Selection Block Size

Visual LANSA Framework

Selection Block Size

This is the block size parameter used by the CONNECT_FILE Built-In function when connecting to the server. This property defines the number of records that are transferred, in one hit, from the server by SELECT commands executed on the client system. Performance is improved by using large block sizes, so the default when you define a new server is 500. Conversely, using small block sizes degrades the performance of your application.  

It is recommended that you do not set this to a value less than 50.

You can override this value in any program by use the CONNECT_FILE built-in function.

You can do this for all files, generic groups of files or individual files.

Refer to the CONNECT_FILE built-in function in the LANSA Technical Guide for more information.

Note that if your code performs UPDATE or DELETE operations without WITH_KEY or WITH_RRN parameters, the operations are performed on the last record in the block, which may not be the the last record read into your program.

Therefore, if you must use UPDATE or DELETE operations against the last record read, it is recommended that you supply a WITH_KEY or WITH_RRN value instead, or temporarily use the CONNECT_FILE built-in function to push the block size down to 1, then restore it back to a high value.

This property is in the Server Details tab.