From: | Peter Geoghegan <pg(at)bowt(dot)ie> |
---|---|
To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
Cc: | Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: [PATCH] pageinspect function to decode infomasks |
Date: | 2017-10-12 23:35:34 |
Message-ID: | CAH2-Wz==wy_hssq1gLh-ryMf5dYE3KdLBhc+jZGzmbzWk4wUzQ@mail.gmail.com |
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On Tue, Aug 15, 2017 at 10:54 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> Or at least make the filtering optional.
>
> I don't think "filtering" is the right way to think about it. It's
> just labeling each combination of bits with the meaning appropriate to
> that combination of bits.
I do. -1 to not just showing what's on the page -- if the
HEAP_XMIN_COMMITTED and HEAP_XMIN_ABORTED bits are set, then I think
we should show them. Yeah, I accept that there is a real danger of
confusing people with that. Unfortunately, I think that displaying
HEAP_XMIN_FROZEN will cause even more confusion. I don't think that
HEAP_XMIN_FROZEN is an abstraction at all. It's a notational
convenience.
I don't think it's our place to "interpret" the bits. Are we *also*
going to show HEAP_XMIN_FROZEN when xmin is physically set to
FrozenTransactionId? Where does it end?
I think that we should prominently document that HEAP_XMIN_COMMITTED
|HEAP_XMIN_ABORTED == HEAP_XMIN_FROZEN, rather than trying to hide
complexity that we have no business hiding in a tool like pageinspect.
--
Peter Geoghegan
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