The value n may be 1 or 0:
When 1 (true): when an SQL Select statement is executed, forces all pending ECP requests to the DB-server. On completion it guarantees that the client cache is in sync.
When 0 (false): Does not guarantee that the client cache is in sync. Default.
0 or 1. The default is 0.
On the page System Administration > Configuration > SQL and Object Settings > General SQL Settings, for the SQL SELECT Synchronizes ECP Cache setting, choose Yes (true) or No (false).