Re: Making jsonb_agg() faster

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>

To: Chao Li <li.evan.chao@gmail.com>

Cc: jian he <jian.universality@gmail.com>, pgsql-hackers@lists.postgresql.org

Date: 2025-11-20T18:56:37Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Fix jsonb_object_agg crash after eliminating null-valued pairs.
- ef5f559b95e2 19 (unreleased) landed
Micro-optimize datatype conversions in datum_to_jsonb_internal.
- 005a2907dc30 19 (unreleased) landed
Remove fundamentally-redundant processing in jsonb_agg() et al.
- b61aa76e4585 19 (unreleased) landed
Revise APIs for pushJsonbValue() and associated routines.
- 0986e95161ce 19 (unreleased) landed
Add a macro for the declared typlen of type timetz.
- 3628af42107d 19 (unreleased) landed

Attachments

v4-0001-Revise-APIs-for-pushJsonbValue-and-associated-rou.patch (text/x-diff) patch v4-0001
v4-0002-Remove-fundamentally-redundant-processing-in-json.patch (text/x-diff) patch v4-0002
v4-0003-Micro-optimize-datatype-conversions-in-datum_to_j.patch (text/x-diff) patch v4-0003

I wrote:
> Chao Li <li.evan.chao@gmail.com> writes:
>> You left two “ugly hack” comments. Maybe add a short description for why they are hack and what can be improved in the future.

> It's the same ugly hack as before, I just formatted the code more
> legibly ... I didn't stop to look at whether there's a better way to
> do it.  Again, that seems like material for a different patch.

I took another look at that code and decided that it wasn't quite
as bad a hack as I first thought: it's relying on the upcoming
JsonbValueToJsonb call to wrap the scalar value into the right
array structure for a "raw scalar" JSONB.  Improving the comments
about what this code is doing is definitely within the charter of
my 0001 patch, so here's a new version that improves those two
comments.  Otherwise this is the same as v3.

			regards, tom lane