Re: Unable to make use of "deep" JSONB index - Mailing list pgsql-bugs

Op 12-06-2022 om 11:34 schreef Shaheed Haque:
> OK, I have corrected and simplified the test case (including switching
> to a btree index). The WHERE clause and the inex now look like this:
> 
>      ...WHERE         ((snapshot -> 'employee' -> '999' ->>
> 'pay_graph')::integer != 0);
>      ...USING btree (((snapshot -> 'employee' -> '$.*'  ->>
> 'pay_graph')::integer != 0));
> 
> But the index is still not being used (test case below). I have
> confirmed that the equality operator is listed for "search" (I assume
> inequality is the same as equality, but I tried both):
> 
> # \dAo btree jsonb*
>              List of operators of operator families
>   AM   | Operator family |    Operator     | Strategy | Purpose
> -------+-----------------+-----------------+----------+---------
> btree | jsonb_ops       | <(jsonb,jsonb)  |        1 | search
> btree | jsonb_ops       | <=(jsonb,jsonb) |        2 | search
> btree | jsonb_ops       | =(jsonb,jsonb)  |        3 | search
> btree | jsonb_ops       | >=(jsonb,jsonb) |        4 | search
> btree | jsonb_ops       | >(jsonb,jsonb)  |        5 | search
> (5 rows)
> 
> If this is not a bug, then how should the query or the index be
> changed to make this work?
> 
> 
> === begin test case ===
> 
> CREATE TABLE payrun (
>      id serial primary key,
>      snapshot JSONB
> );
> 
> INSERT INTO payrun(snapshot)
> VALUES
>    ('{"employee": {"999": {"id": 999, "state": {"employment":
> [["1920-01-01", null, 3]]}, "pay_graph": 0, "last_run_of_employment":
> false}, "111": {"id": 111, "state": {"employment": [["1920-01-01",
> null, 5]]}, "pay_graph": 3, "last_run_of_employment": true}}}'),
>    ('{"employee": {"999": {"id": 999, "state": {"employment":
> [["1970-01-01", null, 3]]}, "pay_graph": 6, "last_run_of_employment":
> true}, "222": {"id": 222, "state": {"employment": [["1920-01-01",
> null, 5]]}, "pay_graph": 5, "last_run_of_employment": true}}}'),
>    ('{"employee": {"998": {"id": 998, "state": {"employment":
> [["1980-01-01", null, 3]]}, "pay_graph": 7, "last_run_of_employment":
> false}, "333": {"id": 333, "state": {"employment": [["1920-01-01",
> null, 5]]}, "pay_graph": 3, "last_run_of_employment": true}}}')
> ;
> 
> SELECT id,snapshot #>'{employee,999,state,employment}' FROM "payrun"
> WHERE ((snapshot -> 'employee' -> '999' ->> 'pay_graph')::integer !=
> 0);
> 
> --
> -- Create index designed to match the query.
> --
> CREATE INDEX idx1 ON payrun USING btree (((snapshot -> 'employee' ->
> '$.*' ->> 'pay_graph')::integer != 0));
> 
> set enable_seqscan = OFF;
> 

How is this?

I took the triple condition from your earlier email.
I did not use your index.
I added one index using gin jsonb_path_ops.

create index payrun_jspathop_idx ON payrun using gin (snapshot 
jsonb_path_ops);
set enable_seqscan = OFF;
\timing on
     select id, snapshot #>'{employee,999,state,employment}' from payrun
where snapshot @? '$."employee"."999" ?
    ( @.pay_graph <> 0
   || @.last_run_of_employment == true
   || @.state.employment[last][2] == 0
)';
  id |         ?column?
----+---------------------------
   2 | [["1970-01-01", null, 3]]
(1 row)

Time: 0.897 ms
explain analyze  select id, snapshot #>'{employee,999,state,employment}' 
from payrun
where snapshot @? '$."employee"."999" ?
    ( @.pay_graph <> 0
   || @.last_run_of_employment == true
   || @.state.employment[last][2] == 0
)';
 
        QUERY PLAN 


-----------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Bitmap Heap Scan on payrun  (cost=136.00..140.02 rows=1 width=36) 
(actual time=0.018..0.019 rows=1 loops=1)
    Recheck Cond: (snapshot @? '$."employee"."999"?((@."pay_graph" != 0 
|| @."last_run_of_employment" == true) || 
@."state"."employment"[last][2] == 0)'::jsonpath)
    Rows Removed by Index Recheck: 2
    Heap Blocks: exact=1
    ->  Bitmap Index Scan on payrun_jspathop_idx  (cost=0.00..136.00 
rows=1 width=0) (actual time=0.007..0.007 rows=3 loops=1)
          Index Cond: (snapshot @? '$."employee"."999"?((@."pay_graph" 
!= 0 || @."last_run_of_employment" == true) || 
@."state"."employment"[last][2] == 0)'::jsonpath)
  Planning Time: 0.034 ms
  Execution Time: 0.033 ms
(8 rows)

Time: 0.284 ms


hope that helps.

Erik Rijkers