…table to store an interim result set, and then use that to ultimately…’t the query optimizer take care the execution decisions? Since they are all logically …distributed uniformly over the range 1..MAX(id)? Yes, there’s a risk… a query that took half the time. An important conclusion of my presentation…
Post: Apache PHP MySQL and Runaway Scripts
May 20, 2008 By 20 Comments
… “TightLoop” script terminated after 30 seconds with “Fatal error: Maximum execution time of 30 seconds exceeded in /var/www/html/tightloop.php… you can set an alarm and have script terminated after certain amount of seconds: Unlike set_time_limit() which specifies cpu time, pcntl_alarm… would use real MySQL queries this would be counted to max_execution_time and so script will be terminated within few seconds. This…
Comment: Apache PHP MySQL and Runaway Scripts
May 21, 2008 By 20 Comments
I have not encountered the same problem as you. When it reach the max_execution_time (setting in php.ini, I set it to 60), the script automatically stoped and print an error: “Fatal error: Maximum execution time of 60 seconds exceeded…”
Post: Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
… 128MB single file working set we can use the following command: [root@DB10 sysbench]# ./sysbench –test=fileio –max-time=60 –max-requests=1000000 –file…: 0.0001s max: 0.0086s approx. 95 percentile: 0.0001s Threads fairness: events (avg/stddev): 773835.0000/0.00 execution time (avg/stddev…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
… # InnoDB_pages_distinct: 973 SET timestamp=1325146286; select count(*) …max avg 95% stddev median # ============ ======= ======= ======= ======= ======= ======= ======= # Exec time 8s 1us 44ms 403us 541us 2ms 98us # Lock time…total query execution time and the average query execution time, the number…
Post: Improved InnoDB fast index creation
November 6, 2011 By 4 Comments
… a new column and see what execution time is like when the default method is used: mysql> SET profiling=1; Query OK, 0… default method, where the execution time is proportional to the number of indexes, with fast index creation the time required to copy the… Max_data_length: 0 Index_length: 278839296 Data_free: 1838153728 Auto_increment: 4587468 Create_time: 2011-11-06 10:01:18 Update_time…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
…). An MV is essentially a cached result set at one point in time. The contents of the MV will become…execution time. It may be possible, therefore, to refresh an MV based on a query that takes 45 minutes to execute…(41 min 52.04 sec) *If you use MIN/MAX/COUNT_DISTINCT, a secondary view will be built …
Post: Distributed Set Processing with Shard-Query
May 14, 2011 By 27 Comments
… distribute the computation of aggregation queries over time. I realised that I could apply these… essentially a proxy for the distributed set based SQL operations executed on the nodes under the … IF EXISTS `aggregation_tmp#74082863` ; Edit *MIN/MAX are only distributable in INSERT-only workloads…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… ‘%table_size%’; +———————+———–+ | Variable_name | Value | +———————+———–+ | max_heap_table_size | 268435456 | | tmp_table_size …t spend a lot of time on settings and status. It …information mysqlsla outputs about it (execution times, etc), the EXPLAIN plan, and…
Post: Using any general purpose computer as a special purpose SIMD computer
May 16, 2011 By 5 Comments
…0063340663909912s) The set of three numbers are wall clock time (as calculated by microtime()), SQL execution time, and parse time, respectively… select min(id),max(id) from words; +———+———+ | min(id) | max(id) | +———+———+ | 1 | 3088896 | +———+———+ 1 row in set (0….
