Significantly reduce the amount of InnoDB, XtraDB and Mariabackup
code changes by defining pfs_os_file_t as something that is
transparently compatible with os_file_t.
Do not silence uncertain cases, or fix any bugs.
The only functional change should be that ha_federated::extra()
is not calling DBUG_PRINT to report an unhandled case for
HA_EXTRA_PREPARE_FOR_DROP.
Do not silence uncertain cases, or fix any bugs.
The only functional change should be that ha_federated::extra()
is not calling DBUG_PRINT to report an unhandled case for
HA_EXTRA_PREPARE_FOR_DROP.
At some conditions the function opt_sum_query() can apply MIN/MAX
optimizations to to Item_sum objects of a select These optimizations
becomes invalid if this select is the subquery of an IN subquery
predicate that is converted to a EXISTS subquery. Thus in this case
the MIX/MAX optimizations that have been applied in opt_sum_query()
must be rolled back.
This bug appeared in 5.3 when the code for the cost base choice between
materialization and in-to-exists transformation of non-correlated
IN subqueries was introduced. Before this code in-to-exists
transformations were always performed before the call of opt_sum_query().
Cherry-pick: f4a0af070ce49abae60040f6f32e1074309c27fb
Author: Dmitry Lenev <dmitry.lenev@oracle.com>
Date: Mon Jul 25 16:06:52 2016 +0300
Fix for bug #16672723 "CAN'T FIND TEMPORARY TABLE".
Attempt to execute prepared CREATE TABLE SELECT statement which used
temporary table in the subquery in FROM clause and stored function
failed with unwarranted ER_NO_SUCH_TABLE error. The same happened
when such statement was used in stored procedure and this procedure
was re-executed.
The problem occurred because execution of such prepared statement/its
re-execution as part of stored procedure incorrectly set
Query_table_list::query_tables_own_last marker, indicating the last
table which is directly used by statement. As result temporary table
used in the subquery was treated as indirectly used/belonging to
prelocking list and was not pre-opened by open_temporary_tables()
call before statement execution. Thus causing ER_NO_SUCH_TABLE errors
since our code assumes that temporary tables need to be correctly
pre-opened before statement execution.
This problem became visible only in version 5.6 after patches related to
bug 11746602/27480 "EXTEND CREATE TEMPORARY TABLES PRIVILEGE TO ALLOW
TEMP TABLE OPERATIONS" since they have introduced pre-opening of temporary
tables for statements.
Incorrect setting of Query_table_list::query_tables_own_last happened
in LEX::first_lists_tables_same() method which is called by CREATE TABLE
SELECT implementation as part of LEX::unlink_first_table(), which temporary
excludes table list element for table being created from the query table
list before handling SELECT part.
LEX::first_lists_tables_same() tries to ensure that global table list of
the statement starts with the first table list element from the first
statement select. To do this it moves such table list element to the head
of the global table list. If this table happens to be last directly-used
table for the statement, query_tables_own_last marker is pointing to it.
Since this marker was not updated when table list element was moved we
ended up with all tables except the first table separated by it as if
they were not directly used by statement (i.e. belonged to prelocked
tables list).
This fix changes code of LEX::first_lists_tables_same() to update
query_tables_own_last marker in cases when it points to the table
being moved. It is set to the table which precedes table being moved
in this case.
* only copy args[0] to args[2] after fix_fields (when all item
substitutions have already happened)
* change QT_ITEM_FUNC_NULLIF_TO_CASE (that allows to print NULLIF
as CASE) to QT_ITEM_ORIGINAL_FUNC_NULLIF (that prohibits it).
So that NULLIF-to-CASE is allowed by default and only disabled
explicitly for SHOW VIEW|FUNCTION|PROCEDURE and mysql_make_view.
By default it is allowed (in particular in error messages and
debug output, that can happen anytime before or after optimizer).
Problem:
At the end of first execution select_lex->prep_where is pointing to
a runtime created object (temporary table field). As a result
server exits trying to access a invalid pointer during second
execution.
Analysis:
While optimizing the join conditions for the query, after the
permanent transformation, optimizer makes a copy of the new
where conditions in select_lex->prep_where. "prep_where" is what
is used as the "where condition" for the query at the start of execution.
W.r.t the query in question, "where" condition is actually pointing
to a field in the temporary table. As a result, for the second
execution the pointer is no more valid resulting in server exit.
Fix:
At the end of the first execution, select_lex->where will have the
original item of the where condition.
Make prep_where the new place where the original item of select->where
has to be rolled back.
Fixed in 5.7 with the wl#7082 - Move permanent transformations from
JOIN::optimize to JOIN::prepare
Patch for 5.5 includes the following backports from 5.6:
Bugfix for Bug12603141 - This makes the first execute statement in the testcase
pass in 5.5
However it was noted later in in Bug16163596 that the above bugfix needed to
be modified. Although Bug16163596 is reproducible only with changes done for
Bug12582849, we have decided include the fix.
Considering that Bug12582849 is related to Bug12603141, the fix is
also included here. However this results in Bug16317817, Bug16317685,
Bug16739050. So fix for the above three bugs is also part of this patch.
When CHANGE MASTER was executed as a PS, its attributes were wrongly
getting reset toward the end of PREPARE. As a result, the subsequent
executions had no effect. Fixed by making sure that the CHANGE MASTER
attributes are preserved during the lifetime of the PS.
When CHANGE MASTER was executed as a PS, its attributes were wrongly
getting reset toward the end of PREPARE. As a result, the subsequent
executions had no effect. Fixed by making sure that the CHANGE MASTER
attributes are preserved during the lifetime of the PS.
- Part 3: Adding mem_root to push_back() and push_front()
Other things:
- Added THD as an argument to some partition functions.
- Added memory overflow checking for XML tag's in read_xml()
This is MDEV-7601, including it's sub tasks MDEV-7594, MDEV-7555, MDEV-7590, MDEV-7581, MDEV-7589
The problem was that select_lex->non_agg_fields was not properly reset for re-execution and this caused an overwrite of a random memory position.
The fix was move non_agg_fields from select_lext to JOIN, which is properly reset.
remove the code that checks for correct options for
for CHECK/REPAIR VIEW. Rewrite the grammar for the parser
to check that. This changes error messages as
-ERROR 42000: You have an error ... near '' at line 1
+ERROR 42000: You have an error ... near 'quick' at line 1
To make st_select_lex::master_unit() inlinable:
- moved it's definition to sql_lex.h
- removed base class virtual master_unit() declaration since this method is
specific to st_select_lex
Overhead change:
st_select_lex::master_unit() 0.17% -> out of radar
execute_sqlcom_select() 0.13% -> 0.12%
JOIN::save_explain_data_intern() 0.27% -> 0.23%
JOIN::optimize_inner() 0.76% -> 0.72%
JOIN::exec_inner() 0.30% -> 0.24%
JOIN::prepare() 0.30% -> 0.29%
JOIN::optimize() 0.05% -> 0.05%
Part 1: first 2 cases of valgrind complain. context_analysis_only can be used on non-started LEX (opening tables)
obviouse fixes in DBUG and is_lex_started assignment.
sql_alloc() has additional costs compared to direct mem_root allocation:
- function call: it is defined in a separate translation unit and can't be
inlined
- it needs to call pthread_getspecific() to get THD::mem_root
It is called dozens of times implicitely at least by:
- List<>::push_back()
- List<>::push_front()
- new (for Sql_alloc derived classes)
- sql_memdup()
Replaced lots of implicit sql_alloc() calls with direct mem_root allocation,
passing through THD pointer whenever it is needed.
Number of sql_alloc() calls reduced 345 -> 41 per OLTP RO transaction.
pthread_getspecific() overhead dropped 0.76 -> 0.59
sql_alloc() overhed dropped 0.25 -> 0.06
delete_dynamic() was called 9-11x per OLTP RO query + 3x per BEGIN/COMMIT.
3 calls were performed by LEX_MASTER_INFO. Added condition to call those only
for CHANGE MASTER.
1 call was performed by lock_table_names()/Hash_set/my_hash_free(). Hash_set was
supposed to be used for DDL and LOCK TABLES to gather database names, while it
was initialized/freed for DML too. In fact Hash_set didn't do any useful job
here. Hash_set was removed and MDL requests are now added directly to the list.
The rest 5-7 calls are done by optimizer, mostly by Explain_query and friends.
Since dynamic arrays are used in most cases, they can hardly be optimized.
my_hash_free() overhead dropped 0.02 -> out of radar.
delete_dynamic() overhead dropped 0.12 -> 0.04.
