Re: Columns correlation and adaptive query optimization

From: Yugo NAGATA <nagata(at)sraoss(dot)co(dot)jp>
To: Tomas Vondra <tomas(dot)vondra(at)enterprisedb(dot)com>
Cc: Konstantin Knizhnik <k(dot)knizhnik(at)postgrespro(dot)ru>, Rafia Sabih <rafia(dot)pghackers(at)gmail(dot)com>, David Steele <david(at)pgmasters(dot)net>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Columns correlation and adaptive query optimization
Date: 2021-03-19 09:17:26
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On Wed, 10 Mar 2021 03:00:25 +0100
Tomas Vondra <tomas(dot)vondra(at)enterprisedb(dot)com> wrote:

> What is being proposed here - an extension suggesting which statistics
> to create (and possibly creating them automatically) is certainly
> useful, but I'm not sure I'd call it "adaptive query optimization". I
> think "adaptive" means the extension directly modifies the estimates
> based on past executions. So I propose calling it maybe "statistics
> advisor" or something like that.

I am also agree with the idea to implement this feature as a new
extension for statistics advisor.

> BTW Why is "qual" in
> static void
> AddMultiColumnStatisticsForQual(void* qual, ExplainState *es)
> declared as "void *"? Shouldn't that be "List *"?

When I tested this extension using TPC-H queries, it raised segmentation
fault in this function. I think the cause would be around this argument.

Yugo Nagata

Yugo NAGATA <nagata(at)sraoss(dot)co(dot)jp>

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