… the ratio is derived (but not the ratio itself, which you should ignore). Read on for the details. In this article, I will… bad advice: Bad advice #1: you should care about the key cache hit ratio. Bad advice #2: you should set your key_buffer_size…, but still makes no sense, why wouldn’t you obsess over it? What about InnoDB tuning? You might be wondering, what about InnoDB…
Post: Why MySQL's binlog-do-db option is dangerous
May 14, 2009 By 12 Comments
…: they don’t work the way you think they do. Consider the following scenario: you set binlog-ignore-db to “garbage” so data… user isn’t disabled on the slave. Why? Because binlog-ignore-db doesn’t do what you think. The phrase I used earlier… and has fewer gotchas. If you are confused, you should read the replication rules section of the manual until you know it by heart 
Post: Give me 8 hours, and I'll help you build a better application
August 29, 2009 By 4 Comments
… who are numb to the monitoring system and ignore it when something really does go wrong. Keep … in the log when that happened, but not why. The Cacti graph for disk space had a …? Unlike with monitoring, you should measure and store everything you can, for as long as you can. You will never stay …
Comment: Using LVM for MySQL Backup and Replication Setup
August 15, 2008 By 53 Comments
…system. Is this always consistent? If so, then you should be able to create a slave from a… Why does this matter? If your nightly backup doesn’t capture master status, that shouldn’t prevent you… UNLOCK TABLES; > MYSQL File Position Binlog_Do_DB Binlog_Ignore_DB mysql-bin.000156 956920476 -rw-rw—- 1…
Comment: Percona Replication Manager, a solution for MySQL high availability with replication using Pacemaker
December 1, 2011 By 94 Comments
…. 1. Why do you use no-quorum-policy=”ignore” at all (there is expected-quorum-votes=”3″ defined also). Having 3 nodes you should be able to go for quorum 2. binary=”/usr/bin/mysqld_safe” why not just simple take… only pacemaker should do it. 3. I don’t see where/how you are starting your master initially. I.e. if you want…
Post: Multi Column indexes vs Index Merge
September 19, 2009 By 30 Comments
…index on (AGE,STATE). Lets see why it is the case. MySQL indexes…(test) > explain select avg(length(val)) from idxtest ignore index (combined) where i1=50 and i2=50; … 1 row in set (0.00 sec) As you can see in this case …when MySQL does not think it should be used. I hope hint would…
Post: Recovering Innodb table Corruption
July 4, 2008 By 19 Comments
…MyISAM table for the reason you‘ll see later. You may think why do not you simply rebuild table by…with LIMIT can be handly if you recover manually: mysql> insert ignore into test2 select * from test limit …helpful in cases you‘ve want to recover deleted rows or dropped table. I should also mention at…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… tables that should be archived, tables that I should be aware of if I see them in queries, or what have you. I… should have identified a handful of tables that really matter. That’s why I save this part of the analysis for last. You… themselves, and which to just ignore. The above process may look like a static recipe that you can just mechanically execute, and…
Post: MySQL Users Conference - Innodb
May 9, 2007 By 6 Comments
…I also should mention this feature is not that easy to use as it is implemented now – you have … used. There are probably similar problems in INSERT IGNORE and ON DUPLICATE KEY UPDATE cases. Now In …while RAID10 is better than RAID5, why large stripes are better and why battery backed up cache is so …
Post: How much space does empty Innodb table take ?
December 16, 2008 By 7 Comments
… so about 10 times more for MyISAM. This is ignored space which needs to be allocated in main tablespace … 16 21:06 test_innodb.ibd If you do the math here you can see there is only about 1MB …the case above no single segment should require more than 32 pages so It is surprising why all of them take …
