plans or wrong results due to the fact that JOIN_CACHE functions
ignored the possibility of interleaving materialized semijoin
tables with tables whose records were stored in join buffers.
This fixes would become mostly unnecessary if the new code of
mwl 90 was merged into 5.3 right now.
Yet the fix the code of optimize_wo_join_buffering was needed
in any case.
Applied the fix for bug #47217 from the mysql-6.0 codebase.
The patch adds not null predicates generated for the left parts
of the equality predicates used for ref accesses. This is done
for such predicates both in where conditions and on conditions.
For the where conditions the not null predicates were generated
but in 5.0/5.1 they actually never were used due to some lame
merge from 4.1 to 5.0. The fix for bug #47217 made these
predicates to be used in the condition pushed to the tables.
Yet only this patch generates not null predicates for equality
predicated from on conditions of outer joins.
This patch introduces a performance regression that can be
observed on a test case from null_key.test. The regression
will disappear after the fix for bug #57024 from mariadb-5.1
is pulled into mariadb-5.3.
The patch contains many changes in the outputs of the EXPLAIN
commands since generated not null predicates are considered as
parts of the conditions pushed to join tables and may add
'Usingwhere' in some rows of EXPLAINs where there used
to be no such comments.
5.3 had
handler::index_only_read_time(uint keynr, double records)
while 5.2 got:
handler::keyread_read_time(uint index, uint ranges, ha_rows rows)
which causes floor()'ing of rows parameter, which makes all further costs different.
union...order by (select... where...)
The problem is mysql is trying to materialize and
cache the scalar sub-queries at JOIN::optimize
even for EXPLAIN where the number of columns is
totally different from what's expected.
Fixed by not executing the scalar subqueries
for EXPLAIN.
on index
'my_decimal' class has two members which can be used to access the
value. The member variable buf (inherited from parent class decimal_t)
is set to member variable buffer so that both are pointing to same value.
Item_copy_decimal::copy() uses memcpy to clone 'my_decimal'. The member
buffer is declared as an array and memcpy results in copying the values
of the array, but the inherited member buf, which should be pointing at
the begining of the array 'buffer' starts pointing to the begining of
buffer in original object (which is being cloned). Further updates on
'my_decimal' updates only the inherited member 'buf' but leaves
buffer unchanged.
Later when the new object (which now holds a inconsistent value) is cloned
again using proper cloning function 'my_decimal2decimal' the buf pointer
is fixed resulting in loss of the current value.
Using my_decimal2decimal instead of memcpy in Item_copy_decimal::copy()
fixed this problem.
mysql-test/r/subselect.result:
Updated result file after addding test case for bug#47904.
mysql-test/t/subselect.test:
Added test case for bug#47904.
sql/item.cc:
Memcopy shouldn't be used to clone my_decimal. Use my_decimal2decimal
instead.
This patch does three things:
- It adds the possibility to force the execution of top-level [NOT] IN
subquery predicates via the IN=>EXISTS transformation. This is done by
setting both optimizer switches partial_match_rowid_merge and
partial_match_table_scan to "off".
- It adjusts all test cases where the complete optimizer_switch is
selected because now we have two more switches.
- For those test cases where the plan changes because of the new available
strategies, we switch off both partial match strategies in order to
force the "old" IN=>EXISTS strategy. This is done because most of these
test cases specifically test bugs in this strategy.
sql/opt_subselect.cc:
Adds the possibility to force the execution of top-level [NOT] IN
subquery predicates via the IN=>EXISTS transformation. This is done by
setting both optimizer switches partial_match_rowid_merge and
partial_match_table_scan to "off".
The problem is that not all column names retrieved from a SELECT
statement can be used as view column names due to length and format
restrictions. The server failed to properly check the conformity
of those automatically generated column names before storing the
final view definition on disk.
Since columns retrieved from a SELECT statement can be anything
ranging from functions to constants values of any format and length,
the solution is to rewrite to a pre-defined format any names that
are not acceptable as a view column name.
The name is rewritten to "Name_exp_%u" where %u translates to the
position of the column. To avoid this conversion scheme, define
explict names for the view columns via the column_list clause.
Also, aliases are now only generated for top level statements.
mysql-test/include/view_alias.inc:
Add test case for Bug#40277
mysql-test/r/compare.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/group_by.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/ps.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/subselect.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/subselect3.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/type_datetime.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/union.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/view.result:
Add test case result for Bug#40277
mysql-test/r/view_alias.result:
Add test case result for Bug#40277
mysql-test/t/view_alias.test:
Add test case for Bug#40277
sql/sql_view.cc:
Check if auto generated column names are conforming. Also, the
make_unique_view_field_name function is not used as it uses the
original name to construct a new one, which does not work if the
name is invalid.
Item_field::print method does not take into
account fields whose values may be null.
The fix is to print 'NULL' if field value is null.
mysql-test/r/explain.result:
test case
mysql-test/r/func_str.result:
result fix
mysql-test/r/having.result:
result fix
mysql-test/r/select.result:
result fix
mysql-test/r/subselect.result:
result fix
mysql-test/r/union.result:
result fix
mysql-test/t/explain.test:
test case
sql/item.cc:
print 'NULL' if field value is null.
subselect_single_select_engine::exec()
When a subquery doesn't need to be evaluated because
it returns only aggregate functions and these aggregates
can be calculated from the metadata about the table it
was not updating all the relevant members of the JOIN
structure to reflect that this is a constant query.
This caused problems to the enclosing subquery
('<> SOME' in the test case above) trying to read some
data about the tables.
Fixed by setting const_tables to the number of tables
when the SELECT is optimized away.
error in the query.
Fixes a leak after materializing a GROUP BY subquery to a
temp table when the subquery has a blob column in the SELECT
list.
Fixed by correctly destructing temporary buffers after doing
the conversion.
error in the query.
Fixes a leak after materializing a GROUP BY subquery to a
temp table when the subquery has a blob column in the SELECT
list.
Fixed by correctly destructing temporary buffers for re-usable
queries
int join_read_key(JOIN_TAB*)
The eq_ref access method TABLE_REF (accessed through
JOIN_TAB) to save state and to track if this is the
first row it finds or not.
This state was not reset on subquery re-execution
causing an assert.
Fixed by resetting the state before the subquery
re-execution.
WL#2474 "Multi Range Read: Change the default MRR implementation to implement new MRR interface"
WL#2475 "Batched range read functions for MyISAM/InnoDb"
"Index condition pushdown for MyISAM/InnoDB"
Igor's fix from sp1r-igor@olga.mysql.com-20080330055902-07614:
There could be observed the following problems:
1. EXPLAIN did not mention pushdown conditions from on expressions in the
'extra' column. As a result if a query had no where conditions pushed
down to a table, but had on conditions pushed to this table the 'extra'
column in the EXPLAIN for the table missed 'using where'.
2. Conditions for ref access were not eliminated from on expressions
though such conditions were eliminated from the where condition.
- Moved some code from innodb_plugin to xtradb, to ensure that all tests runs
- Did changes in pbxt and maria storage engines becasue of changes in thd->query
- Reverted wrong code in sql_table.cc for how ROW_FORMAT is used.
This is a re-commit of Monty's merge to eliminate an extra commit from
MySQL-5.1.42 that was accidentally included in the merge.
This is a merge of the MySQL 5.1.41 clone-off (clone-5.1.41-build). In
case there are any extra changes done before final MySQL 5.1.41
release, these will need to be merged later before MariaDB 5.1.41
release.
having clause...
The fix for bug 46184 was not very complete. It was not covering
views using temporary tables and multiple tables in a FROM clause.
Fixed by reverting the fix for 46184 and making a more general
check that is checking at the right execution stage and for all
of the non-supported cases.
Now PROCEDURE ANALYZE on non-top level SELECT is also forbidden.
Updated the analyse.test and subselect.test accordingly.
The problem was in incorrect handling of predicates involving
NULL as a constant value by the range optimizer.
For example, when creating a SEL_ARG node from a condition of
the form "field < const" (which would normally result in the
"NULL < field < const" SEL_ARG), the special case when "const"
is NULL was not taken into account, so "NULL < field < NULL"
was produced for the "field < NULL" condition.
As a result, SEL_ARG structures of this form could not be
further optimized which in turn could lead to incorrectly
constructed SEL_ARG trees. In particular, code assuming SEL_ARG
structures to always form a sequence of ordered disjoint
intervals could enter an infinite loop under some
circumstances.
Fixed by changing get_mm_leaf() so that for any sargable
predicate except "<=>" involving NULL as a constant, "empty"
SEL_ARG is returned, since such a predicate is always false.
mysql-test/r/partition_pruning.result:
Fixed a broken test case.
mysql-test/r/range.result:
Added a test case for bug #47123.
mysql-test/r/subselect.result:
Fixed a broken test cases.
mysql-test/t/range.test:
Added a test case for bug #47123.
sql/opt_range.cc:
Fixed get_mm_leaf() so that for any sargable
predicate except "<=>" involving NULL as a constant, "empty"
SEL_ARG is returned, since such a predicate is always false.
* Finished Monty and Jani's merge
* Some InnoDB tests still fail (because it's old xtradb code run against
newer testsuite). They are expected to go after mergning with the latest
xtradb.
field references
This error requires a combination of factors :
1. An "impossible where" in the outermost SELECT
2. An aggregate in the outermost SELECT
3. A correlated subquery with a WHERE clause that includes an outer
field reference as a top level WHERE sargable predicate
When JOIN::optimize detects an "impossible WHERE" it will bail out
without doing the rest of the work and initializations. It will not
call make_join_statistics() as well. And make_join_statistics fills
in various structures for each table referenced.
When processing the result of the "impossible WHERE" the query must
send a single row of data if there are aggregate functions in it.
In this case the server marks all the aggregates as having received
no rows and calls the relevant Item::val_xxx() method on the SELECT
list. However if this SELECT list happens to contain a correlated
subquery this subquery is evaluated in a normal evaluation mode.
And if this correlated subquery has a reference to a field from the
outermost "impossible where" SELECT the add_key_fields will mistakenly
consider the outer field reference as a "local" field reference when
looking for sargable predicates.
But since the SELECT where the outer field reference refers to is not
completely initialized due to the "impossible WHERE" in this level
we'll get a NULL pointer reference.
Fixed by making a better condition for discovering if a field is "local"
to the SELECT level being processed.
It's not enough to look for OUTER_REF_TABLE_BIT in this case since
for outer references to constant tables the Item_field::used_tables()
will return 0 regardless of whether the field reference is from the
local SELECT or not.
The crash happens because select_union object is used as result set
for queries which have derived tables.
select_union use temporary table as data storage and if
fields count exceeds 10(count of values for procedure ANALYSE())
then we get a crash on fill_record() function.
mysql-test/r/analyse.result:
test result
mysql-test/r/subselect.result:
result fix
mysql-test/t/analyse.test:
test case
mysql-test/t/subselect.test:
test fix
sql/sql_yacc.yy:
The crash happens because select_union object is used as result set
for queries which have derived tables.
select_union use temporary table as data storage and if
fields count exceeds 10(count of values for procedure ANALYSE())
then we get a crash on fill_record() function.
When during the optimization an item is moved to the upper select
the item's context left unchanged. This caused wrong result in the
PS/SP mode.
The Item_ident::remove_dependence_processor now sets the context
of the select to which the item is moved to.
mysql-test/r/subselect.result:
The test case for the bug#46051 is adjusted.
mysql-test/t/subselect.test:
The test case for the bug#46051 is adjusted.
sql/item.cc:
Bug#46051: Incorrectly market field caused wrong result.
The Item_ident::remove_dependence_processor now sets the context
of the select to which the item is moved to.
In a subselect all fields from outer selects are marked as dependent on
selects they are belong to. In some cases optimizer substitutes it for an
equivalent expression. For example "a_field IN (SELECT outer_field)" is
substituted with "a_field = outer_field". As we moved the outer_field to the
upper select it's not really outer anymore. But it was left marked as outer.
If exists an index over a_field optimizer choose wrong execution plan and thus
return wrong result.
Now the Item_in_subselect::single_value_transformer function removes dependent
marking from fields when a subselect is optimized away.
mysql-test/r/subselect.result:
Added a test case for the bug#46051.
mysql-test/t/subselect.test:
Added a test case for the bug#46051.
sql/item_subselect.cc:
Bug#46051: Incorrectly market field caused wrong result.
Now the Item_in_subselect::single_value_transformer function removes dependent
marking from fields when a subselect is optimized away.
- Make elimination work with aggregate functions. The problem was that aggregate functions
reported all table bits in used_tables(), and that prevented table elimination. Fixed by
making aggregate functions return more correct value from used_tables().
mysql-test/r/ps_11bugs.result:
MWL#17: Table elimination
- Update test results. The difference is because of Item_ref change: outer references to constants
are now recognized as constants, too.
mysql-test/r/subselect.result:
- Update test results. The difference is because of Item_ref change: outer references to constants
are now recognized as constants, too.
mysql-test/r/table_elim.result:
MWL#17: Table elimination
- Check that elimination works in presense of aggreagate functions
mysql-test/t/table_elim.test:
MWL#17: Table elimination
- Check that elimination works in presense of aggreagate functions
sql/item.h:
MWL#17: Table elimination
- Add Item_ref::const_item() which calls (*ref)->const_item(). Before this diff Item_ref used the
default implementation of const_item(){ return used_tables()==0; }. This is no longer true, as
COUNT(*) now has used_tables()==0 but const_item()==FALSE.
sql/item_sum.cc:
MWL#17: Table elimination
- Make Item_sum() and it descendants not to return all bits in used_tables(). This is needed
because otherwise table elimination can't work in presense of aggregate functions
- COUNT(*) now has used_tables()==0 and const_item()==FALSE. Had to change
Item_ref::const_item() to account for this.
sql/item_sum.h:
MWL#17: Table elimination
- Add comments
There were so many changes into mtr (this is the new mtr coming) that I rather
copied mtr from 6.0-main here (at least this one knows how to run Maria tests).
I also fixed suite/maria tests to be accepted by the new mtr.
mysys/thr_mutex.c:
adding DBUG_PRINT here, so that we can locate where the warning is issued.
