… to run this experiment that long. So there we see the strong… is 7800 tps. Something to take into account: TokuDB results are not…low selectivity is not good for fast inserts, but it is suitable for range selects …oltp-tables-count=32 –mysql_table_engine=tokudb –oltp_auto_inc=on –max-time=18000 …
Post: How much memory Innodb locks really take ?
July 13, 2006 By 11 Comments
…_free: 0 Auto_increment: 1638401 Create_time: 2006-07-12 07:31:51 Update_time: NULL Check_time: NULL Collation: utf8_general_ci… long does it take: mysql> begin; Query OK, 0 rows affected (0.00 sec) mysql> select count(i) from sample lock in share mode; +———-+ | count… exclusinve locks take: mysql> begin; Query OK, 0 rows affected (0.00 sec) mysql> select count(i) from sample for update; +———-+ | count(i) | +———-+ | 1638400…
Post: Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs
February 23, 2012 By 3 Comments
… /root/bin/lvmsnap.sh snapshot Taking a new snapshot .. done Trimming excess…mysql mysql> select count(*) from salaries where emp_no = 10001; +———-+ | count(*) | +———-+ | 0 | +———-+…your snapshots – they are one time use! However, if …planning to execute a long running ALTER or server…
Post: Faster MySQL failover with SELECT mirroring
February 1, 2009 By 9 Comments
…the standby (passive) master for serving some SELECT queries, taking backups, etc as usual. However, …reality, it can be completely unusable for a long time. To measure how much this really matters,…with the following query: select table_schema, table_name, page_type, count(*) from information_schema….
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
… COUNT(*). mysql> select count(*) cnt from order_lines\G *************************** 1. row *************************** cnt: 155187034 1 row in set (32.03 sec) mysql> select…The view which uses the complete refresh method takes a very long time to refresh: mysql> call flexviews.refresh( -> flexviews….
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
… enough value for long_query_time. We normally use a value of long_query_time=0, because if… # Query_time: 2.365434 Lock_time: 0.000000 Rows_sent: 1 Rows_examined: 655360 use test; SET timestamp=1325145746; select count… shows the Count of number of times this query was executed. Now let’s take a look…
Post: To SQL_CALC_FOUND_ROWS or not to SQL_CALC_FOUND_ROWS?
August 28, 2007 By 57 Comments
… check, how long it’d take if we’ll try to use two separate queries: mysql> SELECT SQL_NO_CACHE * FROM count_test WHERE… now – we need too check how long our COUNT query would take: mysql> SELECT SQL_NO_CACHE count(*) FROM count_test WHERE b = 666; Result is… time for SELECT+COUNT (0.00-0.15 sec) is much less than execution time for original query (2-100 sec). Let’s take a…
Post: A workaround for the performance problems of TEMPTABLE views
May 19, 2010 By 7 Comments
… | c1 | count(*) | +——+———-+ | 10 | 130 | +——+———-+ 1 row in set (1.66 sec) Even a query with an impossible where clause takes a long time to process: mysql> select * from v2 where c1 = 100; Empty set …
Post: UDF -vs- MySQL Stored Function
September 6, 2010 By 8 Comments
…taking 10 minutes, was now taking…long it took to process 100k rows: mysql> select…times if comparing to stored function or 2 times…select count(*) from paintings where title != ltrim_junk(title); +———-+ | count(*) | +———-+ | 101533 | +———-+ 1 row in set (6.82 sec) mysql> select count…
Post: How much overhead is caused by on disk temporary tables
August 16, 2007 By 26 Comments
… “c” column. mysql> explain select count(*) cnt,c from gt group by c order by null limit 10; +—-+————-+——-+——+—————+——+———+——+———+—————–+ | id | select_type | table | type… have seen 50MB sequentially written once per certain amount of time which takes fraction of second to do, but it is not… rows in set (0.00 sec) So how long does it take: mysql> select count(*) cnt,c from gt group by c order by…
