…Ori – thank you. In response to MySQL Cluster, I throw this into a different category of sharding (… you. Having said that: I’d still consider “migrating to MySQL Cluster” as a similar decision to “migrating to another database… into an existing application. I’d like to see join performance (via hash joins) improved for example, but there are a few more…
Comment: MariaDB 5.3.4 benchmarks
February 22, 2012 By 24 Comments
… iteration. Mysql is slow there as it does not support hash join. But it compensates by caching the results and the joined temp table. However if you insert a record you will force mysql to expire its cache related to that join. Mariadb is faster with those joins but seems like its…
Comment: Why MySQL could be slow with large tables ?
August 17, 2010 By 141 Comments
… MySQL is lack of advanced join methods at this point (the work is on a way) – MySQL can’t do hash join or sort merge join… of index lookups which may be random.” Are the advanced join methods available now?
Comment: A workaround for the performance problems of TEMPTABLE views
May 19, 2010 By 7 Comments
It’s unbelievable how bad the mysql query execution engine is. MS SQL, Oracle and even Postgres … across views. And they have merge and hash join so you are not forced to join manually in PHP like some very big sites are forced to… I cannot believe that MySql still does…
Post: TPC-H Run on MySQL 5.1 and 6.0
April 10, 2008 By 16 Comments
… to 3 hours to give MySQL more time to complete the queries: Query MySQL 5.0.23 MySQL 6.0.4Ratio Query13784.453737… be as surprised by these results – MySQL 6.0 still does not have hash or merge join which are frequently used for these kind of queries, and there is also no query parallelization which would allow MySQL…
Comment: Air traffic queries in InfiniDB: early alpha
November 3, 2009 By 19 Comments
… hash joins in the engine first (which are in) and then come back to do subqueries that perform much better than general MySQL…
Post: Where does HandlerSocket really save you time?
March 16, 2011 By Leave a Comment
…_lock 2056062.1262make_join_statistics(…) 1982342.0500btr_search_guess_on_hash 1807311.8690JOIN::optimize() 1771201.8317row_search_for_mysql 1711851.7703lex_one…) samples%symbol name 11968414.7394btr_search_guess_on_hash 582027.1678row_search_for_mysql 469465.7815mutex_delay 386174.7558my_pthread_fastmutex_lock…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… hash table 0 LIST OF TRANSACTIONS FOR EACH SESSION: —TRANSACTION 0 0, not started, process no 3396, OS thread id 1152440672 MySQL… id 1148250464, thread declared inside InnoDB 442 mysql tables in use 1, locked 0 MySQL thread id 8079, query id 728899 localhost… status could be “waiting in InnoDB queue” or “sleeping before joining InnoDB queue”. Latest one is quite interesting – to avoid too…
Post: How well does your table fits in innodb buffer pool ?
December 9, 2010 By 12 Comments
… in cache, for example being washed away by other queries. MySQL Server does not provide any information of this type, Percona…(hashed = 1) hashed FROM innodb_buffer_pool_pages_index GROUP BY index_id) bp JOIN innodb_sys_indexes ON id = index_id JOIN innodb… LIMIT 20; +————–+————–+————–+——+——-+——–+———+ | table_schema | table_name | index_name | cnt | dirty | hashed | fit_pct | +————–+————–+————–+——+——-+——–+———+ | test | a | c | 7976 | 0 | 0 | 13.73…
Post: Using Multiple Key Caches for MyISAM Scalability
November 26, 2008 By 8 Comments
… or something similar, or actually just keep hash of locks instead of one. When you …about table usage I will use Percona Patches: mysql> select * from information_schema.table_statistics where …)),”;”) cmd from information_schema.table_statistics ts join information_schema.tables t on t.table_…
