Re: Turning off HOT/Cleanup sometimes

On Fri, Sep 19, 2014 at 4:30 PM, Andres Freund <andres(at)anarazel(dot)de> wrote:
> On September 19, 2014 10:16:35 PM CEST, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>>On 19 September 2014 13:04, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>>
>>> What I'm thinking about is that the smarts to enable pruning is all
>>in
>>> the executor nodes. So anything that updates the catalog without
>>> going through the executor will never be subject to pruning. That
>>> includes nearly all catalog-modifying code throughout the backend.
>>
>>Are you saying this is a problem or a benefit? (and please explain
>>why).
>
> I have no idea what Robert is thinking of, but I'd imagine its horrible for workloads with catalog bloat. Like ones involving temp tables.

Right, that's what I was going for.

> I generally have serious doubts about disabling it generally for read workloads. I imagine it e.g. will significantly penalize workloads where its likely that a cleanup lock can't be acquired every time...

I share that doubt. But I understand why Simon wants to do something,
too, because the current situation is not great either.

--
Robert Haas
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