Re: Document default values for pgoutput options + fix missing initialization for "origin"

On Fri, May 16, 2025, at 12:06 PM, Fujii Masao wrote:
> The pgoutput plugin options are documented in the logical streaming
> replication protocol, but their default values are not mentioned.
> This can be inconvenient for users - for example, when using pg_recvlogical
> with pgoutput plugin and needing to know the default behavior of each option.
> https://www.postgresql.org/docs/devel/protocol-logical-replication.html
> 
> I'd like to propose adding the default values to the documentation to
> improve clarity and usability. Patch attached (0001 patch).

Good catch.

Should we use "on" and "off" as other enum GUCs (wal_compression,
recovery_prefetch, compute_query_id)? The current convention is to support
other ways (true / false / 1 / 0) to write boolean but only document one way
(on / off).

Since you are changing this page, I would like to suggest removing "Boolean"
from streaming option. It is not a boolean anymore since protocol version 4.
The suggested description is:

+       Option to enable streaming of in-progress transactions. Valid values are
+       <literal>off</literal> (the default), <literal>on</literal> and
+       <literal>parallel</literal>. The setting <literal>parallel</literal>
+       enables sending extra information with some messages to be used for
+       parallelization. Minimum protocol version 2 is required to turn it
+       <literal>on</literal>.  Minimum protocol version 4 is required for the
+       <literal>parallel</literal> value.


> While working on this, I also noticed that although most optional parameters
> (like "binary") are explicitly initialized in parse_output_parameters(),
> the "origin" parameter is not. Its value (PGOutputData->publish_no_origin)
> is implicitly set to false due to zero-initialization, but unlike other
> parameters, it lacks an explicit default assignment.
> 
> To ensure consistency and make the behavior clearer, I propose explicitly
> initializing the "origin" parameter as well. A patch for this is also attached
> (0002 patch).

LGTM. It seems an oversight from the original commit 366283961ac0.


--
Euler Taveira
EDB   https://www.enterprisedb.com/