Information about new schema and table versions propagates through the Main IQ Store. To help recover space from old versions of database objects, IQ uses a data-replication tool called SQL Remote. It lets the write server recover space when it is no longer needed by any server in the multiplex.
Before it can reclaim space used by old versions of database objects, the write server requires information about version use in the query servers. IQ uses the data store replicated to SQL Remote to gather this information.
SQL Remote exchanges data between servers using messages. Each message carries its destination address and other control information, so that no direct connection is needed between servers exchanging information.
