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

>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...

If I correctly remember, the report was regarding 6.4.2. I will check
if it happens with current, and report back soon.
---
Tatsuo Ishii