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Displaying posts with tag: mtr (reset)
Fun with Bugs #45 - On Some Bugs Fixed in MySQL 5.7.15

Oracle released MySQL 5.7.15 recently, earlier than expected. The reason for this "unexpected" release is not clear to me, but it could happen because of a couple of security related internal bug reports that got fixed:

  • "It was possible to write log files ending with .ini or .cnf that later could be parsed as option files. The general query log and slow query log can no longer be written to a file ending with .ini or .cnf. (Bug #24388753)
  • Privilege escalation was possible by exploiting the way REPAIR TABLE used temporary files. (Bug #24388746)"

Let me concentrate on the most important fixes to bugs and problems reported by Community users. …

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Fun with Bugs #10 - recently reported bugs affecting MySQL 5.6.12

MySQL 5.6.12 is available to community for more than a week already, so people started to test and use it. And, no wonder, new bug reports started to appear. Let's concentrate on them in this issue.

I'd like to start with a funny one.  Bug #69413 had scared some of my Facebook readers to death, as we see kernel mutex mentioned clearly in the release notes for 5.6.12. What, kernel mutex comes back again? No, it's just a result of null merge and, probably, copy/paste from the release notes for 5.5.32.

It seems recent bug reports for 5.6.12 are mostly related to small details that may not be of any importance to a typical user. For example, …

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My way to verify MySQL bug reports

I promised to write this blog post long time ago at one of conferences in Russia. Don't know why I delayed this, but finally I did.

We, members of MySQL bugs verification group, have to verify bugs in all currently supported versions. We use not only version reported, but test in development source tree for each of supported major versions and identify recent regressions.

You can imagine that even if I would do so for simple bug report about wrong results with perfect test case, which requires me simply run few queries I would have to start 4 or more MySQL servers: one for each of currently supported versions 5.0, 5.1, 5.5 plus one for current development. And unknown number of servers if I could not repeat or if I want to check if this is regression.

Even if I have all these basic 4 servers running I still should type all these queries at least 4 times. How much time it would take to verify single bug …

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Graphing memory usage during an MTR run

In order to optimally size the amount of RAM to allocate to a set of new machines for running MTR, I ran a few tests to check the memory usage of an MTR run for mysql-trunk and cluster-7.1. As using a RAM disk considerably speeds things up, I set the vardir to be on /ramdisk and logged the usage of that too.

The tests were performed on an 8-core E5450 @ 3.00GHz with 24GB RAM, with 8GB allocated to /ramdisk. Each branch ran the default.daily collection, which generally contains the most testing we do per-run. Between each run I rebooted the machine to clear the buffer cache and /ramdisk.

I used something like the script below, which saved the per-second usage of /ramdisk, the total RAM used, and the RAM used minus buffers.



  rm …
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