Horton

Re: [HACKERS] Runtime Partition Pruning

David Rowley <david.rowley@2ndquadrant.com>

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From: David Rowley <david.rowley@2ndquadrant.com>
To: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Cc: Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, Beena Emerson <memissemerson@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Robert Haas <robertmhaas@gmail.com>, amul sul <sulamul@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Dilip Kumar <dilipbalaut@gmail.com>
Date: 2018-02-22T12:15:26Z
Lists: pgsql-hackers 
On 22 February 2018 at 22:31, Amit Langote
<Langote_Amit_f8@lab.ntt.co.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...?

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

Commits

  1. Initialize ExprStates once in run-time partition pruning

  2. Add bms_prev_member function

  3. Support partition pruning at execution time

  4. Document partprune.c a little better

  5. Fix crash in pg_replication_slot_advance

  6. Add parallel-aware hash joins.

  7. Fix typo.

  8. Allow --with-bonjour to work with non-macOS implementations of Bonjour.

  9. Mention need for --no-inc-recursive in rsync command