Key Features

Using direct memory access method

It collects Oracle DB internal state and active session details in memory using direct memory access method without accessing Oracle DB. Zamong agent doesn't use SQL queries and it also doesn't connect to oracle DB. It reads statistics and session details every second in Memory.
For table descriptions used by zamong, see this link.
For chart descriptions and simple manual, see this link.

No load on oracle db and server at all

It does not connect to the db server, nor does it use SQL queries. Using direct memory access, Oracle DB internal state and active session details are extracted, but no load is placed on the DB server. Direct memory access method is really fast and light enough to be done more than 100 times per second. but zamong accesses the memory once per second. that is enough.

Stats and Session details can be extracted in hang state

Even when Oracle DB is in HANG state or serious performance degradation occurs on the server so that it can not receive a query response in each session connected to the DB, zamong can extract the details without affecting the DB

You can analyze oracle instance and sessions at a certain point in the past

The extracted data is stored in the db (mariadb or mysql), and the ORACLE DB internal state and the active session state can be analyzed at one-second intervals at any time

Intuitive dashboard for real time monitoring, web-based user interface for analysis

Dashboard for real time monitoring, web-based user interface for analysis are provided to identify DB state intuitively.
You can perform a drill-down analysis, such as a zoom in, by dragging the range. refer to this example

Other Features

It's Simple, DBA can build the system on his own

If your system has mariadb( or mysql), apache http server + php installed, you can build your monitoring system very quickly.
Build a DB monitoring environment yourself.
Download zamong files and copy it to a specific directory. That's all.

The overall structure of zamong web pages is very simple. if you know Web programming a little, you can create your own web pages using the collected data.

Please refer to the setup pages for details .

All character set supported

Zamong web-based user interface works only with the chrome browser. Zamong stores SQL queries of active sessions as binary and the SQL query strings are viewed through a browser. So character encoding-decoding is done in the chrome browser and will be displayed on the screen.

If you add Chrome Set Character Encoding extension on your chrome browser, SQL statements containing your language character set are viewed correctly. (Such as Korean,Chinese,Japanese ...)     refer to this link
We have already tested it.

Just Free

This product is subject to free software licenses.

Query-based DB monitoring softwares

Query-based DB monitoring softwares increase the risk of unexpected failures.

The method of extracting information of the oracle instance state and the active sessions by executing the query is performed by executing many recursive queries internally in the DB in order to execute a single query.
These resursive queries can cause latch contention in the shared pool.

Query-based DB monitoring solution might be a good idea if these indicators are 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.

Data in the v$ view is cleared when instance down or restart occurs. If a failure occurs, data in the "dba_" view at that point in time is also not saved. you will find that query-based db monitoring software is useless to analyze failures.

Oracle Automatic Workload Repository (AWR)

When oracle db was in hang state, and db server performance was not good enough to receive a response to the query quickly, a system admin rebooted the server or restarted database to resolve such problems.
In this situation, when you are trying to analyze AWR data to find out the clues of the failure, you'll find AWR data was not stored. this is because the data in v$ views will be cleared after the database is restarted.

First of all, DBA must need to check if a Diagnostics Pack license was purchased when using AWR features.
This is an important part of the LMS issue.

 Oracle Diagnostics Pack license includes the following features

    DBMS_WORKLOAD_REPOSITORY package
    DBMS_ADDM package
    DBMS_ADVISOR package
    V$ACTIVE_SESSION_HISTORY dynamic performance view
    All views beginning with DBA_ADDM_
    All data dictionary views beginning with the prefix DBA_HIST_

    (Only Exception List)
      DBA_HIST_SNAPSHOT
      DBA_HIST_DATABASE_INSTANCE
      DBA_HIST_SNAP_ERROR
      DBA_HIST_SEG_STAT
      DBA_HIST_SEG_STAT_OBJ
      DBA_HIST_UNDOSTAT

To use oracle AWR features, you must purchase an 'oracle database diagnostics pack' license separately from the oralce enterprise license.
The diagnostics pack license is an additional license item that you can purchase with 'oracle database enterprise edition' license only.
DBA must need to check if a diagnostics pack license was purchased when using AWR features.
This is a way to avoid problems that can arise in the future and that can be costly.
And If you are using an oracle standard edition products, you should not use AWR features.

Refer to "Database Licensing Information User Manual" to review Oracle diagnostics pack license.
And you can use this query to see if the AWR features were used on your system.This sql query is also included in the script that Oracle uses to check the license.

     SELECT * FROM DBA_FEATURE_USAGE_STATISTICS

Zamong works well on both Oracle standard edition and Oracle enterprise edition without enabling AWR or ASH.