Horton

Re: speeding up planning with partitions

Amit Langote <langote_amit_f8@lab.ntt.co.jp>

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From: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
To: "Imai, Yoshikazu" <imai.yoshikazu@jp.fujitsu.com>
Cc: Pg Hackers <pgsql-hackers@postgresql.org>, David Rowley <david.rowley@2ndquadrant.com>
Date: 2018-11-09T08:26:27Z
Lists: pgsql-hackers 
Imai-san,

On 2018/11/07 10:00, Imai, Yoshikazu wrote:
> About inheritance_make_rel_from_joinlist(), I considered how it processes
> joins for sub-partitioned-table.
> 
> sub-partitioned-table image:
> part
>   sub1
>     leaf1
>     leaf2
> 
> inheritance_make_rel_from_joinlist() translates join_list and join_info_list
> for each leafs(leaf1, leaf2 in above image). To translate those two lists for
> leaf1, inheritance_make_rel_from_joinlist() translates lists from part to sub1
> and nextly from sub1 to leaf1. For leaf2, inheritance_make_rel_from_joinlist() 
> translates lists from part to sub1 and from sub1 to leaf2. There are same
> translation from part to sub1, and I think it is better if we can eliminate it.
> I attached 0002-delta.patch.
> 
> In the patch, inheritance_make_rel_from_joinlist() translates lists not only for
> leafs but for mid-nodes, in a depth-first manner, so it can use lists of
> mid-nodes for translating lists from mid-node to leafs, which eliminates same
> translation.

I don't think the translation happens twice for the same leaf partitions.

Applying adjust_appendrel_attrs_*multilevel* for only leaf nodes, as
happens with the current code, is same as first translating using
adjust_appendrel_attrs from part to sub1 and then from sub1 to leaf1 and
leaf2 during recursion with sub1 as the parent.

> I think it might be better if we can apply same logic to inheritance_planner(),
> which once implemented the same logic as below. 
> 
> 
>     foreach(lc, root->append_rel_list)
>     {
>         AppendRelInfo *appinfo = lfirst_node(AppendRelInfo, lc);
>         ...
>         /*
>          * expand_inherited_rtentry() always processes a parent before any of
>          * that parent's children, so the parent_root for this relation should
>          * already be available.
>          */
>         parent_root = parent_roots[appinfo->parent_relid];
>         Assert(parent_root != NULL);
>         parent_parse = parent_root->parse;
>         ...
>         subroot->parse = (Query *)
>             adjust_appendrel_attrs(parent_root,
>                                    (Node *) parent_parse,
>                                    1, &appinfo);

Actually, inheritance_planner is also using
adjust_appendrel_attrs_multilevel.  I'm not sure if you're looking at the
latest (10/26) patch.

Thanks,
Amit

Commits

  1. Clean up handling of constraint_exclusion and enable_partition_pruning.

  2. Add test case exercising formerly-unreached code in inheritance_planner.

  3. Speed up planning when partitions can be pruned at plan time.

  4. Avoid crash in partitionwise join planning under GEQO.

  5. Avoid passing query tlist around separately from root->processed_tlist.

  6. Build "other rels" of appendrel baserels in a separate step.

  7. Get rid of duplicate child RTE for a partitioned table.

  8. Rearrange make_partitionedrel_pruneinfo to avoid work when we can't prune.

  9. Don't copy PartitionBoundInfo in set_relation_partition_info.

  10. Move building of child base quals out into a new function

  11. Reorganize planner code moved in b60c39759908

  12. Move inheritance expansion code into its own file

  13. Fix inherited UPDATE/DELETE with UNION ALL subqueries.

  14. Rearrange planner to save the whole PlannerInfo (subroot) for a subquery.