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Calculating common performance metrics – HP 3PAR System Reporter Software User Manual

Page 209

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Table 78 Common Performance Columns (continued)

Comment

Type

Column

Number of reads in service time bucket number 0.

DOUBLE PRECISION
NOT NULL

rhist0

Difference between rhist0 value from last sample for the same object.

DOUBLE PRECISION
NOT NULL

d_rhist0

...

...

...

Number of reads in service time bucket number 31.

DOUBLE PRECISION
NOT NULL

rhist31

Difference between rhist31 value from last sample for same object.

DOUBLE PRECISION
NOT NULL

d_rhist31

Number of writes in service time bucket number 0.

DOUBLE PRECISION
NOT NULL

whist0

Difference between whist0 value from last sample for the same object.

DOUBLE PRECISION
NOT NULL

d_whist0

...

...

...

Number of writes in service time bucket number 31.

DOUBLE PRECISION
NOT NULL

whist31

Difference between whist31 value from last sample for same object.

DOUBLE PRECISION
NOT NULL

d_whist31

Number of reads in IO size bucket number 0 (512 bytes).

DOUBLE PRECISION
NOT NULL

rsize0

Difference between rsize0 value from last sample for the same object.

DOUBLE PRECISION
NOT NULL

d_rsize0

...

...

...

Number of reads in IO size bucket number 15 (16 MiBytes).

DOUBLE PRECISION
NOT NULL

rsize15

Difference between rsize15 value from last sample for same object.

DOUBLE PRECISION
NOT NULL

d_rsize15

Number of writes in IO size bucket number 0 (512 bytes).

DOUBLE PRECISION
NOT NULL

wrsize0

Difference between wsize0 value from last sample for the same object.

DOUBLE PRECISION
NOT NULL

d_wsize0

...

...

...

Number of writes in IO size bucket number 16 (16 MiBytest).

DOUBLE PRECISION
NOT NULL

wsize15

Difference between wsize15 value from last sample for same object.

DOUBLE PRECISION
NOT NULL

d_wsize15

Although in principle it was not necessary to store the difference values (d_rcount for example),
since these can be derived from previous samples of the same object, in practice having the
difference values stored in the data tables greatly simplifies the queries and improves the
performance of the queries. As described in the comment for the begin column in

Table 78

(page 207)

, the differences are only valid when the objects have the same begin time.

Calculating Common Performance Metrics

Table 79 (page 210)

shows SQL expressions that can be used to calculate various performance

metrics from the common performance columns for any sample row.

The Sample Data and Inventory Tables 209