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replication causing replication to fail. In parallel replication, we run transactions from the master in parallel, but force them to commit in the same order they did on the master. If we force T1 to commit before T2, but T2 holds eg. a row lock that is needed by T1, we get a deadlock when T2 waits until T1 has committed. Usually, we do not run T1 and T2 in parallel if there is a chance that they can have conflicting locks like this, but there are certain edge cases where it can occasionally happen (eg. MDEV-5914, MDEV-5941, MDEV-6020). The bug was that this would cause replication to hang, eventually getting a lock timeout and causing the slave to stop with error. With this patch, InnoDB will report back to the upper layer whenever a transactions T1 is about to do a lock wait on T2. If T1 and T2 are parallel replication transactions, and T2 needs to commit later than T1, we can thus detect the deadlock; we then kill T2, setting a flag that causes it to catch the kill and convert it to a deadlock error; this error will then cause T2 to roll back and release its locks (so that T1 can commit), and later T2 will be re-tried and eventually also committed. The kill happens asynchroneously in a slave background thread; this is necessary, as the reporting from InnoDB about lock waits happen deep inside the locking code, at a point where it is not possible to directly call THD::awake() due to mutexes held. Deadlock is assumed to be (very) rarely occuring, so this patch tries to minimise the performance impact on the normal case where no deadlocks occur, rather than optimise the handling of the occasional deadlock. Also fix transaction retry due to deadlock when it happens after a transaction already signalled to later transactions that it started to commit. In this case we need to undo this signalling (and later redo it when we commit again during retry), so following transactions will not start too early. Also add a missing thd->send_kill_message() that got triggered during testing (this corrects an incorrect fix for MySQL Bug#58933). |
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| .. | ||
| collections | ||
| extra | ||
| include | ||
| lib | ||
| r | ||
| std_data | ||
| suite | ||
| t | ||
| CMakeLists.txt | ||
| disabled.def | ||
| mtr.out-of-source | ||
| mysql-stress-test.pl | ||
| mysql-test-run.pl | ||
| purify.supp | ||
| README | ||
| README.gcov | ||
| README.stress | ||
| suite.pm | ||
| valgrind.supp | ||
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. To run the test suite in a source directory, you must do make first. 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://kb.askmonty.org/v/reporting-bugs 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 socket=/tmp/mysql.sock 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 --database test --result-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. If you want to submit your test case you can send it to maria-developers@lists.launchpad.com or attach it to a bug report on http://mariadb.org/jira/. If the test case is really big or if it contains 'not public' data, then 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://ftp.askmonty.org/private and submit a report to http://mariadb.org/jira about it.