Re: Proposed doc-patch: Identifying the Current WAL file

Jeff Frost wrote:
> On Sat, 15 Apr 2006, Bruce Momjian wrote:
>
> > Tom Lane wrote:
> >
> > No, I am not:
> >
> >     $ touch x1 x2; touch x2
> >     $ sleep 2; ls -lt
> >     total 0
> >     -rw-r--r--  1 root  postgres  0 Apr 15 14:04 x1
> >     -rw-r--r--  1 root  postgres  0 Apr 15 14:04 x2
> >
> > If the write to x2 happens in the first second, but no later writes
> > happen, you still see x1 as first, even though x2 is the new one and
> > might have WAL data in it.  The point is that the test does not have a
> > one-second window of showing the wrong answer, meaning I could wait for
> > 60 seconds, and still see the wrong WAL file at the top.
>
> Bruce, what does
>
> stat x1 x2
>
> look like on your system?  Which OS?  Maybe we need caveats for various OSes?

System is BSD/OS:

    $ touch x1 x2; stat x1 x2
        filename: x1
           inode: 4547362
          device: 18,7
            size: 0
            type: regular file
           links: 1
            mode: 0644(-rw-r--r--)
           owner: 0(root)
           group: 102(postgres)
          access: Sat Apr 15 14:41:12 2006
    modification: Sat Apr 15 14:41:12 2006
          change: Sat Apr 15 14:41:12 2006

        filename: x2
           inode: 4547363
          device: 18,7
            size: 0
            type: regular file
           links: 1
            mode: 0644(-rw-r--r--)
           owner: 0(root)
           group: 102(postgres)
          access: Sat Apr 15 14:41:12 2006
    modification: Sat Apr 15 14:41:12 2006
          change: Sat Apr 15 14:41:12 2006

And I tried it on Fedora Core 2:

    bmomjian@x86-linux2:~$ touch x1 x2 ; stat x1 x2
      File: `x1'
      Size: 0               Blocks: 0          IO Block: 8192   regular
    empty file
    Device: 11h/17d Inode: 24707337    Links: 1
    Access: (0644/-rw-r--r--)  Uid: ( 7078/bmomjian)   Gid: (  100/   users)
    Access: 2006-04-15 11:41:53.000000000 -0700
    Modify: 2006-04-15 11:41:53.000000000 -0700
    Change: 2006-04-15 11:41:53.000000000 -0700
      File: `x2'
      Size: 0               Blocks: 0          IO Block: 8192   regular
    empty file
    Device: 11h/17d Inode: 24707338    Links: 1
    Access: (0644/-rw-r--r--)  Uid: ( 7078/bmomjian)   Gid: (  100/   users)
    Access: 2006-04-15 11:41:53.000000000 -0700
    Modify: 2006-04-15 11:41:53.000000000 -0700
    Change: 2006-04-15 11:41:53.000000000 -0700

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  Bruce Momjian   http://candle.pha.pa.us
  EnterpriseDB    http://www.enterprisedb.com

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