Memory leak detection

René Cannaò edited this page Jul 19, 2017 · 2 revisions

Starting from version v1.3.0g , jemalloc embedded in ProxySQL is compiled with --enable-prof, allowing memory profiling. Memory profiling is disabled by default.

To enable profiling, it is required to restart proxysql with an environment variable MALLOC_CONF to override the embedded/default jemalloc configuration. The current jemalloc configuration is xmalloc:true,lg_tcache_max:16,purge:decay. To enable memory profiling, prof and prof_leak need to be enabled, while lg_prof_sample and lg_prof_interval need to be tuned. A suggested tuning for jemalloc memory profiler could be the follow:

"xmalloc:true,lg_tcache_max:16,purge:decay,prof:true,prof_leak:true,lg_prof_sample:18,lg_prof_interval:30"

Therefore, the environment variable should be:

MALLOC_CONF="xmalloc:true,lg_tcache_max:16,purge:decay,prof:true,prof_leak:true,lg_prof_sample:18,lg_prof_interval:30"

Details about jemalloc configuration can be found here.

Start ProxySQL with memory profiler

using init script

If you are running proxysql using init script /etc/init.d/proxysql , it is enough to add the follow line before the point when the process is started, for example at around line 19 in /etc/init.d/proxysql:

export MALLOC_CONF="xmalloc:true,lg_tcache_max:16,purge:decay,prof:true,prof_leak:true,lg_prof_sample:18,lg_prof_interval:30"

without init script

If you are running proxysql without init script /etc/init.d/proxysql , you need to ensure that the environment variable is set before starting proxysql. For example, if you run proxysql in foreground, you need to execute it similar to the following:

MALLOC_CONF="xmalloc:true,lg_tcache_max:16,purge:decay,prof:true,prof_leak:true,lg_prof_sample:18,lg_prof_interval:30" proxysql -f -c /etc/proxysql.cnf

How to report a memory leak?

jemalloc profiler will regularly write memory profile dumps in /var/lib/proxysql , with names proxysql.<pid>.<seq>.i<iseq>.heap . To report a memory leak, please create a tarball with the dumps generated by jemalloc profiler and either create an issue or drop me an email. Please also include which exact version of ProxySQL you are using, and on which OS:

  • if you used an rpm or a deb package, specify which one exactly
  • if you compiled proxysql yourself, include proxysql binary in the report

Disable profiling

To disable profiling, ProxySQL needs to be restarted without MALLOC_CONF set.

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