RE: [HACKERS] postgresql-v6.5beta2.tar.gz ...

> -----Original Message-----
> From: owner-pgsql-hackers(at)postgreSQL(dot)org
> [mailto:owner-pgsql-hackers(at)postgreSQL(dot)org]On Behalf Of Tom Lane
> Sent: Tuesday, June 08, 1999 11:34 AM
> To: pgsql-hackers(at)postgreSQL(dot)org
> Subject: Re: [HACKERS] postgresql-v6.5beta2.tar.gz ...
>
>
> "Hiroshi Inoue" <Inoue(at)tpf(dot)co(dot)jp> writes:
> > vacuum calls open() directly to create pg_vlock file.
> > Sometimes I was not able to open the file because of the lack of
> > file descriptors().
> > FileNameOpenFile()/FileClose() etc should be called instead of
> > open()/close() etc ?
>
> That is a good point, but actually I think it should not be a problem.
> vacuum.c just does open() and immediately close() on pg_vlock; it
> doesn't hold the file descriptor open.
>
> When I fixed psort.c a few weeks ago, I looked through all the other
> direct calls of open() and fopen() in the backend. There are still half
> a dozen or so, but none of them open more than one file or will hold the
> file descriptor for longer than the execution of the function they're
> in. So I felt it was OK to leave them alone.
>
> The reason it's OK is that fd.c doesn't use up all the available
> file descriptors --- it tries to leave ten or so unused. That's
> necessary to ensure that library functions like dlopen() will work,
> because they don't know anything about using fd.c's routines.
>
> So, the occasional short-term file opening in vacuum.c and similar
> places should not matter. If those do fail for lack of FDs, then the
> *real* problem is that fd.c is not estimating correctly how many file
> descriptors it can safely use; that's what we need to fix.
>
> But what I want to know right now is whether this behavior has been
> seen with code from the last week or two. Maybe the report is just
> a side-effect of the FD leaks that used to exist in several places...
>

I don't remember correctly how the phenomenon occured,sorry.
I couldn't reproduce it now.

Regards.

Hiroshi Inoue
Inoue(at)tpf(dot)co(dot)jp