When you monitor database server performance, you use tools from the host operating system and run command-line utilities at regular intervals from scripts or batch files. You can also use graphical interface tools to monitor critical aspects of performance as queries and transactions are performed.
The database server relies on the operating system of the host computer to provide access to system resources such as the CPU, memory, and various unbuffered disk I/O interfaces and files. Each operating system has a set of utilities for reporting how system resources are used. Different implementations of some operating systems have monitoring utilities with the same name but different options and informational outputs.
You might be able to use some of the following typical UNIX operating-system utilities to monitor resources.
To capture the status of operating system resources at regular intervals, write scripts and use scheduling tools that are available with your host operating system, such as cron.
Your operating system might also provide graphical monitoring tools that you can use to monitor operating system resources dynamically across coservers. However, such tools are not intended to create performance history data.
For information about using operating system tools to monitor your operating-system resources, consult the reference manual, the online man pages, your system administration guide, and your system-administration team members.
The IBM Informix Server Administrator (ISA) provides a graphical use interface in a Web browser that lets you monitor aspects of the database server activity. ISA uses onstat output to display information about the current state of the database server.
Informix database servers provide command-line utility programs to monitor performance. In Extended Parallel Server, you can use these utility programs as arguments to the xctl utility to collect performance data from all coservers in the database server, or from specified coservers, and display it in a single output report. You can also run the command-line utilities on an individual coserver to retrieve performance information for that coserver only.
To capture information about configuration and performance across all coservers, use the xctl utility with the onstat options described in Monitoring Overall Performance. You can also use xctl with onlog to examine the logical logs, as the IBM Informix: Extended Parallel Server Administrator's Reference describes. For detailed information about these command-line utilities, refer to the IBM Informix: Extended Parallel Server Administrator's Reference.
Use xctl (execute utilities across coservers) to capture performance-related information for all coservers in your database server.
Use xctl with onstat and its arguments to display information about the current status and activities of the database server on all or specified coservers. To display a complete list of the onstat options, use onstat - -. Use xctl with onlog to display all or part of the logical log or to check the status of the logical logs.
You can run onstat either as an argument to xctl or alone from the command line on the coserver where you are logged in. When you run onstat without xctl, you see information about the local coserver only.
Enter xctl onstat without any arguments to see the current status of the database server, how long it has been running, a list of user threads, and a summary of current activity.
Use the following xctl onstat options to display general performance-related information.
For the performance implications of LRU queue statistics, see Specifying the Number of Least Recently Used Queues.
For detailed information about these command-line utilities, refer to the IBM Informix: Extended Parallel Server Administrator's Reference. For more information about specific options that provide performance-related information, see the following sections:
The database server maintains information about the database server itself in the system-monitoring interface (SMI) pseudo tables, which are recreated each time the database server starts. The database server also stores permanent information about each database in the system catalog tables.
For information about SMI tables, refer to the IBM Informix: Extended Parallel Server Administrator's Reference. For information about system catalog tables, refer to the IBM Informix: Guide to SQL Reference.
You can also use SQL SELECT statements to query the system-monitoring interface (SMI) from within your application.
The SMI tables are a collection of tables and pseudo-tables in the sysmaster database that contain dynamically updated information about the operation of the database server. The tables are constructed in memory but are not recorded on disk. To query SMI tables at regular intervals, use cron jobs and SQL scripts with DB-Access. For information about SQL scripts, refer to the IBM Informix: DB-Access User's Guide.
For additional information, see Examining Information in the sysptprof System-Monitoring Interface Table.
For each database, the database server creates a set of system catalog tables that describe the structure and activity of the database.
System catalog tables contain permanently stored and updated information about each database and its tables. For example, you can query the sysfragments and systables system catalog tables to get information about all tblspaces that hold a fragment and the table to which each fragment belongs and you can query the sysdistrib table for information about data distributions for a specific table. For detailed information about the system catalog tables, refer to the IBM Informix: Guide to SQL Reference.
For specific information, see to Examining Information in the sysfragments System Catalog Table.
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