V$LOGMNR_LATCH

V$LOGMNR_LATCH can be joined with the V$LATCH and the V$LATCH_CHILDREN views to obtain statistics about different latches used by active LogMiner persistent sessions. A persistent LogMiner session is created either by starting Data Guard SQL Apply on a logical standby database for the first time or by creating a Streams capture.

Column	Datatype	Description
`SESSION_ID`	`NUMBER`	Unique identifier of the LogMiner persistent session
`NAME`	`VARCHAR2(32)`	Name of the Latch: `LogMiner internal state` - Identifies the latch that protects communications between the LogMiner `READER`, `PREPARER`, and `BUILDER` processes `LogMiner memory allocation` - Identifies the latch that protects all memory allocation and deallocation inside LogMiner `LogMiner transaction list` - Identifies the latch that protects interaction between the LogMiner layer and its clients (Data Guard SQL Apply on a logical standby database or Oracle Streams)
`CHILD_ADDR`	`RAW(4)`	Address of the child latch object. This column matches the corresponding `ADDR` column in the `V$LATCH_CHLDREN` view
`STATE`	`VARCHAR2(6)`	State of the Latch: `UNINIT` - The latch structure is uninitialized; that is, it is not currently assigned to any LogMiner persistent session `READY` - The latch structure is being used by a persistent LogMiner session