The response time behavior on accessing remote configurations essentially depends on the length and the amount of data to be transmitted. The following recommendations are made, taking this aspect into account:
As far as possible, transactions should essentially contain accesses to local databases.
The amount of data to be transmitted is reduced in COBOL DML programs if the programmer uses the smallest possible subschemas.
Definitions such as SUBSCHEMA=SCHEMA should not be used!The amount of data to be transmitted for CALL DML programs is less than for COBOL-DML programs, since only the current record and not the entire RECORD-AREA is transmitted for CALL DML.
In the case of distributed databases, status code 141 (“Invalid subschema definition“) may be generated due to the following causes:
The addressed subschema
is not contained in the local configuration and is not specified in the distribution table.
is specified in the distribution table, but is not present in the corresponding configuration.
is specified in the distribution table, but the appropriate configuration is unavailable, either because the computer cannot be accessed or because UDS-D mode has not been turned on in the running configuration.
is contained in the distribution table, but is locked, or the associated database or configuration is locked.
is not contained in the local configuration, and UDS-D mode was not started in the local configuration.
The number of remote databases addressed by this transaction exceeds the value of PP DISDB.
A configuration is temporarily inaccessible due to a networking problem. It is therefore advisable to repeat the transaction.