Spotlight on Oracle 11.0 - Getting Started Guide

Every chart has a legend (list of symbols) to its right that describes the various series (line graphs) on the chart.
Click an item in the legend to highlight its series (line) in the chart. Click a second time to return the series to its normal appearance.
Move the mouse pointer over an item in the legend to view the current value for that series within the chart.

Note: Applicable to Oracle 12c. From the Container field select to filter the data in these charts for:

All - An aggregate of the container database and plugged in databases.
CDB$ROOT - The container database.
PDB-seed - The template for plugged in databases.
Other - Select any of the plugged in databases.

Chart

Description

IO Demand

Shows all user IO demand over time. User I/O is broken down into the following categories:

I/O Type	Description
Block changes	The rate at which changes are made to blocks in the buffer cache.
Current reads	The rate at which blocks in memory are read in current mode. Current mode reads are usually associated with updates.
Current reads direct	The rate of current reads (not from the buffer cache).
Consistent reads	The rate at which blocks in memory are read in consistent mode. Consistent mode reads are usually associated with a query, and are taken from the point in time when the query began. Current reads added to consistent reads equate to all logical reads.
Consistent reads direct	The rate of consistent reads (not from the buffer cache).
Direct writes	The rate at which changes are made to blocks (not from the buffer cache).

For more details on logical I/O, view the I/O drilldown | Summary Page.

Average Active Sessions

Shows the DB time for all sessions over time. DB time is broken down into the following categories:

Session Type	Description
CPU	CPU activity.
IO	I/O activity.
Other	Other activity (which together with CPU and I/O adds to DB time).

See also Average Active Sessions on the Spotlight on Oracle home page | Service Panel.

Event Waits

Shows the amount of time (in milliseconds) that sessions have spent waiting on various events per second. Event wait categories from V$SYSTEM_EVENT are aggregated into categories so that they can be graphed.

To see a further breakdown of Disk I/O see Activity | Waits Page | Event Waits.

For more information on wait events, see Deal With Wait Events.

Top Waits

Shows the wait events (from the Activity | Waits Page) that have shown the highest rate of wait time over the past hour.

For more information on wait events, see Deal With Wait Events.

Throughput - requests

The rate of I/O requests according to file type. As the number of requests approaches the limit of the I/O system being used for the database, latency will start to degrade.

Latency is the average time (in milliseconds) taken to process a physical I/O request.

Values that are consistently high over the displayed period are those most likely to contribute to performance bottlenecks.

This chart replicates the I/O drilldown | Summary Page | File Type | Throughput - requests chart.

Latency

The average time delay experienced while the database performs I/O activities.

To maximize response time to end users, the latency should remain low – in general a latency below 10ms will give users good response time. As the latency increases, the response time may degrade. This time will vary from database to database – for example in a large batch job – the latency might not be as important as the throughput, but when there is a lot of users on the system, a low latency is important to ensure response time.

This chart replicates the I/O drilldown | Summary Page | File Type | Latency chart.

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Spotlight on Oracle 11.0 - Getting Started Guide

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