_Disclaimer: produced using Claude Opus 4.6, reviewed by me, and
validated against Dogfood dataset._
The `ListAIBridgeSessions` query materialized and aggregated all
matching interceptions before paginating, then ran expensive
token/prompt lookups across the full dataset. For a page of 25 sessions
against ~200k interceptions (our dogfood dataset), this meant:
- Three CTEs scanning all rows (filtered_interceptions, session_tokens,
session_root)
- ARRAY_AGG(fi.id) collecting every interception ID per session
- Lateral prompt lookup via ANY(array_of_all_ids) running for every
session, not just the page
- ~90MB of disk sorts and JIT compilation kicking in
The improvement is to restructure to paginate first and enrich after: a
single CTE groups interceptions into sessions with only cheap aggregates
(MIN, MAX, COUNT), applies cursor pagination and LIMIT, then lateral
joins fetch metadata, tokens, and prompts for just the ~25-row page.
Measured against 220k interceptions / 160k sessions:
| Metric | Before | After |
|--------------------|--------|-------|
| Execution time | 1800ms | 185ms |
| Shared buffer hits | 737k | 2.6k |
| Disk sort spill | 86MB | 16MB |
| Lateral loops | 160k | 25 |
https://grafana.dev.coder.com/goto/fbODPGtvR?orgId=1 the results are
identical, just _much_ faster.
---
Also includes some additional tests which I added prior to refactoring
the query to ensure no regressions on edge-cases.
---------
Signed-off-by: Danny Kopping <danny@coder.com>
Danny Kopping
9fa103929a