… can not support such a degree. mysql> select min(id),max(id) from words; +———+———+ | min(id) | max(id) | +———+———+ | 1 | 3088896 | +———+———+ 1 row… divide, and you want to use 1024 way parallelism: select min(result) == 0 is_prime from ( select mod({$NUMBER_TO_FACTOR…
Post: Using any general purpose computer as a special purpose SIMD computer
May 16, 2011 By 5 Comments
Comment: Using any general purpose computer as a special purpose SIMD computer
May 16, 2011 By 5 Comments
… expr1, count(distinct b) expr2, count(*) expr3, max(a) expr4, min(b) expr5 from some_table; This query is sent to each processor: select a expr1, b expr2, sum(1) expr3, min(a) expr4, max(b) exp4 from some_table; The results… finish: select expr1, count(distinct expr2) expr2, sum(expr3) expr3, min(a), max(b) from #tmp; A having clause would be…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…_user_connectionsblogpercona.commanual max_write_lock_countblogpercona.commanual memlockblogpercona.commanual min_examined_row_limitblogpercona.commanual myisam_block_sizeblogpercona.commanual myisam_data…_alloc_block_sizeblogpercona.commanual query_cache_limitblogpercona.commanual query_cache_min_res_unitblogpercona.commanual query_cache_sizeblogpercona.commanual query_cache_typeblogpercona…
Post: Thinking about running OPTIMIZE on your Innodb Table ? Stop!
December 9, 2010 By 18 Comments
… | optimize | status | OK | +——–+———-+———-+——————————————————————-+ 2 rows in set (3 hours 3 min 35.15 sec) mysql> alter table a drop key c… | | test.a | optimize | status | OK | +——–+———-+———-+——————————————————————-+ 2 rows in set (4 min 5.52 sec) mysql> alter table a add key(c…
Post: InnoDB: look after fragmentation
November 5, 2009 By 12 Comments
… order. +—————————+ | count(distinct username) | +—————————+ | 5903053 | +—————————+ 1 row in set (2 min 8.92 sec) mysql> SHOW STATUS LIKE ‘Innodb_scan_pages…
Post: How to calculate a good InnoDB log file size
November 21, 2008 By 38 Comments
… in set (0.06 sec) 1 row in set (1 min 0.00 sec) Log sequence number 84 3838334638 1 row….) mysql> select (3838334638 – 3836410803) / 1024 / 1024 as MB_per_min; +————+ | MB_per_min | +————+ | 1.83471203 | +————+ As a rough rule of thumb, you…
Comment: Why MySQL could be slow with large tables ?
November 14, 2008 By 141 Comments
… disk space Load avg: 0.81 (1 min) 0.68 (5 mins) 0.73 (15 mins) Real memory 3.86 GB total, 1…
Comment: Slow Query Log analyzes tools
June 10, 2008 By 84 Comments
…, $4, $3, $2-1, “20″.$1); $dt_min = $datetime if (($datetime < $dt_min) || !(defined $dt_min)); } # query type line if(s/^\s+([0…
Post: Updated msl (microslow) patch, installation walk-through!
April 20, 2008 By 17 Comments
… to be logged it must match long_query_time AND min_examined_row_limit AND log_slow_filter. log-slow-queries… at run time with both SET SESSION and SET GLOBAL. min_examined_row_limit=# Don’t log queries which examine less than min_examined_row_limit rows to file. If you are not…
Post: InnoDB vs MyISAM vs Falcon benchmarks - part 1
January 8, 2007 By 117 Comments
… startup params: Falcon: libexec/mysqld –no-defaults –user=root –falcon_min_record_memory=1G –falcon_max_record_memory=2GB –falcon_page… a big room for optimization. READ_PK_RANGE Query: SELECT min(dob) FROM $tableName WHERE id between %d and %d Access… between %d and %d LIMIT 50 READ_FTS Query: SELECT min(dob) FROM $tableName The hardest query performs a scan of…
