Re: Support for dumping extended statistics

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.

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

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