February 22, 2012

Post: DBD::mysql 4.014 breaks pt-table-checksum 2.0

…pt-table-checksum line 7216.

The fix is simple: upgrade (or even downgrade) DBD::mysql to any version except 4.014. To see which version of DBD::mysql … version does not. It seems, although I have not verified this, that DBD::mysql 4.014 has some sort of caching mechanism which causes it to use …

Comment: The relationship between Innodb Log checkpointing and dirty Buffer pool pages

… your query throughput gets very bad.

Even on 5.1, you may consider using the Innodb plugin, which has some of these variables: http://dev.mysql.com/doc/innodb-plugin/1.0/en/innodb-parameters-new.html

http://dev.mysql.com/doc/innodb-plugin/1.0/en/innodb-plugin-installation-overview.html

Comment: The relationship between Innodb Log checkpointing and dirty Buffer pool pages

I had the issue issue with mysql 5.1 version, unfortunately, i can’t tune those parameters besides decreasing innodb_max_dirty_pages_pct to 1 and increase log file size to 3.9G. As I understand,once the checkpoing ago is reaching 7/8 of innodb_log_file_size, flush process use sync instead of async …

Post: Can we improve MySQL variable handling ?

… to extend SELECT syntax to ease querying of variable global value Right now I can select:

mysql> select @@global.sort_buffer_size;
+—————————+
| @@global.sort_buffer_size |
+—————————+
| 2097152 |
+—————————+
1 row in …

Post: How to convert MySQL's SHOW PROFILES into a real profile

… in set (0.18 sec)

The query consumed 0.18 seconds. Where did the time go?

mysql> SHOW PROFILE FOR QUERY 1;
+———————-+———-+
| Status | Duration |
+———————-+———-+
| starting | 0.000032 |
| checking permissions | 0.000005 |…

Post: Announcing MySQL Monitoring Plugins from Percona

… APT repositories.

The new monitoring plugins add first-rate support for MySQL to popular enterprise opensource monitoring systems, and that’s why we’… support contracts. If you’re an existing customer of Percona’s MySQL Support services, your contract automatically covers these new plugins, too; …

Post: MySQL Meetups in North Carolina this week

A quick reminder. I’m speaking on two MySQL meetups in North Carolina this week. Tuesday,Feb 21 on Raleigh MySQL/PHP Meetup and when Wednesday, Feb 22 on Charlotte Queen City PHP Note the last meetup date has changed, it was originally planned for February 23 but had to be rescheduled due to …

Post: How to recover deleted rows from an InnoDB Tablespace

… “salaries”. After the “accidental” deletion of rows you should stop MySQL, take a copy of the salaries.ibd and start it….01 sec)
Records: 3 Deleted: 0 Skipped: 0 Warnings: 0

mysql (employees) > select * from salaries where emp_no=10008;
+——–+——–+————+————+
| emp_no…

Post: Why don't our new Nagios plugins use caching?

… might have been a misunderstanding — perhaps caching was understood to reduce load on MySQL, rather than reducing load on the Cacti server and speeding up the … be at all useful, you should not monitor too many things inside of MySQL. If you take the typical mass-market monitoring program’s silly “…

Comment: MariaDB 5.3.4 benchmarks

…of a gap, not less. See http://www.mysqlperformanceblog.com/2011/10/10/mysql-versions-shootout/

I think it is also a reasonable point of view …at extensive benchmarks: http://www.odbms.org/blog/2011/09/mariadb-the-new-mysql-interview-with-michael-monty-widenius/ The obvious question is if so much …