Operations › Performance Factors › Estimating USERSETS I/Os with Standard Auditing

Estimating USERSETS I/Os with Standard Auditing

You can use the following formula to calculate the approximate number of I/Os to audit USERSETS in your database (when you have not specified WALKNEXT or DISCONNECT). Additional I/Os are required if CA IDMS/DB Audit detects integrity errors.

I/Os = p + n + (s * v)

p — represents the number of pages swept

n — represents the number of CALC or DIRECT member record occurrences
    for sets being audited

s — the number of set occurrences whose VIA members are stored in a different page
    range than the set owner

v — represents the number of VIA member record types stored in different page
    ranges than the set owner

Refer to Figure 5.1 for an example. If you were to audit USERSETS only in AREA-1 (AREA-2 is NOSWEEP), you would estimate the number of I/Os as follows:

  10,000 pages swept
+ 75,000 type E records for set F-E
+ 120,000 type G records for set E-G
+ 120,000 type G records for set H-G
+ 185,000 type D-B set occurrences
= 510,000 I/Os

(v=1, because all B records are in AREA-2.)

If record type G were stored VIA set E-G, it would take approximately 120,000 fewer I/Os to audit the database for a total of 390,000 I/Os. If, in addition, record type E were stored VIA set F-E, it would take approximately 75,000 fewer I/Os to audit the database for a total of 315,000 I/Os.

Figure 5.1: AREA-1 and AREA-2, Estimating USERSETS I/Os