Add Covering Index to Nodes Table

[genematx]

This pull request adds a new PostgreSQL covering index to the nodes table to improve query performance for key lookups. The changes include updating the migration history, introducing a new Alembic migration for the index, and modifying the ORM model to define the index.

EXPLAIN ANALYZE SELECT nodes.key FROM nodes WHERE nodes.parent = 0::INTEGER ORDER BY nodes.time_created, nodes.id LIMIT 10::INTEGER OFFSET 0::INTEGER;

Before:

                                                                  QUERY PLAN                                                                  
----------------------------------------------------------------------------------------------------------------------------------------------
 Limit  (cost=18586.51..18586.53 rows=10 width=26) (actual time=110.079..110.082 rows=10 loops=1)
   ->  Sort  (cost=18586.51..18699.39 rows=45153 width=26) (actual time=110.078..110.079 rows=10 loops=1)
         Sort Key: time_created, id
         Sort Method: top-N heapsort  Memory: 26kB
         ->  Bitmap Heap Scan on nodes  (cost=778.36..17610.77 rows=45153 width=26) (actual time=4.395..104.736 rows=45895 loops=1)
               Recheck Cond: (parent = 0)
               Heap Blocks: exact=16268
               ->  Bitmap Index Scan on ix_nodes_parent  (cost=0.00..767.07 rows=45153 width=0) (actual time=2.647..2.647 rows=47294 loops=1)
                     Index Cond: (parent = 0)
 Planning Time: 0.107 ms
 Execution Time: 110.103 ms
(11 rows)

After:

                                                                       QUERY PLAN                                                                       
--------------------------------------------------------------------------------------------------------------------------------------------------------
 Limit  (cost=0.42..2.83 rows=10 width=26) (actual time=0.032..0.033 rows=10 loops=1)
   ->  Index Only Scan using ix_nodes_parent_time_id_key on nodes  (cost=0.42..11778.21 rows=48825 width=26) (actual time=0.032..0.033 rows=10 loops=1)
         Index Cond: (parent = 0)
         Heap Fetches: 0
 Planning Time: 0.370 ms
 Execution Time: 0.041 ms
(6 rows)

Checklist

• Add a Changelog entry
• Add the ticket number which this PR closes to the comment section

[danielballan]

I can see how this would probably be useful, but can you give examples of HTTP requests that would exercise it?

[genematx]

I can see how this would probably be useful, but can you give examples of HTTP requests that would exercise it?

of course! any /api/v1/search/?page[offset]=0&fields=&sort= does this when the clients builds a __repr__ for a container. Maybe it shouldn't, though..

[danielballan]

Will that query also pull the access_blob column, to apply authorization-related filtering, as well as time_created and id for default sorting?

[genematx]

yes, most likely. I had a single user in my example.