Re: Support for dumping extended statistics

Thanks Team for showing interest.

Please find the attached patch, which uses the same approach as mentioned in previous email to implement input functions to parse pg_distinct, pg_dependency and pg_mcv_list strings.

Regards,
Hari
From: Bruce Momjian <bruce(at)momjian(dot)us>
Date: Saturday, 7 January 2023 at 8:10 AM
To: Hari krishna Maddileti <hmaddileti(at)vmware(dot)com>
Cc: PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Support for dumping extended statistics
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On Thu, Jan 5, 2023 at 06:29:03PM +0000, Hari krishna Maddileti wrote:
> Hi Team,
> In order to restore dumped extended statistics (stxdndistinct,
> stxddependencies, stxdmcv) we need to provide input functions to parse
> pg_distinct/pg_dependency/pg_mcv_list strings.
>
> Today we get the ERROR "cannot accept a value of type pg_ndistinct/
> pg_dependencies/pg_mcv_list" when we try to do an insert of any type.
>
> Approch tried:
>
> - Using yacc grammar file (statistics_gram.y) to parse the input string to its
> internal format for the types pg_distinct and pg_dependencies
>
> - We are just calling byteain() for serialized input text of type pg_mcv_list.
>
> Currently the changes are working locally, I would like to push the commit
> changes to upstream if there any usecase for postgres. Would like to know if
> there any interest from postgres side.

There is certainly interest in allowing the optimizer statistics to be
dumped and reloaded. This could be used by pg_restore and pg_upgrade.

--
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