A SHOW UDB command indicates either the DATA or INDX component of a product VSAM file is over 90% used. Is this a problem?

Document ID : KB000028862
Last Modified Date : 14/02/2018
Show Technical Document Details

When using a SHOW UDB (User Database) command to display the status of product VSAM files, you may see output similar to the following - notice the DATA field and its corresponding EXT (extents) field from the display below:

N13521 DDNAME   FILEID   TYPE A/U SM DATA EXT INDX EXT RKP KYL UKY STUS OPTNS

N13522 IPLOG    IPLOG    BASE   5 29 100%   1   8%   1   0  50 -   AVAL SLD

N13503 *END*

 

At first glance the DATA component percent used value of 100% may seem alarming, but there's actually nothing to worry about. VSAM sees the current extent as the end of the file, so in the case above, the DATA component is 100% used in the first extent only. 

The DATA percent used value will drop once the another extent is allocated to reflect the additional space now available in the file - notice below that as more records were added, a second extent has been added and the DATA percent used has now dropped to 53%:

N13521 DDNAME   FILEID   TYPE A/U SM DATA EXT INDX EXT RKP KYL UKY STUS OPTNS

N13522 IPLOG    IPLOG    BASE   5 29  53%   2  25%   1   0  50 -   AVAL SLD

N13503 *END*

 

So, it is normal to see high percent used values for either the DATA or INDX component when it is time for a new extent to be allocated.  High percentages are not a problem as long as the VSAM file has extents available.