Category Archives: innodb internals

Innodb Compression: When More is Less

So Vadim posted on the MySQL Performance Blog about poor benchmarks when running innodb compressed pages.  I ran some tests a few weeks ago and did not see the same results as him and checked into my previous tests and … Continue reading

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Filtering by table is now possible with WaffleGrid

Since I have been a home recently, I put some time correcting bugs in WaffleGrid and adding new features. Thanks to gdb, I have been able to understand a silly bug that was affecting WaffleGrid with sysbench but, weird enough, … Continue reading

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You know you have really screwed up when …

You crash MySQL/Innodb and you trace the error to a function that says: “This function checks the consistency of an index page when we do not know the index. This is also resilient so that this should never crash even … Continue reading

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Waffle: Progress and a Rearchtecture?

So I spent several hours over the last few days on the Secondary index bug. Out of frustration I decided to try and bypass the LRU concept all together and try going to a true secondary page cache. In standard … Continue reading

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Waffle: The Mystery Continues

So I spent the weekend looking at places where we may have missed something in the code for waffle. You can actually see some of the stuff I tried in the bug on launchpad about this, but the weird thing … Continue reading

Posted in innodb internals, Matt, mysql, Waffle Grid | 2 Comments

Waffle: limiting the space ids being pushed to memcached

If you read Yves blog post about waffle yesterday we are seeing some weird gremlins in the system and could use some scoobey doo detective work if you have some ideas. The strange thing is it only exhibits under high … Continue reading

Posted in innodb internals, Matt, mysql, Waffle Grid | 3 Comments

Oracle really….

Ummmmmfff…. wind out of my sails today. I believe their was an analyst who predicted this a year ago when Sun bought MySQL…. I wish I could find the article. I am going to head down to the UC floor … Continue reading

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How much does it cost to update an index?

I was asked today about what is the cost of adding an index on a frequently updated column ( like a timestamp, count, or weight )… typically my answer is it depends. But for this question it was narrowed down … Continue reading

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Waffle Grid: Async IO Concerns

Last night I was on a plane to a client site and I was reviewing the waffle grid code for inclusion of multi-gets when calling read-ahead functions (potentially in other area’s as well)…  their I noticed something that may slow … Continue reading

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InnoDB secondary index file structure

In my previous Post, we took a look at the file structure of the InnoDB primary key index. With the same table structure, but a slightly different dataset: mysql> select * from test_innodb_growth limit 10; +—-+————+——–+ | id | data … Continue reading

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