Track live PostgreSQL readiness - #1602
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Probe the devshard PostgreSQL pool in the background so readiness reflects a database outage that happens after startup instead of remaining latched forever. Use two-sample failure and recovery hysteresis to avoid flapping, combine the result with session-index readiness, and stop the monitor cleanly when storage closes. Add a unit test for the hysteresis state machine and a Docker test that verifies readiness withdrawal when the live database stops.
This was referenced Aug 18, 2026
snevolin
marked this pull request as ready for review
August 18, 2026 18:08
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Summary
Track the live PostgreSQL connection after devshard storage has started:
Pingcalls;Why
Previously, PostgreSQL readiness represented only successful startup and completion of the initial session-index rebuild. If the database became unavailable later, devshardd stayed alive and could continue reporting ready from stale startup state.
The process should remain alive so a transient database outage does not cause a restart loop, while readiness-aware routing must be able to withdraw it until PostgreSQL recovers.
Behavior
This applies whenever a live PostgreSQL backend is attached. In fail-closed
DEVSHARD_STORAGE_MODE=postgres, database loss makes/readyzunready without terminating devshardd, and readiness recovers automatically when the database returns. Hybrid storage uses the same PostgreSQL signal while attached. SQLite-only mode is unaffected.This PR does not change storage-mode selection, compare database identities, migrate SQL data, or change the PostgreSQL data-directory layout.
Validation
go test -race ./storageHistory
This focused PR extracts the PostgreSQL live-readiness work previously developed in the closed umbrella PRs #1517 and #1587 so it can be reviewed and merged independently.