When installing a database adapter on a server other then the database server what happens when the network is down. Do you lose the notification for that database record or the modification?
When you create a notification event, the database adapter creates a new table based upon the fields that you are sending as part of your notification. For example, if you select the unique identifier “PO_NUMBER” and the field “ITEM_DESCRIPTION” from the source table, there will be a new table created by the database adapter which serves as a buffer table and consists of two columns – “PO_NUMBER” and “ITEM_DESCRIPTION”. This is the table that the adapter “watches”. The table will have a name resembling “AWB_CAGO_[SOURCE TABLE NAME]_I”.
Additionally, the adapter writes a trigger to your source table schema so that with every insert (or update or delete), the fields that are required by the notification event are selected and written to the buffer table. This action occurs on the database server and does not involve the database adapter.
When your adapter comes back online, it will resume its normal operation and poll the buffer table that it created when the notification event was originally defined. Because the trigger continued to operate on the database server while the database adapter was offline, the buffer table may have multiple rows when the database adapter comes back online.
When the database adapter re-connects, it will begin to poll the buffer table and will select – row by row – your notification event fields.
That your database adapter is not configured on the same machine as the database server will not affect this process. webMethods recommends installing the adapter on the same machine as the server because the polling process is much more expensive to your network if the connection is remote as opposed to local.