Zamong is a free tool for real time oracle monitoring and failure analysis.

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Zamong is a tool for real time oracle monitoring using direct sga memory access method. So zamong does not connect to db for db monitoring. It collects Oracle DB internal status , instance stats and active session details including sql query using direct memory access method without accessing Oracle DB.

The advantage of this software is that there is no load on the server at all. Direct memory access is really fast and light enough to be done more than 100 times per second.

Query based DB monitoring method is performed by executing many recursive queries internally in the DB in order to execute queries for db monitoring. These recursive queries can cause latch contention in the shared pool.

Query based DB monitoring method can be used if these indicators are only normal, such as the server’s query response time, cpu usage, active session count, etc.
However, as the db response time increases, the number of active sessions increases, using a query based DB monitoring method is dangerous because it can further increase the latch contention in the shared pool.

Running queries for db monitoring every second will increase the latch, In more serious cases, you can cause a db instance hang.

So DMA method for oracle db monitoring is the best solution.

Database instance statistics are displayed as several real time charts in zamong dashboard and details of real time active sessions are also displayed in the dashboard.
these active sessions are refreshed every 2 seconds and you can see the session details by double clicking a active session in the dashboard.
zamong is also used to analyze the cause of the failure at a point in time.
you specify a time range for analyzing failure, and then you can check details of active sessions on every second in the range.

The DMA method is very powerful. Even if a oracle database is in hang state, zamong can store all information of each session in sga.
So you can use zamong for failure analysis or performance degradation analysis.

 

 

Refer to this link for a use case