DB2 Version 9.7 for Linux, UNIX, and Windows

ClientBuffersUnboundLOBS CLI/ODBC configuration keyword

Specifies whether LOB data is fetched instead of the LOB locator for LOB columns that have not been bound to application parameters.

db2cli.ini keyword syntax:

ClientBuffersUnboundLOBS = 0 | 1

Default setting:

A LOB locator is retrieved instead of the actual LOB data for LOB columns that have not been bound to application parameters.

Usage notes:

By default, when a result set contains a LOB column that has not been bound to an application parameter, CLI will fetch the corresponding LOB locator rather than the LOB data itself. The application must then use the SQLGetLength(), SQLGetPosition(), and SQLGetSubString() CLI functions to retrieve the LOB data. If the application regularly wants to retrieve the LOB data, then this default two-step process is unnecessary and could decrease performance. In this case, set ClientBuffersUnboundLOBS = 1 to force DB2® CLI to fetch the LOB data instead of the LOB locator.

Servers that support Dynamic Data Format, also known as progressive streaming, optimize the return of LOB and XML data depending on the actual length of the data. The LOB and XML data can be returned in its entirety, or as an internal token called a progressive reference. CLI manages progressive reference data retrieval.

For applications that are querying data on a server that supports Dynamic Data Format, setting the LOBCacheSize keyword sets a threshold that is used to determine if the data is returned in its entirety, or as a progressive reference. If the data has a length greater than the LOBCacheSize threshold value, the progressive reference will be returned to CLI to manage, but if the data has a length less than or equal to the LOBCacheSize threshold value, the data will be returned in its entirety. Setting ClientBuffersUnboundLOBS to 1 is equivalent to setting LOBCacheSize to 2147483647 and will force the server to return the data in its entirety rather than as a progressive reference.