by Alexey Kovyrin | Jan 24, 2008 | Benchmarks
Really often in customers’ application we can see a huge tables with varchar/char fields, with small sets of possible values. These are “state”, “gender”, “status”, “weapon_type”, etc, etc. Frequently we suggest to...
by Peter Zaitsev | Dec 20, 2007 | Insight for DBAs
In MySQL 4.1 and above the longest part of recovery after crash for Innodb tables could be UNDO stage – it was happening in foreground and was basically unbound – if you have large enough transaction which needed to be undone this could take long hours....
by Alexey Kovyrin | Nov 26, 2007 | Insight for DBAs
As Peter mentioned in one of previous posts, we’ve done huge work developing robust strategies of InnoDB data recovery to provide our customers effective data recovery services and one of major parts of these strategies is our toolkit for InnoDB data recovery....
by Peter Zaitsev | Nov 4, 2007 | Insight for Developers
I now got answers to the second portions of the questions you asked Heikki. If you have not seen the first part it can be found here. Same as during last time I will provide my comments for some of the answers under PZ and will use HT for original Heikkis answer. Q26:...
by Maciej Dobrzanski | Oct 31, 2007 | Percona Software
Microslow patch is used by many DBAs and developers to accurately time their queries and to catch those which run less than a second as they can also be a performance killer for a busy application. Recently I have started the development of an updated version of the...
by Aurimas Mikalauskas | Oct 29, 2007 | Insight for DBAs
Suppose you want to remove auto_increment from 100G table. No matter if it’s InnoDB or MyISAM, you’d usually ALTER TABLE huge_table CHANGE id id int(6) NOT NULL and then wait hours for table rebuild to complete. If you’re unlucky i.e. you have a lot...
by Peter Zaitsev | Oct 26, 2007 | Insight for Developers
Its almost a month since I promised Heikki Tuuri to answer Innodb Questions. Heikki is a busy man so I got answers to only some of the questions but as people still poking me about this I decided to publish the answers I have so far. Plus we may get some interesting...
by Vadim Tkachenko | Oct 12, 2007 | Uncategorized
We many times wrote about InnoDB scalability problems, this time We are faced with one for MyISAM tables. We saw that several times in synthetic benchmarks but never in production, that’s why we did not escalate MyISAM scalability question. This time working on...
by Peter Zaitsev | Oct 11, 2007 | Insight for DBAs
I already wrote about this issue but as I is third team I’m helping customers to resolve this “frm corruption” issue it is the time to return to it again. During MySQL 5.0 release cycle the change was made so now MySQL does not stop if Innodb storage...
by Peter Zaitsev | Sep 28, 2007 | Insight for Developers
Have you ever had a question about Innodb internal design or behavior which is not well covered in MySQL manual ? I surely had. Now you have a great chance to have them answered ! Heikki Tuuri, Creator of Innodb will answer your Questions about Innodb at MySQL...
by Peter Zaitsev | Sep 28, 2007 | Insight for DBAs
It always surprised me how little Innodb team seems to think about product usability/ease of use, when it comes to settings, performance management etc. I could understand many things 5 years ago, like a lot of information being available only in hard to parse SHOW...
by Vadim Tkachenko | Sep 26, 2007 | Insight for DBAs
There was long played scalability issue with InnoDB auto-increment field. For details check Bug 16979. In short words the problem is in case of insert into table with auto-increment column the special AUTO_INC table level lock is obtained, instead of usual row-level...
by Vadim Tkachenko | Sep 13, 2007 | Insight for DBAs
If you like to compile MySQL from sources by yourself, for different needs, like debugging, testing etc, you probably can face this issue. What I usually do to fast compile and test is ./configure --prefix=/dir/to/mysql make make install 123 ./configure...
by Peter Zaitsev | Jul 27, 2007 | Insight for DBAs
Working on large upgrade of MySQL 4.1 running Innodb to MySQL 5.0 and doing oprofile analyzes we found very interesting issue of buf_get_latched_pages_number being responsible for most CPU usage. It did not look right. The close look revealed this is the function...
by Peter Zaitsev | Jul 25, 2007 | Benchmarks
Listening to Josh Berkus presentation on OSCON today I decided to take a closer look at SpecJAppServer benchmarks results which were published by PostgreSQL recently and which as Josh Puts it “This publication shows that a properly tuned PostgreSQL is not only...
by Peter Zaitsev | Jul 18, 2007 | Insight for DBAs
In my previous post I was a bit wrong giving Innodb some properties it does not have. In fact Innodb does not currently sort pages in their position order flushing them to disk. Pages to be flushed are instead identified by other means – LRU and pages which...
by Peter Zaitsev | Jul 17, 2007 | Insight for DBAs
How does Buffer Pool size affects Innodb Performance ? I always expected the effect to be positive, Innodb with large buffer pool to performing better. Including Recovery of course. I even blogged about it. It turns out it is not always the case. Last week I was...
by Peter Zaitsev | Jun 26, 2007 | Insight for DBAs
I ran into pretty interesting behavior today. We needed to dump and reload large database and we had pretty good IO subsystem so we started number of mysqldump processes in parallel. Unlike in other case when we did load in parallel, dump in parallel did not increase...
by Peter Zaitsev | Jun 18, 2007 | Insight for Developers
I prefer to use Integers for joins whenever possible and today I worked with client which used character keys, in my opinion without a big need. I told them this is suboptimal but was challenged with rightful question about the difference. I did not know so I decided...
by Peter Zaitsev | Jun 16, 2007 | Insight for DBAs
I filed the following bug today. Basically it looks like in certain conditions Innodb may be started twice in the parallel on the same data files which can hurt database badly. It is true it does not seems to be 100% repeatable but I’ve seen it multiple times in...
