Currently BNLH join uses a simplified implementation of hash function
when hash function is calculated over the whole key buffer, not only
the significant bytes of it. It means that both building keys and
probing keys both must fill insignificant bytes with the same filler.
Usually 0 is used as such a filler.
Yet the code before patch filled insignificant bytes only for probing
keys.
When probing into the hash table of a hashed join cache is performed
the key value should not constructed in the buffer used to build keys
in the hash tables. The constant parts of these keys copied only once,
so they should not be ever overwritten. Otherwise wrong results
can be produced by queries that employ hashed join buffers.
Implement os_event_wait_time() for POSIX systems.
In the purge thread, use os_event_wait_time() when sleeping rather than sleep,
and signal the event when server shuts down, so we do not need to wait for
upto 10 seconds until the purge thread wakes up.
Also fix bug that warnings that were pushed after we call set_ok_status() were
not included in the waning count sent to the client in the result packet.
Also in mysqltest, in recursive die() invocation at least print the message
before aborting.
client/mysqltest.cc:
If we detect recursive die(), at least print the message before aborting.
mysql-test/r/warnings_debug.result:
Test case.
mysql-test/t/warnings_debug.test:
Test case.
sql/handler.cc:
Force generation of a warning with specific debug option, for testing.
sql/protocol.cc:
Fix wrong DBUG_ENTER
sql/sql_class.h:
Add method to count warnings pushed after set_ok_status() is called.
sql/sql_error.cc:
Also count warnings pushed after set_ok_status() is called.
storage/xtradb/include/os0sync.h:
Implement working os_sync_wait_time() for POSIX.
storage/xtradb/include/srv0srv.h:
Make the purge thread wait for an event when sleeping, so we can signal it to
wakeup immediately at shutdown.
storage/xtradb/log/log0log.c:
Make the purge thread wait for an event when sleeping, so we can signal it to
wakeup immediately at shutdown.
storage/xtradb/os/os0sync.c:
Implement working os_sync_wait_time() for POSIX.
storage/xtradb/srv/srv0srv.c:
Make the purge thread wait for an event when sleeping, so we can signal it to
wakeup immediately at shutdown.
- Make optimize_wo_join_buffering() handle cases where position->records_read=0 (this
happens for outer joins that have constant tables inside them). The number of
0 is not correct (should be 1 because outer join will produce at least a NULL-complemented
record) but for now we just make it work with incorrect number.
This bug in the MRR code for Maria engine caused wrong results when
MRR was used to scan ranges for each record.
Added test cases for bugs 669420 and 669423 (as a duplicate of 669420).
Added locking of lock mutex when updating status in external_unlock() for Aria and MyISAM tables.
Fixed that 'source' command doesn't cause mysql command line tool to exit on error.
DEBUG_EXECUTE() and DEBUG_EVALUATE_IF() should not execute things based on wildcards. (Allows one to run --debug with mysql-test-run scripts that uses @debug)
Fixed several core dump, deadlock and crashed table bugs in handling of LOCK TABLE with MERGE tables:
- Added priority of locks to avoid crashes with MERGE tables.
- Added thr_lock_merge() to allow one to merge two results of thr_lock().
Fixed 'not found row' bug in REPLACE with Aria tables.
Mark MyISAM tables that are part of MERGE with HA_OPEN_MERGE_TABLE and set the locks to have priority THR_LOCK_MERGE_PRIV.
- By sorting MERGE tables last in thr_multi_unlock() it's safer to release and relock them many times (can happen when TRIGGERS are created)
Avoid printing (null) in debug file (to easier find out wrong NULL pointer usage with %s).
client/mysql.cc:
Fixed that 'source' command doesn't cause mysql command line tool to exit on error.
client/mysqltest.cc:
Don't send NULL to fn_format(). (Can cause crash on Solaris when using --debug)
dbug/dbug.c:
DEBUG_EXECUTE() and DEBUG_EVALUATE_IF() should not execute things based on wildcards.
include/my_base.h:
Added flag to signal if one opens a MERGE table.
Added extra() command to signal that one is not part of a MERGE table anymore.
include/thr_lock.h:
Added priority for locks (needed to fix bug in thr_lock when using MERGE tables)
Added option to thr_unlock() if get_status() should be called.
Added prototype for thr_merge_locks().
mysql-test/mysql-test-run.pl:
Ignore crashed table warnings for tables named 'crashed'.
mysql-test/r/merge.result:
Renamed triggers to make debugging easier.
Added some CHECK TABLES to catch errors earlier.
Additional tests.
mysql-test/r/merge_debug.result:
Test of error handling when reopening MERGE tables.
mysql-test/r/udf_query_cache.result:
Added missing flush status
mysql-test/suite/parts/r/partition_repair_myisam.result:
Update results
mysql-test/t/merge.test:
Renamed triggers to make debugging easier.
Added some CHECK TABLES to catch errors earlier.
Additional tests.
mysql-test/t/merge_debug.test:
Test of error handling when reopening MERGE tables.
mysql-test/t/udf_query_cache.test:
Added missing flush status
mysys/my_getopt.c:
Removed not used variable
mysys/my_symlink2.c:
Changed (null) to (NULL) to make it easier to find NULL arguments to DBUG_PRINT() functions.
(On linux, NULL to sprintf is printed 'null')
mysys/thr_lock.c:
Added priority of locks to avoid crashes with MERGE tables.
Added thr_lock_merge() to allow one to merge two results of thr_lock().
- This is needed for MyISAM as all locked table must share the same status. If not, you will not see newly inserted rows in other instances of the table.
If calling thr_unlock() with THR_UNLOCK_UPDATE_STATUS, call update_status() and restore_status() for the locks. This is needed in some rare cases where we call thr_unlock() followed by thr_lock() without calling external_unlock/external_lock in between.
Simplify loop in thr_multi_lock().
Added 'start_trans', which is called at end of thr_multi_lock() when all locks are taken.
- This was needed by Aria to ensure that transaction is started when we got all locks, not at get_status(). Without this, some rows could not be visible when we lock two tables at the same time, causing REPLACE using two tables to fail unexpectedly.
sql/handler.cc:
Add an assert() in handler::print_error() for "impossible errors" (like table is crashed) when --debug-assert-if-crashed-table is used.
sql/lock.cc:
Simplify mysql_lock_tables() code if get_lock_data() returns 0 locks.
Added new parameter to thr_multi_unlock()
In mysql_unlock_read_tables(), call first externa_unlock(), then thr_multi_unlock(); This is same order as we do in mysql_unlock_tables().
Don't abort locks in mysql_lock_abort() for merged tables when a MERGE table is deleted; Would cause a spin lock.
Added call to thr_merge_locks() in mysql_lock_merge() to ensure consistency in thr_locks().
- New locks of same type and table is stored after the old lock to ensure that we get the status from the original lock.
sql/mysql_priv.h:
Added debug_assert_if_crashed_table
sql/mysqld.cc:
Added --debug-assert-if-crashed-table
sql/parse_file.cc:
Don't print '(null)' in DBUG_PRINT of no dir given
sql/set_var.cc:
Increase default size of buffer for @debug variable.
sql/sql_base.cc:
In case of error from reopen_table() in reopen_tables(), call unlock_open_table() and restart loop.
- This fixed bug when we twice deleted same table from open_cache.
Don't take name lock for already name locked table in open_unireg_entry().
- Fixed bug when doing repair in reopen_table().
- In detach_merge_children(), always detach if 'clear_refs' is given. We can't trust parent->children_attached as this function can be called twice, first time with clear_refs set to 0.
sql/sql_class.cc:
Changed printing of (null) to "" in set_thd_proc_info()
sql/sql_parse.cc:
Added DBUG
sql/sql_trigger.cc:
Don't call unlink_open_table() if reopen_table() fails as the table may already be freed.
storage/maria/ma_bitmap.c:
Fixed DBUG_ASSERT() in allocate_tail()
storage/maria/ma_blockrec.c:
Fixed wrong calculation of row length for very small rows in undo_row_update().
- Fixes ASSERT() when doing undo.
storage/maria/ma_blockrec.h:
Added _ma_block_start_trans() and _ma_block_start_trans_no_versioning()
storage/maria/ma_locking.c:
Call _ma_update_status_with_lock() when releasing write locks.
- Fixes potential problem with updating status without the proper lock.
storage/maria/ma_open.c:
Changed to use start_trans() instead of get_status() to ensure that we see all rows in all locked tables when we got the locks.
- Fixed 'not found row' bug in REPLACE with Aria tables.
storage/maria/ma_state.c:
Added _ma_update_status_with_lock() and _ma_block_start_trans().
This is to ensure that we see all rows in all locked tables when we got the locks.
storage/maria/ma_state.h:
Added _ma_update_status_with_lock()
storage/maria/ma_write.c:
More DBUG_PRINT
storage/myisam/mi_check.c:
Fixed error message
storage/myisam/mi_extra.c:
Added HA_EXTRA_DETACH_CHILD:
- Detach MyISAM table to not be part of MERGE table (remove flag & lock priority).
storage/myisam/mi_locking.c:
Call mi_update_status_with_lock() when releasing write locks.
- Fixes potential problem with updating status without the proper lock.
Change to use new HA_OPEN_MERGE_TABLE flag to test if MERGE table.
Added mi_fix_status(), called by thr_merge().
storage/myisam/mi_open.c:
Added marker if part of MERGE table.
Call mi_fix_status() in thr_lock() for transactional tables.
storage/myisam/myisamdef.h:
Change my_once_flag to uint, as it stored different values than just 0/1
Added 'open_flag' to store state given to mi_open()
storage/myisammrg/ha_myisammrg.cc:
Add THR_LOCK_MERGE_PRIV to THR_LOCK_DATA to get MERGE locks sorted after other types of locks.
storage/myisammrg/myrg_locking.c:
Remove windows specific code.
storage/myisammrg/myrg_open.c:
Use HA_OPEN_MERGE_TABLE to mi_open().
Set HA_OPEN_MERGE_TABLE for linked MyISAM tables.
storage/xtradb/buf/buf0buf.c:
Fixed compiler warning
storage/xtradb/buf/buf0lru.c:
Initialize variable that could be used not initialized.
Prohibited to use hash join algorithm BNLH if join attributes
need non-binary collations. It has to be done because BNLH does
not support join for such attributes yet.
Later this limitations will be lifted.
Changed default collations for the schemes of some test cases
to preserve the old execution plans.
Lines below which were added in the patch for Bug#56814 cause this crash:
+ if (table->table)
+ table->table->maybe_null= FALSE;
Consider following test case:
--
CREATE TABLE t1(f1 INT NOT NULL);
INSERT INTO t1 VALUES (16777214),(0);
SELECT COUNT(*) FROM t1 LEFT JOIN t1 t2
ON 1 WHERE t2.f1 > 1 GROUP BY t2.f1;
DROP TABLE t1;
--
We set TABLE::maybe_null to FALSE for t2 table
and in create_tmp_field() we create appropriate tmp table field
using create_tmp_field_from_item() function instead of
create_tmp_field_from_field. As a result we have
LONGLONG field. As we have GROUP BY clause we calculate
group buffer length, see calc_group_buffer().
Item from group list which is used for calculation
refer to the field from real tables and have LONG type.
So group buffer length become insufficient for storing of
LONGLONG value. It leads to overwriting of wrong memory
area in do_field_int() function which is called from
end_update().
After some investigation I found out that
create_tmp_field_from_item() is used only for OLAP
grouping and can not be used for common grouping
as it could be an incompatibility between tmp
table fields and group buffer length.
We can not remove create_tmp_field_from_item() call from
create_tmp_field as OLAP needs it and we can not use this
function for common grouping. So we should remove setting
TABLE::maybe_null to FALSE from simplify_joins().
In this case we'll get wrong behaviour of
list_contains_unique_index() back. To fix it we
could use Field::real_maybe_null() check instead of
Field::maybe_null() and add addition check of
TABLE_LIST::outer_join.
mysql-test/r/group_by.result:
test case
mysql-test/r/join_outer.result:
test case
mysql-test/t/group_by.test:
test case
mysql-test/t/join_outer.test:
test case
sql/sql_select.cc:
--remove wrong code
--use Field::real_maybe_null() check instead of
Field::maybe_null() and add addition check of
TABLE_LIST::outer_join
The problem is caused by bug49487 fix and became visible
after after bug56679 fix.
Items are cleaned up and set to unfixed state after filling derived table.
So we can not rely on item::fixed state in Item_func_group_concat::print
and we can not use 'args' array as items there may be cleaned up.
The fix is always to use orig_args array of items as it
always should contain the correct data.
mysql-test/r/func_gconcat.result:
test case
mysql-test/t/func_gconcat.test:
test case
sql/item_sum.cc:
The fix is always to use orig_args array of items.
The problem is dividing by const value when
the result is out of supported range.
The fix:
-return LONGLONG_MIN if the result is out of supported range for DIV operator.
-return 0 if divisor is -1 for MOD operator.
mysql-test/r/func_math.result:
test case
mysql-test/t/func_math.test:
test case
sql/item_func.cc:
-return LONGLONG_MIN if the result is out of supported range for DIV operator.
-return 0 if divisor is -1 for MOD operator.
The set of Ordered keys of a rowid merge engine is dense. Thus when
we decide not to create a key for a column that has only NULLs, this
column shouldn't be counted.
Notice that the caller has already precomputed the correct total
number of keys that should be created.
The main.ps_ddl test does SELECT * FROM mysql.general_log; that can be really
expensive with --valgrind if previous test cases put lots of data in the
general log since last server restart. Fix by truncating the log at test start.
The cause for this bug is that MariaDB 5.3 still processes derived tables
(subqueries in the FROM clause) by fully executing them during the parse
phase. This will be remedied by MWL#106 once merged into the main 5.3.
The assert statement is triggered when MATERIALIZATION is ON for EXPLAIN
EXTENDED for derived tables with an IN subquery as follows:
- mysql_parse calls JOIN::exec for the derived table as if it is regular
execution (not explain).
- When materialization is ON, this call goes all the way to
subselect_hash_sj_engine::exec, which creates a partial match engine
because of NULL presence.
- In order to proceed with normal execution, the hash_sj engine substitutes
itself with the created partial match engine.
- After the parse phase it turns out that this execution was part of
EXPLAIN EXTENDED, which in turn calls
Item_cond::print -> ... -> Item_subselect::print,
which calls engine->print().
Since subselect_hash_sj_engine::exec substituted the current
Item_subselect engine with a partial match engine, eventually we call
its ::print() method. However the partial match engines are designed only
for execution, hence there is no implementation of this print() method.
The fix temporarily removes the assert, until this code is merged with
MWL#106.
The bug was a result of missing logic to handle the case
when there are 'expensive' predicates that are not evaluated
during constant table optimization. Such is the case for
the IN predicate, which is considered expensive if it is
computed via materialization. In general this bug can be
triggered with any expensive predicate instead of IN.
When FALSE constant predicates are not evaluated during constant
optimization, the execution path changes so that instead of
setting JOIN::zero_result_cause after make_join_select, and
exiting JOIN::exec via the call to return_zero_rows(), execution
ends in JOIN::exec in the branch:
if (join->tables == join->const_tables)
{
...
else if (join->send_row_on_empty_set())
...
rc= join->result->send_data(*columns_list);
}
Unlike return_zero_rows(), this branch didn't evaluate the
having clause of the query.
The patch adds a call to evaluate the HAVING clause of a query even
when all tables are constant, because even for an empty result set
some aggregate functions may produce a NULL value.
When join buffers are employed no index scan for the first
table with grouping columns can be used.
mysql-test/r/join_cache.result:
Added a test case for bug #664508.
Sorted results for some other test cases.
mysql-test/t/join_cache.test:
Added a test case for bug #664508.
Sorted results for some other test cases.
After the patch for bug 663840 had been applied the test case for
bug 663818 triggered the assert introduced by this patch.
It happened because the the patch turned out to be incomplete:
the space needed for a key entry must be taken into account
for the record written into the buffer, and, for the next record
as well, when figuring out whether the record being written is
the last for the buffer or not.
When adding a new record into the join buffer that is employed by
BNLH join algorithm the writing procedure JOIN_CACHE::write_record_data
checks whether there is enough space for the record in the buffer.
When doing this it must take into account a possible new key entry
added to the buffer. It might happen, as it has been demonstrated by
the bug test case, that there is enough remaining space in the buffer
for the record, but not for the additional key entry for this record.
In this case the key entry overwrites the end of the record that might
cause a crash or wrong results.
Fixed by taking into account a possible addition of new key entry when
estimating the remaining free space in the buffer.
main.mysqltest skipped on Windows because a perl intentionally does exit(1)
Use exit(2), as exit(1) on Windows is indistinguishable from failing to
execute perl.
data dictionary confusion
On file systems with case insensitive file names, and
lower_case_table_names set to '2', the server could crash
due to a table definition cache inconsistency. This is
the default setting on MacOSX, but may also be set and
used on MS Windows.
The bug is caused by using two different strategies for
creating the hash key for the table definition cache, resulting
in failure to look up an entry which is present in the cache,
or failure to delete an existing entry. One strategy was to
use the real table name (with case preserved), and the other
to use a normalized table name (i.e a lower case version).
This is manifested in two cases. One is during 'DROP DATABASE',
where all known files are removed. The removal from
the table definition cache is done via a generated list of
TABLE_LIST with keys (wrongly) created using the case preserved
name. The other is during CREATE TABLE, where the cache lookup
is also (wrongly) based on the case preserved name.
The fix was to use only the normalized table name when
creating hash keys.
sql/sql_db.cc:
Normalize table name (i.e lower case it)
sql/sql_table.cc:
table_name contains the normalized name
alias contains the real table name
create_sort_index() function overwrites original JOIN_TAB::type field.
At re-execution of subquery overwritten JOIN_TAB::type(JT_ALL) is
used instead of JT_FT. It misleads test_if_skip_sort_order() and
the function tries to find suitable key for the order that should
not be allowed for FULLTEXT(JT_FT) table.
The fix is to restore JOIN_TAB strucures for subselect on re-execution
for EXPLAIN.
Additional fix:
Update TABLE::maybe_null field which
affects list_contains_unique_index() behaviour as it
could have the value(maybe_null==TRUE) based on the
assumption that this join is outer
(see setup_table_map() func).
mysql-test/r/explain.result:
test case
mysql-test/t/explain.test:
test case
sql/item_subselect.cc:
Make subquery uncacheable in case of EXPLAIN. It allows to keep
original JOIN_TAB::type(see JOIN::save_join_tab) and restore it
on re-execution.
sql/sql_select.cc:
-restore JOIN_TAB strucures for subselect on re-execution for EXPLAIN
-Update TABLE::maybe_null field as it could have
the value(maybe_null==TRUE) based on the assumption
that this join is outer(see setup_table_map() func).
This change is not related to the crash problem but
affects EXPLAIN results in the test case.
Subquery executes twice, at top level JOIN::optimize and ::execute stages.
At first execution create_sort_index() function is called and
FT_SELECT object is created and destroyed. HANDLER::ft_handler is cleaned up
in the object destructor and at second execution FT_SELECT::get_next() method
returns error.
The fix is to reinit HANDLER::ft_handler field before re-execution of subquery.
mysql-test/r/fulltext.result:
test case
mysql-test/t/fulltext.test:
test case
sql/item_func.cc:
reinit ft_handler before re-execution of subquery
sql/item_func.h:
Fixed method name
sql/sql_select.cc:
reinit ft_handler before re-execution of subquery
