24 Replication Dynamic Performance Views

All Oracle installations include the dynamic performance views, often referred to as V$ views, described in this chapter. These views are used by master sites and materialized view sites to determine such information as which materialized views are being refreshed currently and statistics about the deferred transaction queue.

This chapter contains these topics:

V$MVREFRESH
V$REPLPROP
V$REPLQUEUE

V$MVREFRESH

Contains information about the materialized views currently being refreshed.

Column	Data Type	Description
`SID`	`NUMBER`	Session identifier.
`SERIAL#`	`NUMBER`	Session serial number, which is used to identify uniquely a session's objects. Guarantees that session-level commands are applied to the correct session objects if the session ends and another session begins with the same session ID.
`CURRMVOWNER`	`VARCHAR2(31)`	Owner of the materialized view currently being refreshed. The materialized view resides in this user's schema.
`CURRMVNAME`	`VARCHAR2(31)`	Name of the materialized view currently being refreshed.

V$REPLPROP

Contains information about the parallel propagation currently in progress at the replication site. Use this view to determine which transactions are currently being propagated, the number of calls propagated in each transaction, and the current activity of the parallel propagation processes or parallel propagation coordinator process.

Note:

This view only contains data when deferred transactions are being pushed using parallel propagation at the current site. The parallelism parameter must be set to 1 or higher in the DBMS_DEFER_SYS.PUSH function for a push to use parallel propagation. Otherwise, the push uses serial propagation, and no data appears in this view during the push.

Column	Data Type	Description
`SID`	`NUMBER`	Session identifier.
`SERIAL#`	`NUMBER`	Session serial number. Used to identify uniquely a session's objects. Guarantees that session-level commands are applied to the correct session objects if the session ends and another session begins with the same session ID.
`NAME`	`VARCHAR2(71)`	`Replication` `Parallel` `Prop` `Slave` `n` indicates that the process is active, either waiting, pushing deferred transactions, purging metadata, or creating an error transaction. `Replication` `Parallel` `Prop` `Coordinator` indicates that the coordinator process is active, either waiting, sleeping, or scheduling processes to perform operations. The `Replication` `Parallel` `Prop` `Coordinator` reads transactions from the deferred transaction queue and assigns them to the `Replication` `Parallel` `Prop` `Slaves`. Then, the processes propagate the transactions to the destination site. When the processes push transactions in a push session, the processes remain active until the push session completes, even if there are no more transactions to push.
`DBLINK`	`VARCHAR2(128)`	Database link on which this replication session is propagating.
`STATE`	`VARCHAR2(12)`	`WAIT` indicates that either the slave or coordinator process is waiting for an event (that is, a message). `SLEEP` indicates that the coordinator process is sleeping for the duration of the `delay_seconds` setting. You set `delay_seconds` with the `SCHEDULE_PUSH` procedure in the `DBMS_DEFER_SYS` package. `PUSH` indicates that the slave process is pushing transactions from the deferred transaction queue to the remote site. `PURGE` indicates that the slave process is purging metadata related to successfully applied transactions from the remote site. `CREATE` `ERROR` indicates that the slave process is creating an error transaction. In this case, an error or a conflict occurred while the slave was pushing deferred transactions to the remote site. `SCHEDULE` `TXN` indicates that the coordinator process is determining the order that transactions are applied and assigning slave processes to execute the transactions.
`XID`	`VARCHAR2(22)`	If the session is a slave session, then indicates the transaction id of the transaction that the slave is currently propagating.
`SEQUENCE`	`NUMBER`	If the process is a slave process, then the sequence number of the calls propagated in the current operation, if relevant. Each transaction must process one or more calls, and the value of `SEQUENCE` starts at zero and increases as each call is processed. So, the `SEQUENCE` value shows the call that is currently being processed in each transaction. This value increases until the slave has processed all of the calls in a transaction.

V$REPLQUEUE

Contains statistics about the replication deferred transactions queue. All values are stored since the start of the current database instance.

Column	Data Type	Description
`TXNS_ENQUEUED`	`NUMBER`	Number of transactions enqueued in the deferred transactions queue.
`CALLS_ENQUEUED`	`NUMBER`	Number of calls enqueued into the deferred transactions queue.
`TXNS_PURGED`	`NUMBER`	Number of transactions purged from the deferred transactions queue.
`LAST_ENQUEUE_TIME`	`DATE`	Date when the last transaction was enqueued into the deferred transaction queue. `NULL` if no transactions have been enqueued into the deferred transaction queue since the instance started.
`LAST_PURGE_TIME`	`DATE`	Date when the last transaction was purged from the deferred transaction queue. `NULL` if no transactions have been purged from the deferred transaction queue since the instance started.