PostgreSQL › PostgreSQL - general

New operators and class for jsonb with gin indexing

_‹ Previous Topic Next Topic _›

Classic

List

Threaded

4 messages Options

Luka Zivkovic

New operators and class for jsonb with gin indexing

Hello all!

I am having problems applying gin indexing to my new operator class for type jsonb.

I created an operator that can query(jsonb column) keys and dates where dates are more than, less than, equal and not equal to the one provided inside another jsonb.

Because I want to make it use index search and not sequential search, I wanted to use gin indexing, but it says that i'm missing support functions. Did anybody try to do something like this? I searched everywhere online, and I didn't see an example of how they should look like. This is how i created an operator class

CREATE OPERATOR CLASS custom_jsonb_dates_operators FOR TYPE jsonb
USING gin AS
OPERATOR 1 #>? (jsonb, jsonb),

OPERATOR 2 #<? (jsonb, jsonb),
OPERATOR 3 #=? (jsonb, jsonb),
OPERATOR 4 #!=? (jsonb, jsonb)

After this, when i created an index with this operator class, i got the following error:

missing support function 2 for attribute 1 of index "idx_name"

I tried writing my own support functions, but none worked(after creating an index, it just never returned any results.

Thanks,

Luka Zivkovic

Tom Lane-2

Re: New operators and class for jsonb with gin indexing

Luka Zivkovic <[hidden email]> writes:
> I am having problems applying gin indexing to my new operator class for
> type jsonb.
> I created an operator that can query(jsonb column) keys and dates where
> dates are more than, less than, equal and not equal to the one provided
> inside another jsonb.
> Because I want to make it use index search and not sequential search, I
> wanted to use gin indexing, but it says that i'm missing support functions.
> Did anybody try to do something like this?

There's not a whole lot of documentation about this, but there is some:

https://www.postgresql.org/docs/13/gin-extensibility.html

After reading that, I'd suggest looking into the code for gin opclass
support in various contrib modules (hstore might be a good start).

regards, tom lane

Luka Zivkovic

Re: New operators and class for jsonb with gin indexing

Thank you for your response!

Yeah, i was looking i to that, and it looks like i just didn't implement it correctly. I'm just wondering because I'm using it for jsonb type, can i just use already implemented support functions for jsonb? I'm just not too sure how those functions work

Thanks,

Luka Živković

On Tue, Feb 23, 2021, 16:28 Tom Lane <[hidden email]> wrote:

Luka Zivkovic <[hidden email]> writes:
> I am having problems applying gin indexing to my new operator class for
> type jsonb.
> I created an operator that can query(jsonb column) keys and dates where
> dates are more than, less than, equal and not equal to the one provided
> inside another jsonb.
> Because I want to make it use index search and not sequential search, I
> wanted to use gin indexing, but it says that i'm missing support functions.
> Did anybody try to do something like this?

There's not a whole lot of documentation about this, but there is some:

https://www.postgresql.org/docs/13/gin-extensibility.html

After reading that, I'd suggest looking into the code for gin opclass
support in various contrib modules (hstore might be a good start).

regards, tom lane

Tom Lane-2

Re: New operators and class for jsonb with gin indexing

Luka Zivkovic <[hidden email]> writes:
> Yeah, i was looking i to that, and it looks like i just didn't implement
> it correctly. I'm just wondering because I'm using it for jsonb type, can i
> just use already implemented support functions for jsonb? I'm just not too
> sure how those functions work

The support functions need to know about the operators' semantics, so
you have to write your own when inventing new operators.

regards, tom lane