Re: Effects of IDLE processes - Mailing list pgsql-performance

From Christopher Browne
Subject Re: Effects of IDLE processes
Date
Msg-id m3r7jaa9dk.fsf@knuth.knuth.cbbrowne.com
Whole thread Raw
In response to Effects of IDLE processes  (JM <jerome@gmanmi.tv>)
Responses Re: Effects of IDLE processes  (Gaetano Mendola <mendola@bigfoot.com>)
List pgsql-performance
After a long battle with technology, Gaetano Mendola <mendola@bigfoot.com>, an earthling, wrote:
> JM wrote:
>> Hi ALL,
>>
>>     I was wondering if there is a DB performance reduction if
>> there are a lot of IDLE processes.
>>
>> 30786 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>> 32504 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>> 32596 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  1722 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  1724 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  3881 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  6332 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  6678 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  6700 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  6768 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  8544 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  8873 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  8986 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  9000 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  9010 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  9013 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  9016 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  9019 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>  9020 ?        S      0:00 postgres: user1 gmadb 10.10.10.1 idle
>>

> In my experience not at all, you have to wonder if some of that are
> "idle in transaction" that are really a pain in the @#$

I'd be concerned about "idle" processes insofar as they are holding on
to _some_ memory that isn't shared.

"idle in transaction" is quite another matter; long-running
transactions certainly do lead to evil.  When running Slony-I, for
instance, "idle in transaction" means that pg_listener entries are
being held onto so they cannot be vacuumed out, and that's only one
example of a possible evil...
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