Re: Time limit for a process to hold Content lock in Buffer Cache - Mailing list pgsql-hackers

From Atri Sharma
Subject Re: Time limit for a process to hold Content lock in Buffer Cache
Date
Msg-id CC9C31E4-EB9C-4B59-8A11-4738ABA55AF9@gmail.com
Whole thread Raw
In response to Time limit for a process to hold Content lock in Buffer Cache  (Atri Sharma <atri.jiit@gmail.com>)
Responses Re: Time limit for a process to hold Content lock in Buffer Cache  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers

Sent from my iPad

On 23-May-2013, at 16:27, Amit Kapila <amit.kapila@huawei.com> wrote:

> On Thursday, May 23, 2013 3:35 PM Atri Sharma wrote:
>> Hi all,
>>
>> I was searching for an existing mechanism which ensures that a crashed
>> process releases a content lock held on a page in buffer cache. Also,
>> a similar mechanism for refcount of the page.
>>
>> I seem to have missed it. Do we have a mechanism,and if yes,where can I
>> find it?
>
> On any process (backend, bgwriter,checkpointer, ..) crash, it reinitialize
> the shared memory which will clear any locks held.
> Please refer functions HandleChildCrash() and PostmasterStateMachine().
>
>


Thanks a ton.

On a different note, shouldn't we have a time out for a content lock in buffer cache? There is a limit to the time any
saneprocess would want to hold a lock,especially when many tasks can be accomplish with only pinning the page.  

I am just musing here,but it seems that we could potentially analyse this.I may be completely wrong.

Regards,

Atri


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