PURGE_WINDOW Procedure

The subscriber calls this procedure to notify the capture system it is finished processing a block of changes. The PURGE_WINDOW procedure sets the low-water mark so that the subscription no longer sees any data, effectively making the subscription window empty.

Syntax

DBMS_CDC_SUBSCRIBE.PURGE_WINDOW(
subscription_handle	IN NUMBER)

Parameters

Table 26-14 PURGE_WINDOW Procedure Parameters  

Parameter	Description
subscription_handle	Unique number of the subscription handle that was returned by a previous call to the GET_SUBSCRIPTION_HANDLE procedure.

Exceptions

Table 26-15 PURGE_WINDOW Procedure Exceptions  

Exception	Description
ORA-31425	Subscription handle does not exist or handle does not belong to this user. Call the function again with a valid subscription handle.
ORA-31429	The subscription handle must be activated before you use the EXTEND_WINDOW procedure. Call the ACTIVATE_SUBSCRIPTION procedure for this subscription handle and then try the original command again.
ORA-31430	The subscriber view was not dropped prior to making this call. Call the DROP_SUBSCRIBER_VIEW Procedure and then try the original command again.

Usage Notes

• When finished with a set of changes, the subscriber purges the subscription window with the PURGE_WINDOW procedure. By this action the subscriber performs the following functions:
  • Informs the change capture system that the subscriber is ready to receive the next batch of change data.

  • Enables the system to remove change data that is no longer needed by any subscribers.

  The Change Data Capture system manages the change data to ensure that it is available as long as there are subscribers who need it.

Example

EXECUTE sys.DBMS_CDC_SUBSCRIBE.PURGE_WINDOW ( \
SUBSCRIPTION_HANDLE=>:subhandle);