Re: Allow table AMs to define their own reloptions

Julien Tachoires <julien@tachoires.me>

From: Julien Tachoires <julien@tachoires.me>
To: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2025-05-26T11:06:19Z
Lists: pgsql-hackers

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On Sat, Mar 29, 2025 at 08:46:01AM +0100, Julien Tachoires wrote:
> On Sun, Mar 02, 2025 at 02:23:54PM +0100, Julien Tachoires wrote:
> > On Sun, Mar 02, 2025 at 09:56:41AM +0100, Julien Tachoires wrote:
> > > With the help of the new TAM routine 'relation_options', table access 
> > > methods can with this patch define their own reloptions 
> > > parser/validator.
> > > 
> > > These reloptions can be set via the following commands:
> > > 1. CREATE TABLE ... USING table_am
> > >        WITH (option1='value1', option2='value2');
> > > 2. ALTER TABLE ...
> > >        SET (option1 'value1', option2 'value2');
> > > 3. ALTER TABLE ... SET ACCESS METHOD table_am
> > >        OPTIONS (option1 'value1', option2 'value2');
> > > 
> > > When changing table's access method, the settings inherited from the 
> > > former TAM can be dropped (if not supported by the new TAM) via: DROP 
> > > option, or, updated via: SET option 'value'.
> > > 
> > > Currently, tables using different TAMs than heap are able to use heap's 
> > > reloptions (fillfactor, toast_tuple_target, etc...). With this patch 
> > > applied, this is not the case anymore: if the TAM needs to have access 
> > > to similar settings to heap ones, they have to explicitly define them.
> > > 
> > > The 2nd patch file includes a new test module 'dummy_table_am' which 
> > > implements a dummy table access method utilized to exercise TAM 
> > > reloptions. This test module is strongly based on what we already have 
> > > in 'dummy_index_am'. 'dummy_table_am' provides a complete example of TAM 
> > > reloptions definition.
> > > 
> > > This work is directly derived from SadhuPrasad's patch here [2]. Others 
> > > attempts were posted here [1] and here [3].
> > > 
> > > [1] https://www.postgresql.org/message-id/flat/429fb58fa3218221bb17c7bf9e70e1aa6cfc6b5d.camel%40j-davis.com
> > > [2] https://www.postgresql.org/message-id/flat/CAFF0-CG4KZHdtYHMsonWiXNzj16gWZpduXAn8yF7pDDub+GQMg@mail.gmail.com
> > > [3] https://www.postgresql.org/message-id/flat/AMUA1wBBBxfc3tKRLLdU64rb.1.1683276279979.Hmail.wuhao%40hashdata.cn
> > 
> > Please find a new version including minor fixes: 'TAM' terms are
> > replaced by 'table AM'
> 
> Please find a new rebased version. 

New rebased version.

-- 
Julien Tachoires