Details
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Bug
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Status: Done
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Low
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Resolution: Fixed
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3.0.11, 3.0.12
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None
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Yes
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2
Description
Output from pt-mysql-summary will determine if jemalloc is enabled:
[root@centos7-pxc57-1 sbin]# /usr/bin/pt-mysql-summary
Memory management library ##################################
jemalloc enabled in mysql config for process with id 3403
Using jemalloc from /usr/lib64/libjemalloc.so.1
The End ####################################################
But it checks it using find which isn't guaranteed to be correct if two versions of jemalloc are installed:
JEMALLOC_LOCATION=$(find /usr/lib64/ /usr/lib/x86_64-linux-gnu /usr/lib -name "libjemalloc.*" 2>/dev/null | head -n 1)
So for instance in this case it gives incorrect results:
[root@centos7-pxc57-1 lib64]# touch libjemalloc.empty
[root@centos7-pxc57-1 lib64]# rm libjemalloc.so.1
rm: remove regular file ‘libjemalloc.so.1’? y
[root@centos7-pxc57-1 lib64]# /usr/bin/pt-mysql-summary
Memory management library ##################################
jemalloc enabled in mysql config for process with id 3403
Using jemalloc from /usr/lib64/libjemalloc.empty
The End ####################################################
The tool checks if jemalloc is in use from checking environ and ldd:
for pid in $(pidof mysqld); do grep -qc jemalloc /proc/${pid}/environ || ldd $(which mysqld) 2>/dev/null| grep -qc jemalloc jemalloc_status=$?
It would be much better to check this output again to find the correct version loaded, for example:
# strings /proc/$(pidof mysqld)/environ | grep jemalloc LD_PRELOAD=/usr/lib64/libjemalloc.so.1