- 16 May, 2007 3 commits
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kostja@vajra.(none) authored
into vajra.(none):/opt/local/work/mysql-5.1-21483
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kostja@vajra.(none) authored
into vajra.(none):/opt/local/work/mysql-5.0-21483
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kostja@vajra.(none) authored
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.
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- 15 May, 2007 6 commits
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kostja@vajra.(none) authored
into vajra.(none):/opt/local/work/mysql-5.1-runtime
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kostja@vajra.(none) authored
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kostja@vajra.(none) authored
into vajra.(none):/opt/local/work/mysql-5.1-runtime
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kostja@vajra.(none) authored
into vajra.(none):/opt/local/work/mysql-5.0-runtime
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kostja@vajra.(none) authored
into vajra.(none):/opt/local/work/mysql-5.0-runtime
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kostja@vajra.(none) authored
into vajra.(none):/opt/local/work/mysql-4.1-runtime
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- 14 May, 2007 9 commits
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dlenev@mockturtle.local authored
into mockturtle.local:/home/dlenev/src/mysql-5.1-cts-3
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dlenev@mockturtle.local authored
TABLES" and failures of alter_table.test on Windows which occured after pushing fix for bugs #20662, #20903, #24508, #24738 (various problems with CREATE TABLE SELECT). ALTER TABLE statements which were handled using "fast" alter table optimization were not properly working under LOCK TABLES if table was transactional (for all table types under Windows). Code implementing "fast" version of ALTER TABLE tried to open and lock table using open_ltable() after renaming .FRM files (which corresponds to renaming tables in normal case) in some cases (for transactional tables or on Windows). This caused problems under LOCK TABLES and conflicted with name-lock taken by ALTER TABLE RENAME on target tables. This patch solves this issue by using reopen_name_locked_table() instead of open_ltable().
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anozdrin/alik@ibm. authored
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anozdrin/alik@ibm. authored
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anozdrin/alik@ibm. authored
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anozdrin/alik@ibm. authored
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anozdrin/alik@ibm. authored
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kostja@vajra.(none) authored
into vajra.(none):/opt/local/work/mysql-5.1-runtime
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kostja@vajra.(none) authored
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- 12 May, 2007 6 commits
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ibabaev@bk-internal.mysql.com authored
into bk-internal.mysql.com:/data0/bk/mysql-5.1-opt
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ibabaev@bk-internal.mysql.com authored
into bk-internal.mysql.com:/data0/bk/mysql-5.0-opt
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igor@olga.mysql.com authored
into olga.mysql.com:/home/igor/mysql-5.1-opt
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igor@olga.mysql.com authored
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igor@olga.mysql.com authored
into olga.mysql.com:/home/igor/mysql-5.1-opt
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igor@olga.mysql.com authored
a crash when the left operand of the predicate is evaluated to NULL. It happens when the rows from the inner tables (tables from the subquery) are accessed by index methods with key values obtained by evaluation of the left operand of the subquery predicate. When this predicate is evaluated to NULL an alternative access with full table scan is used to check whether the result set returned by the subquery is empty or not. The crash was due to the fact the info about the access methods used for regular key values was not properly restored after a switch back from the full scan access method had occurred. The patch restores this info properly. The same problem existed for queries with IN subquery predicates if they were used not at the top level of the queries.
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- 11 May, 2007 16 commits
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evgen@moonbone.local authored
into moonbone.local:/mnt/gentoo64/work/27878-bug-5.0-opt-mysql
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evgen@moonbone.local authored
Corrected test case for the bug#27878.
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dlenev@mockturtle.local authored
into mockturtle.local:/home/dlenev/src/mysql-5.1-cts-3
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dlenev@mockturtle.local authored
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holyfoot/hf@mysql.com/hfmain.(none) authored
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holyfoot/hf@hfmain.(none) authored
into mysql.com:/home/hf/work/27957/my51-27957
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holyfoot/hf@mysql.com/hfmain.(none) authored
into mysql.com:/home/hf/work/27957/my50-27957
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evgen@moonbone.local authored
into moonbone.local:/mnt/gentoo64/work/27878-bug-5.0-opt-mysql
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evgen@moonbone.local authored
database. If a user has a right to update anything in the current database then the access was granted and further checks of access rights for underlying tables wasn't done correctly. The check is done before a view is opened and thus no check of access rights for underlying tables can be carried out. This allows a user to update through a view a table from another database for which he hasn't enough rights. Now the mysql_update() and the mysql_test_update() functions are forces re-checking of access rights after a view is opened.
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holyfoot/hf@mysql.com/hfmain.(none) authored
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dlenev@mockturtle.local authored
into mockturtle.local:/home/dlenev/src/mysql-5.1-cts-3
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dlenev@mockturtle.local authored
into mockturtle.local:/home/dlenev/src/mysql-5.0-cts-3
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dlenev@mockturtle.local authored
into mockturtle.local:/home/dlenev/src/mysql-5.1-cts-3
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dlenev@mockturtle.local authored
Bug #20662 "Infinite loop in CREATE TABLE IF NOT EXISTS ... SELECT with locked tables" Bug #20903 "Crash when using CREATE TABLE .. SELECT and triggers" Bug #24738 "CREATE TABLE ... SELECT is not isolated properly" Bug #24508 "Inconsistent results of CREATE TABLE ... SELECT when temporary table exists" Deadlock occured when one tried to execute CREATE TABLE IF NOT EXISTS ... SELECT statement under LOCK TABLES which held read lock on target table. Attempt to execute the same statement for already existing target table with triggers caused server crashes. Also concurrent execution of CREATE TABLE ... SELECT statement and other statements involving target table suffered from various races (some of which might've led to deadlocks). Finally, attempt to execute CREATE TABLE ... SELECT in case when a temporary table with same name was already present led to the insertion of data into this temporary table and creation of empty non-temporary table. All above problems stemmed from the old implementation of CREATE TABLE ... SELECT in which we created, opened and locked target table without any special protection in a separate step and not with the rest of tables used by this statement. This underminded deadlock-avoidance approach used in server and created window for races. It also excluded target table from prelocking causing problems with trigger execution. The patch solves these problems by implementing new approach to handling of CREATE TABLE ... SELECT for base tables. We try to open and lock table to be created at the same time as the rest of tables used by this statement. If such table does not exist at this moment we create and place in the table cache special placeholder for it which prevents its creation or any other usage by other threads. We still use old approach for creation of temporary tables. Note that we have separate fix for 5.0 since there we use slightly different less intrusive approach.
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dlenev@mockturtle.local authored
Bug #20662 "Infinite loop in CREATE TABLE IF NOT EXISTS ... SELECT with locked tables" Bug #20903 "Crash when using CREATE TABLE .. SELECT and triggers" Bug #24738 "CREATE TABLE ... SELECT is not isolated properly" Bug #24508 "Inconsistent results of CREATE TABLE ... SELECT when temporary table exists" Deadlock occured when one tried to execute CREATE TABLE IF NOT EXISTS ... SELECT statement under LOCK TABLES which held read lock on target table. Attempt to execute the same statement for already existing target table with triggers caused server crashes. Also concurrent execution of CREATE TABLE ... SELECT statement and other statements involving target table suffered from various races (some of which might've led to deadlocks). Finally, attempt to execute CREATE TABLE ... SELECT in case when a temporary table with same name was already present led to the insertion of data into this temporary table and creation of empty non-temporary table. All above problems stemmed from the old implementation of CREATE TABLE ... SELECT in which we created, opened and locked target table without any special protection in a separate step and not with the rest of tables used by this statement. This underminded deadlock-avoidance approach used in server and created window for races. It also excluded target table from prelocking causing problems with trigger execution. The patch solves these problems by implementing new approach to handling of CREATE TABLE ... SELECT for base tables. We try to open and lock table to be created at the same time as the rest of tables used by this statement. If such table does not exist at this moment we create and place in the table cache special placeholder for it which prevents its creation or any other usage by other threads. We still use old approach for creation of temporary tables. Also note that we decided to postpone introduction of some tests for concurrent behaviour of CREATE TABLE ... SELECT till 5.1. The main reason for this is absence in 5.0 ability to set @@debug variable at runtime, which can be circumvented only by using several test files with individual .opt files. Since the latter is likely to slowdown test-suite unnecessary we chose not to push this tests into 5.0, but run them manually for this version and later push their optimized version into 5.1
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holyfoot/hf@hfmain.(none) authored
into mysql.com:/home/hf/work/27957/my51-27957
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