🎉 Initial commit

db/init/001_schema.sql

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+-- TimescaleDB schema for MQTT telemetry ingestion.
+-- Executed automatically on first container start.
+
+CREATE EXTENSION IF NOT EXISTS timescaledb;
+
+CREATE TABLE IF NOT EXISTS telemetry (
+    time        TIMESTAMPTZ NOT NULL,
+    topic       TEXT        NOT NULL,
+    device_id   TEXT,
+    payload     JSONB       NOT NULL
+);
+
+-- Convert to hypertable for time-series storage.
+SELECT create_hypertable('telemetry', 'time', if_not_exists => TRUE);
+
+-- Indexes for common query patterns.
+-- (topic, time) and (device_id, time) serve the filtered API queries;
+-- a bare (time) index serves the unfiltered /telemetry/latest lookup,
+-- which would otherwise require a full backward scan of the hypertable.
+CREATE INDEX IF NOT EXISTS idx_telemetry_topic_time ON telemetry (topic, time DESC);
+CREATE INDEX IF NOT EXISTS idx_telemetry_device_time ON telemetry (device_id, time DESC);
+CREATE INDEX IF NOT EXISTS idx_telemetry_time ON telemetry (time DESC);
+
+-- Compression: older chunks are squeezed on a background schedule.
+ALTER TABLE telemetry SET (
+    timescaledb.compress,
+    timescaledb.compress_segmentby = 'topic, device_id'
+);
+
+-- Compress chunks older than 7 days, drop data older than 1 year.
+SELECT add_compression_policy('telemetry', INTERVAL '7 days');
+SELECT add_retention_policy('telemetry', INTERVAL '365 days');