…mysql-username playback –mysql-password PaSSwOrd –mysql-schema schema_name –query-log-stdin –dispatcher-plugin thread-pool –thread-pool-threads-count…step because update statements that match no rows or insert statements that…expected everything to be cached if we warmed the cache with the exact …
Post: Virident vCache vs. FlashCache: Part 2
May 17, 2013 By 3 Comments
… vCache, and I also included a “no cache” test run as well using the base HDD MySQL configuration for purposes of comparison. Given… have “no cache“, “FlashCache”, “vCache with no time-based flushing”, and “vCache with time-based flushing.” As the images demonstrate, the no-cache system is… = 5000 max_prepared_stmt_count=500000 max_connect_errors = 10 table_open_cache = 10240 max_allowed_packet = 16M binlog_cache_size = 16M max…
Post: More on MySQL transaction descriptors optimization
April 26, 2013 By Leave a Comment
…-node (on the right) configuration. No surprises here, the general…connections=5000 table_open_cache=5000 query_cache_type=OFF performance… –test=oltp.lua –oltp_tables_count=8 –oltp-table-size=1000000… –mysql-user=root –mysql-db=sbtest8t1M –mysql-table-engine=INNODB –mysql-socket=/tmp/mysql.sock…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
…(Battery or capacitor-backed write cache), etc., but the principle is …no effect on standard MySQL replication from this instance, since MySQL replication is asynchronous. What about semi-sync MySQL…( $last_count % 100 == 0 ) { $db->do( “UPDATE achievements SET count = $last_count where achievement = …
Post: MySQL 5.5 and MySQL 5.6 default variable values differences
February 21, 2013 By 8 Comments
… be scaled down compared to MySQL 5.5 default values. Such as performance_schema auto scales to count up to 445 tables…. query_cache_type and query_cache_size. The behavior is “no cache” by default still but it is achieved differently now. The query_cache_type… size of 1MB while in MySQL 5.5 and before it was “ON” by default with query cache size of 0 which…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…MySQL manual, …newblogpercona.commanual no_defaultsblogpercona….cache_hitsblogpercona.commanual Ssl_session_cache_missesblogpercona.commanual Ssl_session_cache_modeblogpercona.commanual Ssl_session_cache_overflowsblogpercona.commanual Ssl_session_cache_sizeblogpercona.commanual Ssl_session_cache…
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
… servers. Table Cache Merge Tables – Table Cache is allocated in entries and it is normally assumed each entry will use no more than… would both overload IO system and wipe off both MySQL and OS caches which can cause other users queries to perform order… max_prepared_stmt_count are designed to protect from typical application mistakes not from someone intentionally trying to bring MySQL Server down…
Post: MySQL-Memcached or NOSQL Tokyo Tyrant - part 1
October 15, 2009 By 16 Comments
… people force themselves into using a database like MySQL with no thought into whether if its the best … “lookup†via username, or even the rare count. But for the most part they are designed …from disk, expunge record 500,001, cache record 1 you keep overwriting the cache before you can use it. …
Post: MySQL Query Cache
July 27, 2006 By 70 Comments
… thinking MySQL Query Cache is the same as Oracle Query Cache – meaning cache where execution plans are cached. MySQL Query Cache is not. It does not cache …also use SQL_NO_CACHE to block caching for certain queries, which you know do not need to be cached. Counting query cache efficiency There are…
Post: How expensive is a WHERE clause in MySQL?
October 31, 2008 By 17 Comments
… see how long a table scan with no WHERE clause takes: mysql> select sql_no_cache count(*) from t; +———-+ | count(*) | +———-+ | 8388608 | +———-+ 1 row in set (5… trivial WHERE clause: mysql> select count(*) from t where a = current_date; (Pop quiz: do I need SQL_NO_CACHE on this query?) The…
