Re: [PATCH] Extend the length of BackgroundWorker.bgw_library_name

> On 13 Mar 2023, at 18:35, Nathan Bossart <nathandbossart(at)gmail(dot)com> wrote:
>
> On Mon, Mar 13, 2023 at 07:57:47AM -0700, Yurii Rashkovskii wrote:
>> However, there are use cases where [potentially] longer names are
>> expected/desired; for example, test benches (where library files may not
>> [or can not] be copied to Postgres installation) or alternative library
>> installation methods that do not put them into $libdir.
>>
>> The patch is backwards-compatible and ensures that bgw_library_name stays
>> *at least* as long as BGW_MAXLEN. Existing external code that uses
>> BGW_MAXLEN is a length boundary (for example, in `strncpy`) will continue
>> to work as expected.
>
> I see that BGW_MAXLEN was originally set to 64 in 2013 (7f7485a) [0], but
> was increased to 96 in 2018 (3a4b891) [1]. It seems generally reasonable
> to me to increase the length of bgw_library_name further for the use-case
> you describe, but I wonder if it'd be better to simply increase BGW_MAXLEN
> again. However, IIUC bgw_library_name is the only field that is likely to
> be used for absolute paths, so only increasing that one to MAXPGPATH makes
> sense.

Yeah, raising just bgw_library_name to MAXPGPATH seems reasonable here. While
the memory usage does grow it's still quite modest, and has an upper limit in
max_worker_processes.

While here, I wonder if we should document what BGW_MAXLEN is defined as in
bgworker.sgml?

--
Daniel Gustafsson