…how one would sync a cluster that, in theory, doesn‘t become out-of-sync. As Percona XtraDB …t have a problem finding queries to run and compare. pt-query-digest is simpler pt-query-digest 2.2 …by default, so specify –iterations or –run-time to limit how long they run. There are more changes in …
Post: More on MySQL transaction descriptors optimization
April 26, 2013 By Leave a Comment
…Dimitri’s environment. To put a long story short, the results are …updates to the database, all SELECT queries, even those participating in read-only… are read-only transactions, but it doesn‘t help much, because e.g…rand-type=uniform –forced-shutdown=1 –max-time=120 –max-requests=0 –percentile=99 …
Post: How to use tcpdump on very busy hosts
April 18, 2011 By 17 Comments
…: use “mk-query-digest –filter ‘$event->{time} && $event->{time} > 1′” to exclude all queries which it believes took longer than the servers long-query-time of 1… has an obvious flaw — if your long-query-time is 1 second, and mkqd believes that a query which actually took 10ms instead took…, aborting” exit 1 fi # set trap to be sure tcpdump doesn‘t run for ever # and clean up the temp file…
Comment: Backport of micro-time patch to mysql 4.1
October 9, 2006 By 9 Comments
I patch mysql source, but it doesn‘t work. I can not set long_query_time=0 . The least value of long_query_time – 1. If I set long_query_time=0, “SHOW VARIABLES;” show me long_query_time=1. And I see always seconds in slow log: Query_time: 2 Lock_time: 0 . How to turn on the patch?
Post: Replaying database load with Percona Playback
October 25, 2012 By 9 Comments
… can do but it doesn‘t care about your workload, data set or queries. Those tools just run random queries against random generated… the peak time to get valuable information: SET GLOBAL slow_query_log=1; SET GLOBAL long_query_time=0; With long_query_time we are logging all queries that…
Comment: Why MySQL could be slow with large tables ?
June 20, 2007 By 141 Comments
… SCSI RAID: [mysqld] long_query_time=5 skip-bdb skip-innodb skip-locking query_cache_limit=1M query_cache_size=32M query_cache_type=1 max…=utf8_unicode_ci set-variable=max_connections=1500 log_slow_queries=/var/log/mysql-slow.log sql-mode=TRADITIONAL concurrent_insert… as a file system on steroids and nothing more. InnoDB doesn‘t cut it for me if the backup and all…
Post: Percona Server 5.1.47-rel11.0
June 21, 2010 By 13 Comments
… slow-query logging globally without restarting, similar to –use_global_long_query_time. Added the –query_cache_strip_comments option to strip comments from query before using it in query cache. Added a… it will be replaced by Percona Server. However Percona-Server doesn‘t obsolete MySQL, so you have to deinstall it first…
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
…to parallelize. As you know, MySQL doesn‘t do intra-query parallelization, so ETL jobs written to rely on…be getting bad data back for a long time. And every time you have some incremental job to update …not what you need unless you’re okay with long queries that read a lot of rows — MySQL can’t…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
… faster than the original query execution time. It may be possible, therefore, to refresh an MV based on a query that takes 45…. More on this later. SQL features used in the query Incremental refresh doesn‘t support all of the SQL features available to… takes a very long time to refresh: mysql> call flexviews.refresh( -> flexviews.get_id(‘demo’,'complete_example2′),’BOTH’,NULL); Query OK, 0 rows…
Post: How to debug long-running transactions in MySQL
March 8, 2011 By 6 Comments
…is if it’s a long-running query. If that’s the case, then you’ll see the query in the processlist, …INNODB STATUS and assume that it’s the culprit. This doesn‘t always work, and I hate things that sometimes … getting full. I’ve learned the hard way a long time ago never to run a script that will let …
