This document is the source of truth for PostgreSQL parameter group customizations required by Sippy. These settings must be configured in the RDS parameter group (or equivalent server-level configuration) and are not controlled by the application code.
Session-level parameters set by the application on each connection are in
pkg/db/db.go. Per-query transaction overrides are in the query code itself
(look for SET LOCAL). This document covers only the server-level settings
that live outside the codebase.
Differences from the default default.postgres14 parameter group:
| Parameter | Value | Default | Rationale |
|---|---|---|---|
effective_io_concurrency |
200 | 1 | Number of concurrent I/O operations the OS can handle. Set high for SSD/NVMe-backed storage (gp3, io1). |
max_parallel_workers |
16 | GREATEST({DBInstanceVCPU/2},8) |
Total parallel workers available across all concurrent queries. Component readiness queries request 4 workers each via SET LOCAL, and multiple queries run concurrently. Fixed to avoid dependence on instance vCPU count. |
random_page_cost |
1.1 | 4.0 | Favors index scans over sequential scans, appropriate for SSD/NVMe storage. Also set per-session by the application in pkg/db/db.go. |