---
title: "Why You Should Prefer MERGE INTO Over INSERT OVERWRITE in Apache Iceberg"
url: https://daily.dev/posts/why-you-should-prefer-merge-into-over-insert-overwrite-in-apache-iceberg-ejy35u8s5
source_url: https://medium.com/expedia-group-tech/why-you-should-prefer-merge-into-over-insert-overwrite-in-apache-iceberg-b6b130cc27d2
type: article
source: "Expedia Group Tech"
published: 2025-10-01T04:51:53.547Z
updated: 2025-10-01T04:52:16.081Z
tags: ["aws", "performance", "sql", "data-engineering", "apache-iceberg"]
reading_time: 8
upvotes: 1
comments: 0
language: en
---

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# Why You Should Prefer MERGE INTO Over INSERT OVERWRITE in Apache Iceberg

**[Expedia Group Tech](https://daily.dev/sources/expedia)** · 8 min read · 1 upvotes · 0 comments

## Summary

Apache Iceberg's MERGE INTO with Merge-on-Read strategy provides significant advantages over INSERT OVERWRITE for data lake operations. MERGE INTO offers up to 66% cost savings by only modifying affected rows rather than rewriting entire partitions, reduces I/O operations, and handles partition evolution more gracefully. The approach is particularly effective for incremental loads, CDC, and slowly changing dimensions, though proper compaction maintenance is essential for long-term performance.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://medium.com/expedia-group-tech/why-you-should-prefer-merge-into-over-insert-overwrite-in-apache-iceberg-b6b130cc27d2>

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---

Tags: [#aws](https://daily.dev/tags/aws), [#performance](https://daily.dev/tags/performance), [#sql](https://daily.dev/tags/sql), [#data-engineering](https://daily.dev/tags/data-engineering), [#apache-iceberg](https://daily.dev/tags/apache-iceberg)

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