From 095b686c09f5c143abbfb99839c1d1e2810a5a35 Mon Sep 17 00:00:00 2001 From: unknown Date: Sat, 21 Aug 2004 02:02:46 +0400 Subject: Fix for bug#4912 "mysqld crashs in case a statement is executed a second time". The bug was caused by incompatibility of negations elimination algorithm and PS: during first statement execute a subtree with negation was replaced with equivalent subtree without NOTs. The problem was that although this transformation was permanent, items of the new subtree were created in execute-local memory. The patch adds means to check if it is the first execute of a prepared statement, and if this is the case, to allocate items in memory of the prepared statement. The implementation: - backports Item_arena from 5.0 - adds Item_arena::is_stmt_prepare(), Item_arena::is_first_stmt_execute(). - deletes THD::allocate_temporary_pool_for_ps_preparing(), THD::free_temporary_pool_for_ps_preparing(); they were redundant. and adds a few invariants: - thd->free_list never contains junk (= freed items) - thd->current_arena is never null. If there is no prepared statement, it points at the thd. The rest of the patch contains mainly mechanical changes and cleanups. mysql-test/r/ps.result: Test results updated (test case for Bug#4912) mysql-test/t/ps.test: A test case for Bug#4912 "mysqld crashs in case a statement is executed a second time" sql/item_cmpfunc.cc: current_statement -> current_arena sql/item_subselect.cc: Statement -> Item_arena, current_statement -> current_arena sql/item_subselect.h: Item_subselect does not need to save thd->current_statement. sql/item_sum.cc: Statement -> Item_arena sql/item_sum.h: Statement -> Item_arena sql/mysql_priv.h: Statement -> Item_arena sql/sql_base.cc: current_statement -> current_arena sql/sql_class.cc: - Item_arena - convenient set_n_backup_statement, restore_backup_statement (nice idea, Sanja) sql/sql_class.h: - Item_arena: backport from 5.0 - allocate_temporary_pool_for_ps_preparing, free_temporary_pool_for_ps_preparing removed. sql/sql_derived.cc: current_statement -> current_arena sql/sql_lex.cc: current_statement -> current_arena sql/sql_parse.cc: Deploy invariant that thd->free_list never contains junk items (backport from 5.0). sql/sql_prepare.cc: - backporting Item_arena - no need to allocate_temporary_pool_for_ps_preparing(). sql/sql_select.cc: Fix for bug#4912 "mysqld crashs in case a statement is executed a second time": if this is the first execute of a prepared statement, negation elimination is done in memory of the prepared statement. sql/sql_union.cc: Backporting Item_arena from 5.0. --- mysql-test/r/ps.result | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'mysql-test/r') diff --git a/mysql-test/r/ps.result b/mysql-test/r/ps.result index 27f4ce7f815..0523143f91d 100644 --- a/mysql-test/r/ps.result +++ b/mysql-test/r/ps.result @@ -219,3 +219,10 @@ Name Engine Version Row_format Rows Avg_row_length Data_length Max_data_length I t1 MyISAM 9 Dynamic 0 0 0 4294967295 1024 0 NULL # # # latin1_swedish_ci NULL deallocate prepare stmt1 ; drop table t1; +create table t1(a varchar(2), b varchar(3)); +prepare stmt1 from "select a, b from t1 where (not (a='aa' and b < 'zzz'))"; +execute stmt1; +a b +execute stmt1; +a b +deallocate prepare stmt1; -- cgit v1.2.1