DROP BLOOM FILTER INDEX

Removes bloom filter indexes from a Delta table.

Category: indexingDeltaForge extension

Syntax

DROP BLOOM FILTER INDEX ON TABLE <table> [FOR COLUMNS (<columns>)]

Description

## Overview Removes bloom filter index definitions from a Delta table. When columns are specified, only those column indexes are removed. When no columns are specified, all bloom filter indexes on the table are dropped. ## Behavior - Dropping a bloom filter index removes the index definition from the table metadata. - Existing bloom filter data in previously written files is not immediately cleaned up. It becomes orphaned metadata that is ignored during query planning. - Subsequent write and OPTIMIZE operations will no longer generate bloom filter data for the dropped columns. - The operation is metadata-only and completes immediately without scanning data files. - If FOR COLUMNS is omitted, all bloom filter indexes on the table are removed in a single operation. ## Access Control No specific privilege required beyond table-level access. ## Compatibility DROP BLOOM FILTER INDEX is a DeltaForge extension.

Parameters

Name	Type	Description
`table`		Specifies the Delta table from which to remove bloom filter indexes.
`columns`		Specifies the columns whose bloom filter indexes should be removed. If omitted, all bloom filter indexes on the table are removed.

Examples

-- Remove all bloom filter indexes from a table
DROP BLOOM FILTER INDEX ON TABLE orders;

-- Remove bloom filter indexes for specific columns
DROP BLOOM FILTER INDEX ON TABLE orders FOR COLUMNS (txn_id);

-- Remove bloom filters from multiple columns
DROP BLOOM FILTER INDEX ON TABLE events FOR COLUMNS (session_id, event_type);

Pitfalls

Dropping a bloom filter index does not remove existing bloom filter data from previously written files. The orphaned metadata is simply ignored. Run OPTIMIZE after dropping to clean up.
Omitting the FOR COLUMNS clause removes all bloom filter indexes on the table, not just a specific column. Use FOR COLUMNS to selectively remove indexes.