Diagnostic tools gather and format the following types of performance data:
- Cumulative statistics:
- Wait events with time information
- The raw counts have little meaning until the counts are compared over time. The events that collect the most time tend to be the most important.
- Time model
- The statistics in Oracle Database 11g are correlated by the use of a time model. The time model statistics are based on a percentage of DB time, giving them a common basis for comparison.
- Metrics: Statistic rates /count per unit
- Metrics provide a basis to proactively monitor performance.
- You can set thresholds on a metric causing an alert to be generated. For example, you can set thresholds for when the reads per millisecond exceed a previously recorded peak value or when the archive log area is 95% full.
- Sampled statistics: Active Session History (allow you to look back in time)
- Statistics by session
- Statistics by SQL
- Statistics by service
- Other dimensions
No comments:
Post a Comment