When communicating with a remote server, CIS needs to know the maximum length of a char/varchar column that can be supported by the DBMS.
For connections to servers in classes ASEnterprise, ASAnywhere, ASIQ, sql_server and db2, the maximum size is determined based on known attributes of these servers (according to version).
For servers in class direct_connect and sds, this information is provided by an addition to the result set returned by the sp_capabilities RPC. A new capability is specified to allow the Direct Connect to indicate the maximum length of columns supported by the DBMS for which the Direct Connect is configured.
Additionally, it is necessary for the Direct Connect to know about the maximum length of char columns that can be supported by CIS. For this reason, changes to the existing RPC sp_thread_props are required:
sp_thread_props "maximum ASE column length", n
This RPC is sent to a Direct Connect after CIS has established a connection for the first time. The value of n is an integer indicating the maximum column size, in bytes, allowed by ASE/CIS.