… because of “Opening Tables” stage was taking long. Part of the problem is Innodb is updating stats on each table open which is possibly… he confirmed MySQL has global table cache mutex (LOCK_open) which is held for all open table operation so table opens are serialized. Do not think… blocking physical IO or network operation if you care about scalability. MySQL has same problem with key buffer but that was…
Post: table_cache negative scalability
November 16, 2009 By 23 Comments
… not expect such a table_cache issue – the LRU for cache management is classics and there are scalable algorithms to deal with…. So if you tune table cache is “normal” case and is able to bring down your miss rate (opened_tables) to 10/sec or less by using large table_cache you should do so. However if you have so many tables you…
Post: My "hot" list for next InnoDB features
March 30, 2009 By 18 Comments
…-productive Open InnoDB tables in parallel. Currently opening table is serialized, and it is especially bad at start time, when InnoDB takes probes during opening table, as it is slow operation. See also http://www.mysqlperformanceblog.com/2006/11/21/opening-tables-scalability/. Partially it can…
Comment: Why you don't want to shard.
August 6, 2009 By 33 Comments
…. In MySQL-terms that means at least 1 file per table (.frm), and a lot of pressure on your filesystem to… opening tables scalability in MySQL. See http://www.mysqlperformanceblog.com/2006/11/21/opening-tables-scalability/ and http://www.mysqlperformanceblog.com/2009/06/16/slow-drop-table…
Comment: Opening Tables scalability
March 31, 2009 By 27 Comments
[...] bad at start time, when InnoDB takes probes during opening table, as it is slow operation. See also http://www.mysqlperformanceblog.com/2006/11/21/opening-tables-scalability/. Partially it can be fixed by recent patches by enabling / disabling probes and changing count of [...]
Comment: Opening Tables scalability
November 22, 2006 By 27 Comments
[...] Inspired by PeterZ’s Opening Tables scalability post, I decided to try a little benchmark. This benchmark involved the following: [...]
Post: Is VoltDB really as scalable as they claim?
February 28, 2011 By 3 Comments
… is an in-memory shared-nothing system, and tables are partitioned across multiple servers in the cluster;…J. Gunther’s Universal Scalability Law (USL) to model the cluster’s scalability. If you are not familiar…of benchmarks to satisfy my curiosity. In the opening of this post, I say “should scale” …
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…, scalability,…tables, I’ll paste in mysql> show global variables like ‘%table_size%’; +———————+———–+ | Variable_name | Value | +———————+———–+ | max_heap_table_size | 268435456 | | tmp_table…openings in chess — the great chess players study openings…
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
…_pool_size Q36: There have been several MySQL bugs opened about multi-core scalability (concurrent queries, autoincrement, concurrent inserts, instrumentation, etc.). Rather… a bit. I also like to keep tables small enough, “sharding” to many tables before they become so large it would take…
Post: Scaling problems still exist in MySQL 5.5 and Percona Server 5.5
May 20, 2011 By 11 Comments
…. The query looks something like this: SELECT * FROM table WHERE deleted = 0 AND group_id IN (62715996, 62716592…physical cores and 24 threads, which is almost perfect scalability. So there are workloads where the problem is …_cur_search_to_nth_level,btr_p cur_open_with_no_init_func,row_sel_get_clust_…
