Re: [HACKERS] Open 6.5 items - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: [HACKERS] Open 6.5 items
Date
Msg-id 199906070133.VAA18372@candle.pha.pa.us
Whole thread Raw
In response to RE: [HACKERS] Open 6.5 items  ("Hiroshi Inoue" <Inoue@tpf.co.jp>)
Responses Re: [HACKERS] Open 6.5 items
Re: [HACKERS] Open 6.5 items
List pgsql-hackers
> Future TODO items ?
> 
> As far as I see,there's no consensus of opinion whether we would 
> remove useless segments(I also think it's preferable if possible) or 
> we would only truncate the segments(as my trial patch does).
> 
> Only Bruce and Ole objected to my opinion and no one agreed 
> with me.
> How do other people who would use segmented relations think ?  
>   

I liked unlinking because it allowed old backends to still see the
segments if they still have open file descriptors, and new backends can
see there is no file there.  That seemed nice, but you clearly
demostrated it caused major problems.  Maybe truncation is the answer. 
I don't know, but we need to resolve this for 6.5.  I can't imagine us
focusing on this like we have in the past few weeks.  Let's just figure
out an answer.  I am on IRC now if someone can get on to discuss this. I
will even phone someone in US or Canada to discuss it.

What is it on the backend that causes some backend to think there is
another segment.  Does it just go off the end of the max segment size
and try to open another, or do we store the number of segments
somewhere. I thought it was the former in sgml() area.  I honestly don't
care if the segment files stay around if that is going to be a reliable
solution.

--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
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