Conversion Problems
Some of the problems that occur occasionally during conversions are listed here. See also
Conversion Process.Termination due to Tablespace Overflow
Since the data is present in both the QCM8 table and the QCM table during the conversion, more space is required when the conversion is performed. Before converting large tables, you should therefore check whether there is enough space in the tablespace concerned.
If there is a tablespace overflow when data is reloaded from the QCM table into the QCM8 table, the conversion terminates at this point. If this happens, you must extend the tablespace and resume the conversion in the database utility with Continue adjustment (see
Continuing Terminated Conversions). The system then continues the conversion at the point at which it terminated.Deletion of a Client Field
If the client field is removed from a client-specific table, it may no longer be possible to distinguish the new key of records from different clients.
If deleting a client field resulted in records having the same key, only one of these records can be reloaded into the table. Which record this is depends on the order in which the records are reloaded to the table. You therefore cannot be sure that the reloaded records only come from one client. In such a case, you should clean up the table before conversion.
Data Loss when Keys are Shortened
If a table key is shortened (for example, by removing or shortening the field length of key fields), the new key of existing table records can no longer be distinguished. When data is reloaded from the QCM table, only one of these records can be reloaded into the table (since the database does not allow duplicate records).
It is not possible to say in advance which of the records can be reloaded. If there are particular records you want to reload, you must clean up the table before the conversion!
Type Conversion not Possible
During a conversion, the data is copied from the QCM table back to the QCM8 table using the ABAP command MOVE-CORRESPONDING. A type can only be changed during a conversion if this can be executed with MOVE-CORRESPONDING. If a field type cannot be changed using MOVE-CORRESPONDING, the conversion terminates when the data is reloaded into the QCM8 table.
If the conversion terminates because a particular type change is not supported, you must restore the old state before the conversion.
To do this, you need to delete the QCM8 table in the first step with database means and rename the QCM table to its original name. In the second step, you have to remove the lock in the database utility with Unlock table. In the third step you must reconstruct the runtime object for the table using the database utility (see
Editing Database Tables and Indexes) and return the table definition in the ABAP Dictionary to the state it had before the conversion. The last step is to activate the table in the ABAP Dictionary.Note that problems occurring during type conversions depend on the contents of the field concerned.
If the accuracy of a DECIMAL field (the number of places before the period) is reduced and there are entries in the field in which all positions before the period are used, a termination occurs when the records are reloaded into the table. If there are no such entries, the records can be reloaded.
Termination during Conversion of Pooled or Cluster Tables
When a pooled or cluster table is converted (see
Pooled and Cluster Tables), the QCM table is created in the database as a transparent table and the data from the pooled or cluster table is copied to it. There is an upper limit for the number of fields in a database table depending on the database system used.It is therefore not possible to convert pooled and cluster tables if the number of fields in the pooled or cluster table exceeds the maximum number of fields possible in a database table.
See also:
Continuing Terminated Conversions Finding Terminated Conversions The Database Utility