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* Export and import of statistics data
@ 2021-02-23 18:53 Holger Jakobs <holger@jakobs.com>
2021-02-23 19:32 ` Re: Export and import of statistics data Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 1 reply; 2+ messages in thread
From: Holger Jakobs @ 2021-02-23 18:53 UTC (permalink / raw)
To: pgsql-admin
Hi everybody,
Is there a way of exporting statistics data from a database cluster
containing a lot of rows and import them into a similar structured, but
small database cluster.
The purpose of this is testing and comparing execution plans on a small
machine. Of course executing the statement wouldn't make much sense, so
I would use only EXPLAIN, not EXPLAIN ANALYZE.
Due to data protection and capacity it's not possible to copy the
production database or even access it.
Thanks and best regards
Holger
--
Holger Jakobs, Bergisch Gladbach, Tel. +49-178-9759012
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* Re: Export and import of statistics data
2021-02-23 18:53 Export and import of statistics data Holger Jakobs <holger@jakobs.com>
@ 2021-02-23 19:32 ` Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 0 replies; 2+ messages in thread
From: Tom Lane @ 2021-02-23 19:32 UTC (permalink / raw)
To: Holger Jakobs <holger@jakobs.com>; +Cc: pgsql-admin
Holger Jakobs <holger@jakobs.com> writes:
> Is there a way of exporting statistics data from a database cluster
> containing a lot of rows and import them into a similar structured, but
> small database cluster.
Not at present, AFAIK. There have been discussions of creating a
way to do that, and I know of at least one non-public tool that
does it, but nobody's pushed things to the point of having code
the community would accept.
The key stumbling block is inventing a dump representation that
would have realistic prospects of still being importable if/when
we change the contents of pg_statistic. Certainly there are a
lot of applications where cross-version compatibility isn't a
requirement; but I don't think the community would take code that
isn't usable by pg_upgrade, and for that you need an upgradable
design.
regards, tom lane
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2021-02-23 18:53 Export and import of statistics data Holger Jakobs <holger@jakobs.com>
2021-02-23 19:32 ` Tom Lane <tgl@sss.pgh.pa.us>
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