Re: speeding up planning with partitions

From: Amit Langote <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp>
To: "Imai, Yoshikazu" <imai(dot)yoshikazu(at)jp(dot)fujitsu(dot)com>
Cc: Pg Hackers <pgsql-hackers(at)postgresql(dot)org>, David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>
Subject: Re: speeding up planning with partitions
Date: 2018-11-09 08:26:27
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-hackers


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.


In response to


Browse pgsql-hackers by date

  From Date Subject
Next Message Kyotaro HORIGUCHI 2018-11-09 08:33:15 Re: shared-memory based stats collector
Previous Message Amit Langote 2018-11-09 08:04:24 Re: speeding up planning with partitions