Posts Categorized: MySQL
What Was Going On Around 2:30pm? This is a question a customer asked us. To answer it we ran MySAR for a few days and queried the results for analysis. Looking at the data, we determined that the number of INSERT operations was significantly higher than any other, so we queried for the Com_insert status values. Com_insert is a counter that accumulates the number of INSERTs issued since the last server start (or since the last FLUSH STATUS command). For details on the variables available check Chapter 1. mysqld Options/Variables Reference.
This presentation was done by Sheeri Cabral of The Pythian Group and went into how to use SHOW ENGINE INNODB STATUS to get more information about your Innodb tables, foreign keys and transactions. This is a great presentation to learn how InnoDB works.
Welcome to the 165th edition of Log Buffer, the weekly review of database blogs.
This is a hack, but it is a good one. I was looking at some machines on a new client, and they had the general log turned on. I was surprised, because it was a fairly busy server, and they had had many problems with the server a few months ago. I thought perhaps they had turned on the general log to diagnose a problem and forgotten to turn it off, or something similar.
One day, while looking into slave lag problem, the idea of MySAR popped into my head and a few hours later I was using its first incarnation. I was able to relate the server’s I/O activity peaks with these lags and in turn, discovered that it was caused by a great number of INSERT statements coming in in waves. It was an encouraging outcome for what was nothing more than a proof of concept.
Welcome to the 164th edition of Log Buffer, the weekly review of database blogs.
After running both InnoDB Hot Backup and Xtrabackup, we have found that there is a measurable but not large difference between the resources that Xtrabackup and InnoDB Hot Backup consume. Here they are.
I will be giving a presentation explaining SHOW ENGINE INNODB STATUS for the Boston MySQL User Group. There is information about foreign keys, transactions, deadlocks and mutexes just waiting to be discovered, and I will show how to decipher the information.
We are often asked to “do a schema diff and create a script that will ‘patch’ one server.”. We like to use the best tool for the job, and while diff is good, I like to use MySQL workbench. The OSS (Community) edition provides all the functionality we need for creating a schema diff and patch. MySQL workbench does both reverse engineering and “forward engineer” alter script for free in the OSS/Community version. Step by step, here’s how to do it:
I spent Friday examining the systems for a more traditional consulting gig. It is a familiar story to many people — the database performance was unacceptable. The company had a few log tables that had huge amounts of inserts and foreign keys, so they used InnoDB. Unfortunately, they also used a GUID as a primary key — varchar(32) and utf8. That’s right — their primary key for many of these tables was 96 bytes long (32 characters * 3 bytes per character), and as an InnoDB table, the primary key is clustered with every other index.
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