- "Using MRR" is no longer shown with range access.
- Instead, both range and BKA accesses will show one of the following:
= "Rowid-ordered scan"
= "Key-ordered scan"
= "Key-ordered Rowid-ordered scan"
depending on whether DS-MRR implementation will do scan keys in order, rowids in order,
or both.
- The patch also introduces a way for other storage engines/MRR implementations to
pass information to EXPLAIN output about the properties of employed MRR scans.
- put the code that sets HA_NULL_PART bit back
- Fix test_if_ref/part_of_refkey() so that
= NULL-ability of lookup columns does not prevent the equality
from being removed (we now have early/late NULLs filtering which
will filter out NULL values)
= equality is not removed if it is ref_or_null access, and the value
of the lookup column can alternate between the lookup value and NULL.
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.
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.
- Fixed problem with oqgraph and 'make dist'
Note that after this merge we have a problem show in join_outer where we examine too many rows in one specific case (related to BUG#57024).
This will be fixed when mwl#128 is merged into 5.3.
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.
ORDER BY computed col
GROUP BY implies ORDER BY in the MySQL dialect of SQL. Therefore, when an
index on the first table in the query is used, and that index satisfies
ordering according to the GROUP BY clause, the query optimizer estimates the
number of tuples that need to be read from this index. If there is a LIMIT
clause, table statistics on tables following this 'sort table' are employed.
There may be a separate ORDER BY clause however, which mandates reading the
whole 'sort table' anyway. But the previous estimate was left untouched.
Fixed by removing the estimate from EXPLAIN output if GROUP BY is used in
conjunction with an ORDER BY clause that mandates using a temporary table.
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.
Part 2 :
There was a special optimization on the ref access method for
ORDER BY ... DESC that was set without actually looking on the type of the
selected index for ORDER BY.
Fixed the SELECT ... ORDER BY .. DESC (it uses a different code path compared
to the ASC that has been fixed with the previous fix).
values
We should re-set the access method functions when changing the access
method when switching to another index to avoid sorting.
Fixed by doing a little re-engineering : encapsulating all the function
assignment into a special function and calling it when flipping the
indexes.
buffering is used
FORCE INDEX FOR ORDER BY now prevents the optimizer from
using join buffering. As a result the optimizer can use
indexed access on the first table and doesn't need to
sort the complete resultset at the end of the statement.
Problem 1:
When the 'Using index' optimization is used, the optimizer may still - after
cost-based optimization - decide to use another index in order to avoid using
a temporary table. But when this happens, the flag to the storage engine to
read index only (not table) was still set. Fixed by resetting the flag in the
storage engine and TABLE structure in the above scenario, unless the new index
allows for the same optimization.
Problem 2:
When a 'ref' access method was employed by cost-based optimizer, (when the column
is non-NULLable), it was assumed that it needed no initialization if 'quick' access
methods (since they are based on range scan). When ORDER BY optimization overrides
the decision, however, it expects to have this initialized and hence crashes.
Fixed in 5.1 (was fixed in 6.0 already) by initializing 'quick' even when there's
'ref' access.
mysql-test/r/order_by.result:
Bug#46454: Test result.
mysql-test/t/order_by.test:
Bug#46454: Test case.
sql/sql_select.cc:
Bug#46454:
Problem 1 fixed in make_join_select()
Problem 2 fixed in test_if_skip_sort_order()
sql/table.h:
Bug#46454: Added comment to field.
Server crashed during a sort order optimization
of a dependent subquery:
SELECT
(SELECT t1.a FROM t1, t2
WHERE t1.a = t2.b AND t2.a = t3.c
ORDER BY t1.a)
FROM t3;
Bitmap of tables, that the reference to outer table
column uses, in addition to the regular table bit
has the OUTER_REF_TABLE_BIT bit set.
The only_eq_ref_tables function traverses this map
bit by bit simultaneously with join->map2table list.
Obviously join->map2table never contains an entry
for the OUTER_REF_TABLE_BIT pseudo-table, so the
server crashed there.
The only_eq_ref_tables function has been modified
to traverse regular table bits only like the
update_depend_map function (resetting of the
OUTER_REF_TABLE_BIT there is enough, but
resetting of the whole set of PSEUDO_TABLE_BITS
is used there for sure).
mysql-test/r/order_by.result:
Added test case for bug #39844.
mysql-test/t/order_by.test:
Added test case for bug #39844.
sql/sql_select.cc:
Bug #39844: Query Crash Mysql Server 5.0.67
The only_eq_ref_tables function has been modified
to traverse regular table bits only like the
update_depend_map function (resetting of the
OUTER_REF_TABLE_BIT there is enough, but
resetting of the whole set of PSEUDO_TABLE_BITS
is used there for sure).
The function test_if_skip_sort_order ignored any covering index used for ref
access of a table in a query with ORDER BY if this index was incompatible
with the ORDER BY list and there was another covering index compatible with
this list.
As a result sub-optimal execution plans were chosen for some queries with
ORDER BY clause.
mysql-test/r/distinct.result:
Adjusted results after the fix for bug#35844.
mysql-test/r/order_by.result:
Added a test case for bug#35844.
mysql-test/t/order_by.test:
Added a test case for bug#35844.
The code for executing indexed ORDER BY was not setting all the
internal fields correctly when selecting to execute ORDER BY over
and index.
Fixed by change the access method to one that will use the
quick indexed access if one is selected while selecting indexed
ORDER BY.
mysql-test/r/order_by.result:
Bug #35206: test case
mysql-test/t/order_by.test:
Bug #35206: test case
sql/sql_select.cc:
Bug #35206: Change the access method when selecting a
quick indexed access.
The out of memory error was thrown when the sort buffer size were too small.
This led to a user confusion.
Now filesort throws the error message about sort buffer being too small.
mysql-test/t/order_by.test:
Added a test case for the bug#31590: Wrong error message on sort buffer being too small.
mysql-test/r/order_by.result:
Added a test case for the bug#31590: Wrong error message on sort buffer being too small.
sql/filesort.cc:
Bug#31590: Wrong error message on sort buffer being too small.
Now filesort throws the error message about sort buffer being too small
instead of out of memory error.
The optimizer takes different execution paths during EXPLAIN than SELECT,
this fix relates only to EXPLAIN, hence no behavior changes.
The test of sort keys for ORDER BY was prohibited from considering keys
that were mentioned in IGNORE KEYS FOR ORDER BY. This led to two
inconsistencies: One was that IGNORE INDEX FOR GROUP BY and
IGNORE INDEX FOR ORDER BY gave apparently different EXPLAINs; the latter
erroneously claimed to do filesort. The second inconsistency
is that the test of sort keys is called twice, finding a sort key the first
time but not the second time, leading to the mentioned filesort.
Fixed by making the test of sort keys consider all enabled
keys on the table. This test rejects keys that are not covering, and for
covering keys the hint should be ignored anyway.
mysql-test/r/group_by.result:
Bug#30665: Changed test result. The plan gets more efficient here.
The output is included in order to show that it is still correct.
mysql-test/r/order_by.result:
Bug#30665: Test result
mysql-test/t/group_by.test:
Bug#30665: Changed test case to show correctness of changed plan
mysql-test/t/order_by.test:
Bug#30665: Test case
sql/sql_select.cc:
Bug#30665:
- the fix: Give test_if_skip_sort_order all keys not the subset of non-disabled keys.
- Added comment to test_if_skip_sort_order
This patch adds cost estimation for the queries with ORDER BY / GROUP BY
and LIMIT.
If there was a ref/range access to the table whose rows were required
to be ordered in the result set the optimizer always employed this access
though a scan by a different index that was compatible with the required
order could be cheaper to produce the first L rows of the result set.
Now for such queries the optimizer makes a choice between the cheapest
ref/range accesses not compatible with the given order and index scans
compatible with it.
mysql-test/r/distinct.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/endspace.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/group_by.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/group_min_max.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/innodb.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/innodb_mysql.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/merge.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/order_by.result:
Added a test case for bug #28404.
mysql-test/r/select_found.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/r/subselect.result:
Adjusted results for test cases affected fy the fix for bug #28404.
mysql-test/t/distinct.test:
Changed a test case after adding the fix for bug #28404.
mysql-test/t/order_by.test:
Added a test case for bug #28404.
sql/sql_select.cc:
Fixed bug#28404.
This patch adds cost estimation for the queries with ORDER BY / GROUP BY
and LIMIT.
Now for such queries the optimizer makes a choice between the cheapest
ref/range accesses not compatible with the given order and index scans
compatible with it.
Modified the function test_if_skip_sort_order to make the above mentioned
choice cost based.
sql/sql_select.h:
Fixed bug#28404.
This patch adds cost estimation for the queries with ORDER BY / GROUP BY
and LIMIT.
Added a new field fot the JOIN_TAB structure.
into mysql.com:/d2/hf/mrg/mysql-5.1-opt
mysql-test/r/order_by.result:
Auto merged
mysql-test/r/type_set.result:
Auto merged
mysql-test/t/order_by.test:
Auto merged
sql/field.cc:
Auto merged
sql/item_cmpfunc.cc:
Auto merged
sql/item_cmpfunc.h:
Auto merged
sql/sql_select.cc:
Auto merged
sql/sql_table.cc:
Auto merged
IN/BETWEEN predicates in sorting expressions.
Wrong results may occur when the select list contains an expression
with IN/BETWEEN predicate that differs from a sorting expression by
an additional NOT only.
Added the method Item_func_opt_neg::eq to compare correctly expressions
containing [NOT] IN/BETWEEN.
The eq method inherited from the Item_func returns TRUE when comparing
'a IN (1,2)' with 'a NOT IN (1,2)' that is not, of course, correct.
mysql-test/r/order_by.result:
Added a test case for bug #27532.
mysql-test/t/order_by.test:
Added a test case for bug #27532.
sql/item_cmpfunc.cc:
Fixed bug #27532.
Added the method Item_func_opt_neg::eq to compare correctly expressions
containing [NOT] IN/BETWEEN.
The eq method inherited from the Item_func returns TRUE when comparing
'a IN (1,2)' with 'a NOT IN (1,2)' that is not, of course, correct.
sql/item_cmpfunc.h:
Added the method Item_func_opt_neg::eq to compare correctly expressions
containing [NOT] IN/BETWEEN.
The eq method inherited from the Item_func returns TRUE when comparing
'a IN (1,2)' with 'a NOT IN (1,2)' that is not, of course, correct.
into mysql.com:/home/hf/work/mrg/mysql-5.1-opt
mysql-test/r/order_by.result:
Auto merged
mysql-test/r/subselect.result:
Auto merged
mysql-test/t/order_by.test:
Auto merged
mysql-test/t/sp.test:
Auto merged
sql/item.cc:
Auto merged
sql/item_cmpfunc.cc:
Auto merged
sql/item_cmpfunc.h:
Auto merged
sql/item_func.cc:
Auto merged
sql/mysql_priv.h:
Auto merged
sql/sql_base.cc:
Auto merged
sql/sql_insert.cc:
Auto merged
sql/sql_lex.cc:
Auto merged
sql/sql_lex.h:
Auto merged
sql/sql_load.cc:
Auto merged
sql/sql_parse.cc:
Auto merged
sql/sql_select.cc:
Auto merged
sql/sql_update.cc:
Auto merged
mysql-test/r/func_str.result:
merging
mysql-test/r/sp.result:
merging
mysql-test/r/view.result:
merging
mysql-test/t/func_str.test:
merging
mysql-test/t/view.test:
merging
into mysql.com:/home/hf/work/mrg/mysql-5.0-opt
mysql-test/r/order_by.result:
Auto merged
mysql-test/r/subselect.result:
Auto merged
mysql-test/t/order_by.test:
Auto merged
mysql-test/t/sp.test:
Auto merged
sql/item.cc:
Auto merged
sql/item_cmpfunc.cc:
Auto merged
sql/item_cmpfunc.h:
Auto merged
sql/item_func.cc:
Auto merged
sql/mysql_priv.h:
Auto merged
sql/sql_base.cc:
Auto merged
sql/sql_insert.cc:
Auto merged
sql/sql_lex.cc:
Auto merged
sql/sql_lex.h:
Auto merged
sql/sql_load.cc:
Auto merged
sql/sql_parse.cc:
Auto merged
sql/sql_select.cc:
Auto merged
sql/sql_update.cc:
Auto merged
mysql-test/r/func_str.result:
merging
mysql-test/r/sp.result:
merging
mysql-test/r/view.result:
merging
mysql-test/t/func_str.test:
merging
mysql-test/t/view.test:
merging
into mysql.com:/home/hf/work/mrg/mysql-5.1-opt
BUILD/check-cpu:
Auto merged
mysql-test/r/explain.result:
Auto merged
mysql-test/r/func_str.result:
Auto merged
mysql-test/r/func_test.result:
Auto merged
mysql-test/r/subselect.result:
Auto merged
mysql-test/r/update.result:
Auto merged
mysql-test/r/view.result:
Auto merged
mysql-test/t/explain.test:
Auto merged
mysql-test/t/func_str.test:
Auto merged
mysql-test/t/sp.test:
Auto merged
sql/item.cc:
Auto merged
sql/item.h:
Auto merged
sql/item_cmpfunc.cc:
Auto merged
sql/item_func.cc:
Auto merged
sql/item_strfunc.h:
Auto merged
sql/sql_base.cc:
Auto merged
sql/sql_delete.cc:
Auto merged
sql/sql_insert.cc:
Auto merged
sql/sql_lex.cc:
Auto merged
sql/sql_lex.h:
Auto merged
sql/sql_load.cc:
Auto merged
sql/sql_parse.cc:
Auto merged
sql/sql_select.h:
Auto merged
sql/sql_update.cc:
Auto merged
mysql-test/r/func_in.result:
SCCS merged
mysql-test/r/order_by.result:
SCCS merged
mysql-test/r/sp.result:
merging
mysql-test/t/func_in.test:
SCCS merged
mysql-test/t/order_by.test:
SCCS merged
mysql-test/t/view.test:
merging
sql/item_cmpfunc.h:
merging
sql/mysql_priv.h:
merging
sql/sql_select.cc:
SCCS merged
DATE/DATETIME values are out of the currently supported
4 basic value types (INT,STRING,REAL and DECIMAL).
So expressions (not fields) of compile type DATE/DATETIME are
generally considered as STRING values. This is not so
when they are compared : then they are compared as
INTEGER values.
But the rule for comparison as INTEGERS must be checked
explicitly each time when a comparison is to be performed.
filesort is one such place. However there the check was
not done and hence the expressions (not fields) of type
DATE/DATETIME were sorted by their string representation.
Fixed to compare them as INTEGER values for filesort.
mysql-test/r/order_by.result:
Bug #26672: test case
mysql-test/t/order_by.test:
Bug #26672: test case
sql/filesort.cc:
Bug #26672: sort dates/times as integers
Functions over sum functions wasn't set up correctly for the ORDER BY clause
which leads to a wrong order of the result set.
The split_sum_func() function is called now for each ORDER BY item that
contains a sum function to set it up correctly.
mysql-test/t/order_by.test:
Added a test case for bug#25376: Incomplete setup of ORDER BY clause results in a wrong result.
mysql-test/r/order_by.result:
Added a test case for bug#25376: Incomplete setup of ORDER BY clause results in a wrong result.
sql/sql_select.cc:
Bug#25376: Incomplete setup of ORDER BY clause results in a wrong result.
The split_sum_func() function is called now for each ORDER BY item that
contains a sum function to set it up correctly.
into calliope.local.cmiller:/Volumes/Source/src/mysql-5.1-maint
mysql-test/r/order_by.result:
Auto merged
mysql-test/t/order_by.test:
Auto merged
sql/item.cc:
Auto merged
sql/mysql_priv.h:
Auto merged
"update existingtable set anycolumn=nonexisting order by nonexisting" would crash
the server.
Though we would find the reference to a field, that doesn't mean we can then use
it to set some values. It could be a reference to another field. If it is NULL,
don't try to use it to set values in the Item_field and instead return an error.
Over the previous patch, this signals an error at the location of the error, rather
than letting the subsequent deref signal it.
mysql-test/r/order_by.result:
Verify that all permutations work.
mysql-test/t/order_by.test:
Verify that all permutations work.
sql/item.cc:
When the field is NULL, don't dereference it when we set_field().
Instead, raise an error.
