If a record management error occurs while CLOSE is flushing buffers, the data set's catalog information is not updated. The catalog cannot properly reflect the data set's status and the index cannot accurately reflect some of the data records. If the program enters an abnormal termination routine (ABEND), all open data sets are closed. The VSAM CLOSE invoked by ABEND does not update the data set's catalog information, it does not complete outstanding I/O requests, and buffers are not flushed. The catalog cannot properly reflect the cluster's status, and the index cannot accurately reference some of the data records. Use the access method services VERIFY command to correct catalog information. The use of VERIFY is described in Using VERIFY to Process Improperly Closed Data Sets.

When processing asynchronous VSAM requests, all strings must be quiesced by issuing the CHECK macro or the ENDREQ macro before issuing CLOSE or CLOSE TYPE=T (temporary CLOSE).

CLOSE TYPE=T causes VSAM to complete any outstanding I/O operations, update the catalog if necessary, and write any required SMF records. Processing can continue after a temporary CLOSE without issuing an OPEN macro.

If a VSAM data set is closed and CLOSE TYPE=T is not specified, you must reopen the data set before performing any additional processing on it.

When you issue a temporary or a permanent CLOSE macro, VSAM updates the data set's catalog records. If your program ends with an abnormal end (ABEND) without closing a VSAM data set the data set's catalog records are not updated, and contain inaccurate statistics.

It is the user's responsibility to ensure that shared DD statements are not dynamically deallocated until all ACBs that share these DD statements are closed. For more information about dynamic allocation, see z/OS MVS JCL User's Guide.