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From: Bruce Momjian <[email protected]>
To: Corey Huinker <[email protected]>
Cc: Tomas Vondra <[email protected]>
Cc: Ashutosh Bapat <[email protected]>
Cc: [email protected]
Subject: Re: Statistics Import and Export
Date: Wed, 27 Dec 2023 22:11:23 -0500
Message-ID: <[email protected]> (raw)
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On Wed, Dec 27, 2023 at 09:41:31PM -0500, Corey Huinker wrote:
>     When I thought about the ability to dump/load statistics in the past, I
>     usually envisioned some sort of DDL that would do the export and import.
>     So for example we'd have EXPORT STATISTICS / IMPORT STATISTICS commands,
>     or something like that, and that'd do all the work. This would mean
>     stats are "first-class citizens" and it'd be fairly straightforward to
>     add this into pg_dump, for example. Or at least I think so ...
> 
>     Alternatively we could have the usual "functional" interface, with a
>     functions to export/import statistics, replacing the DDL commands.
> 
>     Unfortunately, none of this works for the pg_upgrade use case, because
>     existing cluster versions would not support this new interface, of
>     course. That's a significant flaw, as it'd make this useful only for
>     upgrades of future versions.
> 
> 
> This was the reason I settled on the interface that I did: while we can create
> whatever interface we want for importing the statistics, we would need to be
> able to extract stats from databases using only the facilities available in
> those same databases, and then store that in a medium that could be conveyed
> across databases, either by text files or by saving them off in a side table
> prior to upgrade. JSONB met the criteria.

Uh, it wouldn't be crazy to add this capability to pg_upgrade/pg_dump in
a minor version upgrade if it wasn't enabled by default, and if we were
very careful.

-- 
  Bruce Momjian  <[email protected]>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.






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