Re: [HACKERS] Custom compression methods

On 3/20/21 3:03 PM, Tom Lane wrote:
> I wrote:
>> Yeah, _doSetFixedOutputState is the wrong place: that runs on the
>> pg_restore side of the fence, and would not have access to the
>> necessary info in a separated dump/restore run.
>> It might be necessary to explicitly pass the state through in a TOC item,
>> as we do for things like the standard_conforming_strings setting.
> Ah, now that I read your patch I see that's exactly what you did.
>
> I fixed up some issues in 0008/0009 (mostly cosmetic, except that
> you forgot a server version check in dumpToastCompression) and
> pushed that, so we can see if it makes crake happy.
>
>

It's still produced a significant amount more difference between the
dumps. For now I've increased the fuzz factor a bit like this:

diff --git a/PGBuild/Modules/TestUpgradeXversion.pm
b/PGBuild/Modules/TestUpgradeXversion.pm
index 1d1d313..567d7cb 100644
--- a/PGBuild/Modules/TestUpgradeXversion.pm
+++ b/PGBuild/Modules/TestUpgradeXversion.pm
@@ -621,7 +621,7 @@ sub test_upgrade    ## no critic
(Subroutines::ProhibitManyArgs)
    # generally from reordering of larg object output.
    # If not we heuristically allow up to 2000 lines of diffs
 
-   if (   ($oversion ne $this_branch && $difflines < 2000)
+   if (   ($oversion ne $this_branch && $difflines < 2700)
        || ($oversion eq $this_branch) && $difflines < 50)
    {
        return 1;

I'll try to come up with something better. Maybe just ignore lines like

SET default_toast_compression = 'pglz';

when taking the diff.

cheers

andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com