The loop that was looping over subqueries' references to outer field used a
local boolean variable to tell whether the field was grouped or not. But the
implementor failed to reset the variable after each iteration. Thus a field
that was not directly aggregated appeared to be.
Fixed by resetting the variable upon each new iteration.
This bug extends the fix for LP BUG#715027 to cover one
more case of an Item being transformed, and its property
Item::with_subselect not being updated because
quick_fix_fields doesn't recalculate any properties.
Analysis:
Before calling:
write_record= (select->skip_record(thd) > 0);
the function find_all_keys needs to restore the original read/write
sets of the table that is sorted if the condition select->cond
contains a subquery.
This didn't happen in this test case because the flag "with_subselect"
was not set properly for select->cond.
The reason for the flag not being set properly, was that this condition
was rewritten by add_cond_and_fix() inside make_join_select() by:
/* Add conditions added by add_not_null_conds(). */
if (tab->select_cond)
add_cond_and_fix(thd, &tmp, tab->select_cond);
However, the function add_cond_and_fix() called the shortcut method
Item::quick_fix_field() that didn't update the "with_subselect"
property.
Solution:
Call the complete Item::fix_fields() to update all Item properties,
including "with_subselect".
Analysis:
The crash in EXPLAIN resulted from an attempt to print the
name of the internal temporary table created to compute
distinct for the innermost subquery of the test case.
Such tables do not have a corresponding TABLE_LIST (table
reference), hence the crash. The reason for this was that
the subquery was executed as part of constant condition
evaluation before EXPLAIN attempts to print the table name.
During the subquery execution, the subquery JOIN_TAB and
its table are substituted by a temporary table in
make_simple_join.
Solution:
Similar to the analogous case for other Items than the
IS NULL function, do not evaluate expensive constant
conditions.
Also fix bug#59110: Memory leak of QUICK_SELECT_I allocated memory.
Includes Jørgen Lølands review comments.
Root cause of these bugs are that test_if_skip_sort_order() decided to
revert the 'skip_sort_order' descision (and use filesort) after the
query plan has been updated to reflect a 'skip' of the sort order.
This might happen in 'check_reverse_order:' if we have a
select->quick which could not be made descending by appending
a QUICK_SELECT_DESC. ().
The original 'save_quick' was then restored after the QEP has been modified,
which caused:
- An incorrect 'precomputed_group_by= TRUE' may have been set,
and not reverted, as part of the already modifified QEP (Bug#59308)
- A 'select->quick' might have been created which we fail to delete (bug#59110).
This fix is a refactorication of test_if_skip_sort_order() where all logic
related to modification of QEP (controlled by argument 'bool no_changes'), is
moved to the end of test_if_skip_sort_order(), and done after *all* 'test_if_skip'
checks has been performed - including the 'check_reverse_order:' checks.
The refactorication above contains now intentional changes to the logic which
has been moved to the end of the function.
Furthermore, a smaller part of the fix address the handling of the
select->quick objects which may already exists when we call
'test_if_skip_sort_order()' (save_quick) -and
new select->quick's created during test_if_skip_sort_order():
- Before new select->quick may be created by calling ::test_quick_select(), we
set 'select->quick= 0' to avoid that ::test_quick_select() prematurely
delete the save_quick's. (After this call we may have both a 'save_quick'
and 'select->quick')
- All returns from ::test_if_skip_sort_order() where we may have both a
'save_quick' and a 'select->quick' has been changed to goto's to the
exit points 'skiped_sort_order:' or 'need_filesort:' where we
decide which of the QUICK_SELECT's to keep, and delete the other.
with the test case added by this patch.
The bug cannot be reproduced with the same test case for the main
5.3 tree because the backported fix for bug 59696 masks the
problem that causes the crash in the mentioned test case. It's not
clear weather this fix masks this problem in all possible cases.
Anyway the patch for bug 698882 introduced some inconsistent data
structures that could contain indirect references to deleted object.
It happened when two Item_equal objects were merged and the Item_field
list of the second object was joined to such list of the first object.
This operation required adjustment of the backward pointers in
Item fields from the joined list. However the adjustment was missing
and this caused crashes in the tree for mwl#128.
Now the backward pointers are set only when Item_equal items are
completely built and are not changed anymore.
Root cause for this bug is that the optimizer try to detect&
optimize the special case:
'<field> BETWEEN c1 AND c1' and handle this as the condition '<field> = c1'
This was implemented inside add_key_field(.. *field, *value[]...)
which assumed field to refer key Field, and value[] to refer a [low...high]
constant pair. value[0] and value[1] was then compared for equality.
In a 'normal' BETWEEN condition of the form '<field> BETWEEN val1 and val2' the
BETWEEN operation is represented with an argementlist containing the
values [<field>, val1, val2] - add_key_field() is then called with
parameters field=<field>, *value=val1.
However, if the BETWEEN predicate specified:
1) '<const1> BETWEEN<const2> AND<field>
the 'field' and 'value' arguments to add_key_field() had to be swapped.
This was implemented by trying to cheat add_key_field() to handle it like:
2) '<const1> GE<const2> AND<const1> LE<field>'
As we didn't really replace the BETWEEN operation with 'ge' and 'le',
add_key_field() still handled it as a 'BETWEEN' and compared the (swapped)
arguments<const1> and<const2> for equality. If they was equal, the
condition 1) was incorrectly 'optimized' to:
3) '<field> EQ <const1>'
This fix moves this optimization of '<field> BETWEEN c1 AND c1' into
add_key_fields() which then calls add_key_equal_fields() to collect
key equality / comparison for the key fields in the BETWEEN condition.
This was another bug in the patch for bug 698882. The new
code from this patch did not ensured that substitutions
of fields for best equal fields were performed on all
AND-OR levels. As a result substitutions for best fields
in some predicates that had been used by the range optimizer
were not actually performed while range plans could employ
these substitutions. This could lead to inconsistent data
structures and ultimately to a crash.
The bug was in the code of the patch fixing bug 698882.
With improper casting the method store_key_field::change_source_field
was called for the elements of the array TABLE_REF::key_copy that
were either of a different type or not allocated at all. This caused
crashes in some queries.
- fixed incorrect query plans that resulted from emptying the
keyuse array with the access methods of the non-modified query
plan.
- fixed compiler warning.
sql/item.cc:
Wrapper added.
sql/item.h:
Wrapper added.
sql/mysql_priv.h:
Wrap function added.
sql/sql_base.cc:
Wrap function added.
Fix of problem with WHERE consist of alone outer reference field by wrapping it.
sql/sql_select.cc:
Fix of problem with HAVING consist of alone outer reference field by wrapping it.
Added logging of all possible fatal table errors if --log-warnings set to > 1
mysql-test/extra/rpl_tests/rpl_EE_err.test:
Safety fix
mysql-test/extra/rpl_tests/rpl_row_basic.test:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/r/archive.result:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/r/csv.result:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/maria/r/maria-autozerofill.result:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/maria/t/maria-autozerofill.test:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/maria/t/maria-recover.test:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/parts/t/partition_recover_myisam.test:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/rpl/r/rpl_bug38694.result:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/rpl/r/rpl_idempotency.result:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/rpl/r/rpl_ignore_table.result:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/rpl/r/rpl_row_basic_11bugs.result:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/rpl/r/rpl_row_conflicts.result:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/rpl/r/rpl_temporary_errors.result:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/rpl/t/rpl_bug38694.test:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/rpl/t/rpl_idempotency.test:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/rpl/t/rpl_ignore_table.test:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/rpl/t/rpl_row_basic_11bugs.test:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/rpl/t/rpl_row_conflicts.test:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/suite/rpl/t/rpl_temporary_errors.test:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/t/archive.test:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
mysql-test/t/csv.test:
Added suppression of possible error message (so that one can run test with --log-warnings=2)
sql/handler.cc:
If running with --assert-of-crashed-table or --log-warnings > 1 then print engine error to log
sql/sql_select.cc:
Disable not initialized warning from gcc
strings/Makefile.am:
Fixed compiler error on Solaris 10 (duplicate strmov() function)
Analysis:
Close to its end JOIN::optimize() assigns having to tmp_having, and
sets the having clause to NULL:
tmp_having= having;
if (select_options & SELECT_DESCRIBE)
{
error= 0;
DBUG_RETURN(0);
}
having= 0;
At the same time, this query detects an empty result set, and calls
return_zero_rows(), which checks the HAVING clause as follows:
if (having && having->val_int() == 0)
send_row=0;
However having has been already set to NULL, so return_zero_rows
doesn't check the having clause, hence the wrong result.
Solution:
Check join->tmp_having in addition to join->having.
There is no additional test case, because the failure was in
the current regression test.
Aria and MyISAM in create_internal_tmp_table_from_heap()
(safe, as duplicates are impossible).
This gives a HUGE speed boost!
sql/opt_subselect.cc:
Fixed problem with wrong recinfo in create_duplicate_weedout_tmp_tabl()
Tagged the table with 'no_rows' so that when we create the table on disk,
we only store the index data. This gave us a major speedup!
sql/sql_select.cc:
create_tmp_table_from_heap() now uses bulk_insert + repair_by_sort
when creating Aria/MyISAM tables from HEAP tables.
This gives a HUGE speed boost!
storage/maria/ha_maria.cc:
Extended bulk_insert() to recreate UNIQUE keys for
internal temporary tables
storage/maria/ma_open.c:
Initialize m_info->lock.type properly for temporarly tables
(needed for start_bulk_insert())
storage/maria/ma_write.c:
Don't check uniques that are disabled
storage/myisam/ha_myisam.cc:
Extended bulk_insert() to recreate UNIQUE keys for
internal temporary tables.
This will also enable us in the future to collect statistics for
writes to internal tmp tables.
sql/handler.h:
Added ha_write_tmp_row()
sql/opt_subselect.cc:
ha_write_row -> ha_write_tmp_row
sql/sql_class.h:
Added ha_write_tmp_row()
sql/sql_select.cc:
ha_write_row -> ha_write_tmp_row
This makes the keys smaller (no row pointer) and gives us proper errors if we
use the table wrongly.
sql/sql_select.cc:
Use NO_RECORD for tables that doesn't need row data.
storage/maria/Makefile.am:
Added ma_norec.c
storage/maria/ma_check.c:
Added support for NO_RECORD record format (don't store any row data)
storage/maria/ma_norec.c:
Added support for NO_RECORD record format
storage/maria/ma_open.c:
Added support for NO_RECORD record format
storage/maria/ma_search.c:
Added support for 0 size row pointers (used with NO_RECORD)
storage/maria/ma_test1.c:
Added testing of NO_RECORD record format.
storage/maria/maria_chk.c:
Added support for NO_RECORD
storage/maria/maria_def.h:
Added support for NO_RECORD
storage/maria/unittest/ma_test_all-t:
Added testing of NO_RECORD record format
Made sure that the optimal fields are used by TABLE_REF objects
when building index access keys to joined tables.
Fixed a bug in the template function that sorts the elements of
a list using the bubble sort algorithm. The bug caused poor
performance of the function. Also added an optimization that
skips comparison with the most heavy elements that has been
already properly placed in the list.
Made the comparison of the fields belonging to the same Item_equal
more granular: fields belonging to the same table are also ordered
according to some rules.
An assertion failure was triggered for a 6-way join query that uses two
join buffers.
The failure happened because every call of the function flush_cached_records()
saved and restored status of all tables before the table join_tab. It
must do it only for those of them that follow the last table that uses
a join buffer.
Date: Mon, 01 Nov 2010 15:15:25 -0000
3272 Roy Lyseng 2010-11-01
Bug#52068: Optimizer generates invalid semijoin materialization plan
When MaterializeScan semijoin strategy was used and there were one
or more outer dependent tables before the semijoin tables, the scan
over the materialized table was not properly reset for each row of
the prefix outer tables.
Example: suppose we have a join order:
ot1 SJ-Mat-Scan(it2 it3) ot4
Notice that this is called a MaterializeScan, even though there is an
outer table ahead of the materialized tables. Usually a MaterializeScan
has the outer tables after the materialized table, but this is
a special (but legal) case with outer dependent tables both before and
after the materialized table.
For each qualifying row from ot1, a new scan over the materialized
table must be set up. The code failed to do that, so all scans after
the first one returned zero rows from the materialized table.
