Re: BRIN and PageIndexDeleteNoCompact

Heikki Linnakangas wrote:
> BRIN added a new function, PageIndexDeleteNoCompact(), which is like
> PageIndexMultiDelete but does not remove unused line pointers. However, all
> the callers pass it just a single offset. So the callers would really be
> more interested in efficiently squeezing out a single tuple from a page,
> like PageIndexTupleDelete() does, than a bulk operation.

Yeah, I noticed this and yes I agree there's no harm in changing it to a
single-tuple mode rather than bulk operation.

> How about replacing PageIndexDeleteNoCompact() with something more like
> PageIndexTupleDelete()? It ought to be both faster and simpler.

No objection. Are you working on this, or do you intend me to?

How relevant is this given your current PageRepairFragmentation work?
I think it will cause hard merge conflicts if done right away; should it
be attempted prior to the PRF patches, or after it's done? I assume
that if you do it, you can do both things simultaneously ...

> PS. The comment above PageIndexDeleteNoCompact says that unused items at the
> end of the array are removed. But looking at the code, I don't see it doing
> that.

Hmm, it probably lost the capability during the development :-(

--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services