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Introduction to the Teradata® RDBMS for UNIX® Version 2 Release 2.1 - NCR

NCR Introduction to the Teradata® RDBMS for UNIX® Version 2 Release 2.1 - NCR, 1998. - 315 p.
Download (direct link): inntroduktionteradata1998.pdf
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System Administration

Resource Usage

Introduction

ResUsage Data

ResUsage Macros

ResUsage Data Categories

Resource Usage

The Teradata RDBMS has facilities that permit you to monitor the use of resources such as:

• CPUs

• AMPs

• Disk activity

• BYNET/Vnet activity

Resource usage (ResUsage) data handling for the Teradata RDBMS is divided into two phases:

Step Action
1 Various subsystems gather ResUsage data and the Resource Sampling Subsystem (RSS) collects the data into collect buffers.
2 The collected data is logged to ResUsage tables periodically (as determined by user-defined logging intervals).

The logged ResUsage data is then available for analysis by the various ResUsage macros.

The facilities for analyzing resource usage data are provided by means of a set of ResUsage macros tailored to retrieving information from a set of system views designed to collect and present resource usage information.

These views use a base table called DBC.ResUsage for their information source.

Each row of ResUsage data contains two broad categories of information:

• Housekeeping, containing identifying information

• Statistical

Introduction to the Teradata RDBMS for UNIX

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System Administration

Resource Usage

Each item of statistical data falls into a defined kind and class. Each kind corresponds to one (or several) different things that may be measured about a resource.

This kind of measured data . . . Is defined as . . .
track a logical metric that provides the current value of some measurement.
tmon how much time was recorded in some specific state or for some specific activity during the measured logging period.
count a tally of occurrences of some event or a measurement of some resource usage during the logging period.
countshft a special case of count data in which the data is gathered in a specific bit size and then is shifted to a larger grain by some conversion program.

Classes correspond to the different statistical attributes of a piece of data. Defined classes are:

Class name Definition
cnt A simple measure of kind: • tmon • count • countshft
cur A current value of kind track
max A maximum value of kind: • track • tmon
min A minimum value of kind: • track • tmon
avg An average value of kind: • count • tmon

ResUsage Data in Summarization Mode

You can activate summarization mode for many ResUsage tables independently.

Summarization mode reduces database I/O by summarizing data from multiple vprocs and other objects on each node in one representative row.

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Introduction to the Teradata RDBMS for UNIX
System Administration

Resource Usage

ResUsage Column Categories

This summarization reduces detail, but is very useful for exploratory data analysis of performance problems and general resource usage issues.

When summary mode is active, the different data classes are summarized as represented by the following table:

This data class . . . Contains this measure of the summarized values represented . . .
• cnt Sum.
• cur
• avg
max Maximum.
min Minimum.

While it is true that some ResUsage data is for internal use only, all columns found in the ResUsage tables can be categorized as one of the following column types.

Column Type Description
Housekeeping Contain the following data: • Timestamp • Collection element and its characteristics • Current logging characteristics Exclude configuration details.
Process scheduling Contain snapshot data of work started (with current characteristics and states).
Memory Contain memory-related events, subdivided into memory types, for these categories: • Allocation and deallocation • Logical memory reads and writes • Physical disk reads and writes • Access and deaccess • Memory control • Memory management events leading up to — Paging — Swapping — Agmg • Detailed memory snapshot

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System Administration

Resource Usage

Column Type Description
Net Contain network traffic events for these categories: • Number of messages (by transmission type) • Direction of messages (by transmission type) • Physical utilization of net lines (BYNET only) • Controller overhead • Channel utilization • Net contention (BYNET only) Logical messages and direction are identified through subdivisions of the message class.
General concurrency control Contain concurrency control activity information for the following categories: • Control performed for user-level processing • System overhead processing • Database locks Does not include information specific to these controls, which are contained in the disk, memory, or net columns: • Disk concurrency • Memory concurrency • Net concurrency
File system Contain information for the following: • Logical memory reads and writes • Physical disk reads and writes • Locking control activities Other columns identify the purpose of operations performed on disk segments, such as cylinder migration and data updates.
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