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Displaying posts with tag: PMP (reset)
Evaluation of PMP Profiling Tools

In this blog post, we’ll look at some of the available PMP profiling tools.

While debugging or analyzing issues with Percona Server for MySQL, we often need a quick understanding of what’s happening on the server. Percona experts frequently use the pt-pmp tool from Percona Toolkit (inspired by http://poormansprofiler.org).

The

pt-pmp

 tool collects application stack traces GDB and then post-processes them. From this you get a condensed, ordered list of the stack traces. The list helps you understand where the application spent most of the time: either running something or waiting for something.

Getting a profile with

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Fun with Bugs #49 - Applying PMP to MySQL

As you maybe noted, in several recent posts I've provided some additional details for slides used during my FOSDEM talk on profiling MySQL. The only part not covered yet is related to using Poor Man's Profiler (and pt-pmp version of it). I see no reason to explain what it does and how to use it once again, but would like to show several recent enough MySQL bug reports where this tool was essential to find, explain or demonstrate the problem.

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MySQL Support Engineer's Chronicles, Issue #2

It's time to continue my new series that I've started 2 weeks ago. I'd like to start with a reminder that it's time to send your talks for "MySQL and Friends Devroom" at FOSDEM 2017 - the only MySQL-related event next year that I plan to attend in any case. It seems we have one more week to submit, but I've already filled in all the details for the "main" talk, "Understanding MyRocks locks and deadlocks". I'd like to apply my usual source code reading and gdb breakpoints approach in case if by the end of January, 2017 official documentation still misses important details. Official MySQL …

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Poor Man's Profiler using Solaris' pstack

Recently I was working with the output of pstack from a hung MySQL server and wanted to use Poor Man's Profiler in order to combine stack traces. Unfortunately, the awk magic expects the output from gdb's thread apply all bt output.

gdb output:


Thread 10 (Thread 0xa644db90 (LWP 26275)):
#0 0xb7f47410 in __kernel_vsyscall ()
#1 0xb7f33b1a in do_sigwait () from /lib/tls/i686/cmov/libpthread.so.0
#2 0xb7f33bbf in sigwait () from /lib/tls/i686/cmov/libpthread.so.0
#3 0x081cc4fc in signal_hand ()
#4 0xb7f2b4fb in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#5 0xb7d25e5e in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 9 (Thread 0xa641cb90 (LWP 26273)):
#0 0xb7f47410 in __kernel_vsyscall ()
#1 0xb7d1e881 in select …
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Showing entries 1 to 4