Sybase Segments Test

A segment is a label that points to one or more database devices. Segment names are used in create table and create index commands to place tables or indexes on specific database devices. Using segments can improve Adaptive Server performance and give the System Administrator or Database Owner increased control over the placement, size, and space usage of database objects.

If a segment runs out of space, it may no longer be able to accommodate critical database objects such as tables/indexes, and will consequently, hamper the usage of the corresponding databases and adversely impact the performance of the underlying the Syvase server. If this is to be avoided, the space usage of the individual segments should be closely tracked, the segments experiencing a space contention should be rapidly isolated, and more space should be promptly allocated to such segments. This is where the Sybase Segments test helps! This test monitors the space usage of each segment of each database on the Sybase server, and accurately points to those segments that may be running out of space.

Target of the test : A Sybase adaptive server (ver. 12.5 and above) on which MDA tables have been installed

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every database:segment configured for monitoring in the Include Segments text box.

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

Refers to the IP address of the Sybase ASE server.

Port

The port number at which the Sybase server listens to.

User

To enable this test to connect to the Sybase server and collect the required metrics, it is enough if you configure the test with the name of a Sybase user who has the “mon_role”. However, for best results, it is recommended that you configure all Sybase tests with the credentials of a Sybase user who has the “mon_role”, “sa_role’, and “sybase_ts_role”.

Password

The password corresponding to the above user

Confirm Password

Confirm the password by retyping it here.

Include Segments

Specify a comma-separated list of database:segment pairs that you want the test to monitor. By default, this parameter is set to master:default, indicating that the default segment on the master database is monitored.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Total size

Indicates the maximum size up to which this segment can grow.

GB

 

Used size

Indicates the space used by this segment.

GB

A low value is desired for this measure.

Reserved space

Indicates the amount of space allocated to this segment.

GB

 

Free space

Indicates the amount of space that is not used by this segment

GB

A high value is desired for this measure.

Percentage of used space

Indicates the percentage of space used by this segment.

Percent

This measure is the ratio of Used space over the Total size of a segment.

A value close to 100% indicates excessive space usage by the segment. Compare the value of this measure across segments to identify that segment which has very little or no space left. You may want to allocate more space to that segment to prevent performance degradations. 

Percentage of free space

Indicates the percentage of free space for this segment.

Percent

This measure is the ratio of Free space over the Total size of a segment.

A very low value for this measure indicates excessive space usage by the segment. Compare the value of this measure across segments to identify that segment which has very little or no space left. You may want to allocate more space to that segment to prevent performance degradations.