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<<Back to DB Administration Main Page REDO Opcode  Each change vector has an operation code. The operation code consists of a major number and a minor number. These OPCODES are the REDO OPCODES for what layer/action occurred. Actions within each layer can be located by locating the KCOCOMP() macro. This information is the OPCODE in the REDO VECTOR. Layer 1 : Transaction Control - KCOCOTCT               Opcode 1.1 : KTZ ForMaT block - KTZFMT           Opcode 1.2 : Transaction Z Redo Data Header - KTZRDH           Opcode 1.3 : KTZ Allocate Record Callback - KTZARC          Opcode 1.4 : KTZ REPlace record value - KTZREP          Opcode 1.5 : KTZ Undo for RePlace - KTZURP Layer 2 : Transaction Read -  KCOCOTRD ...

<<Back to DB Administration Main Page BYTES column value is greeter than MAXBYTES column in DBA_DATA_FILE table I come across a situation today where I extended a BIG FILE tablespace. After extension tried to verify the new size and got following result. SQL > SELECT file_id,         ROUND(bytes/1024/1024/1024) AS size_gb,         ROUND(maxbytes/1024/1024/1024) AS max_size_gb,         autoextensible,         increment_by,         status  FROM   dba_data_files  where TABLESPACE_NAME='DATA'  ORDER BY file_name    FILE_ID  SIZE_GB   MAX_SIZE_GB     AUT                INCREMENT_BY       STATUS ----------      ----------     -----------         ...

<<Back to Oracle DATAPUMP Main Page While performing import encountering error  ORA-39142 ORA-39001: invalid argument value ORA-39000: bad dump file specification ORA-39142: incompatible version number 4.2 in dump file "/u01/app/oracle/dump/TEST.dmp"  Cause: The issue is caused due to bug as mentioned in Metalink Doc ID 2422236.1. The source database is on higher patch level that target Workaround : Use parameter VERSION=12.1 while performing the export.

<<Back to DB Administration Main Page Database Redo Logs and Redo Log Buffer Pool In Detail This post is simply the continuation of  Oracle Database Architecture. In this post I will try to explore about Redo Logs. What are Redo Logs? Why are Redo Logs so Important? What Purpose they full fill? How oracle manages them etc etc.... If you have already gone through my previous Posts related to oracle database architecture you are good to proceed. It would be worth to review these posts in case you missed them. The link are here Oracle Database Architecture Overview Explain a  high level Architecture  Database Buffer Cache in Details Explains  how Buffer Cache works and how it is implemented Database Shared Pool in Detail Explains all you want to know about Shared Pool So let's get started before wasting any time What is Redo logs? Oracle Database records all the changes to the database in the form of Redo logs. Redo Logs resides in a memory...