Overview

When technical support related to DBMS is provided, there are cases where information for problem-solving is insufficient only with the performance view provided by Altibase.

This document describes several related commands provided by the operating system to obtain necessary information.

Common Command

This section describes commands that do not have special restrictions that can be executed by all operating systems.

netstat

• This command checks whether there is a network configuration or an error packet.

  If a problem occurs between sender and receiver on a packet, the value of R(T)X-ERR/R(T)X-DRP/R(T)X-OVR increases. In this case, there may be some problem on the network, so take measures to have the administrator check.

vmstat

• This command checks system memory, disk, swap in/out, and CPU status at intervals set by the user.

  The main indicators to be checked are as follows.

  	Description
  proc r	The number of threads waiting to occupy the CPU. If the value is large, it can be judged that a CPU bottleneck occurs.
  memory free	Free space on physical memory
  swap si, so	An increase of si/so means that disk I/Os between the swap disk and memory are issued
  CPU us sy id wa st	Change trends for each item should be observed

Linux

CPU usage by thread

• In Linux, the user can also check the CPU for each thread with the top command. If executed with the top -H option, the search is performed for each thread. However, it is possible only if the installed procps version is 3.2.7 or later.
  If not, simply check as follows. (Not well supported in lower version)

  LWP is a unique number for each thread, and the value displayed in the C item is the CPU usage rate.

  	Description
  CPU	CPU share that the thread is currently using
  LWPID	Unique number of thread

pstack