Invalidating query cache mysql
Mutex S, the number of child cursors, parsing – everything pointed on bind variables.
Okay, so lets have a look at 10046 traces, level 12.
Problem After running the new version for two hours, everything became incredibly slow, and the CPU load on the DB server was hitting 100%.
Research in the Oracle Wait Interface quickly showed me the wait event: “Cursor: mutex S”.
So there was an urgent need to know where this behaviour comes from.It was quite unnervig, since the application uses an own connection pool, it was not easily predictable which session out of some 30 will execute my UPDATE next time.But after a while, I managed to collect enough trace files and sorted them out, to see this situation: Trace 1: FYI, the corresponding field to bind #6 in the table is number().User Role Editor Word Press plugin allows you to change standard Word Press user roles capabilities with easiness of a few mouse clicks. Open users list by click on the “All Users” link at the “Users” submenu.Just turn on check boxes of capabilities you wish to add to the selected role and click “Update” button to save your changes. Add and tune your own custom roles which you can assign to the users then. Find needed user, move mouse pointer to his name and click “Capabilities” link as on screenshot below: At the form opened you can assign to user another role and/or add to him capabilities which not included to his role: You can not turn off capabilities included to the role assigned to this user. They will be applied directly to the user as you click the “Update” button.
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With a growth of 200 new child cursors per minute, expect no fun! Workaround Since the number of child cursors and the appearance of the “Cursor: mutex S” wait event was closely related, a stable and well-working workaround was to flush out this particular cursor on a regular basis. In earlier days, with 10g in basic functionality, we would have been toasted at this point – because flushing the whole shared pool once a minute (yes, with a growth of 200/min, and the abyss at 300…) killed us by excessive parse times of everything!