM t3 UNION ALL SELECT d FROM t4)
Supports for statements with nested UNIONs will be
added in a future version.
Index lookup does not always guarantee that we can
simply remove the relevant conditions from the WHERE
clause. Reasons can be e.g. conversion errors,
partial indexes etc.
The optimizer was removing these parts of the WHERE
condition without any further checking.
This leads to "false positives" when using indexes.
Fixed by checking the index reference conditions
(using WHERE) when using indexes with sub-queries.
only on some occasions
Referencing an element from the SELECT list in a WHERE
clause is not permitted. The namespace of the WHERE
clause is the table columns only. This was not enforced
correctly when resolving outer references in sub-queries.
Fixed by not allowing references to aliases in a
sub-query in WHERE.
This bug is actually two. The first one manifests itself on an EXPLAIN
SELECT query with nested subqueries that employs the filesort algorithm.
The whole SELECT under explain is marked as UNCACHEABLE_EXPLAIN to preserve
some temporary structures for explain. As a side-effect of this values of
nested subqueries weren't cached and subqueries were re-evaluated many
times. Each time buffer for filesort was allocated but wasn't freed because
freeing occurs at the end of topmost SELECT. Thus all available memory was
eaten up step by step and OOM event occur.
The second bug manifests itself on SELECT queries with conditions where
a subquery result is compared with a key field and the subquery itself also
has such condition. When a long chain of such nested subqueries is present
the stack overrun occur. This happens because at some point the range optimizer
temporary puts the PARAM structure on the stack. Its size if about 8K and
the stack is exhausted very fast.
Now the subselect_single_select_engine::exec function allows subquery result
caching when the UNCACHEABLE_EXPLAIN flag is set.
Now the SQL_SELECT::test_quick_select function calls the check_stack_overrun
function for stack checking purposes to prevent server crash.
