9.57 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 Replication 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

RESET_TIME

DATE

The time when the 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

PROCESSED_TIME

DATE

The BUILDER process has successfully mined redo records up to this time

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

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:

"V$LOGMNR_CONTENTS"