Allow table AMs to define their own reloptions - Mailing list pgsql-hackers

From Julien Tachoires
Subject Allow table AMs to define their own reloptions
Date
Msg-id 20250302085641.hmjom5ru3w554t2n@poseidon.home.virt
Whole thread Raw
Responses Re: Allow table AMs to define their own reloptions
List pgsql-hackers
Hi,

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

-- 
Julien Tachoires

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