by Peter Zaitsev | Jun 6, 2007 | Insight for DBAs
This week I already had two serious performance regression cases when upgrading from MySQL 4.0 and 4.1 to MySQL 5.0. By serious I mean several times performance difference not just 5-10% you often see for simple queries due to generally fatter code. The problem in...
by Peter Zaitsev | May 24, 2007 | Insight for DBAs
As I wrote we had been recovering corrupted Innodb Tablespace and it is finally done now. As this was over than 1TB worth of data we really tried to avoid dumping the data and find some other way to recovery. Examining Innodb page content and crash information we...
by Peter Zaitsev | May 22, 2007 | Insight for DBAs
I have not had a serious Innodb corruptions for a while, typically even if it happened it was some simple table related corruption which was easy to fix on table level. In couple of cases during last year when it was more than that we had backups and binary logs which...
by Peter Zaitsev | May 22, 2007 | Insight for DBAs
We have certain type of the table corrupting with Innodb, as it is limited to only one particular index on one particular table type it is likely to be Innodb bug but Heikki currently could not find what could be causing it. Happily as we have data stored in many...
by Peter Zaitsev | May 9, 2007 | Insight for DBAs
Today seems to be Innodb day in our Blog, but well this is the question which pops ups quite frequently in Innodb talks and during consulting engagements. It is well known to get better performance you should normally set innodb_log_file_size large. We however usually...
by Peter Zaitsev | May 9, 2007 | Percona Events
It might look like it is too late to write about stuff happened at Users Conference but I’m just starting find bits of time from processing accumulated backlog. The Theme of this Users Conference was surely Storage Engines both looking at number of third party...
by Vadim Tkachenko | Apr 8, 2007 | Benchmarks
The PBXT Storage Engine (http://www.primebase.com/xt/) is getting stable and we decided to benchmark it in different workloads. This time I tested only READ queries, similar to ones in benchmark InnoDB vs MyISAM vs Falcon...
by Peter Zaitsev | Mar 5, 2007 | Insight for DBAs
Where does real power of MySQL Storage Engines, and pluggable storage engines as MySQL 5.1 lays ? It is very much advertised this allows third parties to create their own storage engines and we can see solutions as Solid and PBXT . Plus there is Falcon storage engine...
by Vadim Tkachenko | Feb 25, 2007 | Insight for DBAs
We often recommend to our clients to convert their current database from MyISAM tables to InnoDB. The transfer by itself in most cases is almost plain, however the application can be broken by new unexpected errors 1205 (ER_LOCK_WAIT_TIMEOUT) Lock wait timeout...
by Peter Zaitsev | Feb 19, 2007 | Insight for Developers
In MySQL 5.0 mainly error control was improved, such as strict mode was added to change famous MySQL behavior of cutting too large strings, too big numbers and allowing you to use dates such as February 31st. In one case however reverse change was done – in...
by Vadim Tkachenko | Jan 8, 2007 | Benchmarks
Several days ago MySQL AB made new storage engine Falcon available for wide auditory. We cannot miss this event and executed several benchmarks to see how Falcon performs in comparison to InnoDB and MyISAM. The second goal of benchmark was a popular myth that MyISAM...
by Vadim Tkachenko | Jan 3, 2007 | Benchmarks
There was several changes in InnoDB to fix scalabilty problems, so I ran benchmark to check new results and also compare overall performance of InnoDB in 5.0 and 5.1 before and after fixes. Problems in InnoDB that were fixed: Thread trashing issues with count of...
by Peter Zaitsev | Dec 12, 2006 | Insight for DBAs
Today I was working with application which uses Innodb and foreign keys and got into locking problems possibly due to foreign keys, so I did a little investigation on that matter. Interesting enough it looks like most people do not think about foreign keys overhead in...
by Peter Zaitsev | Dec 1, 2006 | Insight for Developers
I guess note number one about MyISAM to Innodb migration is warning what Innodb is very slow in COUNT(*) queries. The part which I often however see omitted is fact it only applies to COUNT(*) queries without WHERE clause. So if you have query like SELECT COUNT(*)...
by Peter Zaitsev | Nov 30, 2006 | Benchmarks
I had found pile of MySQL and PostgreSQL benchmarks on various platforms which I have not seen before. Very interesting reading. It does not share too much information about how MySQL or PostgreSQL was configured or about queries. Furthermore MySQL and PostgreSQL has...
by Peter Zaitsev | Nov 21, 2006 | Insight for DBAs
I was restarting MySQL on box with 50.000 of Innodb tables and again it took couple of hours to reach decent performance because of “Opening Tables” stage was taking long. Part of the problem is Innodb is updating stats on each table open which is possibly...
by Vadim Tkachenko | Nov 14, 2006 | Insight for DBAs
I was pretty busy last month with project which will be annonced very soon (I hope), but I can’t miss bug fix of my favorite bug 15815. I wrote about this problem before and also investigated in my presentation. Finally bug fix was pushed into 5.0-bk tree and...
by Peter Zaitsev | Nov 9, 2006 | Insight for DBAs
As you can read from my Innodb Architecture and Performance Optimization presentation Innodb automatically manages undo area in system tablespace so you never need to care about it. I present it as positive feature reducing administration effort needed but it also can...
by Peter Zaitsev | Oct 8, 2006 | Insight for Developers
Yesterday I had fun time repairing 1.5Tb ext3 partition, containing many millions of files. Of course it should have never happened – this was decent PowerEdge 2850 box with RAID volume, ECC memory and reliable CentOS 4.4 distribution but still it did. We had...
by Peter Zaitsev | Oct 3, 2006 | Insight for DBAs
Innodb primary key is special in many senses and I was always wondering how well MySQL is integrated with Innodb to take advantage of these special features. Lets see which things work and which things do not: I used the following simple table for tests: CREATE TABLE...
