# CA View How to calculate INDEX and DATA extent sizes

Document ID : KB000047330
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Question:

Is there a formula to calculate the INDEX and DATA extents in CA View?

Estimate the size of the View r11 Index component:

Note: A good guideline for the index size is to compute the amount of space used by View 2.0.

Run the SARDBASE/STATUS FULL function:

//STEP1   EXEC PGM=SARDBASE

//STEPLIB  DD  DISP=SHR,DSN=........VIEW.CAILIB

//SYSPRINT DD  SYSOUT=*

//SYSIN    DD  *

NAME ........db_hlq..........

STATUS FULL

/*

Use the following output from this step:

SARDBA09     BLOCK SIZE:                 nnnnn

SARDBA09        INDEX USED BLOCKS:       nnnnn

SARDBA09        INDEX EMPTY BLOCKS:      nnnnn

(INDEX USED BLOCKS - INDEX EMPTY BLOCKS) *

BLOCK SIZE = bytes_used

((bytes_used / 8906) / 90) * 2 = cylinders

8906 is the recommended block size for the Index component in r11 and 90 is the number of blocks

per cylinder for a 3390 Device. This number should be doubled.

As an example:

BLOCK SIZE:                 3476

INDEX USED BLOCKS:    1522838

INDEX EMPTY BLOCKS:    419345

(1522838 - 419345) * 3476 = 3,835,741,668 bytes

((3835741668 / 8906) / 90) * 2 = 9570 cylinders

(INDEX USED BLOCKS / TOTAL USED BLOCKS) * 100 =

Index Utilization Percentage

Example:

SARDBA09     TOTAL USED BLOCKS:    3594869

Although the space originally occupied by the index component is totally re-useable

for Sysouts in the data extent, it is highly unlikely that this space (as in the example

70% of the original database) is needed since it was used by the index.

A procedure to consider is:

Data Extent Allocation Example:

The View 2.0 Database has 1,117,740 Blocks at a Block Size of 3476. The Index occupied

566,023 Blocks:

SARDBA09     BLOCK SIZE:                 3476

SARDBA09     TOTAL BLOCKS:            1117740

SARDBA09        INDEX BLOCKS:          566023

The new Data Extent size can be computed with the following formula:

(Total Blocks - INDEX Blocks) * Block Size = Data Space Allocation

((Data Space Allocation / New Block Size)) / Block Per Cylinder = Cylinders

The Block Size for the new Data Extent should be specified as 13,682, which is the recommended

|              data extent block size.  Using the sample data, assuming 60 Blocks per 3390 Cylinder:

(1117740 - 566023) * 3476 = 1917768292

((1917768292 / 13682) / 60 = 2336 Cylinders

APAR #: QI87785

Product: VIEW       Release: 11.0        Solution #: 355       Type:

OS: OS           Group: OMXCOM GBL SUP 1

Title: "QUICK REFERENCE GUIDE FOR VIEW 11.0"