Implementation:Lance format Lance Java DeleteOp

Knowledge Sources	Lance
Domains	Java_SDK, Dataset_Management
Last Updated	2026-02-08 19:33 GMT

Overview

Description

The Delete class is an immutable operation that represents the deletion of rows from a Lance dataset. It implements the Operation interface and supports two complementary deletion mechanisms: updating fragment metadata to mark rows as deleted (soft delete via deletion bitmaps), and removing entire fragments when all their rows are deleted.

The operation records a SQL-like predicate string describing the deletion condition, a list of FragmentMetadata objects for fragments that were partially affected (updated with deletion vectors), and a list of fragment IDs for fragments that were entirely removed. All three fields default to empty values when not set.

Usage

Use Delete to remove rows matching a predicate from a Lance dataset. This is the standard row-level delete path. Fragments where only some rows match receive updated deletion vectors, while fragments where all rows match are recorded for full removal.

Code Reference

Source Location

java/src/main/java/org/lance/operation/Delete.java

Signature

public class Delete implements Operation {
    public static Builder builder();
    public List<FragmentMetadata> updatedFragments();
    public List<Long> deletedFragmentIds();
    public String predicate();
    public String name();  // returns "Delete"
}

Import

import org.lance.operation.Delete;

I/O Contract

Inputs

Parameter	Type	Required	Description
updatedFragments	List<FragmentMetadata>	No	Fragments with updated deletion vectors (defaults to empty)
deletedFragmentIds	List<Long>	No	IDs of fully deleted fragments (defaults to empty)
predicate	String	No	SQL filter expression describing which rows to delete (defaults to empty string)

Outputs

Return	Type	Description
updatedFragments()	List<FragmentMetadata>	Fragments that were partially affected with updated deletion bitmaps
deletedFragmentIds()	List<Long>	Fragment IDs for fragments entirely removed
predicate()	String	The deletion predicate expression
name()	String	Returns "Delete" for JNI dispatch

Usage Examples

// Delete rows matching a predicate
Delete deleteOp = Delete.builder()
    .predicate("age < 18")
    .updatedFragments(fragmentsWithDeletionVectors)
    .deletedFragmentIds(List.of(5L, 12L))
    .build();

String opName = deleteOp.name(); // "Delete"
String pred = deleteOp.predicate(); // "age < 18"

Related Pages

• Lance_format_Lance_Java_UpdateOp -- Updates specific rows or columns in the dataset
• Lance_format_Lance_Java_OverwriteOp -- Replaces the entire dataset content
• Lance_format_Lance_Java_AppendOp -- Adds new rows to the dataset