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Sahil Walia on Apache Iceberg

Published 3 Sept 2026

Duration: 51:27

"Apache Iceberg is a scalable, interoperable data framework that unifies OLTP and OLAP workloads, separates storage and compute, and enables efficient metadata-driven operations, governance, and cost savings across industries."

Episode Description

Sahil Walia, Senior Technical Architect at Snowflake, joins host Robert Blumen for a deep dive into Apache Iceberg. The conversation covers OLAP, data...

Overview

The podcast discusses Apache Iceberg, an open table format designed for managing large-scale data in data lakehouse environments. It explains the distinction between OLTP and OLAP workloads, and compares data warehouses, data lakes, and lakehouses - positioning the lakehouse as a structured yet scalable system that combines the benefits of both. The discussion highlights how Iceberg addresses limitations of traditional data lakes by introducing transactional guarantees, schema enforcement, and efficient metadata management, enabling interoperability across multiple compute engines like Spark, Snowflake, and Trino.

Key technical aspects covered include Iceberg's three-layer metadata architecture (catalog, manifest list, and manifest files), which enables fast query performance through pruning and predicate pushdown. The format supports time travel queries for accessing historical data states, aiding in debugging and compliance with regulations like GDPR. Iceberg optimizes read operations using columnar storage (e.g., Parquet) and offers two update strategies: copy-on-write and merge-on-read. It ensures atomicity and isolation during reads and writes using snapshot-based updates and compare-and-swap mechanisms, while also supporting features such as data compaction, snapshot expiration, and cross-engine governance. The podcast underscores Iceberg's role in reducing vendor lock-in, enabling unified data access across clouds, and its growing adoption in AI and analytics workflows.

What If

  • What if you built a personal data product using open lakehouse architecture?

    • Move: Set up an Apache Iceberg table in AWS S3 (or any cloud storage) using a serverless query engine like Trino or Spark, and connect it to your application logs or user behavior data. Use Python or SQL to ingest and query the data.
    • Why Now?: Cloud storage costs are low (~$0.23/TB/month on S3), Iceberg's open spec eliminates vendor lock-in, and engines like Databricks/Snowflake now support it natively - making interoperability seamless for solo developers.
    • Expected Upside: You gain full control over scalable analytics without infrastructure overhead; enable time-travel debugging, GDPR-compliant deletion proofs, and future AI/ML integration - all from a single source of truth.
  • What if you offered data versioning as a service for indie hackers?

    • Move: Build a lightweight API that wraps Iceberg's snapshot and time-travel features, allowing users to version their datasets with AS OF TIMESTAMP queries. Host it on a VPS or edge runtime (e.g., Fly.io) with PostgreSQL-backed metadata catalog.
    • Why Now?: With rising demand for reproducible data workflows in AI and analytics, and Iceberg's REST Catalog enabling HTTP-based access, now is the time to offer simple, self-serve data versioning for non-enterprise users.
    • Expected Upside: Monetize via usage tiers; attract developers needing rollback safety, audit trails, or A/B testing on data - differentiating from basic CSV hosting with real-time governance and recovery.
  • What if you automated compliance for micro-SaaS apps using Iceberg's delete auditing?

    • Move: Integrate Iceberg into your app's backend to log all record deletions via timestamped snapshots. When a user requests data erasure (GDPR "right to be forgotten"), run a soft-delete followed by physical file compaction, then generate a certificate showing deletion proof using snapshot diffs.
    • Why Now?: Iceberg's ability to track historical states and demonstrate when data was removed meets growing regulatory expectations - even for small operators - who can now prove compliance without complex tooling.
    • Expected Upside: Reduce legal risk, build trust with enterprise customers, and use compliance as a marketing differentiator - turning operational rigor into a customer-facing feature.

Takeaway

  • Implement Apache Iceberg in your data stack to enable interoperability across multiple compute engines (e.g., Spark, Snowflake) using low-cost cloud storage like S3, reducing vendor lock-in and duplication of data.

  • Design analytical workloads using rich metadata and predicate pushdown in Iceberg to minimize I/O by reading only relevant files and blocks, significantly improving query performance on large datasets.

  • Leverage time travel queries (via AS OF timestamp or VERSION AS OF) to debug data errors, recover from accidental deletions, and support compliance requirements like GDPR audits without custom backup systems.

  • Use copy-on-write or merge-on-read strategies based on workload: apply copy-on-write for read-heavy analytics where fresh data consistency is key, and merge-on-read for frequent small updates to avoid full file rewrites.

  • Integrate a REST Catalog with your Iceberg tables to standardize metadata access over HTTP, enabling secure, centralized governance and cross-engine collaboration (e.g., Spark writes, Snowflake reads) in a solo-operated environment.

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