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 | 8)

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

CON_ID

NUMBER

The ID of the container to which the data pertains. Possible values include:

  • 0: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs.

  • 1: This value is used for rows containing data that pertain to only the root

  • n: Where n is the applicable container ID for the rows containing data

See Also: