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Dangerous command

 | May 20, 2008 |  Posted In: Insight for DBAs

Remembering that I did RENAME DATABASE in MySQL 5.1.21 and found it useful I tried it with 5.1.24 (I was playing with 20GB InnoDB database, so dumping is not fastest way) and all my tries finished with “Syntax error”. So RTMF and documentation says “This statement was added in MySQL 5.1.7 but was found to […]

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MySQL Error Message Nonsenses

 | March 16, 2008 |  Posted In: Insight for DBAs

What MySQL honestly was never good at is giving good helpful error messages. Start with basics for example – The error message in case of syntax error gives you information about tokens near by but little details:

It would be much better if MySQL would give error give exact position of error (with complex […]

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No more MySQL Crash Safe Replication in 5.0 ?

 | January 29, 2008 |  Posted In: Insight for DBAs

As you might know even if you’re only using Innodb tables your replication is not completely crash safe – if Slave MySQL Server crashes/power goes down it is likely for relay logs to run out of sync (they are not synced to the disk) plus position on the master which slave remembers becomes stale. During […]

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10+ Ways to Crash or Overload MySQL

 | November 13, 2007 |  Posted In: Insight for DBAs

People are sometimes contacting me and asking about bugs like this which provide a trivial way to crash MySQL to the user with basic privileges and asking me what to do. My answer to them is – there is nothing new to it and they just sit should back and relax 🙂 Really – there […]

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Making bugs public – good job MySQL

 | October 22, 2007 |  Posted In: Events and Announcements

If you have been MySQL User for many years you might remember the times when MySQL had “zero bugs policy”, this is when all known bugs really were fixed before release was made. To be honest at that time bugs were reported via bugs mailing list not via bugs database as they are now so […]

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MyISAM Scalability and Innodb, Falcon Benchmarks

 | October 12, 2007 | 

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 the customer system we figured out that box with 1 CPU Core […]

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MySQL Quality of old and new features

 | October 4, 2007 |  Posted In: Insight for DBAs

Recent couple of days our team was pointed to number of bugs in MySQL 5.0 which again seriously shakes the confidence in both MySQL Quality Control and bug fix promptness. Let me just take couple of bugs as examples: Triggers broken with auto-increment columns for Innodb tables (bug 26316). As you can see this bug […]

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Read Buffers, mmap, malloc and MySQL Performance

 | September 12, 2007 |  Posted In: Insight for DBAs

Monty Taylor posted interesting investigation of the fact read_buffer_size variable affects connection speed. This is not something you would expect right ? me too. Not only global user data is expected to be cached on startup but even if it is not why would you do full table scan to fetch single user information ? […]

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