Message Chaining Restrictions

IBM Informix ODBC does not chain the following SQL functions even when you enable message transfer optimization:

• SQLDisconnect
• SQLConnect
• SQLEndTran
• SQLExecute (if the driver returns results using the select or call procedure and when the driver uses insert cursors to perform a bulk insert)
• SQLExtendedFetch
• SQLFetch
• SQLFetchScroll
• SQLPrepare

When the driver reaches one of the functions listed previously, it performs the following actions:

1. Flushes the message queue to the database server only when it encounters SQL statements that require a response from the database server.

   The driver does not flush the message queue when it encounters functions that do not require network traffic, such as SQLAllocStmt.

2. Continues message chaining for subsequent SQL statements.