On 16/05/2025 15:01, Tom Lane wrote:
Aleksander Alekseev <aleksan...@timescale.com> writes:
If I'm right about the limitations of aggregate functions and SRFs
this leaves us the following options:
1. Changing the constraints of aggregate functions or SRFs. However I
don't think we want to do it for such a single niche scenario.
2. Custom syntax and a custom node.
3. To give up
Seems to me the obvious answer is to extend TABLESAMPLE (or at least, some
of the tablesample methods) to allow it to work on a subquery.
Isn't this a job for <fetch first clause>?
Example:
SELECT ...
FROM ... JOIN ...
FETCH SAMPLE FIRST 10 ROWS ONLY
Then the nodeLimit could do some sort of reservoir sampling.
There are several enhancements to <fetch first clause> coming down the
pipe, this could be one of them.
--
Vik Fearing
