This utility was introduced in Oracle 11.1, it is an excellent tool to understand if your actual workload is overloading your disks or file systems. I/O is very important in an Oracle database so I really recommend to all DBAs the use of this great utility to know the actual capacity of your hardware. Below ...
Background Processes From 10g and over, Real Application Cluster databases has two new background processes: LMON – The Global Enqueue Service Monitor monitors the entire cluster to manage the global enqueues and the cluster resources. LMON manages instance and process failures and the associated recovery for the Global Cache Service (GCS) and Global Enqueue Service ...
The contention in blocks can be measured by using the block transfer statistic. The first step is to determine block transfer time examining the gv$sysstat view: global cache cr block receive time global cache cr blocks received. The time is determined by calculating the ratio of global cache cr block receive time to global cache ...
PL/SQL can often add to program functionality and programmer efficiency, and there are certainly many cases in which a procedural language such as PL/SQL can do things that a nonprocedural language such as SQL cannot. For a number of reasons, a PL/SQL approach might offer great performance improvements over a traditional SQL approach. Why to ...
Some useful awr queries, change according your needs. Top 10 queries by resource usage across all executions SELECT * FROM (SELECT SQL_ID, SUM(disk_reads_delta) AS “Disk Reads” FROM DBA_HIST_SQLSTAT S WHERE SNAP_ID > 209 AND SNAP_ID <= 210 AND S.MODULE = ‘ClaimCenter’ GROUP BY SQL_ID HAVING SUM(disk_reads_delta) >= 0 ORDER BY 2 DESC) DERIVED_TABLE WHERE ROWNUM ...
The Query Processing category includes the statistics used to calculate the hit ratio for the database. In this post are just explained the most important. This information is related to the dynamic statistic table v$sysstat. The main purpose of this post is to add basic knowledge when trying to tune queries in oracle database environments ...
UPDATE 02-JUL-2010 : Please read my white paper here. The effect of accessing blocks in the global cache and maintaining coherency is represented by “The Global Cache Service” statistics for current and cr blocks, for example, gc current blocks received, gc cr blocks received, and so on Much of these GC waits are blamed on ...
Worried about how to trace shared connections?, relax, Oracle provides the trcsess command-line utility that consolidates tracing information based on specific criteria, trcsess is useful for consolidating the tracing of a particular session for performance or debugging purposes. The syntax for the trcsess utility is: trcsess [output=output_file_name] [session=session_Id] [clientid=client_Id] [service=service_name] [action=action_name] [module=module_name] [trace_files] where: output ...
Updates Added on Jun 30, 2010: Global Cache Waits http://jose-valerio.com.ar/blog/?p=790 Added on March 23, 2010: If you have doubts about the “Oracle Query Processing” please take a look to my post http://jose-valerio.com.ar/blog/?p=502 . In this post you will find information about sysstat view to understand what is going on in your database on the fly, ...
How to ? 1. If it is possible, avoid reading uncommitted blocks on the remotes nodes. 2. Increase the number of LMS processes(depends of Oracle version) 3. Minimizing the transactions sizes on the remote node. …more ? ok, tuning the hardware can help you. 4. Try to reduce the interconnect latency 5. Change your disks, ...