v2.1.43 - Added subscription retention: prune ended subscription rows at startup and every 10 minutes (db_prune_ended_subscriptions, batched DELETE capped per run). Fixes runaway subscriptions table growth (39M rows / 24 GB) that made admin stats COUNT queries take 42s and spiked server load

relay.pid

@@ -1 +1 @@
-4055658
+66905

src/db_ops.c

@@ -70,6 +70,7 @@ int db_update_subscription_events_sent(const char* sub_id, int events_sent) {
     return postgres_db_update_subscription_events_sent(sub_id, events_sent);
 }
 int db_cleanup_orphaned_subscriptions(void) { return postgres_db_cleanup_orphaned_subscriptions(); }
+int db_prune_ended_subscriptions(int max_batches) { return postgres_db_prune_ended_subscriptions(max_batches); }
 
 int db_get_event_pubkey(const char* event_id, char* pubkey_out, size_t pubkey_out_size) {
     return postgres_db_get_event_pubkey(event_id, pubkey_out, pubkey_out_size);

src/db_ops.h

@@ -65,6 +65,8 @@ int db_log_subscription_closed(const char* sub_id, const char* client_ip);
 int db_log_subscription_disconnected(const char* client_ip);
 int db_update_subscription_events_sent(const char* sub_id, int events_sent);
 int db_cleanup_orphaned_subscriptions(void);
+// Retention: prune ended subscription rows in batches (never touches active rows)
+int db_prune_ended_subscriptions(int max_batches);
 
 // NIP-09 event deletion helpers
 int db_get_event_pubkey(const char* event_id, char* pubkey_out, size_t pubkey_out_size);

src/db_ops_postgres.c

@@ -761,6 +761,61 @@ int postgres_db_update_subscription_events_sent(const char* sub_id, int events_s
 #endif
 }
 
+// Prune ended subscription rows (event_type != 'created' OR ended_at IS NOT NULL).
+// Subscriptions are ephemeral: clients always reconnect with fresh REQs, so
+// ended rows have no value and only create scan burden for the admin stats
+// queries. Runs in batches to avoid long locks; returns total rows deleted
+// (>= 0) or DB_ERROR. Never touches active rows (event_type = 'created' AND
+// ended_at IS NULL).
+int postgres_db_prune_ended_subscriptions(int max_batches) {
+#if defined(DB_BACKEND_POSTGRES) && defined(HAVE_LIBPQ)
+    PGconn* conn = postgres_db_active_connection();
+    if (!conn || PQstatus(conn) != CONNECTION_OK) return DB_ERROR;
+    if (max_batches <= 0) return 0;
+
+    int total_deleted = 0;
+    for (int batch = 0; batch < max_batches; batch++) {
+        PGresult* res = PQexecParams(conn,
+                                     "WITH del AS ( "
+                                     "    DELETE FROM subscriptions "
+                                     "    WHERE id IN ( "
+                                     "        SELECT id FROM subscriptions "
+                                     "        WHERE event_type <> 'created' OR ended_at IS NOT NULL "
+                                     "        LIMIT 50000 "
+                                     "    ) "
+                                     "    RETURNING 1 "
+                                     ") "
+                                     "SELECT count(*) FROM del",
+                                     0, NULL, NULL, NULL, NULL, 0);
+        if (!res || PQresultStatus(res) != PGRES_TUPLES_OK) {
+            if (res) {
+                postgres_set_error_text(PQresultErrorMessage(res));
+                PQclear(res);
+            } else {
+                postgres_set_error_from_conn(conn, "postgres_db_prune_ended_subscriptions failed");
+            }
+            return (total_deleted > 0) ? total_deleted : DB_ERROR;
+        }
+
+        int deleted = 0;
+        if (PQntuples(res) > 0 && !PQgetisnull(res, 0, 0)) {
+            deleted = atoi(PQgetvalue(res, 0, 0));
+        }
+        PQclear(res);
+
+        total_deleted += deleted;
+        if (deleted == 0) {
+            break; // nothing left to prune
+        }
+    }
+
+    return total_deleted;
+#else
+    (void)max_batches;
+    return DB_ERROR;
+#endif
+}
+
 int postgres_db_cleanup_orphaned_subscriptions(void) {
 #if defined(DB_BACKEND_POSTGRES) && defined(HAVE_LIBPQ)
     PGconn* conn = postgres_db_active_connection();

src/db_ops_postgres.h

@@ -42,6 +42,7 @@ int postgres_db_log_subscription_closed(const char* sub_id, const char* client_i
 int postgres_db_log_subscription_disconnected(const char* client_ip);
 int postgres_db_update_subscription_events_sent(const char* sub_id, int events_sent);
 int postgres_db_cleanup_orphaned_subscriptions(void);
+int postgres_db_prune_ended_subscriptions(int max_batches);
 
 int postgres_db_get_event_pubkey(const char* event_id, char* pubkey_out, size_t pubkey_out_size);
 int postgres_db_delete_event_by_id(const char* event_id, const char* requester_pubkey);

src/main.h

@@ -13,8 +13,8 @@
 // Using CRELAY_ prefix to avoid conflicts with nostr_core_lib VERSION macros
 #define CRELAY_VERSION_MAJOR 2
 #define CRELAY_VERSION_MINOR 1
-#define CRELAY_VERSION_PATCH 42
+#define CRELAY_VERSION_PATCH 43
-#define CRELAY_VERSION "v2.1.42"
+#define CRELAY_VERSION "v2.1.43"
 
 // Relay metadata (authoritative source for NIP-11 information)
 #define RELAY_NAME "C-Relay-PG"

src/subscriptions.c

@@ -1274,6 +1274,18 @@ void cleanup_all_subscriptions_on_startup(void) {
     } else {
         DEBUG_LOG("Startup cleanup: no orphaned subscriptions found");
     }
+
+    // Retention: prune ended subscription rows left behind by previous runs.
+    // Subscriptions are ephemeral (clients reconnect with fresh REQs), so
+    // ended rows have no value and only burden the admin stats queries.
+    // Capped at 40 batches (2M rows) per startup; the periodic timer
+    // finishes the rest if the backlog is larger.
+    int pruned = db_prune_ended_subscriptions(40);
+    if (pruned > 0) {
+        DEBUG_LOG("Startup retention: pruned %d ended subscription rows", pruned);
+    } else if (pruned < 0) {
+        DEBUG_WARN("Startup retention: prune failed");
+    }
 }
 
 

src/websockets.c

@@ -3505,6 +3505,8 @@ int start_websocket_relay(int port_override, int strict_port) {
     
     // Static variable for connection age check timing
     static time_t last_connection_age_check = 0;
+    // Static variable for subscription retention pruning (every 10 minutes)
+    static time_t last_subscription_prune = 0;
 
     if (start_async_event_worker() != 0) {
         DEBUG_WARN("Async event worker failed to start; EVENT path will remain synchronous");
@@ -3591,6 +3593,22 @@ int start_websocket_relay(int port_override, int strict_port) {
                 ip_ban_cleanup();
                 ip_ban_log_stats();
             }
+
+            // Subscription retention (every 10 minutes): prune ended rows.
+            // Subscriptions are ephemeral — clients reconnect with fresh REQs —
+            // so ended rows are deleted instead of accumulating forever (this
+            // table previously grew to 39M rows / 24 GB and crushed the admin
+            // stats queries). Small cap keeps each run fast; steady state has
+            // only a few hundred ended rows per interval.
+            if (current_time - last_subscription_prune >= 600) {
+                last_subscription_prune = current_time;
+                int pruned = db_prune_ended_subscriptions(4);
+                if (pruned > 0) {
+                    DEBUG_LOG("Subscription retention: pruned %d ended rows", pruned);
+                } else if (pruned < 0) {
+                    DEBUG_WARN("Subscription retention: prune failed");
+                }
+            }
         }
     }