Re: Memory leak during delete with sequential scan

From: Roman Konoval <rkonoval(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-bugs(at)postgresql(dot)org
Subject: Re: Memory leak during delete with sequential scan
Date: 2014-09-12 13:42:54
Message-ID: CABcZEEDQF8dEj8OpXB7Ajt2KoK825kQE_B9YqqgWkDbTwQBmug@mail.gmail.com
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On Fri, Sep 12, 2014 at 4:30 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Roman Konoval <rkonoval(at)gmail(dot)com> writes:
> > By private memory here I mean the sum of Private_Dirty and Private_Clean
> > values for every memory segment in /proc/<pid>/smaps.
>
> Hm. I'm not terribly familiar with that API, but the notion that it
> *ever* counts shared memory as "Private" sounds pretty bogus from here.
> I'd suggest filing a bug against whichever kernel you're using.
>

This observation is doubled by a side note in this answer
http://unix.stackexchange.com/questions/33381/getting-information-about-a-process-memory-usage-from-proc-pid-smaps

> Note that a "share-able" page is counted as a private mapping until it is
*actually* shared. i.e. if there is only one process currently using libfoo
,
> that library's text section will appear in the process's *private* mappings.
It will be accounted in the shared mappings (and removed from the private
> ones) only if/when another process starts using that library.

It looks like this is by design and for kernel there is distinction between
share-able and shared.

Regards,
Roman Konoval

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