From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
---|---|
To: | Amit Langote <amitlangote09(at)gmail(dot)com> |
Cc: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>, Andres Freund <andres(at)anarazel(dot)de>, Daniel Gustafsson <daniel(at)yesql(dot)se>, David Rowley <dgrowleyml(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>, Thom Brown <thom(at)linux(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Subject: | Re: generic plans and "initial" pruning |
Date: | 2024-08-21 13:10:06 |
Message-ID: | CA+TgmoZGWyMXutfen-NNv9=QM7eCHn9R1bpLZ9N4sRURMOCK2A@mail.gmail.com |
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On Wed, Aug 21, 2024 at 8:45 AM Amit Langote <amitlangote09(at)gmail(dot)com> wrote:
> * The replanning aspect of the lock-in-the-executor design would be
> simpler if a CachedPlan contained the plan for a single query rather
> than a list of queries, as previously mentioned. This is particularly
> due to the requirements of the PORTAL_MULTI_QUERY case. However, this
> option might be impractical.
It might be, but maybe it would be worth a try? I mean,
GetCachedPlan() seems to just call pg_plan_queries() which just loops
over the list of query trees and does the same thing for each one. If
we wanted to replan a single query, why couldn't we do
fake_querytree_list = list_make1(list_nth(querytree_list, n)) and then
call pg_plan_queries(fake_querytree_list)? Or something equivalent to
that. We could have a new GetCachedSinglePlan(cplan, n) to do this.
> * Polish the patch for the old design of doing the initial pruning
> before AcquireExecutorLocks() and focus on hashing out any bugs and
> issues of that design.
That's also an option. It probably has issues too, but I don't know
what they are exactly.
--
Robert Haas
EDB: http://www.enterprisedb.com
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