V$LOGMNR_STATS

V$LOGMNR_STATS displays the activity currently being performed by the active LogMiner persistent sessions.

Column Datatype Description
SESSION_ID NUMBER Unique identifier for the LogMiner persistent sessions
NAME VARCHAR2(64)

Name of the LogMiner statistic, state, or status, including:

  • Bytes of Redo Processed - Cumulative count of bytes processed by SQL Apply

  • Redo Records Processed - Count of redo records processed by SQL Apply

  • Txns Delivered to Client - Count of SQL transactions processed by SQL Apply

  • DML txns delivered - Count of DML transactions processed by SQL Apply

  • DDL txns delivered - Count of DDL transactions processed by SQL Apply

  • CTAS txns delivered - Count of CREATE TABLE AS SELECT (CTAS) transactions processed by SQL Apply

  • Recursive txns delivered - Count of recursive transactions processed by SQL Apply

  • Rolled back txns seen

  • LCRs delivered to client - Number of logical change records (LCRs) processed by SQL Apply

  • Bytes paged out - Cumulative count of bytes that have been paged out. LogMiner pages out memory from the LCR cache to accommodate certain ill-behaved workloads or under-configured systems. The ratio of bytes paged out to bytes of redo processed should be low. If this ratio is high (10% or higher), try increasing the MAX_SGA allocated to SQL Apply.

  • Microsecs spent in pageout - Time spent by LogMiner paging out memory from the LCR cache

  • Bytes checkpointed - Keeps track of the amount of bytes checkpointed. The mining engine takes periodic checkpoints, whereby it writes out logical change records (LCRs) pertaining to long-running transactions. The ratio of Bytes Checkpointed to Bytes of Redo Processed should be low. A high ratio (10% or higher) indicates an ill-behaved workload.

  • Microsecs spent in checkpoint - Time spent by the mining engine taking checkpoints, whereby it writes out logical change records (LCRs) pertaining to long-running transactions.

  • Bytes rolled back - Cumulative value of the number of bytes rolled back by LogMiner. There are times that LogMiner needs to backtrack and reprocess a section of the redo stream. In this case, it will roll back work it has already done. The ratio of Bytes Rolled Back to Bytes of Redo Processed should be low. If this ratio is high (10% or higher), reduce the number of PREPARER processes allocated to SQL Apply.

  • Microsecs spent in rollback - Time spent rolling back transactions already applied to the logical standby database
VALUE VARCHAR2(64) The corresponding metric value
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