Re: Tid scan improvements

On 15 August 2018 at 11:11, Edmund Horner <ejrh00(at)gmail(dot)com> wrote:

> So we'd extend that to:
> - Include in the OR-list "range" subquals of the form (ctid > ? AND
> ctid < ?) (either side could be optional, and we have to deal with >=
> and <= and having ctid on the rhs, etc.).
> - Cost the range subquals by assuming they don't overlap, and
> estimating how many blocks and tuples they span.
> - When beginning the scan, evaluate all the ?s and build an array of
> "tid ranges" to fetch. A tid range is a struct with a starting tid,
> and an ending tid, and might just be a single tid item.
> - Sort and remove duplicates.
> - Iterate over the array, using a single fetch for single-item tid
> ranges, and starting/ending a heap scan for multi-item tid ranges.
>
> I think I'll try implementing this.
>

I've set this patch as waiting on author in the commitfest app.

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David Rowley http://www.2ndQuadrant.com/
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