Schema migration

db/pg/pg.go

@@ -13,6 +13,12 @@ import (
 	"heckel.io/ntfy/v2/db"
 )
 
+// Advisory lock keys. PostgreSQL advisory locks share one database-wide key space, so every
+// ntfy key is defined here, following the "ntfy"+2586+letter scheme
+const (
+	SchemaLockKey = int64(0x6e7466792586a) // Schema setup serialization (transaction-scoped, see db/schema)
+)
+
 // Open opens a PostgreSQL connection pool for a primary database. It pings the database
 // to verify connectivity before returning.
 func Open(dsn string) (*db.Host, error) {