The database system can use the shared SQL function to avoid multiple parsing of SQL statements and multiple storage of parse information (such as execution plans and descriptions of result sets).
If shared SQL is activated, the database system saves all parsed SQL statements and prepared statements with their corresponding information in a global cache, which shared by all users. The system can use this information again later, if needed.
You can activate or deactivate shared SQL using the UseSharedSQL special database parameter. Further parameters are SharedSQLCleanupThreshold and SharedSQLCommandCacheSize.