snapshot of https://github.com/centrifugal/centrifugo.git (master, 2026-09-16; blobs > 131072B omitted)

internal/controllers/controller_postgres_schema.sql

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+-- PostgreSQL Controller schema template.
+-- Placeholders: __PREFIX__ → e.g. "cf_" (includes trailing underscore).
+--
+-- Tables:
+--   __PREFIX__controller_messages        — control message outbox (partitioned by created_at, daily)
+--   __PREFIX__controller_shard_lock      — per-shard serialization lock rows
+--   __PREFIX__controller_schema_version  — schema version tracking
+--
+-- Functions:
+--   __PREFIX__controller_publish(BYTEA, TEXT, INTEGER) — shard lock + INSERT + NOTIFY
+
+-- Messages outbox table — always partitioned by created_at (daily).
+CREATE TABLE IF NOT EXISTS __PREFIX__controller_messages (
+    id          BIGSERIAL,
+    shard_id    SMALLINT NOT NULL DEFAULT 0,
+    node_id     TEXT NOT NULL DEFAULT '',
+    data        BYTEA NOT NULL,
+    created_at  TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    PRIMARY KEY (id, created_at)
+) PARTITION BY RANGE (created_at);
+
+CREATE INDEX IF NOT EXISTS __PREFIX__controller_messages_shard_id_idx
+    ON __PREFIX__controller_messages (shard_id, id);
+
+-- Per-shard serialization lock. Rows populated by EnsureSchema (0..NumShards-1).
+-- The publish function acquires a FOR UPDATE lock on the relevant row before
+-- INSERT, ensuring BIGSERIAL id assignment matches commit order within a shard.
+CREATE TABLE IF NOT EXISTS __PREFIX__controller_shard_lock (
+    shard_id SMALLINT PRIMARY KEY
+);
+
+-- Schema version tracking.
+CREATE TABLE IF NOT EXISTS __PREFIX__controller_schema_version (
+    id              INTEGER PRIMARY KEY,
+    schema_version  INTEGER NOT NULL
+);
+INSERT INTO __PREFIX__controller_schema_version (id, schema_version) VALUES (1, 1)
+    ON CONFLICT (id) DO NOTHING;
+
+-- Publish function: shard lock + INSERT + NOTIFY.
+-- Acquires a FOR UPDATE lock on the shard_lock row for the computed shard,
+-- serializing concurrent publishes within the same shard. This ensures the
+-- BIGSERIAL id order matches commit order — no gaps for cursor-based polling.
+CREATE OR REPLACE FUNCTION __PREFIX__controller_publish(
+    p_data BYTEA,
+    p_node_id TEXT DEFAULT '',
+    p_num_shards INTEGER DEFAULT NULL
+) RETURNS BIGINT AS $$
+DECLARE
+    v_id BIGINT;
+    v_shard_id INTEGER;
+BEGIN
+    -- Auto-derive num_shards from shard_lock table when not provided.
+    IF p_num_shards IS NULL OR p_num_shards <= 0 THEN
+        SELECT COUNT(*)::INTEGER INTO p_num_shards FROM __PREFIX__controller_shard_lock;
+    END IF;
+
+    -- All messages go to shard 0 when num_shards=1. With multiple shards,
+    -- distribute by hash of node_id (targeted) or round-robin via txid (broadcast).
+    IF p_num_shards <= 1 THEN
+        v_shard_id := 0;
+    ELSIF p_node_id != '' THEN
+        v_shard_id := abs(hashtext(p_node_id)::bigint) % p_num_shards;
+    ELSE
+        v_shard_id := (txid_current() % p_num_shards)::INTEGER;
+    END IF;
+
+    -- Serialize within shard.
+    PERFORM 1 FROM __PREFIX__controller_shard_lock WHERE shard_id = v_shard_id FOR UPDATE;
+
+    INSERT INTO __PREFIX__controller_messages (shard_id, node_id, data)
+    VALUES (v_shard_id, p_node_id, p_data)
+    RETURNING id INTO v_id;
+
+    PERFORM pg_notify('__PREFIX__controller_notify', '');
+    RETURN v_id;
+END;
+$$ LANGUAGE plpgsql;