Обсуждение: Re: [HACKERS] Core dump in regression tests.

> Thomas A. Szybist" <szybist@boxhill.com>
> > Bruce Momjian <maillist@candle.pha.pa.us>
> >
> > Again, if someone wants to conditionally compile the directories to find
> > the offending file, I am sure we can get a fix for it.
> >
>
> At first look it seems to be:  backend/catalog/indexing.c.
> Maybe Keith can confirm?
>
> Thanks,

Tom,

I recompiled the latest cvs with -O2 and found that the crash on
table creation was NOT now failing so I'm a little confused :-(

I'm just updating my cvs, and will do another build and see how
things go.

If only I had the same failures as before I'd be able to confirm
your suspicions on indexing.c

Til Later,
Keith.

> > Thomas A. Szybist" <szybist@boxhill.com>
> > > Bruce Momjian <maillist@candle.pha.pa.us>
> > >
> > > Again, if someone wants to conditionally compile the directories to find
> > > the offending file, I am sure we can get a fix for it.
> > >
> >
> > At first look it seems to be:  backend/catalog/indexing.c.
> > Maybe Keith can confirm?
> >
> > Thanks,
>
> Tom,
>
> I recompiled the latest cvs with -O2 and found that the crash on
> table creation was NOT now failing so I'm a little confused :-(
>
> I'm just updating my cvs, and will do another build and see how
> things go.
>
> If only I had the same failures as before I'd be able to confirm
> your suspicions on indexing.c

I have found a problem in indexing.c.  In CatalogIndexFetchTuple(),
there is a particulary weird do..while loop, and in trying to clean it
up as part of the megapatch, I broke it and thought I had it fixed.

It appears it may still be broken.  The ReleaseBuffer(buffer) call could
happen even if no valid tuple is returned because buffer has a random
value.

I am running a test now, and will post the fix as soon as I am sure it
works.

--
Bruce Momjian                          |  830 Blythe Avenue
maillist@candle.pha.pa.us              |  Drexel Hill, Pennsylvania 19026
  +  If your life is a hard drive,     |  (610) 353-9879(w)
  +  Christ can be your backup.        |  (610) 853-3000(h)

> I recompiled the latest cvs with -O2 and found that the crash on
> table creation was NOT now failing so I'm a little confused :-(
>
> I'm just updating my cvs, and will do another build and see how
> things go.
>
> If only I had the same failures as before I'd be able to confirm
> your suspicions on indexing.c
>
> Til Later,
> Keith.
>
>
>

OK, I am applying my patch now.  I certainly fixes a potential problem,
so I suspect it will fix the problems you are seeing.

Thomas, perhaps it will fix the regression problems too.  No way to
know.

Here is the new while loop.  Much better.

---------------------------------------------------------------------------


    sd = index_beginscan(idesc, false, num_keys, skey);
    while (indexRes = index_getnext(sd, ForwardScanDirection))
    {
        ItemPointer iptr;

        iptr = &indexRes->heap_iptr;
        tuple = heap_fetch(heapRelation, SnapshotNow, iptr, &buffer);
        pfree(indexRes);
        if (HeapTupleIsValid(tuple))
            break;
    }

--
Bruce Momjian                          |  830 Blythe Avenue
maillist@candle.pha.pa.us              |  Drexel Hill, Pennsylvania 19026
  +  If your life is a hard drive,     |  (610) 353-9879(w)
  +  Christ can be your backup.        |  (610) 853-3000(h)

In message <199808302324.TAA28018@candle.pha.pa.us>, Bruce Momjian writes:
> > I recompiled the latest cvs with -O2 and found that the crash on
> > table creation was NOT now failing so I'm a little confused :-(
> >
> > I'm just updating my cvs, and will do another build and see how
> > things go.
> >
> > If only I had the same failures as before I'd be able to confirm
> > your suspicions on indexing.c
> >
> > Til Later,
> > Keith.
> >
> >
> >
>
> OK, I am applying my patch now.  I certainly fixes a potential problem,
> so I suspect it will fix the problems you are seeing.
>
> Thomas, perhaps it will fix the regression problems too.  No way to
> know.
>
> Here is the new while loop.  Much better.
>
> ---------------------------------------------------------------------------
>
>
>     sd = index_beginscan(idesc, false, num_keys, skey);
>     while (indexRes = index_getnext(sd, ForwardScanDirection))
>     {
>         ItemPointer iptr;
>
>         iptr = &indexRes->heap_iptr;
>         tuple = heap_fetch(heapRelation, SnapshotNow, iptr, &buffer);
>         pfree(indexRes);
>         if (HeapTupleIsValid(tuple))
>             break;
>     }
>
> --
> Bruce Momjian                          |  830 Blythe Avenue
> maillist@candle.pha.pa.us              |  Drexel Hill, Pennsylvania 19026
>   +  If your life is a hard drive,     |  (610) 353-9879(w)
>   +  Christ can be your backup.        |  (610) 853-3000(h)
>

I tried patching indexing.c with this new loop--no luck.  I just
checked out a fresh copy, still no luck.  I don't understand why it now
works for Keith.

Yesterday I tried this on Solaris, but I was bitten by not having
flock.

Tom Szybist
szybist@boxhill.com