The transaction log file contains information that allows Sybase to recover from a system failure. The transaction log is also required for auditing. 
Sybase IQ records in the transaction log the information necessary to recover from a system failure.
Although the information logged is small for each committed transaction, the transaction log continues to grow in size.
In systems with a high number of transactions that change data, over a period of time the log can grow to be very large.
It becomes then crucial being able to monitor some transaction log key factors such as the number of log pages already used,
the number of log pages reserved for rollbacks or the number of log pages that has not been used yet. 

Monitor features include :

• Monitoring transaction log free pages, used pages and CLR pages
• Choice of the unit of measure you want to set to monitor all the items : KB, MB, GB, number of pages, or expressed in percentage values.
• Setting a muIti threshold alarm policy for every monitored item and to alert in case a threshold is reached

Unit of measure of the monitor:
Select the unit of measure you want the monitor to fetch monitored features data, it includes : KB, MB, GB, PAGES

Surveillance table:

• This is a table of rules that you can use to configure and customize the configuration.
• Each line of the table will define a rule of monitoring. You can combine multiple rules to cover different cases.
• Within a rule, you can configure the feature you want to monitor (Free pages, Used pages, CLR pages), a multi-threshold value for the selected feature and the the unit of measure of the threshold

Monitored feature :
Select the specific Sybase transaction log feature you want to monitor (Free pages, Used pages, CLR Pages)

Feature threshold :

• Use the multi-threshold syntax to set multiple threshold/severity associations: G2W:50 W2M:80 M2C:90 (Green To Warning, Warning To Major, etc…), expressed as the monitor Unit of measure or as percentage values
• An alarm of the corresponding severity will be sent if the monitored feature is over or under threshold (depending on what is being monitored).
• Set 0 in the field if unused
• When setting the multi-thread threshold, notice that for used pages the lower better policy will apply, for free pages and CLR pages a higher better policy.

Unit :
Select “As monitor” if you want to monitor data expressed in the same unit of measure as the monitor or select “Percentage” if you prefer values to be monitored this way.

Effect : For this rule, used pages within the trasaction log file will be monitored

A WARNING alarm is sent if used pages are monitored at 70% or more, a CRITICAL alarm if 85% or more.