On Tue, Aug 4, 2015 at 2:04 AM, Simon Riggs wrote:
> On 3 August 2015 at 17:36, Tom Lane wrote:
>>
>> Alvaro Herrera writes:
>> > Simon Riggs wrote:
>> >> * For emergency anti-wraparound VACUUMs we shouldn't scan indexes at
>> >> all,
>> >> since they aren't critical path activities at that poin
On 8/3/15 12:04 PM, Simon Riggs wrote:
Yes, that's what I was thinking, I just didn't say actually it. I'd been
thinking about having VACUUM do just Phase 1 for some time, since its so
much faster to do that. Will code.
I'd like to see that exposed as an option as well. There are certain
situa
On Mon, Aug 3, 2015 at 4:13 AM, Simon Riggs wrote:
> * For normal VACUUMs we should scan indexes only if (num_dead_tuples * 20) >
> (blocks to be scanned in any one index), which allows some index bloat but
> not much
I think this kind of heuristic is good, but I think we should expose a
setting
On Mon, Aug 3, 2015 at 11:52 AM, Alvaro Herrera
wrote:
> Simon Riggs wrote:
>> * For emergency anti-wraparound VACUUMs we shouldn't scan indexes at all,
>> since they aren't critical path activities at that point
>
> It is not possible to skip scanning indexes completely, unless no tuples
> are to
On 3 August 2015 at 17:36, Tom Lane wrote:
> Alvaro Herrera writes:
> > Simon Riggs wrote:
> >> * For emergency anti-wraparound VACUUMs we shouldn't scan indexes at
> all,
> >> since they aren't critical path activities at that point
>
> > It is not possible to skip scanning indexes completely,
Alvaro Herrera writes:
> Simon Riggs wrote:
>> * For emergency anti-wraparound VACUUMs we shouldn't scan indexes at all,
>> since they aren't critical path activities at that point
> It is not possible to skip scanning indexes completely, unless no tuples
> are to be removed from the heap.
Right
Simon Riggs wrote:
> * For emergency anti-wraparound VACUUMs we shouldn't scan indexes at all,
> since they aren't critical path activities at that point
It is not possible to skip scanning indexes completely, unless no tuples
are to be removed from the heap. Otherwise, index tuples become
linge
On 2 August 2015 at 13:13, Michael Paquier
wrote:
> Hi all,
>
> Commit 4046e58c (dated of 2001) has introduced the following comment
> in vacuumlazy.c:
> + /* If any tuples need to be deleted, perform final vacuum cycle */
> + /* XXX put a threshold on min nuber of tuples here? */
> +
Hi all,
Commit 4046e58c (dated of 2001) has introduced the following comment
in vacuumlazy.c:
+ /* If any tuples need to be deleted, perform final vacuum cycle */
+ /* XXX put a threshold on min nuber of tuples here? */
+ if (vacrelstats->num_dead_tuples > 0)
In short, we may wan
