Thread: Re: ERROR: could not read block

Re: ERROR: could not read block

From
"Kevin Grittner"
Date:
This code generates warnings on both Linux and Windows.  My C
is too rusty to feel confident of what to do.

On Linux:

md.c:445: warning: implicit declaration of function `GetLastError'

On Windows:

md.c:445: warning: int format, DWORD arg (arg 6)
md.c:457: warning: int format, DWORD arg (arg 7)

How should I proceed?

-Kevin


>>> Tom Lane <tgl@sss.pgh.pa.us>  >>>
"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> Is there anything you would like me to include in my build for my
> test runs, or any steps you would like me to take during the tests?

You might want to insert some debugging elog's into mdread() in md.c,
rather than in its caller smgrread.  I'm concerned that by the time
control comes back to smgrread, the Windows last-error might have
been changed; in any case, we'd not know exactly which of the steps
in mdread failed.  I'd suggest something like

    if (FileSeek(v->mdfd_vfd, seekpos, SEEK_SET) != seekpos)
+    {
+        elog(LOG, "seek failed on relation %u/%u/%u: %d",
+             reln->smgr_rnode.spcNode,
+             reln->smgr_rnode.dbNode,
+             reln->smgr_rnode.relNode,
+             GetLastError());
        return false;
+    }

    status = true;
    if ((nbytes = FileRead(v->mdfd_vfd, buffer, BLCKSZ)) != BLCKSZ)
    {
+        elog(LOG, "read failed on relation %u/%u/%u: %d bytes,
%d",
+             reln->smgr_rnode.spcNode,
+             reln->smgr_rnode.dbNode,
+             reln->smgr_rnode.relNode,
+             nbytes,
+             GetLastError());
        /*
         * If we are at or past EOF, return zeroes without
complaining. Also
         * substitute zeroes if we found a partial block at EOF.

(untested, but something like this should do it)

            regards, tom lane


Re: ERROR: could not read block

From
Tom Lane
Date:
"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> On Linux:
> md.c:445: warning: implicit declaration of function `GetLastError'

Of course.  This is a Windows-only hack.

> On Windows:
> md.c:445: warning: int format, DWORD arg (arg 6)
> md.c:457: warning: int format, DWORD arg (arg 7)

I think this is just cosmetic, but try %ld instead of %d in the elog
format strings.

            regards, tom lane