wallet: set a timeout if the db is busy.

This is recommended for litestream, which allows for easy async backup,
and harmless otherwise.

Signed-off-by: Rusty Russell <[email protected]>
Changelog-Changed: db: we now set a busy timeout to safely allow others to access sqlite3 db (e.g. litestream)

Author: rustyrussell

wallet/db_sqlite3.c

@@ -43,6 +43,11 @@ static bool db_sqlite3_setup(struct db *db)
 	}
 	db->conn = sql;
 
+	/* In case another writer (litestream?) grabs a lock, we don't
+	 * want to return SQLITE_BUSY immediately (which will cause a
+	 * fatal error): give it 5 seconds. */
+	sqlite3_busy_timeout(db->conn, 5000);
+
 	sqlite3_prepare_v2(db->conn, "PRAGMA foreign_keys = ON;", -1, &stmt, NULL);
 	err = sqlite3_step(stmt);
 	sqlite3_finalize(stmt);