Re: Hi- How frequently Postgres Poll for trigger file

From: aaliya zarrin <aaliya(dot)zarrin(at)gmail(dot)com>
To: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Hi- How frequently Postgres Poll for trigger file
Date: 2010-12-01 17:23:09
Message-ID: AANLkTi=P4P4XLBB0dps7QkdTuC+VUkJ0=yev5Qy7ny7X@mail.gmail.com
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Thanks for quick response..
Can I change this 5 second time?
I have seen the postgres code as well.
What is the functionality of WaitLatch() function. I could not understand
completely.
Plz help..

On Wed, Dec 1, 2010 at 5:53 PM, Heikki Linnakangas <
heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:

> On 01.12.2010 13:27, aaliya zarrin wrote:
>
>> I want to know how frequently postgres search for trigger file to switch
>> over.
>>
>
> In 9.0, every 100ms while streaming replication is active and connected. 5
> seconds otherwise. In current git master branch, it's always 5 s.
>
>
> Can this switch over time be reduced?
>>
>
> Not without hacking the sources and compiling.
>
> Although, on many platforms, Linux included I believe, sending a signal to
> the startup process should wake it up from the sleep and make it check the
> trigger file immediately. "pg_ctl reload" for example should do it. So if
> ıou send a signal to the startup process immediately after creating the
> trigger file, it should take notice sooner.
>
>
> Plz let me know where postgres poll for trigger file. I could find it out
>> in
>> "backend/access/trans/xlog.c" ? am i right?
>>
>
> Yes. search for callers of CheckForStandbyTrigger() function.
>
>
> --
> Heikki Linnakangas
> EnterpriseDB http://www.enterprisedb.com
>

--
Thanks & Regards,

Aaliya Zarrin
(+91)-9160665888

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