Re: pg_stat_statements query jumbling question

From: Satoshi Nagayasu <snaga(at)uptime(dot)jp>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Peter Geoghegan <pg(at)heroku(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: pg_stat_statements query jumbling question
Date: 2015-09-03 02:41:15
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On 2015/09/01 14:39, Satoshi Nagayasu wrote:
> On 2015/09/01 14:01, Tom Lane wrote:
>> Satoshi Nagayasu <snaga(at)uptime(dot)jp> writes:
>>> On 2015/09/01 13:41, Peter Geoghegan wrote:
>>>> If you want to use the queryId field directly, which I recall you
>>>> mentioning before, then that's harder. There is simply no contract
>>>> among extensions for "owning" a queryId. But when the fingerprinting
>>>> code is moved into core, then I think at that point queryId may cease
>>>> to be even a thing that pg_stat_statements theoretically has the right
>>>> to write into. Rather, it just asks the core system to do the
>>>> fingerprinting, and finds it within queryId. At the same time, other
>>>> extensions may do the same, and don't need to care about each other.
>>>> Does that work for you?
>>> Yes. I think so.
>>> I need some query fingerprint to determine query group. I want queryid
>>> to keep the same value when query strings are the same (except literal
>>> values).
>> The problem I've got with this is the unquestioned assumption that every
>> application for query IDs will have exactly the same requirements for
>> what the ID should include or ignore.
> I'm not confident about that too, but at least, I think we will be able
> to collect most common use cases as of today. (aka best guess. :)
> And IMHO it would be ok to change the spec in future release.

I know this still needs to be discussed, but I would like to submit
a patch for further discussion at the next CF, 2015-11.

NAGAYASU Satoshi <snaga(at)uptime(dot)jp>

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