Replication Views / Prerequisites for Advanced Replication

Posted By Sagar Patil

Prerequisites for Advanced Replication

1. Must have distributed and replication option installed
Must run $ORACLE_HOME/rdbms/admin/catrep.sql as INTERNAL

2. Password for repsys, repadmin, and ACME should be the same on master and master definition site

3. Mandatory INIT.ORA parameters on both databases:
shared_pool_size: 25M
global_names=true
job_queue_processes=2
open_links=6
job_queue_interval= <less than interval for dba_jobs submitted>
job_queue_keep_connections=false

Master Definition Site
The database that has all the objects that you wish to replicate. All suspend and resume commands are to be entered from here, and will be automatically propagated to the master sites.

Master Site
The database that will hold the replicated objects. One master definition site can be replicated to a multiple
number of master definitionsites.

Note that as this is only a one way replication, inserts, updates and deletes should only be performed on the master definition site. Otherwise, a conflict resolution strategy must beimplemented.

Deferred Transactions and Remote Procedure Calls
Oracle’s advanced replication option relies primarily on deferred transactions and remote procedure calls (RPCs). When you commit a transaction against a replicated table, for example, the replication support triggers queue a deferred transaction to do your bidding in one or more remote databases.
In addition to providing many of the underpinnings for the advanced replication option, the packages used to create and manipulate deferred calls are available for direct use in yourapplications.

Package Description
DBMS_DEFER_SYS Performs administrative tasks such as scheduling,executing, and deleting queued transactions.
DBMS_DEFER Builds deferred calls.
DBMS_DEFER_QUERY Provides access to parameters passed to deferred calls, primarily for diagnostic purposes.< BR>

There are eight data dictionary views that contain data about deferred transactions and RPCs. You can query these views to determine information such as the destination of RPC calls, error messages, and scheduled execution times. Most of the packages associated with deferred calls reference and/or modify the data in these views.

Package

Description

DEFCALL

Contains information about all deferred RPCs. Queries SYSTEM.DEF$_CALL table.

DEFCALLDEST

Contains the destination database(s) for each deferred RPC in DEFCALL. Queries SYSTEM.DEF$_CALL, SYSTEM.DEF$_DESTINATION, SYSTEM.DEF$_CALLDEST, SYSTEM.DEF$_ERROR, and SYSTEM.REPCAT$_REPPROP.

DEFDEFAULTDEST

Contains the default destinations for deferred RPCs. Queries SYSTEM.DEF$_DEFAULTDEST.

DEFERROR

Contains error information for deferred calls that could not be applied at their destination. Queries SYSTEM.DEF$_ERROR.

DEFERRORCOUNT

Contains the count of errors for each destination. Queries SYSTEM.DEF$_ERROR.

DEFSCHEDULE

Contains information about the scheduling of deferred jobs. Queries SYSTEM.DEF$_DESTINATION and SYS.JOB$.

DEFTRAN

Contains information about all deferred calls. Queries SYSTEM.DEF$_CALL and SYS.USER$.

DEFTRANDEST

Contains the destination database(s) for each deferred transaction. Queries SYSTEM.DEF$_CALL, SYSTEM.DEF$_DESTINATION, SYSTEM.DEF$_ERROR, SYSTEM.DEF$_CALLDEST, and SYSTEM.REPCAT$_REPPROP

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