Re: [HACKERS] Runtime Partition Pruning

On 22 February 2018 at 22:31, Amit Langote
<Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> Some comments:

Hi Amit,

Thanks for looking at this. I'll work through your comments and
produce a patch sometime in the near future.

One problem that I'm facing now is down to the way I'm gathering the
ParamIds that match the partkeys. As you'll see from the patch I've
added a 'paramids' field to PartitionPruneContext and I'm populating
this when the clauses are being pre-processed in
extract_partition_clauses(). The problem is that the or_clauses are
not pre-processed at all, so the current patch will not properly
perform run-time pruning when the Params are "hidden" in OR branches.

One way I thought to fix this was to change the clause processing to
create an array of PartitionClauseInfos, one for each OR branch. This
would also improve the performance of the run-time pruning, meaning
that all of the or clauses would be already matched to the partition
keys once, rather than having to redo that again each time a Param
changes its value.

If I go and write a patch to do that, would you want it in your patch,
or would you rather I kept it over here? Or perhaps you have a better
idea on how to solve...?

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