REPORT (Generate Reports) › TYPE=DATASP - Data Area Space Report

TYPE=DATASP - Data Area Space Report

The Data Area Space (DATASP) Report provides a detailed space usage map for a selected data area. This function processes the data area using a high speed I/O process analyzing each data block in the data area. The DATASP report provides detailed insight into the data block space usage and available free space.

The DATASP report uses a highly efficient I/O process that has no effect on the MUF processing. The DATASP function reads the data area in place and does not see activity currently occurring in the MUF that is not yet posted to the data area. The DATASP report can be executed when there is only a minimal amount of update activity against the selected data area.

The purpose of the DATASP report is to build a simple report that shows the detailed space usage for a selected data area that can help you determine, among other things, the amount of rows that could be added in the space available in the data area.

Before the DATASP report, most users relied on the information in the CXX report or Dynamic System Tables to determine the “fullness” of a data area. This information is provided in the following CXX report columns:

BLOCKS IN USE - 87

BLOCKS UNUSED - 12

TOTAL BLOCKS - 99

PERCENT FULL - 88

While this information provides a reasonably accurate accounting of the data blocks usage, it may not accurately reflect the data row “fullness.” For example, if a table was loaded with 900 data rows and those rows filled 90 of 100 available data blocks, both the data block and data row “fullness” in the data area would be approximately 90% full. If following the load, an application process deleted 90 data rows where each data row just happened to be in the next data block, the data block fullness would still be at 90%, but the data row fullness would only be 81%.

In many cases, the difference between data block fullness and data row fullness will be minimal. A few examples of where this would occur are the following:

• Data areas with DSOP 0
• Data areas with DSOP 1 where row sizes in the data area are similar and more rows are added than are deleted
• DSOP 3 without a cluster key where row sizes in the data area are similar and more rows are added than are deleted.

In certain other cases, the difference between data block fullness and data row fullness may be significant. A few examples of where this could occur are the following:

• Data areas with DSOP 1 where more rows are deleted than are added
• Data areas with DSOP 2
• Data areas with DSOP 3 where a cluster key has been selected
• Data areas with DSOP 4 after an OLREORG function
• Data areas with DSOP 5

The DATASP report gives you a simple and accurate way to access the data row fullness for a data area. The report also provides other information about the data rows that is beneficial for you to know. For example, it can provide the maximum, minimum, and average compressed row size in a compressed table.