Re: [HACKERS] Current TODO list - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: [HACKERS] Current TODO list
Date
Msg-id 199905240332.XAA12093@candle.pha.pa.us
Whole thread Raw
In response to RE: [HACKERS] Current TODO list  ("Hiroshi Inoue" <Inoue@tpf.co.jp>)
Responses RE: [HACKERS] Current TODO list  ("Hiroshi Inoue" <Inoue@tpf.co.jp>)
List pgsql-hackers
> > I don't think unlink() is a problem.  That other backends have the files
> > open shouldn't matter.  Whenever they close it(should be pretty quick),
> 
> When are those files closed ?
> AFAIC,they are kept open until the backends which reference those files 
> finish.
> 
> Certainly,those files are re-opened(without closing) by backends after 
> vacuum,though I don't know it's intentional or caused by side-effect.
> But unfortunately,re-open is not sufficiently quick. 
> 
> And I think that the assumption of mdtruncate() is not clear.
> Could we suppose that unlinked files are closed quickly for all backends 
> by the caller of mdunlink() ?

If they try and open a file that is already unlinked, they don't get to
see the file.  Unlink removes it from the directory, so the only way to
continue access after an unlink is if you already hold a file descrpitor
on the file.

--  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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