9i: How To Setup Oracle streams replication. (Doc ID 224255.1)To Bottom

APPLIES TO:Oracle Server - Enterprise Edition - Version 9.2.0.1 and laterInformation in this document applies to any platform.

PURPOSEOracle Streams enables the sharing of data and events in a data stream, eitherwithin a database or from one database to another.This article is intended to assist Replication DBAs in setting up andconfiguring Oracle Streams Replication.SCOPETo be used by Oracle support analysts and replication DBAs to setup replicationusing Streams in Oracle 9.2.x.This article discusses the steps to setup Streams Replication from one Oracledatabase to another.The Global Database Name of the Source Database is V920.IDC.ORACLE.COMThe Global Database Name of the Destination Database is TEST920.IDC.ORACLE.COMIn the example setup, DEPT table belonging to SCOTT schema has been used fordemonstration purpose.DETAILS

INTRODUCTION-------------

Oracle 9.2 has introduced a more flexible and efficient way of implementingreplication using streams.

In a nutshell, replication using streams is implemented in the following way.

1) A background capture process is configured to capture changes made totables,schemas, or the entire database. The capture process captureschanges from the redo log and formats each captured change into a logicalchange record (LCR).The capture process uses logminer to mine the redo/archive logs to format LCRs.

2) The capture process enqueues LCR events into a queue that is specified.

3) This queue is scheduled to Propagate events from one queue to another in adifferent database.

4) A background apply process dequeues the events and applies them at thedestination database.

STREAMS SETUP-------------

The Setup is divided into the following 4 sections:

Section 1 : Initialization Parameters Relevant to StreamsSection 2 : Steps to be carried out at the Destination DatabaseSection 3 : Steps to be carried out at the Source DatabaseSection 4 : Export, import and instantiation of tables fromSource to Destination Database

Section 1 - Initialization Parameters Relevant to Streams-------------------------------------------------------------

1.1 COMPATIBLE :To use Streams, Compatible must be set to 9.2.0.

1.2 GLOBAL_NAMES :This parameter must be set to TRUE at each database if you want touse Streams to share information between databases. Streams usesthe GLOBAL_NAME of the database to identify changes from or to aparticular database. Do NOT modify the GLOBAL NAME of a Streamsdatabase after it has been configured. For example, thesystem-generated rules for capture, propagation, and apply typicallyspecify the global name of the source database. In addition, changescaptured by the Streams capture process automatically include thecurrent global name of the source database. If the global name mustbe modified on the database, do it at a time when NO user changesare possible on the database so that the Streams configuration can berecreated.

1.3 JOB_QUEUE_PROCESSES :This parameter specifies the number of processes that canhandle requests created by DBMS_JOB. Ensure that it is set to 2 or higher.

1.4 AQ_TM_PROCESSES :Setting the parameter to 1 or more starts the specified number ofqueue monitor processes.

1.5 LOGMNR_MAX_PERSISTENT_SESSIONS :This parameter specifies the maximum number of persistent LOGMINER miningsessions. Streams Capture Process uses LOGMINER to mine the redo logs.If there is a need to run multiple Streams capture processes on a singledatabase, then this parameter needs to be set equal to or higher than thenumber of planned capture processes.

1.6 LOG_PARALLELISM :This parameter must be set to 1 at each database that captures events.

1.7 PARALLEL_MAX_SERVERS :Each capture process and apply process may use multiple parallel executionservers. The apply process by default needs two parallel servers.So this parameter needs to set to at least 2 even for a single non-parallelapply process.Specify a value for this parameter to ensure that there are enoughparallel execution servers.

1.8 SHARED_POOL_SIZE :Each capture process needs 10MB of shared pool space, but Streams islimited to using a maximum of 10% of the shared pool.So shared_pool_size has to be set to at least 100MB.If you wish to run multiple capture processes, then this parameter needsto be set to an even higher value.

1.9 OPEN_LINKS :Specifies the maximum number of concurrent open connections to remotedatabases in one session. Ensure that it is set to 4 or higher.

1.10 The databases involved in Streams must be running in ARCHIVELOG mode.

Section 2 - Steps to be carried out at the Destination Database (TEST920.IDC.ORACLE.COM)-----------------------------------------------------------------------------------------------------

2.1 Create Streams Administrator :connect SYS/password as SYSDBAcreate user STRMADMIN identified by STRMADMIN;

2.2 Grant the necessary privileges to the Streams Administrator :

GRANT CONNECT, RESOURCE, AQ_ADMINISTRATOR_ROLE to STRMADMIN;

GRANT SELECT ANY DICTIONARY TO STRMADMIN;

GRANT EXECUTE ON DBMS_AQ TO STRMADMIN;GRANT EXECUTE ON DBMS_AQADM TO STRMADMIN;GRANT EXECUTE ON DBMS_FLASHBACK TO STRMADMIN;GRANT EXECUTE ON DBMS_STREAMS_ADM TO STRMADMIN;GRANT EXECUTE ON DBMS_CAPTURE_ADM TO STRMADMIN;GRANT EXECUTE ON DBMS_APPLY_ADM TO STRMADMIN;GRANT EXECUTE ON DBMS_RULE_ADM TO STRMADMIN;GRANT EXECUTE ON DBMS_PROPAGATION_ADM TO STRMADMIN;

BEGINDBMS_AQADM.GRANT_SYSTEM_PRIVILEGE(privilege => 'ENQUEUE_ANY',grantee => 'STRMADMIN',admin_option => FALSE);END;/

BEGINDBMS_AQADM.GRANT_SYSTEM_PRIVILEGE(privilege => 'DEQUEUE_ANY',grantee => 'STRMADMIN',admin_option => FALSE);END;/

BEGINDBMS_AQADM.GRANT_SYSTEM_PRIVILEGE(privilege => 'MANAGE_ANY',grantee => 'STRMADMIN',admin_option => TRUE);END;/

BEGINDBMS_RULE_ADM.GRANT_SYSTEM_PRIVILEGE(privilege => DBMS_RULE_ADM.CREATE_EVALUATION_CONTEXT_OBJ,grantee => 'STRMADMIN',grant_option => TRUE);DBMS_RULE_ADM.GRANT_SYSTEM_PRIVILEGE(privilege => DBMS_RULE_ADM.CREATE_RULE_SET_OBJ,grantee => 'STRMADMIN',grant_option => TRUE);DBMS_RULE_ADM.GRANT_SYSTEM_PRIVILEGE(privilege => DBMS_RULE_ADM.CREATE_RULE_OBJ,grantee => 'STRMADMIN',grant_option => TRUE);END;/

BEGINDBMS_RULE_ADM.GRANT_SYSTEM_PRIVILEGE(privilege => DBMS_RULE_ADM.CREATE_ANY_RULE_SET,grantee => 'STRMADMIN',grant_option => TRUE);DBMS_RULE_ADM.GRANT_SYSTEM_PRIVILEGE(privilege => DBMS_RULE_ADM.ALTER_ANY_RULE_SET,grantee => 'STRMADMIN',grant_option => TRUE);DBMS_RULE_ADM.GRANT_SYSTEM_PRIVILEGE(privilege => DBMS_RULE_ADM.EXECUTE_ANY_RULE_SET,grantee => 'STRMADMIN',grant_option => TRUE);DBMS_RULE_ADM.GRANT_SYSTEM_PRIVILEGE(privilege => DBMS_RULE_ADM.CREATE_ANY_RULE,grantee => 'STRMADMIN',grant_option => TRUE);DBMS_RULE_ADM.GRANT_SYSTEM_PRIVILEGE(privilege => DBMS_RULE_ADM.ALTER_ANY_RULE,grantee => 'STRMADMIN',grant_option => TRUE);DBMS_RULE_ADM.GRANT_SYSTEM_PRIVILEGE(privilege => DBMS_RULE_ADM.EXECUTE_ANY_RULE,grantee => 'STRMADMIN',grant_option => TRUE);END;/

BEGINDBMS_RULE_ADM.GRANT_SYSTEM_PRIVILEGE(privilege => DBMS_RULE_ADM.EXECUTE_ANY_EVALUATION_CONTEXT,grantee => 'STRMADMIN',grant_option => TRUE);END;/

2.3 Create streams queue :

connect STRMADMIN/STRMADMIN

BEGINDBMS_STREAMS_ADM.SET_UP_QUEUE(queue_table => 'STREAMS_QUEUE_TABLE',queue_name => 'STREAMS_QUEUE',queue_user => 'STRMADMIN');END;/

2.4 Add apply rules for the table at the destination database :

BEGINDBMS_STREAMS_ADM.ADD_TABLE_RULES(table_name => 'SCOTT.DEPT',streams_type => 'APPLY',streams_name => 'STRMADMIN_APPLY',queue_name => 'STRMADMIN.STREAMS_QUEUE',include_dml => true,include_ddl => true,source_database => 'V920.IDC.ORACLE.COM');END;/

2.5 Specify an 'APPLY USER' at the destination database:

This is the user who would apply all DML statements and DDL statements.The user specified in the APPLY_USER parameter must have the necessaryprivileges to perform DML and DDL changes on the apply objects.

BEGINDBMS_APPLY_ADM.ALTER_APPLY(apply_name => 'STRMADMIN_APPLY',apply_user => 'SCOTT');END;/

2.6 If you do not wish the apply process to abort for every error that itencounters, you can set the below paramter.The default value is 'Y' which means that apply process would abort due toany error.When set to 'N', the apply process will not abort for any error that itencounters, but the error details would be logged in DBA_APPLY_ERROR.

BEGINDBMS_APPLY_ADM.SET_PARAMETER(apply_name => 'STRMADMIN_APPLY',parameter => 'DISABLE_ON_ERROR',value => 'N' );END;/

2.7 Start the Apply process :BEGINDBMS_APPLY_ADM.START_APPLY(apply_name => 'STRMADMIN_APPLY');END;/

Section 3 - Steps to be carried out at the Source Database (V920.IDC.ORACLE.COM)--------------------------------------------------------------------------------------------

3.1 Move LogMiner tables from SYSTEM tablespace:

By default, all LogMiner tables are created in the SYSTEM tablespace.It is a good practice to create an alternate tablespace for the LogMinertables.

CREATE TABLESPACE LOGMNRTS DATAFILE 'logmnrts.dbf' SIZE 25M AUTOEXTEND ONMAXSIZE UNLIMITED;

BEGINDBMS_LOGMNR_D.SET_TABLESPACE('LOGMNRTS');END;/

3.2 Turn on supplemental logging for DEPT table :connect SYS/password as SYSDBAALTER TABLE scott.dept ADD SUPPLEMENTAL LOG GROUP dept_pk(deptno) ALWAYS;

3.3 Create Streams Administrator and Grant the necessary privileges :Repeat steps 2.1 and 2.2 for creating the user and granting the requiredprivileges.

3.4 Create a database link to the destination database :

connect STRMADMIN/STRMADMINCREATE DATABASE LINK TEST920.IDC.ORACLE.COM connect toSTRMADMIN identified by STRMADMIN using 'TEST920.IDC.ORACLE.COM';

Test the database link to be working properly by querying against thedestination database.Eg : select * from global_name@TEST920.IDC.ORACLE.COM;

3.5 Create streams queue:

BEGINDBMS_STREAMS_ADM.SET_UP_QUEUE(queue_name => 'STREAMS_QUEUE',queue_table =>'STREAMS_QUEUE_TABLE',queue_user => 'STRMADMIN');END;/

3.6 Add capture rules for the table at the source database:BEGINDBMS_STREAMS_ADM.ADD_TABLE_RULES(table_name => 'SCOTT.DEPT',streams_type => 'CAPTURE',streams_name => 'STRMADMIN_CAPTURE',queue_name => 'STRMADMIN.STREAMS_QUEUE',include_dml => true,include_ddl => true,source_database => 'V920.IDC.ORACLE.COM');END;/

3.7 Add propagation rules for the table at the source database.This step will also create a propagation job to the destination database.BEGINDBMS_STREAMS_ADM.ADD_TABLE_PROPAGATION_RULES(table_name => 'SCOTT.DEPT',streams_name => 'STRMADMIN_PROPAGATE',source_queue_name => 'STRMADMIN.STREAMS_QUEUE',destination_queue_name => 'STRMADMIN.STREAMS_QUEUE@TEST920.IDC.ORACLE.COM',include_dml => true,include_ddl => true,source_database => 'V920.IDC.ORACLE.COM');END;/

Section 4 - Export, import and instantiation of tables from Source to Destination Database------------------------------------------------------------------------------------------------

4.1 If the objects are not present in the destination database, perform anexport of the objects from the source database and import them into thedestination database

Export from the Source Database:Specify the OBJECT_CONSISTENT=Y clause on the export command.By doing this, an export is performed that is consistent for eachindividual object at a particular system change number (SCN).exp USERID=SYSTEM@V920.IDC.ORACLE.COM TABLES=SCOTT.DEPT FILE=tables.dmpGRANTS=Y ROWS=Y LOG=exportTables.log OBJECT_CONSISTENT=YINDEXES=Y STATISTICS = NONE

Import into the Destination Database:Specify STREAMS_INSTANTIATION=Y clause in the import command.By doing this, the streams metadata is updated with the appropriateinformation in the destination database corresponding to the SCN thatis recorded in the export file.imp USERID=SYSTEM@TEST920.IDC.ORACLE.COM FULL=Y CONSTRAINTS=YFILE=tables.dmp IGNORE=Y GRANTS=Y ROWS=Y COMMIT=Y LOG=importTables.logSTREAMS_INSTANTIATION=Y

4.2 If the objects are already present in the desination database, check that they are alsoconsistent at data level, otherwise the apply process may fail with error ORA-1403 whenapply a DML on a not consistent row. There are 2 ways of instanitating the objectsat the destination site.

1. By means of Metadata-only export/import :

Export from the Source Database by specifying ROWS=Nexp USERID=SYSTEM@V920.IDC.ORACLE.COM TABLES=SCOTT.DEPT FILE=tables.dmpROWS=N LOG=exportTables.log OBJECT_CONSISTENT=Y

Import into the destination database using IGNORE=Yimp USERID=SYSTEM@TEST920.IDC.ORACLE.COM FULL=Y FILE=tables.dmp IGNORE=YLOG=importTables.log STREAMS_INSTANTIATION=Y

2. By Manaually instantiating the objects

Get the Instantiation SCN at the source database:connect STRMADMIN/STRMADMIN@sourceset serveroutput onDECLAREiscn NUMBER; -- Variable to hold instantiation SCN valueBEGINiscn := DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER();DBMS_OUTPUT.PUT_LINE ('Instantiation SCN is: ' || iscn);END;

Instantiate the objects at the destination database with this SCN value.The SET_TABLE_INSTANTIATION_SCN procedure controls which LCRs for a tableare to be applied by the apply process.If the commit SCN of an LCR from the source database is less than orequal to this instantiation SCN , then the apply process discards the LCR.Else, the apply process applies the LCR.

connect STRMADMIN/STRMADMIN@destinationBEGINDBMS_APPLY_ADM.SET_TABLE_INSTANTIATION_SCN(source_object_name => 'SCOTT.DEPT',source_database_name => 'V920.IDC.ORACLE.COM',instantiation_scn => &iscn);END;

Enter value for iscn:

Finally start the Capture Process:

The setup is now ready to replicate data between the two databases usingOracle Streams.

note:note:note:note:note:connect STRMADMIN/STRMADMIN@sourceBEGINDBMS_CAPTURE_ADM.START_CAPTURE(capture_name => 'STRMADMIN_CAPTURE');END;/