mariadb

Commit Graph

Author	SHA1	Message	Date
Sergey Petrunya	2a16e7674b	BUG#913030: Optimizer chooses a suboptimal excution plan for Q18 from DBT-3 - When doing join optimization, pre-sort the tables so that they mimic the execution order we've had with 'semijoin=off'. - That way, we will not get regressions when there are two query plans (the old and the new) that have indentical costs but different execution times (because of factors that the optimizer was not able to take into account).	14 years ago
Sergey Petrunya	4ac230e557	Better comments	14 years ago
Igor Babaev	841a74a4d6	Fixed LP bug #939009 . The result of materialization of the right part of an IN subquery predicate is placed into a temporary table. Each row of the materialized table is distinct. A unique key over all fields of the temporary table is defined and created. It allows to perform key look-ups into the table. The table created for a materialized subquery can be accessed by key as any other table. The function best_access-path search for the best access to join a table to a given partial join. With some where conditions this function considers a possibility of a ref_or_null access. If such access employs the unique key on the temporary table then when estimating the cost this access the function tries to use the array rec_per_key. Yet, such array is not built for this unique key. This causes a crash of the server. Rows returned by the subquery that contain nulls don't have to be placed into temporary table, as they cannot be match any row produced by the left part of the subquery predicate. So all fields of the temporary table can be defined as non-nullable. In this case any ref_or_null access to the temporary table does not make any sense and it does not make sense to estimate such an access. The fix makes sure that the temporary table for a materialized IN subquery is defined with columns that are all non-nullable. The also ensures that any row with nulls returned by the subquery is not placed into the temporary table.	14 years ago
unknown	5db8b5113b	Fixed creating limit for exists subquery.	14 years ago
Igor Babaev	bb4053afc3	Fixed LP bug #919427 . The function subselect_uniquesubquery_engine::copy_ref_key has to take into account that when EXPLAIN is processed the array of store_key object created for any TABLE_REF may contain elements for constant items. These items should be ignored by thefunction.	14 years ago
unknown	6b4c132bc7	Removed unused code merged from 5.2. In 5.3 we fix this problem by checking if we put max/min group function without GROUP BY artificially in case of MODE_ONLY_FULL_GROUP_BY sql mode.	14 years ago
Igor Babaev	cd55894a52	Fixed LP bug #910083 . The patch for bug 685411 erroneously removed a call of engine->set_thd() from Item_subselect::fix_fields().	14 years ago
Igor Babaev	6dfe0956d6	Back-ported the test cases for bug #12763207 from mysql-5.6 code line into 5.2 Completed the fix for this bug. Note: in 5.3 the affected 'if' statement in Item_in_subselect::single_value_transformer() starting with the condition (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY) should be removed altogether. The change from table.cc is not needed either. This is because in 5.3 - min/max transformation for subqueries are done at the optimization phase - evaluation of the expensive subqueries is done at the execution phase. Added an EXPLAIN EXTENDED to the test case for bug #12329653.	14 years ago
Igor Babaev	c9259f166b	Fixed LP bug #904345 . The MIN/MAX optimizer code from the function opt_sum_query erroneously did not take into account conjunctive conditions that did not depend on any table, yet were not identified as constant items. These could be items containing rand() or PS/SP parameters. These items are supposed to be evaluated at the execution phase. That's why if such conditions can be extracted from the WHERE condition the MIN/MAX optimization is not applied as currently it is always done at the optimization phase. (In 5.3 expensive subqueries are also evaluated only at the execution phase. So, if a constant condition with such subquery can be extracted from the WHERE clause the MIN/MAX optimization should not be applied in 5.3.) IF an IN/ALL/SOME predicate with a constant left part is transformed into an EXISTS subquery the resulting subquery should not be considered uncacheable if the right part of the predicate is not uncacheable. Backported the function dbug_print_item() from 5.3. The function is used only for debugging.	14 years ago
unknown	072073c09e	Backport of WL#5953 from MySQL 5.6 The patch differs from the original MySQL patch as follows: - All test case differences have been reviewed one by one, and care has been taken to restore the original plan so that each test case executes the code path it was designed for. - A bug was found and fixed in MariaDB 5.3 in Item_allany_subselect::cleanup(). - ORDER BY is not removed because we are unsure of all effects, and it would prevent enabling ORDER BY ... LIMIT subqueries. - ref_pointer_array.m_size is not adjusted because we don't do array bounds checking, and because it looks risky. Original comment by Jorgen Loland: ------------------------------------------------------------- WL#5953 - Optimize away useless subquery clauses For IN/ALL/ANY/SOME/EXISTS subqueries, the following clauses are meaningless: * ORDER BY (since we don't support LIMIT in these subqueries) * DISTINCT * GROUP BY if there is no HAVING clause and no aggregate functions This WL detects and optimizes away these useless parts of the query during JOIN::prepare()	14 years ago
Sergey Petrunya	a1b4eadf89	BUG#868908: Crash in check_simple_equality() with semijoin + materialization + prepared statement - Part2: safety and code cleanup	14 years ago
Sergey Petrunya	8e25dcfcd7	BUG#868908: Crash in check_simple_equality() with semijoin + materialization + prepared statement - Part 1 of the fix: for semi-join merged subqueries, calling child_join->optimize() until we're done with all PS-lifetime optimizations in the parent.	14 years ago
unknown	5412e82c01	Fixed LP BUG#747278 The problem was that when we have single row subquery with no rows Item_cache(es) which represent result row was not null and being requested via element_index() returned random value. The fix is setting all Item_cache(es) in NULL before executing the query (reset() method) which guaranty NULL value of whole query or its elements requested in any way if no rows was found. set_null() method was added to Item_cache to guaranty correct NULL value in case of reseting the cache.	14 years ago
unknown	dc1b1d39a1	Fix bug lp:894326 The patch also fixes an unrelated compiler warning. Analysis: The temporary table created during SJ-materialization might be used for sorting for a group by operation. The sort buffers for this internal temporary table were not cleared by the execution code after each subquery re-execution. This resulted in a memory leak detected by valgrind. Solution: Cleanup the sort buffers for the semijon tables as well. sql/item_subselect.cc: - Fix a compiler warning and add logic to revert to table scan partial match when there are more rows in the materialized subquery than there can be bits in the NULL bitmap index used for partial matching. sql/opt_subselect.cc: - Fixed a memory leak detected by valgrind	14 years ago
unknown	fd3295e0ac	Fix bug lp:893486 Analysis: The bug is a result of an incomplete fix for bug lp:869036. That fix didn't take into account that there may be a case when ther are no NULLs in the materialized subquery, however all columns without NULLs may not be grouped in the only non-null index. This is the case when the left subquery expression has nullable columns. Solution: The patch handles two missing sub-cases of the case when there are no value (non-null matches) for any outer expression, and there are both NULLs and non-NUll values in the outer reference. a) If the materialized subquery contains no NULLs there cannot be a partial match, because there are no NULLs in those columns where the outer reference has no NULLs. b) If the materialized subquery contains NULLs, but there exists a column, such that its corresponding outer expression has no NULL, and this column also has no NULL. Then there cannot be a partial match either.	14 years ago
unknown	42221abaed	Fix bug lp:869036 Apart from the fix, the patch also adds few more unrelated test cases for partial matching, and fixes few typos. Analysis: This bug uncovered that partial matching via rowid intersection didn't handle the case when: - the left IN argument has some NULLs, - there are no non-null value matches, and there is no non-null column, - the subquery columns that are not covered with the NULLs in the left IN argument contain at least one row, such that it has NULL values in all columns where the left IN operand has no NULLs. In this case there is a partial match. In addition the analysis of the related code uncovered incorrect handling of few other related cases. Solution: The solution for the bug is to check if there exists a row with NULLs in all columns other than the ones having NULL in the let IN operand. The check is implemented via checking whether the bitmaps that store NULL information in class Ordered_key have a non-empty intersection for the relevant columns. The intersection itself is implemented via the function bitmap_exists_intersection() in my_bitmap.c.	14 years ago
unknown	f76bfc40ea	Fix for LP BUG#824425: Prohibiting subqueries in rows for left part of IN/ALL/ANY Fix for walk() method of subqueries: always call the method on the subquery.	14 years ago
unknown	1d721d0106	Fix MySQL BUG#12329653 In MariaDB, when running in ONLY_FULL_GROUP_BY mode, the server produced in incorrect error message that there is an aggregate function without GROUP BY, for artificially created MIN/MAX functions during subquery MIN/MAX optimization. The fix introduces a way to distinguish between artifially created MIN/MAX functions as a result of a rewrite, and normal ones present in the query. The test for ONLY_FULL_GROUP_BY violation now tests in addition if a MIN/MAX function was part of a MIN/MAX subquery rewrite. In order to be able to distinguish these MIN/MAX functions, the patch introduces an additional flag in Item_in_subselect::in_strategy - SUBS_STRATEGY_CHOSEN. This flag is set when the optimizer makes its final choice of a subuqery strategy. In order to make the choice consistent, access to Item_in_subselect::in_strategy is provided via new class methods. ****** Fix MySQL BUG#12329653 In MariaDB, when running in ONLY_FULL_GROUP_BY mode, the server produced in incorrect error message that there is an aggregate function without GROUP BY, for artificially created MIN/MAX functions during subquery MIN/MAX optimization. The fix introduces a way to distinguish between artifially created MIN/MAX functions as a result of a rewrite, and normal ones present in the query. The test for ONLY_FULL_GROUP_BY violation now tests in addition if a MIN/MAX function was part of a MIN/MAX subquery rewrite. In order to be able to distinguish these MIN/MAX functions, the patch introduces an additional flag in Item_in_subselect::in_strategy - SUBS_STRATEGY_CHOSEN. This flag is set when the optimizer makes its final choice of a subuqery strategy. In order to make the choice consistent, access to Item_in_subselect::in_strategy is provided via new class methods.	14 years ago
unknown	30b396ad4c	- Removed a comment that is not true any more. - Consistent use of the SUBS_NOT_TRANSFORMED constant for in_strategy.	14 years ago
unknown	511459bd14	Enable subquery materialization=ON by default.	14 years ago
unknown	6498687325	Fix bug lp:833702 Analysis: Equality propagation propagated the constant '7' into args[0] of the Item_in_optimizer that stands for the "< ANY" predicate. At the same the min/max subquery rewrite swapped the order of the left and right operands of the "<" predicate, but used Item_in_subselect::left_expr. As a result, when the <ANY predicate is executed early in the execution phase as a contant condition, instead of a constant right (swapped) argument of the < predicate, there was a field (t3.a). This field had no data, since the whole predicate is considered constant, and it is evaluated before any tables are read. Having junk in the field row buffer produced wrong result Solution: Fix create_swap to pick the correct Item_in_optimizer left argument.	14 years ago
unknown	b40bc2b3e3	Fix of LP BUG#872775. The problem was that merged views has its own nest_level numbering => when we compare nest levels we should take into considiration basis (i.e. 0 level), if it is different then nest levels are not comparable.	14 years ago
Igor Babaev	fdf789a7ea	Fixed LP bug #874378 . This bug happened for the queries over multi-table mergeable views because the bitmap TABLE::read_set of the underlying tables were not updated after the views had been merged into the query. Now this bitmaps are updated properly. Also the bitmap TABLE::merge_keys now is updated in prevention of future bugs.	14 years ago
Igor Babaev	945f12cf8f	Fixed LP bug #877316 . This bug happened due to incompleteness of the fix for bug 872735: the occurrences of the fields in the conditions of correlated subqueries were not taken into account when recalculating covering keys bit maps.	14 years ago
Sergey Glukhov	14dc91ff83	Bug#11747970 34660: CRASH WHEN FEDERATED TABLE LOSES CONNECTION DURING INSERT ... SELECT Problematic query: insert ignore into `t1_federated` (`c1`) select `c1` from `t1_local` a where not exists (select 1 from `t1_federated` b where a.c1 = b.c1); When this query is killed in another connection it could lead to crash. The problem is follwing: An attempt to obtain table statistics for subselect table in killed query fails with an error. So JOIN::optimize() for subquery is failed but it does not prevent further subquery evaluation. At the first subquery execution JOIN::optimize() is called (see subselect_single_select_engine::exec()) and fails with an error. 'executed' flag is set to TRUE and it prevents further subquery evaluation. At the second call JOIN::optimize() does not happen as 'JOIN::optimized' is TRUE and in case of uncacheable subquery the 'executed' flag is set to FALSE before subquery evaluation. So we loose 'optimize stage' error indication (see subselect_single_select_engine::exec()). In other words 'executed' flag is used for two purposes, for error indication at JOIN::optimize() stage and for an indication of subquery execution. And it seems it's wrong as the flag could be reset. mysql-test/r/error_simulation.result: test case mysql-test/t/error_simulation.test: test case sql/item_subselect.cc: added new flag subselect_single_select_engine::optimize_error which is used for error detection which could happen at optimize stage. sql/item_subselect.h: added new flag subselect_single_select_engine::optimize_error sql/sql_select.cc: test case	14 years ago
unknown	f40f0ff679	Fix bug lp:856152 Analysis: The cause of the bug was that the method subselect_rowid_merge_engine::partial_match() was not designed for re-execution within the same query. Specifically, it didn't cleanup the bitmap of matching keys after completion. The test query requires double execution of the IN predicate because it first checks the predicate as a constant condition. The second execution during regular execution used the bitmap of matching keys produced by the first execution instead of starting with a clean one. Solution: Cleanup the bitmap of matching keys at the end of the partial matching procedure.	14 years ago
unknown	ada0850c04	Fix bug lp:858038 Analysis: The cause of the bug was the changed meaning of subselect_partial_match_engine::has_covering_null_row. Previously it meant that there is row with NULLs in all nullable fields of the materialized subquery table. Later it was changed to mean a row with NULLs in all fields of this table. At the same time there was a shortcut in subselect_rowid_merge_engine::partial_match() that detected a special case where: - there is no match in any of the columns with NULLs, and - there is no NULL-only row that covers all columns with NULLs. With the change in the meaning of has_covering_null_row, the condition that detected this special case was incomplete. This resulted in an incorrect FALSE, when the result was a partial match. Solution: Expand the condition that detected the special case with the correct test for the existence of a row with NULL values in all columns that contain NULLs (a kind of parially covering NULL-row).	14 years ago
Sergey Petrunya	0200ee7003	BUG#860580: Sporadic crash / valgrind warning in register_field_in_read_map() with semijoin The problem: in an uncorrelated subquery, JOIN execution code may make irreversible cleanups after it has been executed (because the subquery won't be executed again). In particular, JTBM nests and their injected IN-equalities will be invalidated (the materialized table will be dropped and TABLE structure freed). Solution: don't walk into Item_subselect if represents an uncorrelated subselect that has already been executed. The idea is that the subselect will not be executed again (calling Item_subselect_xxx::val_int() will fetch the cached value), so it should not matter what is inside the subselect.	14 years ago
Sergey Petrunya	35ecfa90e3	BUG#860300: Second crash with get_fanout_with_deps() with semijoin + materialization - Make get_post_group_estimate() take into account semi-join materialization nests.	14 years ago
Sergey Petrunya	ebbdb14a02	BUG#849776: Wrong result with semijoin + "Impossible where" - Provide fix_after_pullout() function for Item_in_optimizer and other Item_XXX classes (basically, all of them that have eval_not_null_tables, which means they have special rules for calculating not_null_tables_cache value)	14 years ago
Sergey Petrunya	42b928ca05	Fix after previous cset: update test results	14 years ago
unknown	8b062c1fef	Fix of LP BUG#780386. ALL subquery should return TRUE if subquery rowa set is empty independently of left part. The problem was that Item_func_(eq,ne,gt,ge,lt,le) do not call execution of second argument if first is NULL no in this case subquery will not be executed and when Item_func_not_all calls any_value() of the subquery or aggregation function which report that there was rows. So for NULL < ALL (SELECT...) result was FALSE instead of TRUE. Fix is just swapping of arguments of Item_func_(eq,ne,gt,ge,lt,le) (with changing the operation if it is needed) so that result will be the same (for examole a < b is equal to b > a). This fix exploit the fact that first argument will be executed in any case.	14 years ago
Sergey Petrunya	55cde3b428	BUG#836532: Crash in Item_equal_fields_iterator::get_curr_field with semijoin+materialization - Item_in_subselect::inject_in_to_exists_cond() should not call ((Item_cond*)join->conds)->argument_list()->concat(join->cond_equal->current_level) as that makes two lists share their tail, and the cond_equal list will end up containing non-Item_equal objects when substitute_for_best_equal_field() walks through join->conds and replaces all Item_equal objects with Item_func_eq objects. - So, instead of using List::concat(), manually copy entries from one list to another.	14 years ago
Michael Widenius	949984beed	Fixed lp:828514 "Assertion `! is_set()' failed in Diagnostics_area::set_ok_status with derived table + subquery + concurrent DML" sql/item_subselect.cc: Added check of error condtions (safety) sql/sql_join_cache.cc: Added DBUG to some functions. Added error checking for calls to check_match(); This fixed the bug. sql/sql_select.cc: Moved variable assignment to be close to where it's used (cleanup)	14 years ago
unknown	37a8497d49	LP BUG#823169 fix. For ANY subqueries NULLs should be ignored (if there is other values) when finding max min. For ALL subqueries NULLs should be saved if they found. Optimisation for ALL suqbueries if NULL is possible in the SELECT list with max/min aggregate function switched off. Some test changed where NULL is not used but optimization with max/min aggregate function important so NOT NULL added. mysql-test/r/explain.result: Forced old optimization. mysql-test/r/subselect.result: Forced old optimization. New test suite. mysql-test/t/explain.test: Forced old optimization. mysql-test/t/subselect.test: Forced old optimization. New test suite. sql/item_subselect.cc: Store converted subquery type. Switch off aggregate function optimisation for ALL and nulls. sql/sql_class.cc: Fixed NULL comparison. sql/sql_class.h: Store converted subquery type.	14 years ago
Sergey Petrunya	945a595aa3	BUG#834534: Assertion `0' failed in replace_where_subcondition with semijoin subquery in HAVING - The problem was that the code that made the check whether the subquery is an AND-part of the WHERE clause didn't work correctly for nested subqueries. In particular, grand-child subquery in HAVING was treated as if it was in the WHERE, which eventually caused an assert when replace_where_subcondition looked for the subquery predicate in the WHERE and couldn't find it there. - The fix: Removed implementation of "thd_marker approach". thd->thd_marker was used to determine the location of subquery predicate: setup_conds() would set accordingly it when making the {where\|on_expr}->fix_fields(...) call so that AND-parts of the WHERE/ON clauses can determine they are the AND-parts. Item_cond_or::fix_fields(), Item_func::fix_fields(), Item_subselect::fix_fields (this one was missed), and all other items-that-contain-items had to reset thd->thd_marker before calling fix_fields() for their children items, so that the children can see they are not AND-parts of WHERE/ON. - The "thd_marker approach" required that a lot of code in different locations maintains correct value of thd->thd_marker, so it was replaced with: - The new approach with mark_as_condition_AND_part does not keep context in thd->thd_marker. Instead, setup_conds() now calls {where\|on_expr}->mark_as_condition_AND_part() and implementations of that function make sure that: - parts of AND-expressions get the mark_as_condition_AND_part() call - Item_in_subselect objects record that they are AND-parts of WHERE/ON	14 years ago
unknown	9e60b55fd0	Fix bug lp:825095 Analysis: Partial matching is used even when there are no NULLs in a materialized subquery, as long as the left NOT IN operand may contain NULL values. This case was not handled correctly in two different places. First, the implementation of parital matching did not clear the set of matching columns when the merge process advanced to the next row. Second, there is no need to perform partial matching at all when the left operand has no NULLs. Solution: First fix subselect_rowid_merge_engine::partial_match() to properly cleanup the bitmap of matching keys when advancing to the next row. Second, change subselect_partial_match_engine::exec() so that when the materialized subquery doesn't contain any NULLs, and the left operand of [NOT] IN doesn't contain NULLs either, the method returns without doing any unnecessary partial matching. The correct result in this case is in Item::in_value.	14 years ago
unknown	6b70cc538b	Fix bug lp:813473 The bug is a duplicate of MySQL's Bug#11764086, however MySQL's fix is incomplete for MariaDB, so this fix is slightly different. In addition, this patch renames Item_func_not_all::top_level() to is_top_level_item() to make it in line with the analogous methods of Item_in_optimizer, and Item_subselect. Analysis: It is possible to determine whether a predicate is NULL-rejecting only if it is a top-level one. However, this was not taken into account for Item_in_optimizer. As a result, a NOT IN predicate was erroneously considered as NULL-rejecting, and the NULL-complemented rows generated by the outer join were rejected before being checked by the NOT IN predicate. Solution: Change Item_in_optimizer to be considered as NULL-rejecting only if it a top-level predicate.	14 years ago
unknown	2b6a23447b	Fix of LP BUG#780386. ALL subquery should return TRUE if subquery rowa set is empty independently of left part. The problem was that Item_func_(eq,ne,gt,ge,lt,le) do not call execution of second argument if first is NULL no in this case subquery will not be executed and when Item_func_not_all calls any_value() of the subquery or aggregation function which report that there was rows. So for NULL < ALL (SELECT...) result was FALSE instead of TRUE. Fix is just swapping of arguments of Item_func_(eq,ne,gt,ge,lt,le) (with changing the operation if it is needed) so that result will be the same (for examole a < b is equal to b > a). This fix exploit the fact that first argument will be executed in any case. mysql-test/r/subselect.result: The test suite added. mysql-test/r/subselect_no_mat.result: The test suite added. mysql-test/r/subselect_no_opts.result: The test suite added. mysql-test/r/subselect_no_semijoin.result: The test suite added. mysql-test/r/subselect_scache.result: The test suite added. mysql-test/t/subselect.test: The test suite added. sql/item_cmpfunc.cc: Swap arguments creation methods added. sql/item_cmpfunc.h: Swap arguments creation methods added. sql/item_subselect.cc: Swap arguments of the comparison.	15 years ago
unknown	99cce18955	Fixed LP BUG#800696. The problem was that optimizer removes some outer references (it they are constant for example) and the list of outer items built during prepare phase is not actual during execution phase when we need it as the cache parameters. First solution was use pointer on pointer on outer reference Item and initialize temporary table on demand. This solved most problem except case when optimiser also reduce Item which contains outer references ('OR' in this bug test suite). The solution is to build the list of outer reference items on execution phase (after optimization) on demand (just before temporary table creation) by walking Item tree and finding outer references among Item_ident (Item_field/Item_ref) and Item_sum items. Removed depends_on list (because it is not neede any mnore for the cache, in the place where it was used it replaced with upper_refs). Added processor (collect_outer_ref_processor) and get_cache_parameters() methods to collect outer references (or other expression parameters in future). mysql-test/r/subselect_cache.result: A new test added. mysql-test/r/subselect_scache.result: Changes in creating the cache and its paremeters order or adding arguments of aggregate function (which is a parameter also, but this has no influence on the result). mysql-test/t/subselect_cache.test: Added a new test. sql/item.cc: depends_on removed. Added processor (collect_outer_ref_processor) and get_cache_parameters() methods to collect outer references. Item_cache_wrapper collect parameters befor initialization of its cache. sql/item.h: depends_on removed. Added processor (collect_outer_ref_processor) and get_cache_parameters() methods to collect outer references. sql/item_cmpfunc.cc: depends_on removed. Added processor (collect_outer_ref_processor) to collect outer references. sql/item_cmpfunc.h: Added processor (collect_outer_ref_processor) to collect outer references. sql/item_subselect.cc: depends_on removed. Added processor get_cache_parameters() method to collect outer references. sql/item_subselect.h: depends_on removed. Added processor get_cache_parameters() method to collect outer references. sql/item_sum.cc: Added processor (collect_outer_ref_processor) method to collect outer references. sql/item_sum.h: Added processor (collect_outer_ref_processor) and get_cache_parameters() methods to collect outer references. sql/opt_range.cc: depends_on removed. sql/sql_base.cc: depends_on removed. sql/sql_class.h: New iterator added. sql/sql_expression_cache.cc: Build of list of items resolved in outer query done just before creating expression cache on the first execution of the subquery which removes influence of optimizer removing items (all optimization already done). sql/sql_expression_cache.h: Build of list of items resolved in outer query done just before creating expression cache on the first execution of the subquery which removes influence of optimizer removing items (all optimization already done). sql/sql_lex.cc: depends_on removed. sql/sql_lex.h: depends_on removed. sql/sql_list.h: Added add_unique method to add only unique elements to the list. sql/sql_select.cc: Support of new Item list added. sql/sql_select.h: Support of new Item list added.	15 years ago
unknown	c9e236828e	Fix bug lp:782305 Analysis: Both the wrong result and the valgrind warning were a result of incomplete cleanup of the MIN/MAX subquery rewrite. At the first execution of the query, the non-aggregate subquery is transformed into an aggregate MIN/MAX subquery. During the fix_fields phase of the MIN/MAX function, it sets the property st_select_lex::with_sum_func to true. The second execution of the query finds this flag to be ON. When optimization reaches the same MIN/MAX subquery transformation, it tests if the subquery is an aggregate or not. Since select_lex->with_sum_func == true from the previous execution, the transformation executes the second branch that handles aggregate subqueries. This substitutes the subquery Item into a Item_maxmin_subselect. At the same time elsewhere it is assumed that the subquery Item is of type Item_allany_subselect. Ultimately this results in casting the actual object to the wrong class, and calling the wrong any_value() method from empty_underlying_subquery(). Solution: Cleanup the st_select_lex::with_sum_func property in the case when the MIN/MAX transformation was performed for a non-aggregate subquery, so that the transformation can be repeated.	15 years ago
Igor Babaev	d37465a9cc	Fixed LP bug #794901 . Also: 1. simplified the code of the function mysql_derived_merge_for_insert. 2. moved merge of views/dt for multi-update/delete to the prepare stage. 3. the list of the references to the candidates for semi-join now is allocated in the statement memory.	15 years ago
unknown	445fcaa81a	MWL#68 efficient partial matching - Added an initial set of feature-specific test cases - Handled the special case where the materialized subquery of an IN predicates consists of only NULL values. - Fixed a bug where making Item_in_subselect a constant, didn't respect its null_value value.	15 years ago
unknown	1e6bd6b4df	Fix bug lp:809266 Analysis: This is a bug in MWL#68, where it was incorrectly assumed that if there is a match in the only non-null key, then if there is a covering NULL row on all remaining NULL-able columns there is a partial match. However, this is not the case, because even if there is such a null-only sub-row, it is not guaranteed to be part of the matched sub-row. The matched sub-row and the NULL-only sub-row may be parts of different rows. In fact there are two cases: - there is a complete row with only NULL values, and - all nullable columns contain only NULL values. These two cases were incorrectly mixed up in the class member subselect_partial_match_engine::covering_null_row_width. Solution: The solution is to: - split covering_null_row_width into two members: has_covering_null_row, and has_covering_null_columns, and - take into account each state during initialization and execution.	15 years ago
unknown	990584d73a	Fixed bug lp:809245 In addition to the bug fix explained below, the patch performs few renames, and adds some comments to avoid similar problems. Analysis: The failed assert was due to a bug in MWL#68, where it was incorrectly assumed that the size of the bitmap subselect_rowid_merge_engine::null_only_columns should be the same as the size of the array of Ordered_keys. The bitmap null_only_columns contains bits to mark columns that contain only NULLs. Therefore the indexes of the bits to be set in null_only_columns are different from the indexes of the Ordered_keys. If there is a NULL-only column that appears in a table after the last partial match column with Ordered_key, this NULL-only column would require setting a bit with index bigger than the size of the bitmap null_only_columns. Accessing such a bit caused the failed assert. Solution: Upon analysis, it turns out that null_only_columns is not needed at all, because we are looking for partial matches, and having such columns guarantees that there is a partial match for any corresponding outer value. Therefore the patch removes subselect_rowid_merge_engine::null_only_columns.	15 years ago
Sergey Petrunya	e2eafc3bd1	Fix buildbot failures: - JOIN::prepare would have set JOIN::table_count to incorrect value (bad merge of MWL 106) - optimize_keyuse() would use table-bit as table number (the change in optimize_keyuse is also the reason for query plan changes. Not expected to have much effect because only handles cases of no index statistics) - st_select_lex::register_dependency_item() ignored the fact that some of the selects on the dependency paths could have been merged to their parents (because they were mergeable VIEWs) - Undo the incorrect fix in Item_subselect::recalc_used_tables(): do not call fix_after_pullout() for Item_subselect::Ref_to_outside members.	15 years ago
Kent Boortz	44135d4725	Updated/added copyright headers	15 years ago
Sergey Petrunya	4493197125	Followup to previous commit: - Update test results - Fix a problem with PS: = convert_subq_to_sj() should not save where to prep_where or on_expr to prep_on_expr. = After an unmerged subquery predicate has been pulled, it should call fix_after_pullout() for outer_refs.	15 years ago
unknown	a02682abcc	MWL#89 - Added regression test with queries over the WORLD database. - Discovered and fixed several bugs in the related cost calculation functionality both in the semijoin and non-semijon subquery code. - Added DBUG printing of the cost variables used to decide between IN-EXISTS and MATERIALIZATION.	15 years ago
Sergey Petrunya	0cf912c23f	- Remove compiler warning - Remove garbage comments	15 years ago

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625 Commits (2a16e7674b9462586ef883e5678b21c87ca5f045)