# # Test of MERGE tables with multisession and many waits. # # This test takes rather long time so let us run it only in --big-test mode --source include/big_test.inc # We use some debug-only features in this test --source include/have_debug.inc # We use INFORMATION_SCHEMA.PROCESSLIST in this test --source include/not_embedded.inc --disable_warnings drop table if exists t1,t2,t3,t4,t5,t6; --enable_warnings --echo # --echo # Bug#26379 - Combination of FLUSH TABLE and REPAIR TABLE --echo # corrupts a MERGE table --echo # Problem #3 --echo # # Two FLUSH TABLES within a LOCK TABLES segment could invalidate the lock. # This did *not* require a MERGE table. # # To increase reproducibility it was necessary to enter a sleep of 2 # seconds at the end of wait_for_tables() after unlock of LOCK_open. In # 5.0 and 5.1 the sleep must be inserted in open_and_lock_tables() after # open_tables() instead. wait_for_tables() is not used in this case. The # problem was that FLUSH TABLES releases LOCK_open while having unlocked # and closed all tables. When this happened while a thread was in the # loop in mysql_lock_tables() right after wait_for_tables() # (open_tables()) and before retrying to lock, the thread got the lock. # And it did not notice that the table needed a refresh after the # [re-]open. So it executed its statement on the table. # # The first FLUSH TABLES kicked the INSERT out of thr_multi_lock() and # let it wait in wait_for_tables() (open_table()). The second FLUSH # TABLES must happen while the INSERT was on its way from # wait_for_tables() (open_table()) to the next call of thr_multi_lock(). # This needed to be supported by a sleep to make it repeatable. # CREATE TABLE t1 (c1 INT) ENGINE= MyISAM; LOCK TABLE t1 WRITE; #SELECT NOW(); --echo # connection con1 connect (con1,localhost,root,,); let $con1_id= `SELECT CONNECTION_ID()`; SET @orig_debug=@@debug; SET GLOBAL debug="+d,sleep_open_and_lock_after_open"; send INSERT INTO t1 VALUES (1); --echo # connection default connection default; --echo # Let INSERT go into thr_multi_lock(). #--sleep 8 #SELECT ID,STATE,INFO FROM INFORMATION_SCHEMA.PROCESSLIST; let $wait_condition= SELECT 1 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE ID = $con1_id AND STATE = "Table Lock"; --source include/wait_condition.inc #SELECT NOW(); --echo # Kick INSERT out of thr_multi_lock(). FLUSH TABLES; #SELECT NOW(); --echo # Let INSERT go through open_tables() where it sleeps. #--sleep 8 #SELECT ID,STATE,INFO FROM INFORMATION_SCHEMA.PROCESSLIST; let $wait_condition= SELECT 1 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE ID = $con1_id AND STATE = 'Waiting for table'; --source include/wait_condition.inc #SELECT NOW(); --echo # Unlock and close table and wait for con1 to close too. FLUSH TABLES; #SELECT NOW(); --echo # This should give no result. SELECT * FROM t1; #SELECT NOW(); UNLOCK TABLES; --echo # connection con1 connection con1; reap; SET GLOBAL debug=@orig_debug; disconnect con1; --echo # connection default connection default; DROP TABLE t1;