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2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1 - initial changeset that introduced the fix for Bug#989 and follow up fixes for all test suite failures introduced in the initial changeset. ------------------------------------------------------------ revno: 2617.31.1 committer: Davi Arnaut <Davi.Arnaut@Sun.COM> branch nick: 4284-6.0 timestamp: Fri 2009-03-06 19:17:00 -0300 message: Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order WL#4284: Transactional DDL locking Currently the MySQL server does not keep metadata locks on schema objects for the duration of a transaction, thus failing to guarantee the integrity of the schema objects being used during the transaction and to protect then from concurrent DDL operations. This also poses a problem for replication as a DDL operation might be replicated even thought there are active transactions using the object being modified. The solution is to defer the release of metadata locks until a active transaction is either committed or rolled back. This prevents other statements from modifying the table for the entire duration of the transaction. This provides commitment ordering for guaranteeing serializability across multiple transactions. - Incompatible change: If MySQL's metadata locking system encounters a lock conflict, the usual schema is to use the try and back-off technique to avoid deadlocks -- this schema consists in releasing all locks and trying to acquire them all in one go. But in a transactional context this algorithm can't be utilized as its not possible to release locks acquired during the course of the transaction without breaking the transaction commitments. To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be returned if a lock conflict is encountered during a transaction. Let's consider an example: A transaction has two statements that modify table t1, then table t2, and then commits. The first statement of the transaction will acquire a shared metadata lock on table t1, and it will be kept utill COMMIT to ensure serializability. At the moment when the second statement attempts to acquire a shared metadata lock on t2, a concurrent ALTER or DROP statement might have locked t2 exclusively. The prescription of the current locking protocol is that the acquirer of the shared lock backs off -- gives up all his current locks and retries. This implies that the entire multi-statement transaction has to be rolled back. - Incompatible change: FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ LOCK won't cause locked tables to be implicitly unlocked anymore. mysql-test/extra/binlog_tests/drop_table.test: Add test case for Bug#989. mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix1.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix2.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/r/flush_block_commit.result: Update test case result (WL#4284). mysql-test/r/flush_block_commit_notembedded.result: Update test case result (WL#4284). mysql-test/r/innodb.result: Update test case result (WL#4284). mysql-test/r/innodb_mysql.result: Update test case result (WL#4284). mysql-test/r/lock.result: Add test case result for an effect of WL#4284/Bug#989 (all locks should be released when a connection terminates). mysql-test/r/mix2_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/not_embedded_server.result: Update test case result (effects of WL#4284/Bug#989). Add a test case for interaction of WL#4284 and FLUSH PRIVILEGES. mysql-test/r/partition_innodb_semi_consistent.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/partition_sync.result: Temporarily disable the test case for Bug#43867, which will be fixed by a subsequent backport. mysql-test/r/ps.result: Add a test case for effect of PREPARE on transactional locks: we take a savepoint at beginning of PREAPRE and release it at the end. Thus PREPARE does not accumulate metadata locks (Bug#989/WL#4284). mysql-test/r/read_only_innodb.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_unsafe.result: A side effect of Bug#989 -- slightly different table map ids. mysql-test/suite/binlog/t/binlog_row_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_row.test: Update to the new state name. This is actually a follow up to another patch for WL#4284, that changes Locked thread state to Table lock. mysql-test/suite/ndb/r/ndb_index_ordered.result: Remove result for disabled part of the test case. mysql-test/suite/ndb/t/disabled.def: Temporarily disable a test case (Bug#45621). mysql-test/suite/ndb/t/ndb_index_ordered.test: Disable a part of a test case (needs update to reflect semantics of Bug#989). mysql-test/suite/rpl/t/disabled.def: Disable tests made meaningless by transactional metadata locking. mysql-test/suite/sys_vars/r/autocommit_func.result: Add a commit (Bug#989). mysql-test/suite/sys_vars/t/autocommit_func.test: Add a commit (Bug#989). mysql-test/t/flush_block_commit.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/t/flush_block_commit_notembedded.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. Add a test case for transaction-scope locks and the global read lock (Bug#989/WL#4284). mysql-test/t/innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (effects of Bug#989/WL#4284). mysql-test/t/lock.test: Add a test case for Bug#989/WL#4284. mysql-test/t/not_embedded_server.test: Add a test case for Bug#989/WL#4284. mysql-test/t/partition_innodb_semi_consistent.test: Replace TRUNCATE with DELETE, to not issue an implicit commit of a transaction, and not depend on metadata locks. mysql-test/t/partition_sync.test: Temporarily disable the test case for Bug#43867, which needs a fix to be backported from 6.0. mysql-test/t/ps.test: Add a test case for semantics of PREPARE and transaction-scope locks: metadata locks on tables used in PREPARE are enclosed into a temporary savepoint, taken at the beginning of PREPARE, and released at the end. Thus PREPARE does not effect what locks a transaction owns. mysql-test/t/read_only_innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). Wait for the read_only statement to actually flush tables before sending other concurrent statements that depend on its state. mysql-test/t/xa.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). sql/ha_ndbcluster_binlog.cc: Backport bits of changes of ha_ndbcluster_binlog.cc from 6.0, to fix the failing binlog test suite with WL#4284. WL#4284 implementation does not work with 5.1 implementation of ndbcluster binlog index. sql/log_event.cc: Release metadata locks after issuing a commit. sql/mdl.cc: Style changes (WL#4284). sql/mysql_priv.h: Rename parameter to match the name used in the definition (WL#4284). sql/rpl_injector.cc: Release metadata locks on commit (WL#4284). sql/rpl_rli.cc: Remove assert made meaningless, metadata locks are released at the end of the transaction. sql/set_var.cc: Close tables and release locks if autocommit mode is set. sql/slave.cc: Release metadata locks after a rollback. sql/sql_acl.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_base.cc: Defer the release of metadata locks when closing tables if not required to. Issue a deadlock error if the locking protocol requires that a transaction re-acquire its locks. Release metadata locks when closing tables for reopen. sql/sql_class.cc: Release metadata locks if the thread is killed. sql/sql_parse.cc: Release metadata locks after implicitly committing a active transaction, or after explicit commits or rollbacks. sql/sql_plugin.cc: Allocate MDL request on the stack as the use of the table is contained within the function. It will be removed from the context once close_thread_tables is called at the end of the function. sql/sql_prepare.cc: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. After some discussions with stakeholders it has been decided that metadata locks acquired during a PREPARE statement must be released once the statement is prepared even if it is prepared within a multi statement transaction. sql/sql_servers.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_table.cc: Close table and release metadata locks after a admin operation. sql/table.h: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. sql/transaction.cc: Release metadata locks after the implicitly committed due to a new transaction being started. Also, release metadata locks acquired after a savepoint if the transaction is rolled back to the save point. The problem is that in some cases transaction-long metadata locks could be released before the transaction was committed. This could happen when a active transaction was ended by a "START TRANSACTION" or "BEGIN" statement, in which case the metadata locks would be released before the actual commit of the active transaction. The solution is to defer the release of metadata locks to after the transaction has been implicitly committed. No test case is provided as the effort to provide one is too disproportional to the size of the fix.
This directory contains a test suite for the MySQL daemon. To run the currently existing test cases, simply execute ./mysql-test-run in this directory. It will fire up the newly built mysqld and test it. Note that you do not have to have to do "make install", and you could actually have a co-existing MySQL installation. The tests will not conflict with it. All tests must pass. If one or more of them fail on your system, please read the following manual section for instructions on how to report the problem: http://dev.mysql.com/doc/mysql/en/mysql-test-suite.html If you want to use an already running MySQL server for specific tests, use the --extern option to mysql-test-run. Please note that in this mode, the test suite expects you to provide the names of the tests to run. For example, here is the command to run the "alias" and "analyze" tests with an external server: mysql-test-run --extern alias analyze To match your setup, you might also need to provide --socket, --user, and other relevant options. With no test cases named on the command line, mysql-test-run falls back to the normal "non-extern" behavior. The reason for this is that some tests cannot run with an external server. You can create your own test cases. To create a test case, create a new file in the t subdirectory using a text editor. The file should have a .test extension. For example: xemacs t/test_case_name.test In the file, put a set of SQL statements that create some tables, load test data, and run some queries to manipulate it. We would appreciate it if you name your test tables t1, t2, t3 ... (to not conflict too much with existing tables). Your test should begin by dropping the tables you are going to create and end by dropping them again. This ensures that you can run the test over and over again. If you are using mysqltest commands (like result file names) in your test case, you should create the result file as follows: mysql-test-run --record test_case_name or mysqltest --record < t/test_case_name.test If you only have a simple test cases consisting of SQL statements and comments, you can create the test case in one of the following ways: mysql-test-run --record test_case_name mysql test < t/test_case_name.test > r/test_case_name.result mysqltest --record --record-file=r/test_case_name.result < t/test_case_name.test When this is done, take a look at r/test_case_name.result - If the result is incorrect, you have found a bug. In this case, you should edit the test result to the correct results so that we can verify that the bug is corrected in future releases. To submit your test case, put your .test file and .result file(s) into a tar.gz archive, add a README that explains the problem, ftp the archive to ftp://support.mysql.com/pub/mysql/secret/ and send a mail to bugs@lists.mysql.com