# Postgresql, FreeBSD and mmap



## tanked (Oct 8, 2013)

As Postgresql has now moved from SysV shared memory to mmap, there appears to be a concern that this would affect performance of PostgreSQL running on FreeBSD: 

(http://rhaas.blogspot.co.uk/2012/06/absurd-shared-memory-limits.html)

Are there any serious users of PostgreSQL on FreeBSD who could share their experiences? From the above link it would appear DragonFlyBSD has come up with a fix, does anyone know if there's work going into a fix for FreeBSD?


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## tanked (Apr 22, 2014)

I have been in contact with one of the porters who has confirmed there is a 17% regression in Postgresql 9.3 as compared to Postgresql 9.2 (pre mmap changes) on FreeBSD 10. The performance difference between FreeBSD and other OSs appears to be even larger, so the porter told me that the more people who contribute to the following mailing list thread in freebsd-performance, the more likely the problem will be fixed:

http://freebsd.1045724.n5.nabble.com/Fr ... 95357.html

If you're having performance issues with PostgeSQL 9.3 and above, please let them know in the above thread.


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