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This deadlock happened if DROP DATABASE was blocked due to an open HANDLER table from a different connection. While DROP DATABASE is blocked, it holds the LOCK_mysql_create_db mutex. This results in a deadlock if the connection with the open HANDLER table tries to execute a CREATE/ALTER/DROP DATABASE statement as they all try to acquire LOCK_mysql_create_db. This patch makes this deadlock scenario very unlikely by closing and marking for re-open all HANDLER tables for which there are pending conflicing locks, before LOCK_mysql_create_db is acquired. However, there is still a very slight possibility that a connection could access one of these HANDLER tables between closing/marking for re-open and the acquisition of LOCK_mysql_create_db. This patch is for 5.1 only, a separate and complete fix will be made for 5.5+. Test case added to schema.test.
62 lines
1.5 KiB
Plaintext
62 lines
1.5 KiB
Plaintext
#
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# Just a couple of tests to make sure that schema works.
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#
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# Drop mysqltest1 database, as it can left from the previous tests.
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#
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# Save the initial number of concurrent sessions.
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--source include/count_sessions.inc
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--disable_warnings
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drop database if exists mysqltest1;
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--enable_warnings
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create schema foo;
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show create schema foo;
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show schemas;
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drop schema foo;
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--echo #
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--echo # Bug#54360 Deadlock DROP/ALTER/CREATE DATABASE with open HANDLER
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--echo #
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CREATE DATABASE db1;
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CREATE TABLE db1.t1 (a INT);
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INSERT INTO db1.t1 VALUES (1), (2);
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--echo # Connection con1
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connect (con1, localhost, root);
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HANDLER db1.t1 OPEN;
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--echo # Connection default
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connection default;
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--echo # Sending:
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--send DROP DATABASE db1
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--echo # Connection con2
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connect (con2, localhost, root);
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--echo # Waiting for 'DROP DATABASE db1' to sync in.
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let $wait_condition=SELECT COUNT(*)=1 FROM information_schema.processlist
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WHERE state='Waiting for table' AND info='DROP DATABASE db1';
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--source include/wait_condition.inc
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--echo # Connection con1
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connection con1;
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# All these statements before resulted in deadlock.
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CREATE DATABASE db2;
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ALTER DATABASE db2 DEFAULT CHARACTER SET utf8;
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DROP DATABASE db2;
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--echo # Connection default
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connection default;
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--echo # Reaping: DROP DATABASE db1
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--reap
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disconnect con1;
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disconnect con2;
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# Check that all connections opened by test cases in this file are really
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# gone so execution of other tests won't be affected by their presence.
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--source include/wait_until_count_sessions.inc
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