…long as they don’t touch the same row. Row locks are held for modifications until the transaction commits and that takes…updated more than just a few times a second at best. Some things the rule does not mean on… application updates this table with a statement like this: UPDATE achievements SET count…
Post: Benchmarking Percona Server TokuDB vs InnoDB
May 7, 2013 By 32 Comments
…produce updates in-place (I will use INSERT .. ON DUPLICATE KEY UPDATE … space on this SSD to run this experiment that long…. 7800 tps. Something to take into account: TokuDB results …table-size=10000 –mysql-user=root –oltp-tables-count=32 –mysql_table_engine=tokudb –oltp_auto_inc=on –max-time…
Post: MySQL 5.6 Compatible Percona Toolkit 2.2 Released
March 25, 2013 By 2 Comments
…’s still one noticeable omission: pt-table-sync. It’s still unclear if… pt-upgrade was written once long ago and not updated since. Now that we…results from running queries on a server. Granted, this can take a lot of disk … specify –iterations or –run-time to limit how long they run. There are more…
Post: Slow Query Log analyzes tools
September 6, 2006 By 84 Comments
… efficient queries, which just happen to do full table scans – for example if you would be having… in certain cases query takes long time to execute, for example if plan is different based on constants. How to … often help SELECT queries but slow down INSERT/UPDATE ones. Final Note: You do not have to…
Post: Choosing proper innodb_log_file_size
July 3, 2006 By 12 Comments
…take long time before MySQL Server is operational again. So how to find the optimal combination ? First let me explain what happens on…take quite a long time. The only way you can reduce “undo” phase is size your transactions appropriately – so updates…
Post: Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs
February 23, 2012 By 3 Comments
…updates on CentOS. If you are using InnoDB, it is also important that your transaction logs (ib_logfile*) are on…on time!). mysql> delete from salaries where emp_no = 10001; Query OK, 17 rows affected (0.15 sec) mysql> drop table…. You should take another snapshot now…execute a long running ALTER …
Post: Drilling down to the source of the problem
November 8, 2008 By 7 Comments
…tables would be stalling every so often causing even very simple queries both reads and writes taking long time to complete, with progress almost paused (dropping from thousands to tens of queries per second). On…
Post: MySQL EXPLAIN limits and errors.
July 24, 2006 By 6 Comments
… triggers which can make updates very different. Also there is no way to tell you how ALTER table would be executed – will… do on Cluster ? Is it expected to rebuild index by sort of key_cache as it can for MyISAM. EXPLAIN may take long time In MySQL 5.0 with addition of greedy join the problem on looking at too many table join combinations in…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
…time. A view which has drifted out of sync must be refreshed. Since an MV drifts over time from the “base tables” (those tables on… changelogs collected by FlexCDC to update the snapshot to reflect the …uses the complete refresh method takes a very long time to refresh: mysql> call flexviews.refresh…
Post: Investigating MySQL Replication Latency in Percona XtraDB Cluster
March 3, 2013 By 13 Comments
… query on the master. This is because application of the changes on the master in parallel and updates to the sbtest table and sbtest2 table… times faster still taking tens of seconds for what I would consider medium size transaction modifying 1 million of rows is rather long time…
