What is PS_TXN table in ADF world?

The  PS_TXN Table

The   PS_TXN table stores snapshots of pending changes made to BC4J application module instances. The table manages the B-Tree storage of rows. The snapshot information is stored as an XML document that encodes the unposted changes in an application module instance. Only pending data changes are stored in the snapshot, along with information about the current state of active iterators (i.e. "current row" pointers information). The value of the COLLID column corresponds to the value returned by the   ApplicationModule.passivateState() method.

The  PS_TXN_SEQ Sequence

This sequence is used to assign the next persistent snapshot Id for Application Module pending state management. If the   PS_TXN table contains any rows at the time this sequence is created, the sequence is created so that is   STARTS WITH the integer that is one greater than the   MAX(COLLID) value from the rows in   PS_TXN.