#At file:///home/satya/WORK/mysql-5.1-bugteam-40827/ based on revid:alfranio.correia@stripped
2751 Satya B 2009-02-27
BUG#40827 - Killing insert-select to MyISAM can cause table corruption
Killing insert-select statement on MyISAM corrupts the table.
Killing the insert-select statement corrupts the MyISAM table only
when the destination table is empty and when it has indexes. When
we bulk insert huge data and if the destination table is empty we
disable the indexes for fast inserts, data is then inserted and
indexes are re-enabled after bulk_insert operation
Killing the query, aborts the repair table operation during enable indexes
phase leading to table corruption.
We now truncate the table when we detect that enable indexes is
killed for bulk insert query.As we have an empty table before the operation,
we can fix by truncating the table.
modified:
mysql-test/r/myisam.result
mysql-test/t/myisam.test
storage/myisam/ha_myisam.cc
per-file messages:
mysql-test/r/myisam.result
Modified result file for testcase added for BUG#40827
mysql-test/t/myisam.test
Modified myisam.test for BUG#40827 to add testcase which tests if
myisam table is ok when insert select query is killed.
storage/myisam/ha_myisam.cc
Fixed end_bulk_insert() method to truncate the table when we detect enable
index operation is killed.
=== modified file 'mysql-test/r/myisam.result'
--- a/mysql-test/r/myisam.result 2008-08-26 13:53:22 +0000
+++ b/mysql-test/r/myisam.result 2009-02-27 08:25:35 +0000
@@ -2226,4 +2226,40 @@ Key Start Len Index Type
1 2 30 multip. varchar
2 33 30 multip. char NULL
DROP TABLE t1;
+CREATE TABLE `t1` (
+`id` BIGINT(20) ,
+`id1` BIGINT(20) AUTO_INCREMENT,
+KEY(id1), KEY(id)
+) ENGINE=MyISAM;
+CREATE TABLE `t2` (
+`id` BIGINT(20) ,
+`id1` BIGINT(20) AUTO_INCREMENT,
+KEY (id1), KEY(id)
+) ENGINE=MyISAM;
+INSERT INTO t2 (id) VALUES (123);
+INSERT INTO t2 (id) SELECT id FROM t2;
+INSERT INTO t2 (id) SELECT id FROM t2;
+INSERT INTO t2 (id) SELECT id FROM t2;
+INSERT INTO t2 (id) SELECT id FROM t2;
+INSERT INTO t2 (id) SELECT id FROM t2;
+INSERT INTO t2 (id) SELECT id FROM t2;
+INSERT INTO t2 (id) SELECT id FROM t2;
+INSERT INTO t2 (id) SELECT id FROM t2;
+INSERT INTO t2 (id) SELECT id FROM t2;
+INSERT INTO t2 (id) SELECT id FROM t2;
+# Switch to insert Connection
+SET SESSION debug='+d,wait_in_enable_indexes';
+# Send insert data
+INSERT INTO t1(id) SELECT id FROM t2;
+# Switch to default Connection
+# Wait for insert data to reach the debug point
+SELECT ID FROM INFORMATION_SCHEMA.PROCESSLIST
+WHERE STATE = 'wait_in_enable_indexes' AND
+INFO = "INSERT INTO t1(id) SELECT id FROM t2"
+INTO @thread_id;
+KILL QUERY @thread_id;
+CHECK TABLE t1;
+Table Op Msg_type Msg_text
+test.t1 check status OK
+DROP TABLE t1,t2;
End of 5.1 tests
=== modified file 'mysql-test/t/myisam.test'
--- a/mysql-test/t/myisam.test 2008-08-26 13:53:22 +0000
+++ b/mysql-test/t/myisam.test 2009-02-27 08:25:35 +0000
@@ -1477,5 +1477,56 @@ CREATE TABLE t1 (
--exec $MYISAMCHK -d $MYSQLTEST_VARDIR/master-data/test/t1
DROP TABLE t1;
+#
+# BUG#40827 - Killing insert-select to MyISAM can cause table corruption
+#
+CONNECT (insertConn, localhost, root,,);
+
+CREATE TABLE `t1` (
+`id` BIGINT(20) ,
+`id1` BIGINT(20) AUTO_INCREMENT,
+ KEY(id1), KEY(id)
+) ENGINE=MyISAM;
+
+CREATE TABLE `t2` (
+`id` BIGINT(20) ,
+`id1` BIGINT(20) AUTO_INCREMENT,
+ KEY (id1), KEY(id)
+) ENGINE=MyISAM;
+
+ INSERT INTO t2 (id) VALUES (123);
+
+let $i = 10;
+while ($i > 0)
+{
+ INSERT INTO t2 (id) SELECT id FROM t2;
+ dec $i;
+}
+
+--echo # Switch to insert Connection
+CONNECTION insertConn;
+SET SESSION debug='+d,wait_in_enable_indexes';
+--echo # Send insert data
+SEND INSERT INTO t1(id) SELECT id FROM t2;
+
+--echo # Switch to default Connection
+CONNECTION default;
+--echo # Wait for insert data to reach the debug point
+
+let $wait_condition=
+ SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.PROCESSLIST
+ WHERE STATE = "wait_in_enable_indexes" AND
+ INFO = "INSERT INTO t1(id) SELECT id FROM t2";
+--source include/wait_condition.inc
+
+SELECT ID FROM INFORMATION_SCHEMA.PROCESSLIST
+WHERE STATE = 'wait_in_enable_indexes' AND
+INFO = "INSERT INTO t1(id) SELECT id FROM t2"
+INTO @thread_id;
+
+KILL QUERY @thread_id;
+CHECK TABLE t1;
+DROP TABLE t1,t2;
+DISCONNECT insertConn;
--echo End of 5.1 tests
=== modified file 'storage/myisam/ha_myisam.cc'
--- a/storage/myisam/ha_myisam.cc 2008-03-28 10:14:27 +0000
+++ b/storage/myisam/ha_myisam.cc 2009-02-27 08:25:35 +0000
@@ -43,6 +43,29 @@ TYPELIB myisam_stats_method_typelib= {
array_elements(myisam_stats_method_names) - 1, "",
myisam_stats_method_names, NULL};
+/**
+ Causes the thread to wait in a spin lock for a query kill signal.
+ This function is used by the test frame work to identify race conditions.
+
+ The signal is caught and ignored and the thread is not killed.
+*/
+
+static void debug_wait_for_kill(const char *info)
+{
+ DBUG_ENTER("debug_wait_for_kill");
+ const char *prev_info;
+ THD *thd;
+ thd= current_thd;
+ prev_info= thd->proc_info;
+ thd->proc_info= info;
+ sql_print_information(info);
+ while(!thd->killed)
+ my_sleep(1000);
+ thd->killed= THD::NOT_KILLED;
+ sql_print_information("Exit debug_wait_for_kill");
+ thd->proc_info= prev_info;
+ DBUG_VOID_RETURN;
+}
/*****************************************************************************
** MyISAM tables
@@ -1386,6 +1409,9 @@ int ha_myisam::enable_indexes(uint mode)
{
int error;
+ DBUG_EXECUTE_IF("wait_in_enable_indexes",
+ debug_wait_for_kill("wait_in_enable_indexes"); );
+
if (mi_is_all_keys_active(file->s->state.key_map, file->s->base.keys))
{
/* All indexes are enabled already. */
@@ -1499,6 +1525,9 @@ void ha_myisam::start_bulk_insert(ha_row
/*
Only disable old index if the table was empty and we are inserting
a lot of rows.
+ Note that in end_bulk_insert() we may truncate the table if
+ enable_indexes() failed, thus it's essential that indexes are
+ disabled ONLY for an empty table.
We should not do this for only a few rows as this is slower and
we don't want to update the key statistics based of only a few rows.
*/
@@ -1532,8 +1561,27 @@ int ha_myisam::end_bulk_insert()
{
mi_end_bulk_insert(file);
int err=mi_extra(file, HA_EXTRA_NO_CACHE, 0);
- return err ? err : can_enable_indexes ?
- enable_indexes(HA_KEY_SWITCH_NONUNIQ_SAVE) : 0;
+ if (!err)
+ {
+ if (can_enable_indexes)
+ {
+ /*
+ Truncate the table when enable index operation is killed.
+ After truncating the table we don't need to enable the
+ indexes, because the last repair operation is aborted after
+ setting the indexes as active and trying to recreate them.
+ */
+
+ if (((err= enable_indexes(HA_KEY_SWITCH_NONUNIQ_SAVE)) != 0) &&
+ current_thd->killed)
+ {
+ delete_all_rows();
+ /* not crashed, despite being killed during repair */
+ file->s->state.changed&= ~(STATE_CRASHED|STATE_CRASHED_ON_REPAIR);
+ }
+ }
+ }
+ return err;
}
