a55b951e60
For more convenient monitoring of something that could greatly affect the volume of page writes, we add the status variable Innodb_buffer_pool_pages_split that was previously only available via information_schema.innodb_metrics as "innodb_page_splits". This was suggested by Axel Schwenke. buf_flush_page_count: Replaced with buf_pool.stat.n_pages_written. We protect buf_pool.stat (except n_page_gets) with buf_pool.mutex and remove unnecessary export_vars indirection. buf_pool.flush_list_bytes: Moved from buf_pool.stat.flush_list_bytes. Protected by buf_pool.flush_list_mutex. buf_pool_t::page_cleaner_status: Replaces buf_pool_t::n_flush_LRU_, buf_pool_t::n_flush_list_, and buf_pool_t::page_cleaner_is_idle. Protected by buf_pool.flush_list_mutex. We will exclusively broadcast buf_pool.done_flush_list by the buf_flush_page_cleaner thread, and only wait for it when communicating with buf_flush_page_cleaner. There is no need to keep a count of pending writes by the buf_pool.flush_list processing. A single flag suffices for that. Waits for page write completion can be performed by simply waiting on block->page.lock, or by invoking buf_dblwr.wait_for_page_writes(). buf_LRU_block_free_non_file_page(): Broadcast buf_pool.done_free and set buf_pool.try_LRU_scan when freeing a page. This would be executed also as part of buf_page_write_complete(). buf_page_write_complete(): Do not broadcast buf_pool.done_flush_list, and do not acquire buf_pool.mutex unless buf_pool.LRU eviction is needed. Let buf_dblwr count all writes to persistent pages and broadcast a condition variable when no outstanding writes remain. buf_flush_page_cleaner(): Prioritize LRU flushing and eviction right after "furious flushing" (lsn_limit). Simplify the conditions and reduce the hold time of buf_pool.flush_list_mutex. Refuse to shut down or sleep if buf_pool.ran_out(), that is, LRU eviction is needed. buf_pool_t::page_cleaner_wakeup(): Add the optional parameter for_LRU. buf_LRU_get_free_block(): Protect buf_lru_free_blocks_error_printed with buf_pool.mutex. Invoke buf_pool.page_cleaner_wakeup(true) to to ensure that buf_flush_page_cleaner() will process the LRU flush request. buf_do_LRU_batch(), buf_flush_list(), buf_flush_list_space(): Update buf_pool.stat.n_pages_written when submitting writes (while holding buf_pool.mutex), not when completing them. buf_page_t::flush(), buf_flush_discard_page(): Require that the page U-latch be acquired upfront, and remove buf_page_t::ready_for_flush(). buf_pool_t::delete_from_flush_list(): Remove the parameter "bool clear". buf_flush_page(): Count pending page writes via buf_dblwr. buf_flush_try_neighbors(): Take the block of page_id as a parameter. If the tablespace is dropped before our page has been written out, release the page U-latch. buf_pool_invalidate(): Let the caller ensure that there are no outstanding writes. buf_flush_wait_batch_end(false), buf_flush_wait_batch_end_acquiring_mutex(false): Replaced with buf_dblwr.wait_for_page_writes(). buf_flush_wait_LRU_batch_end(): Replaces buf_flush_wait_batch_end(true). buf_flush_list(): Remove some broadcast of buf_pool.done_flush_list. buf_flush_buffer_pool(): Invoke also buf_dblwr.wait_for_page_writes(). buf_pool_t::io_pending(), buf_pool_t::n_flush_list(): Remove. Outstanding writes are reflected by buf_dblwr.pending_writes(). buf_dblwr_t::init(): New function, to initialize the mutex and the condition variables, but not the backing store. buf_dblwr_t::is_created(): Replaces buf_dblwr_t::is_initialised(). buf_dblwr_t::pending_writes(), buf_dblwr_t::writes_pending: Keeps track of writes of persistent data pages. buf_flush_LRU(): Allow calls while LRU flushing may be in progress in another thread. Tested by Matthias Leich (correctness) and Axel Schwenke (performance) |
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| client | ||
| cmake | ||
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| debian | ||
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| include | ||
| libmariadb@12bd1d5511 | ||
| libmysqld | ||
| libservices | ||
| man | ||
| mysql-test | ||
| mysys | ||
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| sql-common | ||
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| configure.cmake | ||
| CONTRIBUTING.md | ||
| COPYING | ||
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| INSTALL-WIN-SOURCE | ||
| KNOWN_BUGS.txt | ||
| README.md | ||
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Code status:
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MariaDB: The open source relational database
MariaDB was designed as a drop-in replacement of MySQL(R) with more features, new storage engines, fewer bugs, and better performance.
MariaDB is brought to you by the MariaDB Foundation and the MariaDB Corporation. Please read the CREDITS file for details about the MariaDB Foundation, and who is developing MariaDB.
MariaDB is developed by many of the original developers of MySQL who now work for the MariaDB Corporation, the MariaDB Foundation and by many people in the community.
MySQL, which is the base of MariaDB, is a product and trademark of Oracle Corporation, Inc. For a list of developers and other contributors, see the Credits appendix. You can also run 'SHOW authors' to get a list of active contributors.
A description of the MariaDB project and a manual can be found at:
https://mariadb.com/kb/en/mariadb-vs-mysql-features/
https://mariadb.com/kb/en/mariadb-versus-mysql-compatibility/
https://mariadb.com/kb/en/new-and-old-releases/
Help
More help is available from the Maria Discuss mailing list https://launchpad.net/~maria-discuss, MariaDB's Zulip instance, https://mariadb.zulipchat.com/
Live QA for beginner contributors
MariaDB has a dedicated time each week when we answer new contributor questions live on Zulip. From 8:00 to 10:00 UTC on Mondays, and 10:00 to 12:00 UTC on Thursdays, anyone can ask any questions they’d like, and a live developer will be available to assist.
New contributors can ask questions any time, but we will provide immediate feedback during that interval.
Licensing
NOTE:
MariaDB is specifically available only under version 2 of the GNU General Public License (GPLv2). (I.e. Without the "any later version" clause.) This is inherited from MySQL. Please see the README file in the MySQL distribution for more information.
License information can be found in the COPYING file. Third party license information can be found in the THIRDPARTY file.
Bug Reports
Bug and/or error reports regarding MariaDB should be submitted at: https://jira.mariadb.org
For reporting security vulnerabilities see: https://mariadb.org/about/security-policy/
The code for MariaDB, including all revision history, can be found at: https://github.com/MariaDB/server