From ccac0a6e4e5b5b4dc346e4d20236f179576053e3 Mon Sep 17 00:00:00 2001 From: Gleb Shchepa Date: Sat, 6 Feb 2010 23:54:30 +0400 Subject: Bug #45640: optimizer bug produces wrong results Grouping by a subquery in a query with a distinct aggregate function lead to a wrong result (wrong and unordered grouping values). There are two related problems: 1) The query like this: SELECT (SELECT t1.a) aa, COUNT(DISTINCT b) c FROM t1 GROUP BY aa returned wrong result, because the outer reference "t1.a" in the subquery was substituted with the Item_ref item. The Item_ref item obtains data from the result_field object that refreshes once after the end of each group. This data is not applicable to filesort since filesort() doesn't care about groups (and doesn't update result_field objects with copy_fields() and so on). Also that data is not applicable to group separation algorithm: end_send_group() checks every record with test_if_group_changed() that evaluates Item_ref items, but it refreshes those Item_ref-s only after the end of group, that is a vicious circle and the grouped column values in the output are shifted. Fix: if a) we grouping by a subquery and b) that subquery has outer references to FROM list of the grouping query, then we substitute these outer references with Item_direct_ref like references under aggregate functions: Item_direct_ref obtains data directly from the current record. 2) The query with a non-trivial grouping expression like: SELECT (SELECT t1.a) aa, COUNT(DISTINCT b) c FROM t1 GROUP BY aa+0 also returned wrong result, since JOIN::exec() substitutes references to top-level aliases in SELECT list with Item_copy caching items. Item_copy items have same refreshing policy as Item_ref items, so the whole groping expression with Item_copy inside returns wrong result in filesort() and end_send_group(). Fix: include aliased items into GROUP BY item tree instead of Item_ref references to them. mysql-test/r/group_by.result: Test case for bug #45640 mysql-test/t/group_by.test: Test case for bug #45640 sql/item.cc: Bug #45640: optimizer bug produces wrong results Item_field::fix_fields() has been modified to resolve aliases in GROUP BY item trees into aliased items instead of Item_ref items. sql/item.h: Bug #45640: optimizer bug produces wrong results - Item::find_item_processor() has been introduced. - Item_ref::walk() has been modified to apply processors to itself too (not only to referenced item). sql/mysql_priv.h: Bug #45640: optimizer bug produces wrong results fix_inner_refs() has been modified to accept group_list parameter. sql/sql_lex.cc: Bug #45640: optimizer bug produces wrong results Initialization of st_select_lex::group_fix_field has been added. sql/sql_lex.h: Bug #45640: optimizer bug produces wrong results The st_select_lex::group_fix_field field has been introduced to control alias resolution in Itef_fied::fix_fields. sql/sql_select.cc: Bug #45640: optimizer bug produces wrong results - The fix_inner_refs function has been modified to treat subquery outer references like outer fields under aggregate functions, if they are included in GROUP BY item tree. - The find_order_in_list function has been modified to fix Item_field alias fields included in the GROUP BY item trees in a special manner. --- sql/sql_lex.cc | 1 + 1 file changed, 1 insertion(+) (limited to 'sql/sql_lex.cc') diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc index 2adbc44eb12..5097ca2ad5b 100644 --- a/sql/sql_lex.cc +++ b/sql/sql_lex.cc @@ -1592,6 +1592,7 @@ void st_select_lex::init_query() having= prep_having= where= prep_where= 0; olap= UNSPECIFIED_OLAP_TYPE; having_fix_field= 0; + group_fix_field= 0; context.select_lex= this; context.init(); /* -- cgit v1.2.1 From 8c2153a1f1cc3618d334e5245dab98f84603b68a Mon Sep 17 00:00:00 2001 From: Davi Arnaut Date: Thu, 1 Apr 2010 10:15:22 -0300 Subject: Bug#50755: Crash if stored routine def contains version comments The problem was that a syntactically invalid trigger could cause the server to crash when trying to list triggers. The crash would happen due to a mishap in the backup/restore procedure that should protect parser items which are not associated with the trigger. The backup/restore is used to isolate the parse tree (and context) of a statement from the load (and parsing) of a trigger. In this case, a error during the parsing of a trigger could cause the improper backup/restore sequence. The solution is to properly restore the original statement context before the parser is exited due to syntax errors in the trigger body. mysql-test/r/trigger.result: Add test case result for Bug#50755 mysql-test/t/trigger.test: Add test case for Bug#50755 sql/sp_head.cc: Merge sp_head::destroy() and sp_head destructor. Retrieve THD from the LEX so that m_thd is not necessary. sql/sql_lex.cc: Explicitly restore the original environment. --- sql/sql_lex.cc | 1 + 1 file changed, 1 insertion(+) (limited to 'sql/sql_lex.cc') diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc index 5097ca2ad5b..a3776f59241 100644 --- a/sql/sql_lex.cc +++ b/sql/sql_lex.cc @@ -2106,6 +2106,7 @@ void st_lex::cleanup_lex_after_parse_error(THD *thd) */ if (thd->lex->sphead) { + thd->lex->sphead->restore_thd_mem_root(thd); delete thd->lex->sphead; thd->lex->sphead= NULL; } -- cgit v1.2.1 From 13c736f5606290d86d4d6ff698288d6cde2da29f Mon Sep 17 00:00:00 2001 From: Igor Babaev Date: Tue, 25 May 2010 23:14:18 -0700 Subject: Changed the fixes for the following bugs: Bug #39022: completed Bug #39653: reverted as invalid Bug #45640: ameliorated, simplified, optimized Bug #48483: completed Bug #49324: improved Bug #51242/52336: reverted, applied a real fix. --- sql/sql_lex.cc | 1 - 1 file changed, 1 deletion(-) (limited to 'sql/sql_lex.cc') diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc index 411a7f5ec49..5a3907d0f7f 100644 --- a/sql/sql_lex.cc +++ b/sql/sql_lex.cc @@ -1603,7 +1603,6 @@ void st_select_lex::init_query() having= prep_having= where= prep_where= 0; olap= UNSPECIFIED_OLAP_TYPE; having_fix_field= 0; - group_fix_field= 0; context.select_lex= this; context.init(); /* -- cgit v1.2.1