V$LOGMNR_SESSION

V$LOGMNR_SESSION displays information about active LogMiner persistent sessions. (A LogMiner persistent session is created either by starting Data Guard SQL Apply on a logical standby database for the first time or by creating Streams Capture.) Transient LogMiner sessions (those created as a result of querying the V$LOGMNR_CONTENTS view) do not show up in the V$LOGMNR_SESSION view. The statistics shown in this view correspond to snapshots of the system and are not cumulative in nature.

Column Datatype Description
SESSION_ID NUMBER Unique identifier for the LogMiner persistent session
SESSION_NAME VARCHAR2(32) Unique session name
SESSION_STATE VARCHAR2(9) Current state of the LogMiner persistent session:

  • READY - Client has created the LogMiner persistent session and added the relevant archived redo log files, but has not loaded the initial LogMiner dictionary

  • STARTED - The LogMiner dictionary has been loaded

  • ACTIVE - The LogMiner persistent session is mining the redo stream

  • DETACHED - The LogMiner persistent session is not currently active, and it is in the process of becoming inactive

  • DISCARDED - Client is about to destroy the LogMiner persistent session
DB_NAME VARCHAR2(128) Global database name for the source database
DB_ID NUMBER Database identifier of the source database
RESET_SCN NUMBER System change number (SCN) when the session started
RESET_TIMESTAMP NUMBER Time of the RESETLOGs when the LogMiner persistent session started
NUM_PROCESS NUMBER Number of processes allocated to this session
CHUNK_SIZE NUMBER Amount of memory allocated for this chunk
START_SCN NUMBER System change number (SCN) at start of the session
END_SCN NUMBER System change number (SCN) at end of the session
SPILL_SCN NUMBER In the event of a restart, redo records with an SCN lower than this will not be read from the archived redo log files
PROCESSED_SCN NUMBER The BUILDER process has successfully mined redo records up to this SCN
PREPARED_SCN NUMBER The PREPARER processes have successfully transformed all redo records below this SCN into logical change records (LCRs). However the LCRs may not have been grouped into transactions or merged in case they pertain to chained rows or LOB updates.
READ_SCN NUMBER The READER process has read all redo records below this SCN
LOW_MARK_SCN NUMBER LogMiner has delivered all transactions that committed below this SCN to the client
CONSUMED_SCN NUMBER Client has consumed and released all transactions that committed below this SCN.
MAX_MEMORY_SIZE NUMBER Maximum amount of shared memory (in bytes) that LogMiner is allowed to consume
USED_MEMORY_SIZE NUMBER Amount of shared memory (in bytes) actually consumed by LogMiner
BUILDER_WORK_SIZE NUMBER Amount of redo (in bytes) in the current work unit being processed by the BUILDER process.
PREPARED_WORK_SIZE NUMBER Amount of redo (in bytes) that has been prepared by LogMiner
AVAILABLE_WORK_SIZE NUMBER Amount of redo records (in bytes) that are ready, but are yet to be consumed by the client
AVAILABLE_TXN NUMBER Number of transaction chunks ready for consumption
AVAILABLE_COMMITTED_TXN NUMBER Number of committed transactions ready for consumption. This is less than, or equal to, AVAILABLE_TXN.
DELIVERED_TXN NUMBER Number of transaction chunks that the client currently has in its possession
DELIVERED_COMMITTED_TXN NUMBER Number of committed transaction chunks that the client is currently working on. This is less than, or equal to, the value of the DELIVERED_TXN column.
PINNED_TXN NUMBER Number of transactions pinned (the client is actively working on)
PINNED_COMMITTED_TXN NUMBER Number of committed transactions pinned (the client is actively working on)
CHECKPOINT_INTERVAL NUMBER Checkpoint interval