Getting an error on creating an Index in SAP HANA

When you encounter the error message "column already indexed" while creating an index in SAP HANA, it indicates that an index already exists on that column. This is a common issue that occurs when you try to create duplicate indexes.

Understanding Automatic Index Creation

SAP HANA automatically creates indexes on columns with specific data types. If the data type of your column is TEXT, HANA creates an index on it by default. This automatic indexing helps optimize text searches and queries.

Solution: Change Data Type to BLOB

For better performance and to avoid the indexing conflict, you can change the data type of the column from TEXT to BLOB. Here's why this works ?

BLOB ? Stores large amounts of binary data without automatic index creation, giving you more control over indexing strategies.

Steps to Resolve

Follow these steps to fix the index creation error ?

-- Check existing indexes on the table
SELECT * FROM SYS.INDEXES WHERE TABLE_NAME = 'YOUR_TABLE_NAME';

-- Alter column data type from TEXT to BLOB
ALTER TABLE YOUR_TABLE_NAME ALTER (COLUMN_NAME BLOB);

-- Now create your custom index if needed
CREATE INDEX YOUR_INDEX_NAME ON YOUR_TABLE_NAME (COLUMN_NAME);

Alternative Approach

If you need to keep the TEXT data type, you can work with the existing index instead of creating a new one. Check the current index properties and determine if it meets your performance requirements.

-- View index details
SELECT INDEX_NAME, COLUMN_NAME, INDEX_TYPE 
FROM SYS.INDEX_COLUMNS 
WHERE TABLE_NAME = 'YOUR_TABLE_NAME';

Conclusion

The "column already indexed" error occurs because SAP HANA automatically creates indexes on TEXT columns. Converting to BLOB data type or working with existing indexes resolves this issue effectively.