JSON out of memory error on PostgreSQL 9.6.x

Posted on Stack Overflow, sadly no replies, so trying here....

CREATE TABLE X AS
SELECT json_array_elements(json_rmq -> 'orders'::text) AS order
FROM table_name
WHERE blah;

I get out of memory error.

Is there anything I can do to unpack the above?

The JSON column is about ~5 MB and it has about ~150,000 array row elements in 'orders' above.

I tried work_mem values up to ~250MB and it did not help, the query takes about same time to fail.

I guess this parameter does not help JSON processing.

If there another parameter I can try? Something else?

I don't have control of the size of the JSON payload, it arrives, we store it in a JSON column and then we need to crack it open.

Many thanks!