Here are the tuning metrics tables (SQL stats are not in “metric” tables per say) (*DBA_HIST_…_HISTORY views are sort of confusing. AFAI remember they were storing alert history, but apparently they are used for adaptive thresholds – an area for future investigation) I’ve noticed a number of people posting queries using DBA_HIST_SYSSTAT instead of DBA_HIST_SYSMETRIC_SUMMARY which leads me to believe that there is some confusion or lack of information on the metric tables. Oracle 10g introduced metric tables which compute deltas and rates of statistics thus hugely simplifying the ability to answer simple questions like “what is the I/O rate on my…
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Here is a quick table comparison of different types of metrics views The first line of the table is the classic wait event and statistic views. The following lines are the metric views. The metric views were introduced in Oracle 10g. Why Metrics are good Metric views compute deltas and rates which hugely simplifying the ability to answer simple questions like “what is the I/O rate on my databases right now?” This question, before 10g, was surprisingly tedious to answer. To answer the question one would have to query v$sysstat for example: Select value from v$sysstat where name=’physical reads’; but…