Oracle Streams: Step by Step

Transcription

1 Oracle Streams: Step by Step What is Oracle Streams? What is Advanced Queues (AQ)? What is Change Data Capture (CDC)? What is a Logical Change Record (LCR)? How Streams Works How do you configure Streams, AQ and CDC? How do you use Streams in your programs? Adding records automatically Adding record programmatically Pulling records off the queue

2 Who am I Lewis R Cunningham Oracle ACE Certified PL/SQL Developer Author Blogger Database Geek Member of SOUG, IOUG, ODTUG, ACM

3 What is Oracle Streams? Streams enables data and event movement Movement may be within or between databases Can implement replication Data and events can be captured explicitly: programatically Implicitly: redo log Performant Log mining reduces overhead Downstreams mining reduces it even more

4 What is Oracle Streams?, cont'd Streams Features Distinct capture/propagation/apply services Message Queueing (via AQ) Publish Subscribe Rules based Capture/Transform/Apply Database integration Easy configuration Flexible Inline transformations

5 What is Oracle AQ? Oracle's messaging solution Queue based Persistent queues protect data Buffered, non-persistent queues offer maximum performance Oracle provides all of the maintenance code Secure Queue Level Access Control Messages Types Raw XML Object Anydata

6 What is Oracle AQ?, cont'd Publish/Subscribe Multi-consumer Multi-message types RAC integration API support OCI (C), OCCI (C++) Java JMS PL/SQL OO40 (COM) Internet Data Access (IDAP) ODBC via Heterogeneous Gateways

7 What is Change Data Capture? CDC efficiently identifies changed data and make it available for downstrean use CDC enables efficient warehouse loading No flat files Direct data movement Changes are queued Multiple subscribers are allowed Subscribers can receive changed data Data may be transformed Changes can include DDL and DML

8 What is an LCR? LCR = Logical Change Record Committed records generate an LCR to the redo log An LCR shows the difference between an existing record and the new record For DDL, the record is a database object For DML, the record is table data

9 What is an LCR?

10 How it works Source Database Target Database Table 10

11 Data Changes Source Database Target Database Table Data Manipulation Log Writer 11

12 DB Writes to OS File Source Database Target Database Table Log Writer Writes To REDO LOG 12

13 Streams Takes Over Source Database Target Database Table Log Writer REDO LOG Capture Process Reads Redo and Extracts the Logical Change Record (LCR) Streams Capture 13

14 Streams Queues The LCR Source Database Target Database Table Streams Queue Log Writer REDO LOG Streams Capture Streams Capture Process writes the LCR to a local OR REMOTE Streams Queue Table 14

15 LCR Propagates Source Database Target Database Table Streams Queue Streams Queue Log Writer REDO LOG Streams Capture Streams Capture Process writes the LCR to a local OR REMOTE Streams Queue Table 15

16 Changes Are Applied Source Database Target Database Table Streams Queue Streams Queue Log Writer REDO LOG Streams Capture Streams Apply Streams Apply can also transform for one record to many, add columns, etc. Streams Capture Process writes the LCR to a local OR REMOTE Streams Queue Table 16

17 Target Database Source Database Target Database Table Streams Queue Streams Queue Table Log Writer Table REDO LOG Streams Capture Streams Apply Table Streams Capture Process writes the LCR to a local OR REMOTE Streams Queue Table Oracle Streams Overview - US IFS 17

18 The Scenario Capture changes to the Employee table in 10g ORCL instance) Send changes to Employee_audit in 9i (SECOND instance) We will start with capture and apply in 10g Once the capture and apply is working, we will modify the stream to send the data to 9i

19 We need to create the Admin user and streams tablespace sqlplus / as sysdba create tablespace streams_tbs datafile 'c:\temp\stream_tbs.dbf' size 25M reuse autoextend on maxsize unlimited; create user strmadmin identified by strmadmin default tablespace streams_tbs quota unlimited on streams_tbs;

20 We need to grant the appropriate permissions grant dba to strmadmin; BEGIN DBMS_STREAMS_AUTH.GRANT_ADMIN_PRIVILEGE( grantee => 'strmadmin', grant_privileges => true); END; / conn hr/hr grant all on hr.employees to strmadmin;

21 Create the Audit Table CREATE TABLE employee_audit( employee_id NUMBER(6), first_name VARCHAR2(20), last_name VARCHAR2(25), VARCHAR2(25), phone_number VARCHAR2(20), hire_date DATE, job_id VARCHAR2(10), salary NUMBER(8,2), commission_pct NUMBER(2,2), manager_id NUMBER(6), department_id NUMBER(4), upd_date DATE, user_name VARCHAR2(30), action VARCHAR2(30));

22 Grant read on the audit table to the admin user grant all on hr.employee_audit to strmadmin; Connect as the streams admin user and create a monitor table conn strmadmin/strmadmin CREATE TABLE streams_monitor ( date_and_time TIMESTAMP(6) DEFAULT systimestamp, txt_msg CLOB );

23 Create the CDC queue BEGIN DBMS_STREAMS_ADM.SET_UP_QUEUE( queue_table => 'strmadmin.streams_queue_table', queue_name => 'strmadmin.streams_queue'); END; /

24 Create capture rules BEGIN DBMS_STREAMS_ADM.ADD_TABLE_RULES( table_name => 'hr.employees', streams_type => 'capture', streams_name => 'capture_emp', queue_name => 'strmadmin.streams_queue', include_dml => true, include_ddl => false, inclusion_rule => true); END; /

25 Add extra attributes BEGIN DBMS_CAPTURE_ADM.INCLUDE_EXTRA_ATTRI BUTE( capture_name => 'capture_emp', attribute_name => 'username', include => true); END; /

26 Mark redo entry as starting point (SCN) DECLARE iscn NUMBER; BEGIN iscn := DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER(); DBMS_APPLY_ADM.SET_TABLE_INSTANTIATION_SCN ( source_object_name => 'hr.employees', source_database_name => 'ORCL', END; / instantiation_scn => iscn);

27 Create DML Handler Proc CREATE OR REPLACE PROCEDURE emp_dml_handler(in_any IN ANYDATA) IS lcr SYS.LCR$_ROW_RECORD; rc PLS_INTEGER; command VARCHAR2(30); old_values SYS.LCR$_ROW_LIST; BEGIN -- Access the LCR rc := in_any.getobject(lcr); -- Get the object command type command := lcr.get_command_type(); -- I am inserting the XML equivalent of the LCR into the monitoring table. insert into streams_monitor (txt_msg) values (command DBMS_STREAMS.CONVERT_LCR_TO_XML(in_any) );

28 Create DML Handler (cont'd) -- Set the command_type in the row LCR to INSERT lcr.set_command_type('insert'); -- Set the object_name in the row LCR to EMP_DEL lcr.set_object_name('employee_audit'); -- Set the new values to the old values for update and delete IF command IN ('DELETE', 'UPDATE') THEN -- Get the old values in the row LCR old_values := lcr.get_values('old'); -- Set the old values in the row LCR to the new values in the row LCR lcr.set_values('new', old_values); -- Set the old values in the row LCR to NULL lcr.set_values('old', NULL); END IF;

29 Create DML Handler (cont'd) -- Add a SYSDATE for upd_date lcr.add_column('new', 'UPD_DATE', ANYDATA.ConvertDate(SYSDATE)); -- Add a user column lcr.add_column('new', 'user_name', lcr.get_extra_attribute('username') ); -- Add an action column lcr.add_column('new', 'ACTION', ANYDATA.ConvertVarChar2(command)); -- Make the changes lcr.execute(true); commit; END; /

30 Register DML Handler BEGIN DBMS_APPLY_ADM.SET_DML_HANDLER( object_name => 'hr.employees', object_type => 'TABLE', operation_name => 'INSERT', error_handler => false, user_procedure => 'strmadmin.emp_dml_handler', apply_database_link => NULL, END; / apply_name => NULL); Do the exact same for update and delete.

31 Create the apply rule DECLARE emp_rule_name_dml VARCHAR2(30); emp_rule_name_ddl VARCHAR2(30); BEGIN DBMS_STREAMS_ADM.ADD_TABLE_RULES( table_name => 'hr.employees', streams_type => 'apply', streams_name => 'apply_emp', queue_name => 'strmadmin.streams_queue', include_dml => true, include_ddl => false, source_database => 'ORCL', dml_rule_name => emp_rule_name_dml, ddl_rule_name => emp_rule_name_ddl); DBMS_APPLY_ADM.SET_ENQUEUE_DESTINATION( rule_name => emp_rule_name_dml, destination_queue_name => 'strmadmin.streams_queue'); END; /

32 Turn off disable on error, start the apply and capture processes BEGIN DBMS_APPLY_ADM.SET_PARAMETER( apply_name => 'apply_emp', parameter => 'disable_on_error', value => 'n'); END; / BEGIN DBMS_APPLY_ADM.START_APPLY( apply_name => 'apply_emp'); END; / BEGIN DBMS_CAPTURE_ADM.START_CAPTURE( capture_name => 'capture_emp'); END; /

33 Test Insert a record into hr.employees Select from hr.employee_audit to see audit records Select from streams_monitor to see LCR information

34 Configure 9i instance (SECOND) sqlplus / as sysdba create tablespace streams_second_tbs datafile 'c:\temp\stream_2_tbs.dbf' size 25M reuse autoextend on maxsize unlimited; create user strmadmin identified by strmadmin default tablespace streams_second_tbs quota unlimited on streams_second_tbs; grant dba to strmadmin;

35 Create the Audit Table in the 9i instance CREATE TABLE employee_audit( employee_id NUMBER(6), first_name VARCHAR2(20), last_name VARCHAR2(25), VARCHAR2(25), phone_number VARCHAR2(20), hire_date DATE, job_id VARCHAR2(10), salary NUMBER(8,2), commission_pct NUMBER(2,2), manager_id NUMBER(6), department_id NUMBER(4), upd_date DATE, user_name VARCHAR2(30), action VARCHAR2(30));

36 Create the AQ queue in SECOND BEGIN DBMS_AQADM.CREATE_QUEUE_TABLE( queue_table => 'lrc_emp_t', queue_payload_type => 'sys.anydata', multiple_consumers => TRUE, compatible => '8.1'); DBMS_AQADM.CREATE_QUEUE( queue_name => 'lrc_emp_q', queue_table => 'lrc_emp_t'); DBMS_AQADM.START_QUEUE ( queue_name => 'lrc_emp_q'); END; /

37 Create a link from SECOND to ORCL CREATE DATABASE LINK orcl.world CONNECT TO strmadmin IDENTIFIED BY strmadmin USING 'orcl.world'; Create a link from ORCL to SECOND CREATE DATABASE LINK second.world CONNECT TO strmadmin IDENTIFIED BY strmadmin USING 'second.world';

38 In 10g (ORCL), as strmadmin, create a propagation schedule for the captured data BEGIN DBMS_STREAMS_ADM.ADD_TABLE_PROPAGATION_RULES( table_name => 'hr.employees', streams_name => 'orcl_2_second', source_queue_name => 'strmadmin.lrc_emp_q', destination_queue_name => 'strmadmin.lrc_emp_q@second.world', include_dml => true, include_ddl => FALSE, source_database => 'orcl.world'); END; /

39 Modify the DML Handler Proc (add this just before the lcr.execute procedure). DECLARE enqueue_options DBMS_AQ.enqueue_options_t; message_properties DBMS_AQ.message_properties_t; message_handle RAW(16); recipients DBMS_AQ.aq$_recipient_list_t; BEGIN recipients(1) := sys.aq$_agent( 'anydata_subscriber', NULL); message_properties.recipient_list := recipients;

40 Modify the DML Handler Proc (in 10g) DBMS_AQ.ENQUEUE( queue_name => 'strmadmin.lrc_emp_q', enqueue_options message_properties => message_properties, payload => anydata.convertobject(lcr), => enqueue_options, msgid EXCEPTION WHEN OTHERS THEN insert into streams_monitor (txt_msg) values ('Anydata: ' DBMS_UTILITY.FORMAT_ERROR_STACK ); END; => message_handle);

41 Create a DEQUEUE proc in 9i CREATE OR REPLACE PROCEDURE emp_dq (consumer IN VARCHAR2) AS msg ANYDATA; row_lcr SYS.LCR$_ROW_RECORD; num_var pls_integer; more_messages BOOLEAN := true; navigation VARCHAR2(30); BEGIN navigation := 'FIRST MESSAGE'; WHILE (more_messages) LOOP DBMS_OUTPUT.PUT_LINE('Looping thru messages'); BEGIN DBMS_STREAMS_MESSAGING.DEQUEUE( queue_name => 'strmadmin.streams_queue', streams_name => consumer, payload => msg, navigation => navigation, wait => DBMS_STREAMS_MESSAGING.NO_WAIT);

42 Create a DEQUEUE proc in 9i IF msg.gettypename() = 'SYS.LCR$_ROW_RECORD' THEN num_var := msg.getobject(row_lcr); DBMS_OUTPUT.PUT_LINE(row_lcr.GET_COMMAND_TYPE ' row LCR dequeued'); END IF; navigation := 'NEXT MESSAGE'; COMMIT; EXCEPTION WHEN SYS.DBMS_STREAMS_MESSAGING.ENDOFCURTRANS THEN navigation := 'NEXT TRANSACTION'; WHEN DBMS_STREAMS_MESSAGING.NOMOREMSGS THEN more_messages := false; DBMS_OUTPUT.PUT_LINE('No more messages.'); WHEN OTHERS THEN RAISE; END; END LOOP; END; /

43 Test Insert a record into hr.employees@orcl Run emp_dq@second Select from hr.employee_audit@second to see audit records

44 Summary Oracle Streams: As easy as it gets! Flexible, performant, easy Follow items are AnyData XMLType Queues Read my blog An Expert's Guide to Oracle Technology