SYSTEM.DATE_THRESHOLD
SYSTEM.DATE_THRESHOLD represents the database date requery threshold. This variable works in conjunction with the three system variables $$DBDATE$$, $$DBDATETIME$$, and $$DBTIME$$, and controls how often Oracle Forms synchronizes the database date with the RDBMS. The value of this variable must be specified in the following format:
MI:SS
Because frequent RDBMS queries can degrade performance, it is best to keep this value reasonably high. However, keep in mind that if the value is not synchronized often enough, some time discrepancy can occur.
Default
01:00 (Synchronization occurs after one minute of elapsed time.)
This does not mean that Oracle Forms polls the RDBMS once every minute. It means that whenever Oracle Forms needs to generate the value for the system variables $$DBDATE$$, $$DBDATETIME$$, $$DBTIME$$, or SYSTEM.EFFECTIVE_DATE, it updates the effective date by adding the amount of elapsed time (as measured by the local operating system) to the most previously queried RDBMS value.
If the amount of elapsed time exceeds the date threshold, then a new query is executed to retrieve the RDBMS time and the elapsed counter is reset.
If a form never references the database date, Oracle Forms never executes a query to retrieve the RDBMS date, regardless of the value of SYSTEM.DATE_THRESHOLD.
The operating system clock and the RDBMS clock rarely drift by more than one or two seconds, even after hours of elapsed time. However, since your database administrator can reset the RDBMS clock at any time, it is safest to set the threshold no higher than a few minutes.
Often, a Oracle Forms block may contain multiple references to these $$DBDATE$$, $$DBDATETIME$$, or $$DBTIME$$ defaults. By setting SYSTEM.DATE_THRESHOLD to the default of one minute, nearly all such references in a form can be satisfied with a single query of the RDBMS.