Horton

Re: psql leaks memory on query cancellation

Darafei Komяpa Praliaskouski <me@komzpa.net>

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From: Darafei "Komяpa" Praliaskouski <me@komzpa.net>
To: Craig Ringer <craig@2ndquadrant.com>
Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2018-04-12T12:37:54Z
Lists: pgsql-hackers 
>
>
> > Is it expected behavior (so I can have a look at something server
> returned
> > somehow and it's kept there for me), or a plain leak?
>
> This is totally normal behaviour for any C program.
>

Thanks Konstantin and Craig for the help.

To mitigate the issue I've changed the allocator on my laptop to jemalloc.
For single psql run on my Ubuntu system:

sudo apt install libjemalloc1
LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libjemalloc.so.1 psql

A global replacement by putting /usr/lib/x86_64-linux-gnu/libjemalloc.so.1
to /etc/ld.so.preload also had a positive effect fixing this behavior in
all the applications, reducing after-boot memory footprint from 7 GB to 3.

Darafei Praliaskouski,
GIS Engineer / Juno Minsk

Commits

  1. In libpq, free any partial query result before collecting a server error.