Is it possible to use SPI within an age_ function?

Question

I was wondering if I could utilize SPI to access the server and perform a query to return an agtype value. I wanted to implement a function that uses an already created one but then perform an ORDER BY and then return the agtype results from there. Would that be possible? If this is not possible, how could call another age_ function inside another and retrieve it's results and use ODER BY with it?

I have removed the "spi" tag as it is used for the *Serial Peripheral Interface* and not for *Server Programming Interface*. — Codo, Jul 03 '23 at 19:47

score 1 · Answer 1 · answered Jul 03 '23 at 20:52

I don't know about the SPI (Server Programming Interface), but you could look in fmgr.h for the DirectFunctionCall family of functions, which provide various ways to call other functions inside C.

Here's an example that demonstrates the usage:

Datum result;
result = DirectFunctionCall2(numeric_add, num1, num2);

In this code snippet, the DirectFunctionCall2 function is used to call another function that adds two numeric values and returns the result.

score 1 · Answer 2 · answered Jul 04 '23 at 11:22

1

The SPI mechanism should work fine, but I think transform_cypher_order_by function is responsible for handling the ORDER BY clause. You should experiment with it and see if it works.

answered Jul 04 '23 at 11:22

Mohayu Din

433
9

In which file and folder is this function located? – Matheus Farias Jul 04 '23 at 12:57
src/backend/parser/cypher_clause.c – Mohayu Din Jul 04 '23 at 16:43

score 1 · Answer 3 · answered Jul 27 '23 at 09:48

1

Yes it is possible to use the server programming interface in PostgreSQL to work on and perform queries and access the server. Moreover, the ORDER BY query can also be used within the AGE function for custom domains.

answered Jul 27 '23 at 09:48

Haseeb Ashraf

205
2

Is it possible to use SPI within an age_ function?

3 Answers3