… to be an issue. There are lots of things that can go wrong and I won’t end up using anything if I… an NFS hang. And if NFS is the problem, I can tail the binlog to remote storage using something other than…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… to the client. Now I go through it line by line looking for things that look wrong. When I find something, I… to figure out what is happening because it can indicate something else is wrong. This is not a big deal for performance… come. After you’ve done it a few times, you can go through the settings and status pretty quickly. Analyzing MySQL’s…
Post: Using MyISAM in production
June 17, 2006 By 36 Comments
… may happen and go for long unnoticed with MyISAM storage engine. This hidden corruption may later cause crashes wrong query results and…. Concurrency. MyISAM uses table locks and has concurrent inserts which can go concurrently with selects. This is sometimes presented as great concurrency… likely observe very serious corruption with queries failing to run, wrong result sets or crashes. Here is my list what I…
Post: Automation: A case for synchronous replication
September 19, 2012 By 2 Comments
… wrong time can cause downtime and be user visible. Second due to complexity of MySQL replication there are increased chances something would go wrong with failover and you can end up with inconsistent database, broken replication and…
Post: Emulating global transaction ID with pt-heartbeat
November 4, 2011 By 6 Comments
… and forth across datacenters so that if something went really wrong with one of them, there would be a backup on… to its master was ginger-bin.000033:7936, and we can see that the third instance is replicating from ginger-bin… it’s easier to figure out replication positions when things go wrong. It’s not a real global transaction ID, but it…
Post: Recovering Linux software RAID, RAID5 Array
August 27, 2011 By 2 Comments
… be by design as using such commands wrong way can ruin your RAID array. What you can do instead is to re-create… as to be resynced from others, and if it is wrong drive you will lose your data. Creating RAID in such… created RAID wrong way you probably will be unable to mount it, find LVM volumes on it etc, and you can go back…
Post: Economics of Performance Optimization
March 13, 2008 By 9 Comments
… hardware the cost is going to be increasing dramatically after certain hardware size. For example right now you can get 8 core… think about resources and risks – hardware upgrade is straightforward and can be done by operations and data center stuff so developers… well which reduces trial and error and general risk of going wrong way. Plus because they know the stuff they often need…
Post: MySQL EXPLAIN limits and errors.
July 24, 2006 By 6 Comments
… list of things you may wish to watch out. EXPLAIN can be wrong – this does not happen very often but it does… how many rows will be examined in total. This can be rather wrong. One thing to consider is number of rows analyzed… can be done with storing row data in the sort file, not only key values and row pointers. If this is going…
Post: Give me 8 hours, and I'll help you build a better application
August 29, 2009 By 4 Comments
… in memory to function well. That’s because unused rows can bloat and dilute your indexes and tables. Storage engines such… memory is a big step towards better performance, and archiving can help do that. 2. Monitor Your Servers Everybody should have… the monitoring system and ignore it when something really does go wrong. Keep it simple and monitor things that matter to your…
Post: MySQL Crash Recovery
July 30, 2006 By 30 Comments
… system may be flawed, hardware has problems or simply power can go down which all mean similar things – MySQL Shutdown is unexpected… hidden and do not expose itself instantly – you may notice wrong query results days after crash. Sometimes corrupted tables may be… on using binary log for point in time recovery it can go unnoticed. sync_binlog Is helping by syncing binary log, but…
