Re: Separating Buffer LWlocks - Mailing list pgsql-hackers

From Robert Haas
Subject Re: Separating Buffer LWlocks
Date
Msg-id CA+TgmoYWnDJe7qiXozTnViW4sK8Yym0r4PBhBTrehMgTqZXxug@mail.gmail.com
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In response to Re: Separating Buffer LWlocks  (Andres Freund <andres@anarazel.de>)
Responses Re: Separating Buffer LWlocks  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
On Tue, Sep 8, 2015 at 2:19 PM, Andres Freund <andres@anarazel.de> wrote:
> On 2015-09-08 14:15:32 -0400, Robert Haas wrote:
>> We could do that, but I'm not sure just calling LWLockNewTrancheId()
>> for all of the tranches would be so bad either.
>
> To me that seems either fragile or annoying to use. If all backends call
> LWLockNewTrancheId() we need to a be sure the callbacks are always going
> to be called in the same order.

How is that going to work?  The counter is in shared memory.

> Otherwise everyone needs to store the
> tranche in shared memory (like xlog.c now does) which I find to be a
> rather annoying requirement.

Yes, everyone would need to do that.  If that's too annoying to live
with, then we can adopt your suggestion.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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