Seagate ST43401N/ND Informacje Techniczne Pobierz pdf (Strona 108)

7-8 Test: Ensuring Stability and Performance

Writing Performance Scripts Adaptive Server Enterprise 11.5

Deadlock Handling

You have to resubmit deadlocked transactions to get a realistic time

measurement. You can count average response time with and

without deadlocks.

Result Handling

You can capture query results by fetching the entire result set back to

the client and binding it to local variables. Outputting results to a ﬁle

may increase your time by requiring additional ﬁle I/O and

operating system buffering.

Time Measurement

Time measurement is especially important in multi-tiered

applications where a bottleneck could occur at any level. Generally,

you should time database transactions, not business functions. Start

at transaction “send” and stop at the last row processed in the result

set. Logical business operations can be aggregated later.

Granularity is important for problem identiﬁcation and resolution.

Important measurements to take include:

• Throughput (number of transactions per second/minute/hour)

• Average and maximum response time by transaction

• A histogram of response time ranges by transaction. For example:

- Less than 1 second

- Between 1 and 2 seconds

- Between 2 and 3 seconds

- Over 3 seconds

Runtime Data Generation

When using runtime-generated data, skewed keys may be a

problem. Selects may show an unrealistically high cache hit rate, and

inserts, updates, and deletes may appear to have concurrency

problems. To avoid these problems, use the entire range of key

values in your tests, unless you are trying to recreate a particular

business situation.

1 2 ... 103 104 105 106 107 108 109 110 111 112 113 ... 171 172

Brak uwag

Seagate ST43401N/ND Informacje Techniczne Strona 108