1 © 2006 Julian Dyke Supplemental Logging Julian Dyke Independent Consultant juliandyke.com Web Version

© 2006 Julian Dyke juliandyke.com 2 Supplemental Logging

© 2006 Julian Dyke juliandyke.com 3 Supplemental Logging Example Redo Header Change Header KTU KDO Supplementary Header CREATE TABLE t1 ( c1 NUMBER, c2 NUMBER, c3 NUMBER ); ALTER TABLE t1 ADD CONSTRAINT t1_pk PRIMARY KEY (c1,c2); INSERT INTO t1 VALUES (100,20,1); UPDATE t1 SET c3 = 2 WHERE c1 = 100 AND c2 = 20; c3 = 1 c1 = 100 c2 = 20 KTU KDO c3 = 2 ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (PRIMARY KEY) COLUMNS;

© 2006 Julian Dyke juliandyke.com 4 Supplemental Logging Minimal Supplemental Logging  Required for LogMiner  Includes additional information in redo stream  Minimal supplemental logging can be enabled using: ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;  Minimal supplemental logging can be enabled using: ALTER DATABASE DROP SUPPLEMENTAL LOG DATA;

© 2006 Julian Dyke juliandyke.com 5 Supplemental Logging Minimal Supplemental Logging  To check whether minimal supplemental logging is enabled: SELECT supplemental_log_data_min FROM v$database;  Returns YES or IMPLICIT if enabled  Allows LogMiner to support  chained rows  clustered tables  index organized tables (IOTs)

© 2006 Julian Dyke juliandyke.com 6 Supplemental Logging Database Supplemental Logging  Can be enabled  For all columns  For primary key columns  For unique columns  For foreign key columns  All columns  All columns are included with the exception of:  LONG  LOB  LONG RAW  Abstract Data Types  Collections

© 2006 Julian Dyke juliandyke.com 7 Supplemental Logging Database Supplemental Logging  To enable supplemental logging at database level: ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (PRIMARY KEY) COLUMNS;  Database can be mounted and open ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (UNIQUE) COLUMNS; ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (FOREIGN KEY) COLUMNS; ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (ALL) COLUMNS;

© 2006 Julian Dyke juliandyke.com 8 Supplemental Logging Database Supplemental Logging  To disable supplemental logging at database level: ALTER DATABASE DROP SUPPLEMENTAL LOG DATA (PRIMARY KEY) COLUMNS; ALTER DATABASE DROP SUPPLEMENTAL LOG DATA (UNIQUE) COLUMNS; ALTER DATABASE DROP SUPPLEMENTAL LOG DATA (FOREIGN KEY) COLUMNS; ALTER DATABASE DROP SUPPLEMENTAL LOG DATA (ALL) COLUMNS;

© 2006 Julian Dyke juliandyke.com 9 Supplemental Logging Database Supplemental Logging  To monitor database level supplemental logging: SELECT supplemental_log_data_min, supplemental_log_data_pk, supplemental_log_data_ui, supplemental_log_data_fk, supplemental_log_data_all FROM v$database;

© 2006 Julian Dyke juliandyke.com 10 Supplemental Logging Log Groups  Implemented as constraints  If no name specified for log group then system constraint name will be allocated e.g SYS_C  Can be  Unconditional  Before image of supplemental columns always included in redo  Conditional  Before image of supplemental columns only included in redo if supplemental columns have changed  In Oracle 10.2, minimal supplemental logging must be enabled at database level before supplemental logging can be enabled at table level

© 2006 Julian Dyke juliandyke.com 11 Supplemental Logging Unconditional Supplemental Log Groups  To specify an unconditional supplemental log group for primary key column(s): ALTER TABLE t1 ADD SUPPLEMENTAL LOG DATA (PRIMARY KEY) COLUMNS;  To specify an unconditional supplemental log group that includes all table columns: ALTER TABLE t1 ADD SUPPLEMENTAL LOG DATA (ALL) COLUMNS;  To specify an unconditional supplemental log group that includes selected columns: ALTER TABLE t1 ADD SUPPLEMENTAL LOG GROUP t1_g1 (c1,c3) ALWAYS;

© 2006 Julian Dyke juliandyke.com 12 Supplemental Logging Conditional Supplemental Log Groups  To specify a conditional supplemental log group for unique key column(s) and/or bitmap index column(s): ALTER TABLE t1 ADD SUPPLEMENTAL LOG DATA (UNIQUE) COLUMNS;  To specify a conditional supplemental log group that includes all foreign key columns: ALTER TABLE t1 ADD SUPPLEMENTAL LOG DATA (FOREIGN KEY) COLUMNS;  To specify a conditional supplemental log group that includes selected columns: ALTER TABLE t1 ADD SUPPLEMENTAL LOG GROUP t1_g1 (c1,c3);

© 2006 Julian Dyke juliandyke.com 13 Supplemental Logging Dropping Supplemental Log Groups  To drop a supplemental log group: ALTER TABLE t1 DROP SUPPLEMENTAL LOG GROUP t1_g1;  To drop supplemental logging of data use: ALTER TABLE t1 DROP SUPPLEMENTAL LOG DATA (ALL) COLUMNS; ALTER TABLE t1 DROP SUPPLEMENTAL LOG DATA (PRIMARY KEY) COLUMNS; ALTER TABLE t1 DROP SUPPLEMENTAL LOG DATA (UNIQUE) COLUMNS; ALTER TABLE t1 DROP SUPPLEMENTAL LOG DATA (FOREIGN KEY) COLUMNS;

© 2006 Julian Dyke juliandyke.com 14 Supplemental Logging DBA_LOG_GROUPS view  Describes currently configured supplemental log groups: OWNERVARCHAR2(30) LOG_GROUP_NAMEVARCHAR2(30) TABLE_NAMEVARCHAR2(30) LOG_GROUP_TYPEVARCHAR2(19) ALWAYSVARCHAR2(11) GENERATEDVARCHAR2(14)  LOG_GROUP_TYPE can be:  PRIMARY KEY LOGGING  UNIQUE KEY LOGGING  FOREIGN KEY LOGGING  ALL COLUMN LOGGING  USER LOG GROUP  ALWAYS can be:  ALWAYS  CONDITIONAL  GENERATED can be  GENERATED NAME  USER NAME

© 2006 Julian Dyke juliandyke.com 15 Supplemental Logging DBA_LOG_GROUP_COLUMNS view  Describes columns in currently configured supplemental log groups: OWNERVARCHAR2(30) LOG_GROUP_NAMEVARCHAR2(30) TABLE_NAMEVARCHAR2(30) COLUMN_NAMEVARCHAR2(4000) POSITIONNUMBER LOGGING_PROPERTYVARCHAR2(6)  LOGGING_PROPERTY can be:  LOG  NO_LOG  Only applies to log groups (not log data) configurations

© 2006 Julian Dyke juliandyke.com 16 Thank you for your interest