select case wait_rank when 1 then inst_id end "Inst Num", case wait_rank when 1 then snap_id end "Snap Id", case wait_rank when 1 then begin_snap end "Begin Snap", case wait_rank when 1 then end_snap end "End Snap", MK's Oracle DBA and performance tuning blog _max_cr_rollbacks is already set to 200 per <Note 1630755.1>: AWR shows high "gc cr grant 2-way . See the following code: On 'lesser' systems (read that as 'commodity servers') such a buffer allocation could easily and quickly generate long event wait times for the . Tune gc current block 3-way wait event of Oracle RAC ... - dbametrix Common Oracle Wait Events says: October 30, 2014 at 3:00 pm. Important Statistics & Wait Events on Exadata - Uwe Hesse You can detect which wait class are foreground in the database. Advanced Oracle Troubleshooting training, Linux Performance & Troubleshooting training: Learn when it's convenient to you and get your training questions answered even months after taking the class! Oracle I/O latency monitoring. These expose session and query waits. Oracle provides wait events that allow you to understand the total time a query spends in the database. This has been tested and verified . SELECT event, state, wait_time, seconds_in_wait FROM V$SESSION WHERE sid=<sid_parameter> Listing 08 Wait events AWR,ASH Time model scripts - ORACLEAGENT BLOG The Oracle's Automatic Workload Repository (AWR) collects, processes, and maintains performance statistics for problem detection and self-tuning purposes. set lines 180 set pages 1000 col event format a50 PROMPT --> Top 25 Wait Events select * from . As a troubleshooting example, I will explore a system spending 14.22% (a bit of an extreme case) of its DB time waiting on cursor: pin S wait on X. 5 Oracle Performance Tuning Tips for Optimized Performance - Database ... Query to find Top 5 wait events in database: select Day, Event_name, Total_wait from ( You need to query the database to extract the data requried for analysis. SQL Tracing with wait events of a database session shows it is limited mainly by I/O wait events. You can see the current wait class waits by querying the v$system_wait_class view as seen in this example: S QL> Select wait_class, sum (time_waited), sum (time_waited)/sum (total_waits) 2 Sum_Waits 3 From v$system_wait_class see code depot for full script 4 Group by wait_class 5 Order by 3 desc; WAIT_CLASS SUM (time_waited) SUM_WAITS Oracle Database Performance Issues and Solutions - DNSstuff c.USER_CONCURRENT_PROGRAM_NAME='Incentive Compensation Analytics - ODI' — and argument_text like '%, , , , ,%'; — and status_code!='C'. 3 ) One of my business operation takes 300ms (select + insert + update +select+ select etc . oracle - How to find out why this query is in waiting state? - Database ... ORACLE-BASE - DBA Scripts: session_waits.sql : Oracle database SQL scripts. Oracle 10g introduced the Active Session History (ASH) as part of the Diagnostics and Tuning Pack. An Oracle session waits for a direct read I/O request to complete on the direct path read wait event. Performance Tuning Basics 15 : AWR Report Analysis - Expert Oracle