Fix a confusing amcheck corruption message.

Don't complain about the last TOAST chunk number being different
from what we expected if there are no TOAST chunks at all.
In such a case, saying that the final chunk number is 0 is not
really accurate, and the fact the value is missing from the
TOAST table is reported separately anyway.

Mark Dilger

Discussion: http://postgr.es/m/AA5506CE-7D2A-42E4-A51D-358635E3722D@enterprisedb.com

contrib/amcheck/verify_heapam.c

@@ -1100,14 +1100,14 @@ check_tuple_attribute(HeapCheckContext *ctx)
 		check_toast_tuple(toasttup, ctx);
 		ctx->chunkno++;
 	}
-	if (ctx->chunkno != (ctx->endchunk + 1))
-		report_corruption(ctx,
-						  psprintf("final toast chunk number %u differs from expected value %u",
-								   ctx->chunkno, (ctx->endchunk + 1)));
 	if (!found_toasttup)
 		report_corruption(ctx,
 						  psprintf("toasted value for attribute %u missing from toast table",
 								   ctx->attnum));
+	else if (ctx->chunkno != (ctx->endchunk + 1))
+		report_corruption(ctx,
+						  psprintf("final toast chunk number %u differs from expected value %u",
+								   ctx->chunkno, (ctx->endchunk + 1)));
 	systable_endscan_ordered(toastscan);
 
 	return true;

src/bin/pg_amcheck/t/004_verify_heapam.pl

@@ -296,7 +296,7 @@ close($file)
 $node->start;
 
 # Ok, Xids and page layout look ok.  We can run corruption tests.
-plan tests => 20;
+plan tests => 19;
 
 # Check that pg_amcheck runs against the uncorrupted table without error.
 $node->command_ok(['pg_amcheck', '-p', $port, 'postgres'],
@@ -489,7 +489,6 @@ for (my $tupidx = 0; $tupidx < ROWCOUNT; $tupidx++)
 
 		$header = header(0, $offnum, 2);
 		push @expected,
-			qr/${header}final toast chunk number 0 differs from expected value \d+/,
 			qr/${header}toasted value for attribute 2 missing from toast table/;
 	}
 	elsif ($offnum == 14)