railiance-platform/docs/evidence/core-hub-postgres-capacity-preflight-2026-08-20.md

Core Hub PostgreSQL capacity preflight — 2026-08-20

Workplan: RPF-WP-0021-T02

Target: railiance01 databases/platform-pg

Mode: live, read-only, non-secret

Purpose

Record the current platform-pg resource posture before reviewing Core Hub as the fourth declaration on the cell. This is an admission preflight, not the controlled multi-consumer measurement required by rapp-postgres ADR-0004.

Observed baseline

Collected through ssh railiance01 using kubectl top, pod resource metadata, and read-only pg_stat_activity / database-size queries.

Signal	Observation
PostgreSQL pod CPU	9m
PostgreSQL pod memory	362Mi
CPU request / limit	100m / 1 core
Memory request / limit	256Mi / 1Gi
max_connections	100
shared_buffers	128MB
work_mem	4MB
maintenance_work_mem	64MB

Connection snapshot:

Database	Total	Active	Idle
audit_core	1	0	1
postgres	2	1	1
no database	6	0	0

Database sizes were approximately 8MiB each for audit_core, isolation_probe, platform_meta, postgres, and template1.

Interpretation

• The pod was using about 35% of its 1Gi memory limit during this quiet snapshot. That is useful headroom evidence and not a peak or per-backend measurement.
• tenant_engine was not present in the database list, so this sample does not exercise the declared second workload consumer.
• Core Hub would reach the four-declaration ceiling after audit-core, tenant-engine, and the counted isolation probe. It does not exceed the ceiling if the stale, untracked Issue Core draft is removed as required by ISSUE-WP-0007.
• This snapshot does not close ADR-0004 section 5. Admission still needs a coordinated measurement with the declared consumers active, including connection/backend memory under representative load and a recorded peak.

No PostgreSQL credential, query payload, tenant identifier, or secret value was read or recorded.