In AWR, the ‘Wait Classes by Total Wait Time’ table comes under the ‘Report Summary’ section. Refer to the below figure: To analyse this section, firstly check for the ‘Wait Class’ column. If User I/O, System I/O and Others have moderate ‘Waits’ value then it is fine. But if ‘Concurrency’ under the wait class has … Read more
In AWR, the ‘Top 10 Foreground Events’ table comes under the ‘Report Summary’ section. Refer to the below figure: The following metrics are available in the ‘Top 10 Foreground Events’ table of an AWR report: DB CPU It shows the total wait time for DB CPU and waiting %. Referring to Figure 01, the total … Read more
What is Buffer Hit ratio OR Buffer Hit %? ‘Buffer Hit Ratio’ is measured by the percentage of times the data block is requested by the query and available in memory. It is also called the ‘Buffer-Cache Hit Ratio’. Effective use of the buffer cache can greatly reduce the I/O load on the database. If … Read more
What is Execute to Parse ratio OR Execute to Parse %? Every query needs to be parsed before it gets executed. If some queries are quite frequently used, a good design will be to reuse the parsed query. That means it will not parse the same query again. In an ideal world, execution should be … Read more
In AWR, the ‘Instance Efficiency Percentages’ table comes under the ‘Report Summary’ section. Refer to the below figure: The following metrics are available in the ‘Instance Efficiency Percentages’ table of an AWR report: Buffer Nowait % (Buffer Nowait Ratio) This metric provides the percentage of availability of the data buffers. This ratio gives an idea … Read more
In AWR, the Load Profile table comes under the ‘Report Summary’ section. Refer to the below figure: The following metrics are available in the Load Profile table of an AWR report: DB Time(s) DB Time(s) is the number of average active sessions during the given period. The active sessions are calculated by dividing the ‘DB … Read more