Re: Is Patch Ok for deferred trigger disk queue? - Mailing list pgsql-hackers

From Jan Wieck
Subject Re: Is Patch Ok for deferred trigger disk queue?
Date
Msg-id 3F0203BE.4000908@Yahoo.com
Whole thread Raw
In response to Re: Is Patch Ok for deferred trigger disk queue?  (Stephan Szabo <sszabo@megazone23.bigpanda.com>)
List pgsql-hackers
Stuart wrote:
> Tom Lane wrote:
> 
>> Stephan Szabo <sszabo@megazone23.bigpanda.com> writes:
>> 
>>>As a side question, it looks to me that the code stores the first trigger
>>>records in memory and then after some point starts storing all new records
>>>on disk.  Is this correct?  I'd wonder if that's really what you want in
>>>general, since I'd think that the earliest ones are the ones you're least
>>>likely to need until end of transaction (or set constraints in the fk
>>>case) whereas the most recent ones are possibly going to be immediate
>>>triggers which you're going to need as soon as the statement is done.
>> 
>> 
>> Good point.  It would be better to push out stuff from the head of the
>> queue, hoping that stuff near the end might never need to be written
>> at all.
>> 
>>             regards, tom lane
> Hmmm.... I see your point. I will change the patch to write the head to
> disk and reenter when the development branch splits off.
> Also I've noticed that there is an fd.h which has file routines which I
> should be using rather than the stdio routines.
> I will also clean up those errors.

While you are still at it, can you make the arbitrarily choosen trigger 
queue size a config parameter? It is much easier to do tuning without 
the need to recompile the backend.


Jan

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