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Displaying posts with tag: mysqladmin (reset)
When mysqld kills mysqld

The other day a colleague and friend of mine, Peter Boros, had a case where one of our clients had to track down the process shutting down MySQL. This blog is based on the discussion we had about that internally.

Our client wanted Peter to identify the culprit behind periodic shutdowns. This proved to be slightly more difficult than usual, for reasons that you might guess from the title of this blog.

Here is what Peter saw in the logs:

150928 15:15:33 [Note] /usr/sbin/mysqld: Normal shutdown
150928 15:15:36 [Note] Event Scheduler: Purging the queue. 0 events
150928 15:15:39 [Warning] /usr/sbin/mysqld: Forcing close of thread 411515  user: 'dashboard'
150928 15:15:40  InnoDB: Starting shutdown...
150928 15:15:59  InnoDB: Shutdown completed; log sequence number 4873840375
150928 15:16:00 [Note] /usr/sbin/mysqld: Shutdown …
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Advanced InnoDB Deadlock Troubleshooting – What SHOW INNODB STATUS Doesn’t Tell You, and What Diagnostics You Should be Looking At

One common cause for deadlocks when using InnoDB tables is from the existence of foreign key constraints and the shared locks (S-lock) they acquire on referenced rows.

The reason I want to discuss them though is because they are often a bit tricky to diagnose, especially if you are only looking at the SHOW ENGINE INNODB STATUS output (which might be a bit counter-intuitive since one would expect it to contain this info).

Let me show a deadlock error to illustrate (below is from SHOW ENGINE INNODB STATUS\g):

111109 20:10:03
TRANSACTION 65839, ACTIVE 19 sec, OS thread id 4264 starting index read
mysql tables in use 1, locked 1
LOCK WAIT 6 lock struct(s), heap size 1024, 3 row lock(s), undo log entries 1
MySQL thread id 3, query id 74 localhost root Updating
UPDATE parent SET age=age+1 WHERE id=1
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MySQL Conference Liveblogging: Monitoring Tools (Wednesday 5:15PM)
  • Tom Hanlon of MySQL presents
  • monitoring tool basics
  • basic tools
    • mysqladmin is provided with the server
      • mysqladmin -i 10 extended status: will repeat the same command every 10 seconds. Pipe through grep "and smoke it" (bad pun, hah hah)
      • -r: show only changed values
    • MySQL Administrator
  • cacti
    • rrdtool based network graphing tool
    • uses snmp
    • PHP apache and MySQL based solution
    • MySQL plugins, download and install
    • "poller" gathers data and populates the graphs
    • someone offers …
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Showing entries 1 to 3