3 Answers. SQL Ordered by Elapsed Time , includes SQL statements that took significant execution time during processing. We have to look at Executions , Elapsed time per Exec (s) etc. along with Elapsed time to analyze.
How do you read AWR reports?
Analysis AWR Report
- DB Time(s): Sessions elapsed time in the database.
- DB CPU(s): Sessions elapsed time in the CPU.
- Redo Size: Redo size ( byte ) between two snapshot.
- Logical Reads: Logical read count in the database.
- Block Changes: Block changes count between two snapshot.
What does AWR report contains?
The AWR provides a set of tables into which snapshots of system statistics are stored. Generally these snapshots are taken on an hourly basis and include wait interface statistics, top SQL, memory, and I/O information that is cumulative in nature up to the time of the capture.
What is SQL module in AWR report?
SQL ordered by Elapsed Time and the (SQL) Module. The Top SQLs can be matched to long running or slow Processes in the application. In this report, look for query has low executions and high Elapsed time per Exec (s) and this query could be a candidate for troubleshooting or optimizations.
What is db file sequential read and db file scattered read?
A db file scattered read is the same type of event as “db file sequential read”, except that Oracle will read multiple data blocks. Multi-block reads are typically used on full table scans.
What is db file sequential read in Oracle?
“The db file sequential read Oracle metric event signifies that the user process is reading buffers into the SGA buffer cache and is waiting for a physical I/O call to return. This call differs from a scattered read, because a sequential read is reading data into contiguous memory space.
Where is Oracle AWR report?
The AWR report is displayed in the Database Manager object of the Administrator Console in a section labeled Latest Oracle AWR Report.
How do you avoid db file sequential read waits?
There are two things you can do to minimize the db file sequential read waits:
- Optimize the SQL statement that initiated most of the waits by reducing the number of physical and logical reads.
- Reduce the average wait time.
What is db file sequential read in AWR report?
The db file sequential read event signifies that the user process is reading data into the SGA buffer cache and is waiting for a physical I/O call to return. It corresponds to a single-block read.
What is the difference between db file sequential and scattered reads?
A db file sequential read is an event that shows a wait for a foreground process while doing a sequential read from the database. A db file scattered read is the same type of event as “db file sequential read”, except that Oracle will read multiple data blocks. Multi-block reads are typically used on full table scans.
What is the Oracle AWR report?
The Oracle’s Automatic Workload Repository (AWR) collects, processes, and maintains performance statistics for problem detection and self-tuning purposes. The report generated by AWR is a big report and it can take years of experience to actually understand all aspects of this report.
How difficult is it to read an AWR report?
The AWR report is difficult to read and it is many pages long. How do you read an AWR report? Answer: Understanding all of the sections of a AWR report is quite complicated, and I have a whole chapter dedicated to reading a AWR reportin my book ” Oracle Tuning: The Definitive Reference “. . See here for more notes on reading an AWR report.
What is SQL ordered by gets?
SQL Ordered by Gets: These SQLs performed a high number of logical reads while retrieving data. SQL Ordered by Reads: These SQLs performed a high number of physical disk reads while retrieving data. SQL Ordered by Parse Calls: These SQLs experienced a high number of reparsing operations.
Can I use ion for Oracle to generate AWR deltas?
If you are a beginner, you can also use Ion for Oracle to automate the generation of AWR deltas, in a more readable report format, with additional tips. This section contains detailed guidance for evaluating each section of an AWR report.
