…TO BE GRANTED: RECORD LOCKS space id 0 page no 16403 n bits 72 index `PRIMARY` of table `test/iz`…8079, query id 728899 localhost root Sending data select sql_calc_found_rows * from b limit 5 Trx …trx_commit=2 log writes are done to OS cache, and being sequential writes these logs writes are pretty…
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
…created. For example if the left operand has “n” rows, and its size is three times …switch=’join_cache_incremental=on’ optimizer_switch=’join_cache_hashed=on’ optimizer_switch=’join_cache_bka=on’ join_cache_level…in memory to a large table with no WHERE clause The SQL used for this test together with…
Post: Updated msl (microslow) patch, installation walk-through!
April 20, 2008 By 17 Comments
… file sql/slave.cc patching file sql/sql_cache.cc patching file sql/sql_class.cc patching file sql/sql_class.h patching file sql/sql_parse.cc patching file sql/sql_select.cc patching file sql/sql…. If you are not interested in queries which scan no more than N rows, you can set this to the desired value…
Post: Profiling MySQL Memory Usage With Valgrind Massif
January 9, 2013 By 3 Comments
…out of the box’ (i.e. with no changes), you will likely see …(when you see ‘Valgrind: FATAL: VG_N_SEGMENTS is too low’) Newer releases …Log_event::read_log_event(st_io_cache*, st_mysql_mutex*, Format_description_log_event… | ->10.10% (7,135,744B) 0x5316EC: handle_slave_sql (in /usr/local/percona/mysql-…
Comment: Database problems in MySQL/PHP Applications
August 11, 2006 By 13 Comments
…if used properly) help increase security against sql injection. > For example I have little… > database connection may become the issue. Caching should be > good help in this case…a BIGINT UNSIGNED will and gaining no benefit from it. I’ve …is bad is unwise. > 5. The n+1 pattern This probably should …
Post: Four ways to optimize paginated displays
September 24, 2008 By 27 Comments
…of pages and the total count, you either a) use SQL_CALC_FOUND_ROWS (see our post on this) or … cache all the results. Now it’s easy to know how many results there are, and fetching subsequent pages is no… you see the millionth result. You get to see N results and after that, you’re done. Limit the …
Post: mk-query-digest, query comments and the query cache
…this information in a specially formatted SQL comment. This information can then … For example: –embedded-attributes ‘^– [^\n]+’,'(\w+): ([^ ]+)’ The first part: ‘^– [^\n]+’ matches everything starting with …unique and the query cache will use additional resources for no effective benefit. Luckily…