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Showing entries 1 to 7

Displaying posts with tag: knowledge (reset)

Notes on HEAP/MyISAM Index Key Handling on WRITE
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Disclaimer: This post is based on HEAP/MyISAM’s sourcecode in Drizzle.

Here are my brief notes on investigating how index keys are generated in HEAP and MyISAM. I lurked through these because I’ve started preparing for decent index support in BlitzDB. I also wrote this to assist my biological memory for later grepping (I have terrible memory for names). I’m only going to cover key generation on write in this post. Otherwise this post is going to be massive.

HEAP Engine

The index structure of HEAP can be either BTREE or HASH (in MySQL doc terms). Like other engines HEAP has a structure for keeping Key definition …

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The MySQL Librarian is here!
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I have had a wish for a few years. I wanted to find a way to put together the valuable information that the community produces about MySQL, a way that would let me easily find the interesting content that I may have missed when on vacation, or when busy with a conference, a company meeting, or a long stream of coding.

That wish started to take shape last year, when I was traveling with Dups during the East Coast tour. I drove, he took notes. He drove, I took more notes. During meals and walking breaks we discussed and refined the idea. When we went back home, a plan was ready. Dups …

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The MySQL Librarian is here!
Employee +0 Vote Up -0Vote Down

I have had a wish for a few years. I wanted to find a way to put together the valuable information that the community produces about MySQL, a way that would let me easily find the interesting content that I may have missed when on vacation, or when busy with a conference, a company meeting, or a long stream of coding.

That wish started to take shape last year, when I was traveling with Dups during the East Coast tour. I drove, he took notes. He drove, I took more notes. During meals and walking breaks we discussed and refined the idea. When we went back home, a plan was ready. Dups …

  [Read more...]
The MySQL Librarian is here!
Employee +0 Vote Up -0Vote Down

I have had a wish for a few years. I wanted to find a way to put together the valuable information that the community produces about MySQL, a way that would let me easily find the interesting content that I may have missed when on vacation, or when busy with a conference, a company meeting, or a long stream of coding.

That wish started to take shape last year, when I was traveling with Dups during the East Coast tour. I drove, he took notes. He drove, I took more notes. During meals and walking breaks we discussed and refined the idea. When we went back home, a plan was ready. Dups …

  [Read more...]
Storage Engine Dev Journal #3 : Supporting variable width tables
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Something I’ve added to BlitzDB recently that was pretty high on my todo list is support for variable width tables. So what is a variable width table? it is a table that contains columns that can vary in size, namely BLOB and TEXT types.

Going back to the basics, when a new row is to be written, a storage engine is given a pointer to the row data in MySQL format that it must somehow store for later lookup/retrieval. By meaning “somehow”, the storage engine is given the freedom to do whatever it likes with the row.

Writing a row for a fixed length table (a table with …

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Journal of Storage Engine Development on Drizzle
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I’ve decided to start a series of blog entries on not-so-obvious findings that I’ve found while working on my new project. By archiving the findings, I’m hoping that I can help those that are looking into developing a storage engine for the MySQL family in the future.

Accumulating these mini-knowledge would also be useful for me since I can refer back to it when I forget something. Also, once I write enough entries I’m planning on summarizing them and making it available on the Drizzle Wiki. If …

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Understanding how auto increment works with InnoDB
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Lately I’ve been having lots of fun going through Drizzle and InnoDB‘s sourcecode to get a grasp of how auto increment is processed internally. I think I now have a fairly good grasp of what’s going on so I’m writing this entry as a note for myself. I’m also hoping that this will be helpful to those that are interested in this topic too.

So in MySQL and Drizzle, the storage engine (in this case InnoDB) is responsible for computing the auto increment value. Here’s an abbreviated execution path for a simple INSERT …

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Showing entries 1 to 7

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