Exam 918 Troubleshooting

Introduction

Troubleshooting is an iterative process. To approach troubleshooting, it is necessary to understand the processes of what you are looking at. To utilize the various approaches that are introduced here, it is necessary to understand what is normal behavior and what is not. Once you have found out what is wrong with what you are looking at, then you can use these tools to further dig into why.

The onstat utility

onstat is a powerful utility and can be used to look at a variety of things for troubleshooting purposes, including memory usage, network usage, session activities, buffer pool usage, and disk usage.

List of memory usage

onstat -g mem : provides a list of memory usage of different pools in memory.

Mem

  • onstat -g ses can show memory usage for a single session.
  • The onstat -g afr option prints allocated memory fragments for a specified session or shared-memory pool. Each session is allocated a pool of shared memory.

The sysmaster database

Special database designed with both real tables and pseudo-tables, and can be used to gather information about the state of many components of your IDS system. You can query these tables to identify processing bottlenecks, determine resource usage, track session or database server activity, and so on.

The sysadmin database

The scheduler is defined and driven by tasks, and the sysadmin database contains the six tables that contain and organize scheduler task information. The sysadmin database, which contains tables is a logged database. You use the task properties (not configuration parameters) to define the information that the scheduler collects and the statements the scheduler executes.

Concurrency

When using a multiple thread, or multiple process architecture, concurrency is important. Accessing the data in a single-threaded manner causes bottlenecks, as processes or threads have to wait for resources. This can slow processing dramatically. It is more efficient to have multiple applications connecting in parallel to the database.

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