Re: A qsort template

On Sat, Apr 02, 2022 at 06:41:30PM +0700, John Naylor wrote:
> On Sat, Apr 2, 2022 at 5:27 PM Thomas Munro <thomas(dot)munro(at)gmail(dot)com> wrote:
> > Reproduced locally, using the same few lines from the cluster.sql
> > test. I'll try to dig more tomorrow...
>
> Thanks! Unfortunately I can't reproduce locally with clang 13/gcc 11,
> with -Og or -O2 with CFLAGS="-fsanitize=undefined,alignment" ...

Like Thomas just said, I had to use:
CFLAGS="-Og -fsanitize=undefined,alignment -fno-sanitize-recover=all

I'm a couple few steps out of my league here, but it may be an issue with:

commit 4ea51cdfe85ceef8afabceb03c446574daa0ac23
Author: Robert Haas <rhaas(at)postgresql(dot)org>
Date: Mon Jan 19 15:20:31 2015 -0500

Use abbreviated keys for faster sorting of text datums.

This is enough to avoid the crash, which might be a useful hint..

@@ -4126,22 +4126,23 @@ copytup_cluster(Tuplesortstate *state, SortTuple *stup, void *tup)
/*
* set up first-column key value, and potentially abbreviate, if it's a
* simple column
*/
+ stup->isnull1 = false;
if (state->indexInfo->ii_IndexAttrNumbers[0] == 0)
return;

original = heap_getattr(tuple,
state->indexInfo->ii_IndexAttrNumbers[0],
state->tupDesc,
&stup->isnull1);