Re: Set visibility map bit after HOT prune - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Set visibility map bit after HOT prune
Date
Msg-id 19868.1355943150@sss.pgh.pa.us
Whole thread Raw
In response to Re: Set visibility map bit after HOT prune  (Pavan Deolasee <pavan.deolasee@gmail.com>)
Responses Re: Set visibility map bit after HOT prune  (Pavan Deolasee <pavan.deolasee@gmail.com>)
List pgsql-hackers
Pavan Deolasee <pavan.deolasee@gmail.com> writes:
> On Wed, Dec 19, 2012 at 9:51 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> If we start generating a lot of useless WAL activity and I/O as
>> a result of thrashing the all-visible bit, it won't be so tolerable
>> anymore.

> What if we wrap that into the WAL generated by HOT prune itself ?

What WAL?  The case we're worried about here is that there's nothing
else for HOT prune to do.

>> I think my core point still stands: the way that HOT pruning is done now
>> is an artifact of having wanted to shoehorn it into the system with
>> minimum changes.  Which was reasonable at the time given the
>> experimental status of the feature, but now it's time to reconsider.

> ISTM that you already have concret ideas about what are those places
> where HOT prune would be more effective.

No, I don't; I'm just suggesting that we ought to think outside the box
of the way it's being done now.
        regards, tom lane



pgsql-hackers by date:

Previous
From: Tom Lane
Date:
Subject: Re: [GENERAL] trouble with pg_upgrade 9.0 -> 9.1
Next
From: Simon Riggs
Date:
Subject: Re: Review of Row Level Security