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Re: PostgreSQL 10.3 leaving "exiting" (defunct) processes on AIX platform

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On Mon, 18 Mar 2019 13:28:00 -0700, inverasln wrote:

> Curious to know if anyone else has experienced this issue before.
> 
> I have a Postgresql 10.3 database on AIX 7.1 platform and this usually
> does not give us any problems. But after a recent install on a server
> that's handling about 275 users, we suddenly started seeing "exiting"
> processes from every call to open the database.
> 
> Now when the problem first starts, the exiting processes disappear after
> a few seconds. This is normal. But the busier the system gets, the
> longer it takes for them to disappear until it could be stuck there for
> hours. And the problem is that these exiting processes appear to still
> use up one or more of the max_connections, leading to a situation where
> we run out of connections.
> 
> 
> Here's an example of what I'm referring to:
> 
> # ps -ef |grep exiting |wc -l
>     6250
> 
> # ps -ef |grep exiting |tail -5
>        - 33818386        -   -                     - <exiting>
>        - 33949478        -   -                     - <exiting>
>        - 34015016        -   -                     - <exiting>
>        - 34080578        -   -                     - <exiting>
>        - 34211634        -   -                     - <exiting>
> 
> # proctree 33818386 4653070    /apps/pg_10.3/bin/postgres
>    33818386    <defunct>
> 
> 
> According to IBM AIX documentation, the exiting/defunct process will
> wait until the parent PID replies that it no longer needs the exit
> status of the subprocess. And so it looks like PostgreSQL may not be
> sending that reply, or is somehow delayed.

The processes are not zombies yet, they are still dying. 

It seems to be this problem:
https://www.postgresql.org/message-id/flat/554a2676-9b2f-7ecc-d675-
d52f75b5ef4f%40postgrespro.ru#3cd8f5307c2c1004614bc9fb7a526abd

Apparently rebuilding PostgreSQL without mmap support can solve the 
problem.

Yours,
Laurenz Albe

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PostgreSQL 10.3 leaving "exiting" (defunct) processes on AIX platform inverasln@gmail.com - 2019-03-18 13:28 -0700
  Re: PostgreSQL 10.3 leaving "exiting" (defunct) processes on AIX platform Laurenz Albe <laurenz@nospam.pn> - 2019-03-18 23:05 +0000
    Re: PostgreSQL 10.3 leaving "exiting" (defunct) processes on AIX platform inverasln@gmail.com - 2019-03-20 10:53 -0700
      Re: PostgreSQL 10.3 leaving "exiting" (defunct) processes on AIX platform Laurenz Albe <laurenz@nospam.pn> - 2019-03-20 18:24 +0000

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