…_switch=’join_cache_incremental=on’ optimizer_switch=’join_cache_hashed=on’ optimizer_switch=’join_cache_bka=on’ join_cache_level=8 join_buffer_size=6M mrr_buffer… 5.5 w/ join_buffer_size=6M & mrr_buffer_size=6M MariaDB 5.5 Hash Join Disabled w/ join_buffer_size=4M & mrr_buffer_size=4M Created…
Comment: Too many connections? No problem!
March 15, 2012 By 28 Comments
…_size=32M thread_cache_size=30 table_cache=4096 join_buffer_size=6M key_buffer_size=12M server-id = 1 log-bin=/data…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
… introduces a different variable to control the MRR buffer size mrr_buffer_size. Both buffer sizes default to 256K in MySQL 5.6… Innodb_buffer_pool_read_ahead 0 20920 23669 20920 23734 Innodb_buffer_pool_read_requests 1361851 1264739 1235472 1263290 1235781 Innodb_buffer_pool… lookups as well. But this works only with joins and specifically with Block Access Join Algorithms. So I am not going to…
Post: MariaDB 5.3 is released as GA!
March 5, 2012 By 17 Comments
… log enabled Faster queries through speedier joins, faster subqueries, and elimination of useless tables in joins Thread pooling and a segmented key… diagnostics, improvements to partitioning, and the addition of multiple InnoDB buffer pools. Best of all, MariaDB 5.5 might be here…
Post: How is join_buffer_size allocated?
July 5, 2010 By 9 Comments
… (key_buffer_size). There are many examples of this. What about join_buffer_size? I saw a my.cnf with a 128M join_buffer_size the other day and needed to research this quickly before I gave advice. The join buffer is a… per-join-per-thread, in special cases. A join buffer is allocated to cache rows from each table in a join when the join can…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
… Innodb_buffer_pool_read_requestsblogpercona.commanual Innodb_buffer_pool_readsblogpercona.commanual innodb_buffer_pool_sizeblogpercona.commanual Innodb_buffer_pool_wait_freeblogpercona.commanual Innodb_buffer_pool…_write_io_threadsblogpercona.commanual insert_idblogpercona.commanual interactive_timeoutblogpercona.commanual join_buffer_sizeblogpercona.commanual keep_files_on_createblogpercona.commanual Key_blocks_not…
Comment: How much memory can MySQL use in the worst case?
February 12, 2009 By 17 Comments
…*(thread_stack + join_buffer_size + sort_buffer_size + binlog_cache_size…) is so much misleading. In particular, the join_buffer_size, sort_buffer_size are interesting to note: sort_buffer_size is only used when sorting without index join_buffer_size is…
Comment: How is join_buffer_size allocated?
September 22, 2010 By 9 Comments
I disagree with “A join buffer is allocated to cache rows from each table in a join when the join can’t use an… to use the join buffer. Also, there is another variable that determines the max size of join buffer and that is max_join_size (no. of rows to be joined not the buffer size).
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 139 Comments
… you’re dealing with very large data sets are Buffers, Indexes and Joins. Buffers First thing you need to take into account is… reduce the gap but I doubt it will be closed. Joins Joins are used to compose the complex object which was previously… less full table scan may be faster. Avoid joins to large tables Joining of large data sets using nested loops is very…
Post: How well does your table fits in innodb buffer pool ?
December 9, 2010 By 11 Comments
… FROM innodb_buffer_pool_pages_index GROUP BY index_id) bp JOIN innodb_sys_indexes ON id = index_id JOIN innodb_sys_tables… from the cache. You can use this feature to tune buffer pool invalidation strategy, for example play with innodb_old_blocks… and innodb_old_blocks_time actually observing data stored in buffer pool rather than using some form of temporary measures. I…
