How to Efficiently Index and Query JSONB Arrays in PostgreSQL?

Proper Index for Querying Structures in Arrays in Postgres JSONB

To effectively index and query arrays of structured data stored in a Postgres JSONB field, consider the following steps:

1. Correct Array Access:

Use the correct syntax to access array elements in a JSONB context. For example:

e->0->>'event_slug'

2. Custom Operators for JSONB:

Utilize jsonpath operators for greater-than or less-than comparisons on JSONB fields. In Postgres 12 or later, use @?:

e->0->>'end_time' @> '2014-10-13'

Or, in older versions, use jsonb_path_ops:

CREATE INDEX events_gin_idx ON locations USING GIN (events jsonb_path_ops);

3. Basic Solution for Postgres 12 :

For equality checks, use the @? operator:

SELECT l.*
FROM locations l
WHERE l.events @? '$[*] ? (@.event_slug == "test_1")';

For OR-type filters, use the following syntax:

SELECT l.*
FROM locations l
WHERE l.events @? '$[*] ? (@.event_slug == "test_1") ? (@.start_time.datetime() < "2014-10-13".datetime() || @.end_time.datetime() < "2014-10-13".datetime())';

4. Basic Solution for Any Postgres Version:

For equality checks, use the @> operator:

SELECT * FROM locations WHERE events @> '[{"event_slug":"test_1"}]';

For greater-than-or-equal checks, use a subquery:

SELECT l.*
FROM locations l
JOIN jsonb_array_elements(l.events) e ON l.events @> '[{"event_slug":"test_1"}]'
WHERE (e->>'end_time')::timestamp >= '2014-10-30 14:04:06'::timestamptz;

5. Advanced Solution Using Materialized View:

For optimal performance on complex queries, consider creating a materialized view that stores relevant data in normalized form:

CREATE MATERIALIZED VIEW loc_event AS
SELECT l.location_id, e.event_slug, e.end_time
FROM locations l, jsonb_populate_recordset(null::event_type, l.events) e;

6. Index and Query the Materialized View:

CREATE INDEX loc_event_idx ON loc_event (event_slug, end_time, location_id);

SELECT *
FROM loc_event
WHERE event_slug = 'test_1'
AND end_time >= '2014-10-30 14:04:06 -0400'::timestamptz;

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