Merge mysql.com:/home/svoj/devel/mysql/BUG21310/mysql-5.0-engines (f225a57d) · Commits · Software / OSDI20 Artifacts / mariadb

mysql-test/r/myisam.result

+16 −0

Original line number	Diff line number	Diff line
		@@ -1603,6 +1603,22 @@ select * from t1;
		a
		42
		drop table t1;
		CREATE TABLE t1(a VARCHAR(16));
		INSERT INTO t1 VALUES('aaaaaaaa'),(NULL);
		UPDATE t1 AS ta1, t1 AS ta2 SET ta1.a='aaaaaaaaaaaaaaaa';
		SELECT * FROM t1;
		a
		aaaaaaaaaaaaaaaa
		aaaaaaaaaaaaaaaa
		DROP TABLE t1;
		CREATE TABLE t1(a INT);
		INSERT INTO t1 VALUES(1),(2);
		UPDATE t1,t1 AS t2 SET t1.a=t1.a+2 WHERE t1.a=t2.a-1;
		SELECT * FROM t1 ORDER BY a;
		a
		2
		3
		DROP TABLE t1;
		End of 4.1 tests
		create table t1 (c1 int) engine=myisam pack_keys=0;
		create table t2 (c1 int) engine=myisam pack_keys=1;

mysql-test/t/myisam.test

+18 −0

Original line number	Diff line number	Diff line
		@@ -977,6 +977,24 @@ connection default;
		select * from t1;
		drop table t1;

		#
		# BUG#21310 - Trees in SQL causing a "crashed" table with MyISAM storage
		# engine
		#

		# A simplified test case that reflect crashed table issue.
		CREATE TABLE t1(a VARCHAR(16));
		INSERT INTO t1 VALUES('aaaaaaaa'),(NULL);
		UPDATE t1 AS ta1, t1 AS ta2 SET ta1.a='aaaaaaaaaaaaaaaa';
		SELECT * FROM t1;
		DROP TABLE t1;

		# A test case that reflect wrong result set.
		CREATE TABLE t1(a INT);
		INSERT INTO t1 VALUES(1),(2);
		UPDATE t1,t1 AS t2 SET t1.a=t1.a+2 WHERE t1.a=t2.a-1;
		SELECT * FROM t1 ORDER BY a;
		DROP TABLE t1;
		--echo End of 4.1 tests

		#

sql/sql_update.cc

+61 −74

Original line number	Diff line number	Diff line
		@@ -24,8 +24,6 @@
		#include "sp_head.h"
		#include "sql_trigger.h"

		static bool safe_update_on_fly(JOIN_TAB *join_tab);

		/* Return 0 if row hasn't changed */

		static bool compare_record(TABLE *table)
		@@ -1160,27 +1158,71 @@ int multi_update::prepare(List<Item> &not_used_values,
		for (i=0 ; i < table_count ; i++)
		set_if_bigger(max_fields, fields_for_table[i]->elements);
		copy_field= new Copy_field[max_fields];
		DBUG_RETURN(thd->is_fatal_error != 0);
		}


		/*
		Mark all copies of tables that are updates to ensure that
		init_read_record() will not try to enable a cache on them
		Check if table is safe to update on fly

		SYNOPSIS
		safe_update_on_fly()
		thd Thread handler
		join_tab How table is used in join
		all_tables List of tables

		The problem is that for queries like
		NOTES
		We can update the first table in join on the fly if we know that
		a row in this table will never be read twice. This is true under
		the following conditions:

		UPDATE t1, t1 AS t2 SET t1.b=t2.c WHERE t1.a=t2.a;
		- We are doing a table scan and the data is in a separate file (MyISAM) or
		if we don't update a clustered key.

		the row buffer may contain things that doesn't match what is on disk
		which will cause an error when reading a row.
		(This issue is mostly relevent for MyISAM tables)
		- We are doing a range scan and we don't update the scan key or
		the primary key for a clustered table handler.

		- Table is not joined to itself.

		This function gets information about fields to be updated from
		the TABLE::write_set bitmap.

		WARNING
		This code is a bit dependent of how make_join_readinfo() works.

		RETURN
		0 Not safe to update
		1 Safe to update
		*/
		for (table_ref= leaves; table_ref; table_ref= table_ref->next_leaf)

		static bool safe_update_on_fly(THD thd, JOIN_TAB join_tab,
		TABLE_LIST table_ref, TABLE_LIST all_tables)
		{
		TABLE *table=table_ref->table;
		if ((tables_to_update & table->map) &&
		unique_table(thd, table_ref, update_tables))
		table->no_cache= 1; // Disable row cache
		TABLE *table= join_tab->table;
		if (unique_table(thd, table_ref, all_tables))
		return 0;
		switch (join_tab->type) {
		case JT_SYSTEM:
		case JT_CONST:
		case JT_EQ_REF:
		return TRUE; // At most one matching row
		case JT_REF:
		case JT_REF_OR_NULL:
		return !is_key_used(table, join_tab->ref.key, table->write_set);
		case JT_ALL:
		/* If range search on index */
		if (join_tab->quick)
		return !join_tab->quick->is_keys_used(table->write_set);
		/* If scanning in clustered key */
		if ((table->file->ha_table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX) &&
		table->s->primary_key < MAX_KEY)
		return !is_key_used(table, table->s->primary_key, table->write_set);
		return TRUE;
		default:
		break; // Avoid compler warning
		}
		DBUG_RETURN(thd->is_fatal_error != 0);
		return FALSE;

		}


		@@ -1220,7 +1262,7 @@ multi_update::initialize_tables(JOIN *join)
		table->file->extra(HA_EXTRA_IGNORE_DUP_KEY);
		if (table == main_table) // First table in join
		{
		if (safe_update_on_fly(join->join_tab))
		if (safe_update_on_fly(thd, join->join_tab, table_ref, all_tables))
		{
		table_to_update= main_table; // Update table on the fly
		continue;
		@@ -1272,61 +1314,6 @@ multi_update::initialize_tables(JOIN *join)
		DBUG_RETURN(0);
		}

		/*
		Check if table is safe to update on fly

		SYNOPSIS
		safe_update_on_fly
		join_tab How table is used in join

		NOTES
		We can update the first table in join on the fly if we know that
		a row in this table will never be read twice. This is true under
		the following conditions:

		- We are doing a table scan and the data is in a separate file (MyISAM) or
		if we don't update a clustered key.

		- We are doing a range scan and we don't update the scan key or
		the primary key for a clustered table handler.

		This function gets information about fields to be updated from
		the TABLE::write_set bitmap.

		WARNING
		This code is a bit dependent of how make_join_readinfo() works.

		RETURN
		0 Not safe to update
		1 Safe to update
		*/

		static bool safe_update_on_fly(JOIN_TAB *join_tab)
		{
		TABLE *table= join_tab->table;
		switch (join_tab->type) {
		case JT_SYSTEM:
		case JT_CONST:
		case JT_EQ_REF:
		return TRUE; // At most one matching row
		case JT_REF:
		case JT_REF_OR_NULL:
		return !is_key_used(table, join_tab->ref.key, table->write_set);
		case JT_ALL:
		/* If range search on index */
		if (join_tab->quick)
		return !join_tab->quick->is_keys_used(table->write_set);
		/* If scanning in clustered key */
		if ((table->file->ha_table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX) &&
		table->s->primary_key < MAX_KEY)
		return !is_key_used(table, table->s->primary_key, table->write_set);
		return TRUE;
		default:
		break; // Avoid compler warning
		}
		return FALSE;
		}


		multi_update::~multi_update()
		{