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Bug#21483 "Server abort or deadlock on INSERT DELAYED with another implicit insert" Also fixes and adds test cases for bugs: 20497 "Trigger with INSERT DELAYED causes Error 1165" 21714 "Wrong NEW.value and server abort on INSERT DELAYED to a table with a trigger". Post-review fixes. Problem: In MySQL INSERT DELAYED is a way to pipe all inserts into a given table through a dedicated thread. This is necessary for simplistic storage engines like MyISAM, which do not have internal concurrency control or threading and thus can not achieve efficient INSERT throughput without support from SQL layer. DELAYED INSERT works as follows: For every distinct table, which can accept DELAYED inserts and has pending data to insert, a dedicated thread is created to write data to disk. All user connection threads that attempt to delayed-insert into this table interact with the dedicated thread in producer/consumer fashion: all records to-be inserted are pushed into a queue of the dedicated thread, which fetches the records and writes them. In this design, client connection threads never open or lock the delayed insert table. This functionality was introduced in version 3.23 and does not take into account existence of triggers, views, or pre-locking. E.g. if INSERT DELAYED is called from a stored function, which, in turn, is called from another stored function that uses the delayed table, a deadlock can occur, because delayed locking by-passes pre-locking. Besides: * the delayed thread works directly with the subject table through the storage engine API and does not invoke triggers * even if it was patched to invoke triggers, if triggers, in turn, used other tables, the delayed thread would have to open and lock involved tables (use pre-locking). * even if it was patched to use pre-locking, without deadlock detection the delayed thread could easily lock out user connection threads in case when the same table is used both in a trigger and on the right side of the insert query: the delayed thread would not release locks until all inserts are complete, and user connection can not complete inserts without having locks on the tables used on the right side of the query. Solution: These considerations suggest two general alternatives for the future of INSERT DELAYED: * it is considered a full-fledged alternative to normal INSERT * it is regarded as an optimisation that is only relevant for simplistic engines. Since we missed our chance to provide complete support of new features when 5.0 was in development, the first alternative currently renders infeasible. However, even the second alternative, which is to detect new features and convert DELAYED insert into a normal insert, is not easy to implement. The catch-22 is that we don't know if the subject table has triggers or is a view before we open it, and we only open it in the delayed thread. We don't know if the query involves pre-locking until we have opened all tables, and we always first create the delayed thread, and only then open the remaining tables. This patch detects the problematic scenarios and converts DELAYED INSERT to a normal INSERT using the following approach: * if the statement is executed under pre-locking (e.g. from within a stored function or trigger) or the right side may require pre-locking, we detect the situation before creating a delayed insert thread and convert the statement to a conventional INSERT. * if the subject table is a view or has triggers, we shutdown the delayed thread and convert the statement to a conventional INSERT. mysql-test/r/insert.result: Update test results. mysql-test/t/insert.test: Add a test case for Bug#21483, Bug#20497, Bug#21714 (INSERT DELAYED and stored routines, triggers). sql/sp_head.cc: Upgrade lock type to TL_WRITE when computing the pre-locking set. sql/sql_base.cc: Use a new method. sql/sql_insert.cc: INSERT DELAYED and pre-locking: - if under pre-locking, upgrade the lock type to TL_WRITE and proceed as a normal write - if DELAYED table has triggers, also request a lock upgrade. - make sure errors in the delayed thread are propagated correctly sql/sql_lex.h: Add a method to check if a parsed tree refers to stored routines. |
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| misc | ||
| ndb | ||
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| suite | ||
| t | ||
| create-test-result | ||
| fix-result | ||
| install_test_db.sh | ||
| Makefile.am | ||
| mysql-stress-test.pl | ||
| mysql-test-run-shell.sh | ||
| mysql-test-run.pl | ||
| purify.supp | ||
| README | ||
| README.gcov | ||
| README.stress | ||
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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