On Mon, Aug 26, 2024 at 1:18 AM Peter Eisentraut <peter@eisentraut.org> wrote:
> Or, if people find that too scary, something like
>
> #ifdef JSONAPI_USE_PQEXPBUFFER
>
> #define jsonapi_StringInfo PQExpBuffer
> [...]
>
> That way, it's at least more easy to follow the source code because
> you see a mostly-familiar API.
I was having trouble reasoning about the palloc-that-isn't-palloc code
during the first few drafts, so I will try a round with the jsonapi_
prefix.
> Also, we should make this PQExpBuffer-using mode only used by libpq,
> not by frontend programs. So libpq takes its own copy of jsonapi.c
> and compiles it using JSONAPI_USE_PQEXPBUFFER. That will make the
> libpq build descriptions a bit more complicated, but everyone who is
> not libpq doesn't need to change.
Sounds reasonable. It complicates the test coverage situation a little
bit, but I think my current patch was maybe insufficient there anyway,
since the coverage for the backend flavor silently dropped...
> Or maybe there is a clever way to avoid even that: Create a
> fixed JsonLexContext like
>
> static const JsonLexContext failed_oom;
>
> and on OOM you return that one from makeJsonLexContext*(). And then
> in pg_parse_json(), when you get handed that context, you return
> JSON_OUT_OF_MEMORY immediately.
I like this idea.
Thanks!
--Jacob
