If you're a database administrator, you must have faced the headache-inducing partition unusable error. To give a more technical description, the error occurs when an attempted DML operation, such as an insert or an update, fails due to an Oracle error ORA-14402 (or "Partition Unusable"). Learning how to fix this error and tackle the issue can be quite tricky. But fear not, we’ve got all the tools and techniques that you need to sort out this issue in a jiffy.
What is partition unusable?
Partition unusable is an Oracle database error that occurs when a DML statement fails due to an index not being able to find or access a certain partition in the database. It is generally caused when the index sub-partition has split or became unusable due to data mismanagement. The Oracle error number for this error is ORA-14402 and can be seen as follows in the alert log:
ORA-14402: partition change request already used.
Steps to fix the partition unusable error
Analyse the Index: The first step to troubleshoot the unusable index is to analyze the index, and determine the cause of the issue. Use Oracle's data dictionary to get index's information and metadata. Once identified, execute the SQL statement ANALYZE INDEXVALIDATE STRUCTURE to check the information related to each index partition.
Ensure index is usable: To make sure it is usable, execute the SQL statement ALTER INDEXINDEXNAME REBUILD UNUSABLE. This will ensure that the data can be read from the index by verifying its data blocks.
Drop the index partition: If the unusable index is causing performance issues, it is advised to drop the index either from the GUI or by issuing the SQL statement ALTER INDEXINDEXNAME DROP PARTITION DROP PARTITION PARTITIONNAME.
Rebuild the index partition: Once the index partition has been dropped, the next step is to rebuild the index with the SQL statement ALTER INDEXINDEXNAME REBUILD PARTITION PARTITIONNAME TABLESPACE NEWTABLESPACENAME;.
Recreate the index partition: To recreate the index, execute the SQL statement ALTER INDEXINDEXNAME ADD PARTITIONPARTITIONNAME TABLESPACE NEWTABLESPACENAME;.
Validate the index structure: To make sure the index is functioning properly, execute once again the SQL statement ANALYZE INDEX VALIDATE STRUCTURE;
These are the basic steps required to prepare and fix the partition unusable error. It is important to follow the above steps carefully and ensure the index is properly rebuilt in order to avoid any further issues.
FAQ
Q. What is Partition Unusable error?
A. Partition Unusable is an Oracle database error that occurs when a DML statement fails due to an index not being able to find or access a certain partition in the database. It is generally caused when the index sub-partition has split or became unusable due to data mismanagement.
Q. How do I fix partition unusable error?
A. First, analyze the index and determine the cause of the issue. Then, ensure the index is usable by executing SQL statement ANALYZE INDEXVALIDATE STRUCTURE. Drop the index partition, either from the GUI or by running a SQL statement. Rebuild the index partition with a SQL statement, and then recreate the index with a SQL statement. Finally, validate the index structure with another SQL statement ANALYZE INDEX VALIDATE STRUCTURE;.
Q. What is the Oracle error number for the partition unusable error?
A. The Oracle error number for the partition unusable error is ORA-14402, and can be seen in the alert log.
Q. What is the SQL statement to rebuild the index partition?
A. The SQL statement to rebuild the index PARTITION is ALTER INDEXINDEXNAME REBUILD PARTITION PARTITIONNAME TABLESPACE NEWTABLESPACENAME;.
Q. What is the SQL statement to analyze and validate the index structure?
A. The SQL statement to analyze and validate the index structure is ANALYZE INDEX VALIDATE STRUCTURE;.