If the optimizer switch 'semijoin_with_cache' is set to 'off' then
join cache cannot be used to join inner tables of a semijoin.
Also fixed a bug in the function check_join_cache_usage() that led
to wrong output of the EXPLAIN commands for some test cases.
sql/sql_insert.cc:
CREATE ... IF NOT EXISTS may do nothing, but
it is still not a failure. don't forget to my_ok it.
******
CREATE ... IF NOT EXISTS may do nothing, but
it is still not a failure. don't forget to my_ok it.
sql/sql_table.cc:
small cleanup
******
small cleanup
of the 5.3 code line after a merge with 5.2 on 2010-10-28
in order not to allow the cost to access a joined table to be equal
to 0 ever.
Expanded data sets for many test cases to get the same execution plans
as before.
semijoin=on,firstmatch=on,loosescan=on
to
semijoin=off,firstmatch=off,loosescan=off
Adjust the testcases:
- Modify subselect*.test and join_cache.test so that all tests
use the same execution paths as before (i.e. optimizations that
are being tested are enabled)
- Let all other test files run with the new default settings (i.e.
with new optimizations disabled)
- Copy subquery testcases from these files into t/subselect_extra.test
which will run them with new optimizations enabled.
- Let advance_sj_state() save the value of JOIN::cur_dups_producing_tables
in POSITION::prefix_dups_producing_tables, and restore_sj_state() restore
it.
Phase 3: Implementation of re-optimization of subqueries with injected predicates
and cost comparison between Materialization and IN->EXISTS strategies.
The commit contains the following known problems:
- The implementation of EXPLAIN has not been re-engineered to reflect the
changes in subquery optimization. EXPLAIN for subqueries is called during
the execute phase, which results in different code paths during JOIN::optimize
and thus in differing EXPLAIN messages for constant/system tables.
- There are some valgrind warnings that need investigation
- Several EXPLAINs with minor differences need to be reconsidered after fixing
the EXPLAIN problem above.
This patch also adds one extra optimizer_switch: 'in_to_exists' for complete
manual control of the subquery execution strategies.
libmysqld/Makefile.am:
The new file added.
mysql-test/r/index_merge_myisam.result:
subquery_cache optimization option added.
mysql-test/r/myisam_mrr.result:
subquery_cache optimization option added.
mysql-test/r/subquery_cache.result:
The subquery cache tests added.
mysql-test/r/subselect3.result:
Subquery cache switched off to avoid changing read statistics.
mysql-test/r/subselect3_jcl6.result:
Subquery cache switched off to avoid changing read statistics.
mysql-test/r/subselect_no_mat.result:
subquery_cache optimization option added.
mysql-test/r/subselect_no_opts.result:
subquery_cache optimization option added.
mysql-test/r/subselect_no_semijoin.result:
subquery_cache optimization option added.
mysql-test/r/subselect_sj.result:
subquery_cache optimization option added.
mysql-test/r/subselect_sj_jcl6.result:
subquery_cache optimization option added.
mysql-test/t/subquery_cache.test:
The subquery cache tests added.
mysql-test/t/subselect3.test:
Subquery cache switched off to avoid changing read statistics.
sql/CMakeLists.txt:
The new file added.
sql/Makefile.am:
The new files added.
sql/item.cc:
Expression cache item (Item_cache_wrapper) added.
Item_ref and Item_field fixed for correct usage of result field and fast resolwing in SP.
sql/item.h:
Expression cache item (Item_cache_wrapper) added.
Item_ref and Item_field fixed for correct usage of result field and fast resolwing in SP.
sql/item_cmpfunc.cc:
Subquery cache added.
sql/item_cmpfunc.h:
Subquery cache added.
sql/item_subselect.cc:
Subquery cache added.
sql/item_subselect.h:
Subquery cache added.
sql/item_sum.cc:
Registration of subquery parameters added.
sql/mysql_priv.h:
subquery_cache optimization option added.
sql/mysqld.cc:
subquery_cache optimization option added.
sql/opt_range.cc:
Fix due to subquery cache.
sql/opt_subselect.cc:
Parameters of the function cahnged.
sql/procedure.h:
.h file guard added.
sql/sql_base.cc:
Registration of subquery parameters added.
sql/sql_class.cc:
Option to allow add indeces to temporary table.
sql/sql_class.h:
Item iterators added.
Option to allow add indeces to temporary table.
sql/sql_expression_cache.cc:
Expression cache for caching subqueries added.
sql/sql_expression_cache.h:
Expression cache for caching subqueries added.
sql/sql_lex.cc:
Registration of subquery parameters added.
sql/sql_lex.h:
Registration of subqueries and subquery parameters added.
sql/sql_select.cc:
Subquery cache added.
sql/sql_select.h:
Subquery cache added.
sql/sql_union.cc:
A new parameter to the function added.
sql/sql_update.cc:
A new parameter to the function added.
sql/table.cc:
Procedures to manage temporarty tables index added.
sql/table.h:
Procedures to manage temporarty tables index added.
storage/maria/ha_maria.cc:
Fix of handler to allow destoy a table in case of error during the table creation.
storage/maria/ha_maria.h:
.h file guard added.
storage/myisam/ha_myisam.cc:
Fix of handler to allow destoy a table in case of error during the table creation.
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".
subquery in the select list
When a dependent subquery with count(distinct <col>) was
evaluated multiple times, the Distinct_Aggregator was reused.
However, the Aggregator was not reset, so when the subquery was
evaluated for the next record in the outer select, old dependent
info was used.
The fix is to clear() the existing aggregator in
Item_sum::set_aggregator(). This ensures that the aggregator is
reevaluated with the new dependent information.
mysql-test/r/subselect3.result:
Added test case for BUG#48920
mysql-test/t/subselect3.test:
Added test case for BUG#48920
sql/item_sum.cc:
If an aggregator exists when Item_sum::set_aggregator() is
called (i.e., set_aggregator is called in a dependent
subquery), the aggregator is reset so that the aggregator is
reevaluated with the dependent information from the outer
record being evaluated.
values return too many records
WHERE clauses with "outer_value_list NOT IN subselect" were
handled incorrectly if the outer value list contained multiple
items where at least one of these could be NULL. The first
outer record with NULL value was handled correctly, but if a
second record with NULL value existed, the optimizer would
choose to reuse the result it got on the last execution of the
subselect. This is incorrect if the outer value list has
multiple items.
The fix is to make Item_in_optimizer::val_int (in
item_cmpfunc.cc) reuse the result of the latest execution
for NULL values only if all values in the outer_value_list
are NULL.
mysql-test/r/subselect3.result:
Added test for BUG#48177
mysql-test/t/subselect3.test:
Added test for BUG#48177
sql/item_cmpfunc.cc:
Make Item_in_optimizer::val_int (in item_cmpfunc.cc) reuse the result of the latest execution for NULL values only if all values in the outer_value_list are NULL.
EXPLAIN EXTENDED of nested query containing a error:
1054 Unknown column '...' in 'field list'
may cause a server crash.
Parse error like described above forces a call to
JOIN::destroy() on malformed subquery.
That JOIN::destroy function closes and frees temporary
tables. However, temporary fields of these tables
may be listed in st_select_lex::group_list of outer
query, and that st_select_lex may not cleanup them
properly. So, after the JOIN::destroy call that
st_select_lex::group_list may have Item_field
objects with dangling pointers to freed temporary
table Field objects. That caused a crash.
mysql-test/r/subselect3.result:
Added test case for bug #37362.
mysql-test/t/subselect3.test:
Added test case for bug #37362.
sql/sql_select.cc:
Bug #37362: Crash in do_field_eq
The JOIN::destroy function has been modified to
cleanup temporary table column items.
messed up
"ROW(...) IN (SELECT ... FROM DUAL)" always returned TRUE.
Item_in_subselect::row_value_transformer rewrites "ROW(...)
IN SELECT" conditions into the "EXISTS (SELECT ... HAVING ...)"
form.
For a subquery from the DUAL pseudotable resulting HAVING
condition is an expression on constant values, so further
transformation with optimize_cond() eliminates this HAVING
condition and resets JOIN::having to NULL.
Then JOIN::exec treated that NULL as an always-true-HAVING
and that caused a bug.
To distinguish an optimized out "HAVING TRUE" clause from
"HAVING FALSE" we already have the JOIN::having_value flag.
However, JOIN::exec() ignored JOIN::having_value as described
above as if it always set to COND_TRUE.
The JOIN::exec method has been modified to take into account
the value of the JOIN::having_value field.
mysql-test/r/subselect3.result:
Added test case for bug #39069.
mysql-test/t/subselect3.test:
Added test case for bug #39069.
sql/sql_select.cc:
Bug #39069: <row constructor> IN <table-subquery> seriously
messed up
The JOIN::exec method has been modified to take into account
the value of the JOIN::having_value field.
Select with a "NULL NOT IN" condition containing complex
subselect from the same table as in the outer select failed
with an assertion.
The failure was caused by a concatenation of circumstances:
1) an inner select was optimized by make_join_statistics to use
the QUICK_RANGE_SELECT access method (that implies an index
scan of the table);
2) a subselect was independent (constant) from the outer select;
3) a condition was pushed down into inner select.
During the evaluation of a constant IN expression an optimizer
temporary changed the access method from index scan to table
scan, but an engine handler was already initialized for index
access by make_join_statistics. That caused an assertion.
Unnecessary index initialization has been removed from
the QUICK_RANGE_SELECT::init method (QUICK_RANGE_SELECT::reset
reinvokes this initialization).
mysql-test/r/subselect3.result:
Added test case for bug #37894.
mysql-test/t/subselect3.test:
Added test case for bug #37894.
sql/opt_range.cc:
Bug #37894: Assertion in init_read_record_seq in handler.h line 1444
Unnecessary index initialization has been removed from
the QUICK_RANGE_SELECT::init method (QUICK_RANGE_SELECT::reset
reinvokes this initialization).
impossible WHERE/HAVING clause
(subselect_single_select_engine::exec).
Allocation and initialization of joined table list t1, t2... of
subqueries like:
NOT IN (SELECT ... FROM t1,t2,... WHERE 0)
is optimized out, however server tries to traverse this list.
mysql-test/r/subselect3.result:
Added test case for bug#36005.
mysql-test/t/subselect3.test:
Added test case for bug#36005.
sql/sql_select.cc:
Fixed bug#36005.
1. JOIN::prepare initializes JOIN::table counter (actually a size
of the JOIN::join_tab array) and sets it to a number of joined tables.
2. The make_join_statistics function (when called from JOIN::optimize)
allocates and fills the JOIN::join_tab array.
However, when optimizing subselect has impossible (definite false)
WHERE or HAVING clause, optimizer skips call to make_join_statistics
and leaves JOIN::join_tab == NULL.
3. subselect_single_select_engine::exec does traversal of the JOIN::join_tab
array and the server dies because array is not allocated but array
counter is greater than 0.
The JOIN::optimize method has been modified to reset the JOIN::table
counter to 0 in cause of impossible WHERE/HAVING clause.
Queries like:
SELECT ROW(1, 2) IN (SELECT t1.a, 2)
FROM t1 GROUP BY t1.a
or
SELECT ROW(1, 2) IN (SELECT t1.a, 2 FROM t2)
FROM t1 GROUP BY t1.a
lead to assertion failure in the
Item_in_subselect::row_value_transformer method in debugging
build, or to unexpected error message in release build:
ERROR 1247 (42S22): Reference '<list ref>' not supported (forward
reference in item list)
Unexpected error message and assertion failure have been
eliminated.
mysql-test/r/subselect3.result:
Added test case for bug #34763.
mysql-test/t/subselect3.test:
Added test case for bug #34763.
sql/item.cc:
Fixed bug #34763.
The Item_ref::fix_fields method has been modified to silently
ignore not fixed outer references: by the definition, those
references should be fixed later by the call to the
fix_inner_refs function.
sql/item_subselect.cc:
Fixed bug #34763.
The Item_in_subselect::row_value_transformer method has been
modified to eliminate assertion failure on not fixed outer
references: by the definition those references are allowed in
this context and should be fixed later by the call to the
fix_inner_refs function.
into bk-internal.mysql.com:/data0/bk/mysql-5.0-opt
mysql-test/r/sp.result:
Auto merged
mysql-test/t/sp.test:
Auto merged
mysql-test/t/strict.test:
Auto merged
mysql-test/t/subselect3.test:
Auto merged
sql/mysqld.cc:
Auto merged
sql/sp_head.cc:
Auto merged
sql/sql_base.cc:
Auto merged
sql/sql_class.h:
Auto merged
sql/sql_table.cc:
Auto merged
sql/sql_update.cc:
Auto merged
sql/sql_view.cc:
Manual merge
mysql-test/r/sp.result:
Update results.
mysql-test/t/mysql.test:
Fix a typo.
mysql-test/t/mysqltest.test:
Fix a typo.
mysql-test/t/order_by.test:
Fix a typo.
mysql-test/t/row.test:
Remove an unsupported command.
mysql-test/t/sp.test:
Fix a typo.
mysql-test/t/subselect3.test:
Fix mysqltest warnings - now it warns when sees some suspicious --
comment
Conversion errors when constructing the condition for an
IN predicates were treated as if the affected column contains
NULL. If such a IN predicate is inside NOT we get wrong
results.
Corrected the handling of conversion errors in an IN predicate
that is resolved by unique_subquery (through
subselect_uniquesubquery_engine).
mysql-test/r/subselect3.result:
Bug#22855: test case
mysql-test/t/subselect3.test:
Bug#22855: test case
sql/item_subselect.cc:
Bug#22855: corrected the handling of conversion errors and
NULL key values in IN predicate that is resolved by index
lookup.
a crash when the left operand of the predicate is evaluated to NULL.
It happens when the rows from the inner tables (tables from the subquery)
are accessed by index methods with key values obtained by evaluation of
the left operand of the subquery predicate. When this predicate is
evaluated to NULL an alternative access with full table scan is used
to check whether the result set returned by the subquery is empty or not.
The crash was due to the fact the info about the access methods used for
regular key values was not properly restored after a switch back from the
full scan access method had occurred.
The patch restores this info properly.
The same problem existed for queries with IN subquery predicates if they
were used not at the top level of the queries.
mysql-test/r/subselect3.result:
Added a test case for bug #28375.
mysql-test/t/subselect3.test:
Added a test case for bug #28375.
sql/item_subselect.cc:
Fixed bug #28375: a query with an NOT IN subquery predicate may cause
a crash when the left operand of the predicate is evaluated to NULL.
It happens when the rows from the inner tables (tables from the subquery)
are accessed by index methods with key values obtained by evaluation of
the left operand of the subquery predicate. When this predicate is
evaluated to NULL an alternative access with full table scan is used
to check whether the result set returned by the subquery is empty or not.
The crash was due to the fact the info about the access methods used for
regular key values was not properly restored after a switch back from the
full scan access method had occurred.
The patch restores this info properly.
sql/sql_select.h:
Fixed bug #28375: a query with an NOT IN subquery predicate may cause
a crash when the left operand of the predicate is evaluated to NULL.
In the JOIN_TAB structure two fields have been added to save info about
index methods used to access the subquery rows. The saved info is used
after a switch back from the alternative full scan access method has
occurred. The full scan is used when the left operand of the subquery
predicate is evaluated to NULL.
conditions when executing an equijoin query with WHERE condition
containing a subquery predicate of the form join_attr NOT IN (SELECT ...).
To resolve a problem of the correct evaluation of the expression
attr NOT IN (SELECT ...)
an array of guards is created to make it possible to filter out some
predicates of the EXISTS subquery into which the original subquery
predicate is transformed, in the cases when a takes the NULL value.
If attr is defined as a field that cannot be NULL than such an array
is not needed and is not created.
However if the field a occurred also an an equijoin predicate t2.a=t1.b
and table t1 is accessed before table t2 then it may happen that the
the EXISTS subquery is pushed down to the condition evaluated just after
table t1 has been accessed. In this case any occurrence of t2.a is
substituted for t1.b. When t1.b takes the value of NULL an attempt is
made to turn on the corresponding guard. This action caused a crash as
no guard array had been created.
Now the code of Item_in_subselect::set_cond_guard_var checks that the guard
array has been created before setting a guard variable on. Otherwise the
method does nothing. It cannot results in returning a row that could be
rejected as the condition t2.a=t1.b will be checked later anyway.
mysql-test/r/subselect3.result:
Added a test case for bug #27870.
mysql-test/t/subselect3.test:
Added a test case for bug #27870.
sql/item_subselect.h:
Fixed bug #27870. The bug that causes crashes manifests itself at some
conditions when executing an equijoin query with WHERE condition
containing a subquery predicate of the form join_attr NOT IN (SELECT ...).
Forced Item_in_subselect::set_cond_guard_var to check that the guard
array has been created before setting a guard variable on. Otherwise the
method does nothing.
The Item_outer_ref class based on the Item_direct_ref class was always used
to represent an outer field. But if the outer select is a grouping one and the
outer field isn't under an aggregate function which is aggregated in that
outer select an Item_ref object should be used to represent such a field.
If the outer select in which the outer field is resolved isn't grouping then
the Item_field class should be used to represent such a field.
This logic also should be used for an outer field resolved through its alias
name.
Now the Item_field::fix_outer_field() uses Item_outer_field objects to
represent aliased and non-aliased outer fields for grouping outer selects
only.
Now the fix_inner_refs() function chooses which class to use to access outer
field - the Item_ref or the Item_direct_ref. An object of the chosen class
substitutes the original field in the Item_outer_ref object.
The direct_ref and the found_in_select_list fields were added to the
Item_outer_ref class.
mysql-test/t/subselect3.test:
Some test cases were corrected after the fix for the bug#27321.
mysql-test/r/subselect3.result:
Some test cases were corrected after the fix for the bug#27321.
mysql-test/t/subselect.test:
Added a test case for the bug#27321: Wrong subquery result in a grouping select.
mysql-test/r/subselect.result:
Added a test case for the bug#27321: Wrong subquery result in a grouping select.
Some test cases were corrected after this fix.
sql/sql_union.cc:
Bug#27321: Wrong subquery result in a grouping select.
Cleanup of the inner_refs_list.
sql/sql_select.cc:
Bug#27321: Wrong subquery result in a grouping select.
Now the fix_inner_refs() function chooses which class to use to access outer
field - the Item_ref or the Item_direct_ref. An object of the chosen class
substitutes the original field in the Item_outer_ref object.
A comment is corrected.
sql/item.cc:
Bug#27321: Wrong subquery result in a grouping select.
Now the Item_field::fix_outer_field() uses Item_outer_field objects to
represent aliased and non-aliased outer fields for grouping outer selects
only.
sql/item.h:
Bug#27321: Wrong subquery result in a grouping select.
The direct_ref and the found_in_select_list fields were added to the
Item_outer_ref class.
To correctly decide which predicates can be evaluated with a given table
the optimizer must know the exact set of tables that a predicate depends
on. If that mask is too wide (refer to non-existing tables) the optimizer
can erroneously skip a predicate.
One such case of wrong table usage mask were the aggregate functions.
The have a all-1 mask (meaning depend on all tables, including non-existent
ones).
Fixed by making a real used_tables mask for the aggregates. The mask is
constructed in the following way :
1. OR the table dependency masks of all the arguments of the aggregate.
2. If all the arguments of the function are from the local name resolution
context and it is evaluated in the same name resolution
context where it is referenced all the tables from that name resolution
context are OR-ed to the dependency mask. This is to denote that an
aggregate function depends on the number of rows it processes.
3. Handle correctly the case of an aggregate function optimization (such that
the aggregate function can be pre-calculated and made a constant).
Made sure that an aggregate function is never a constant (unless subject of a
specific optimization and pre-calculation).
One other flaw was revealed and fixed in the process : references were
not calling the recalculation method for used_tables of their targets.
mysql-test/r/subselect3.result:
Bug #24484: test case
mysql-test/t/subselect3.test:
Bug #24484: test case
sql/item.h:
Bug #24484: Item_ref must update the used tables.
sql/item_sum.cc:
Bug #24484: correct calculation of used_tables for aggregates.
sql/item_sum.h:
Bug #24484: correct calculation of used_tables for aggregates.
sql/opt_range.cc:
Bug #24484: fixed ref resolution in loose index scan
sql/sql_base.cc:
Bug #24484: moved counting of leaf tables inside
setup_tables_and_check_access.
sql/sql_class.h:
Bug #24484: changed table count to more narrow type.
sql/sql_insert.cc:
Bug #24484: moved counting of leaf tables inside
setup_tables_and_check_access. Substract the first
table (and its subtables) of an INSERT statement
from leaf_count.
sql/sql_select.cc:
Bug #24484: correct check for aggregates
Objects of the classes Item_func_is_not_null_test and Item_func_trig_cond
must be transparent for the method Item::split_sum_func2 as these classes
are pure helpers. It means that the method Item::split_sum_func2 should
look at those objects as at pure wrappers.
mysql-test/r/subselect3.result:
Added a test case for bug #24420.
mysql-test/t/subselect3.test:
Added a test case for bug #24420.
- Make the code produce correct result: use an array of triggers to turn on/off equalities for each
compared column. Also turn on/off optimizations based on those equalities.
- Make EXPLAIN output show "Full scan on NULL key" for tables for which we switch between
ref/unique_subquery/index_subquery and ALL access.
- index_subquery engine now has HAVING clause when it is needed, and it is
displayed in EXPLAIN EXTENDED
- Fix incorrect presense of "Using index" for index/unique-based subqueries (BUG#22930)
// bk trigger note: this commit refers to BUG#24127
mysql-test/r/ndb_subquery.result:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
- Updated test results (checked)
mysql-test/r/subselect.result:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
- Updated test results (checked)
mysql-test/r/subselect2.result:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
- Updated test results (checked)
mysql-test/r/subselect3.result:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
- Testcases
mysql-test/t/subselect3.test:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
- Testcases
sql/item_cmpfunc.cc:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
- For row-based IN subqueries, use one flag per each column. Set the flags appropriately before
running the subquery.
sql/item_cmpfunc.h:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
- Added Item_func_trig_cond::get_triv_var()
sql/item_subselect.cc:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
- Item_subselect::exec() and subselect_*_engine::exec() don't have parameter
anymore - now Item_subselect owns the pushed down predicates guard flags.
- A correct set of conditional predicates is now pushed into row-based IN
subquery.
- select_indexsubquery_engine now has "HAVING clause" (needed for correct query
results), and it is shown in EXPLAIN EXTENDED
sql/item_subselect.h:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
- Item_subselect::exec() and subselect_*_engine::exec() don't have parameter
anymore - now Item_subselect owns the pushed down predicates guard flags.
- A correct set of conditional predicates is now pushed into row-based IN
subquery.
- select_indexsubquery_engine now has "HAVING clause" (needed for correct query
results), and it is shown in EXPLAIN EXTENDED
sql/mysql_priv.h:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
- Added "in_having_cond" special Item name
sql/mysqld.cc:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
- Added "in_having_cond" special Item name
sql/sql_lex.h:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
sql/sql_select.cc:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
- Make "ref" analyzer be able to work with conditional equalities
- Fix subquery optimization code to match the changes in what kinds of
conditions are pushed down into subqueries
- Fix wrong EXPLAIN output in some queries with subquery (BUG#22390)
sql/sql_select.h:
BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
- Make "ref" analyzer be able to work with conditional equalities
- Fix wrong EXPLAIN output in some queries with subquery (BUG#22390)
When transforming "oe IN (SELECT ie ...)" wrap the pushed-down predicates
iff "oe can be null", not "ie can be null".
The fix doesn't cover row-based subqueries, those will be fixed in #24127.
mysql-test/r/subselect.result:
BUG#24085: Wrong result for NULL IN (SELECT not_null_val FROM ...)
Update the test results (checked)
mysql-test/r/subselect3.result:
BUG#24085: Wrong result for NULL IN (SELECT not_null_val FROM ...)
- Testcase
mysql-test/t/subselect3.test:
BUG#24085: Wrong result for NULL IN (SELECT not_null_val FROM ...)
- Testcase
sql/item_subselect.cc:
BUG#24085: Wrong result for NULL IN (SELECT not_null_val FROM ...)
When transforming "oe IN (SELECT ie ...)" we should make special
provisions (wrap the pushed predicates) if we can encounter
NULL IN (SELECT ...), i.e. when oe->maybe_null. The code was checking
for ie->maybe_null instead, fixed it for single value based subqueries.
Row-based subqueries (e.g. (a,b) IN (SELECT c,d ...)) are not fixed
because they won't produce correct results for several other reasons
(filed as #24085)
Evaluate "NULL IN (SELECT ...)" in a special way: Disable pushed-down
conditions and their "consequences":
= Do full table scans instead of unique_[index_subquery] lookups.
= Change appropriate "ref_or_null" accesses to full table scans in
subquery's joins.
Also cache value of NULL IN (SELECT ...) if the SELECT is not correlated
wrt any upper select.
mysql-test/r/subselect.result:
BUG#8804: wrong results for NULL IN (SELECT ...):
- Updated test results
sql/item.h:
BUG#8804: wrong results for NULL IN (SELECT ...):
- Added comments
sql/item_cmpfunc.cc:
BUG#8804: wrong results for NULL IN (SELECT ...):
Made Item_in_optimizer to:
- cache the value of "NULL IN (uncorrelated select)"
- Turn off pushed-down predicates when evaluating "NULL IN (SELECT ...)"
sql/item_cmpfunc.h:
BUG#8804: wrong results for NULL IN (SELECT ...):
- Made Item_in_optimizer cache the value of "NULL IN (uncorrelated select)"
- Added comments
sql/item_subselect.cc:
BUG#8804: wrong results for NULL IN (SELECT ...):
- When needed, wrap the predicates we push into subquery into an
Item_func_trig_cond so we're able to turn them off when evaluating
NULL IN (SELECT ...).
- Added code to evaluate NULL IN (SELECT ...) in a special way:
= In [unique_]index_subquery, do full table scan to see if there
are any rows.
= For other subqueries, change ref[_or_null] to ALL if the
ref[_or_null] was created from pushed-down predicate.
sql/item_subselect.h:
BUG#8804: wrong results for NULL IN (SELECT ...):
- Added Item_subselect::is_correlated
- Added comments
sql/records.cc:
BUG#8804: wrong results for NULL IN (SELECT ...):
- Make rr_sequential() non-static
sql/sql_lex.cc:
BUG#8804: wrong results for NULL IN (SELECT ...):
- Added st_select_lex::is_correlated and Item_subselect::is_correlated.
sql/sql_lex.h:
BUG#8804: wrong results for NULL IN (SELECT ...):
- Added st_select_lex::is_correlated
sql/sql_select.cc:
BUG#8804: wrong results for NULL IN (SELECT ...):
- Added KEY_FIELD::outer_ref to keep track of which ref accesses are
created from predicates that were pushed down into the subquery.
sql/sql_select.h:
BUG#8804: wrong results for NULL IN (SELECT ...):
- Added KEYUSE::outer_ref
mysql-test/r/subselect3.result:
New BitKeeper file ``mysql-test/r/subselect3.result''
mysql-test/t/subselect3.test:
New BitKeeper file ``mysql-test/t/subselect3.test''
