On 10 August 2016 at 03:45, Pavan Deolasee <pavan.deolasee@gmail.com> wrote:
>
>
> On Tue, Aug 9, 2016 at 12:06 AM, Claudio Freire <klaussfreire@gmail.com>
> wrote:
>>
>> On Mon, Aug 8, 2016 at 2:52 PM, Pavan Deolasee <pavan.deolasee@gmail.com>
>> wrote:
>>
>> > Some heuristics and limits on amount of work done to detect duplicate
>> > index
>> > entries will help too.
>>
>> I think I prefer a more thorough approach.
>>
>> Increment/decrement may get very complicated with custom opclasses,
>> for instance. A column-change bitmap won't know how to handle
>> funcional indexes, etc.
>>
>> What I intend to try, is modify btree to allow efficient search of a
>> key-ctid pair, by adding the ctid to the sort order.
>
>
> Yes, that's a good medium term plan. And this is kind of independent from
> the core idea.
+1 That seems like a good idea. It would allow us to produce a bitmap
scan in blocksorted order.
> So I'll go ahead and write a patch that implements the core
> idea and some basic optimizations.
+1
> We can then try different approaches such
> as tracking changed columns, tracking increment/decrement and teaching btree
> to skip duplicate (key, CTID) entries.
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
