Open Table Formatにおけるストレージ抽象化の比較

Open Table Format (OTF) は多種多様な分散ファイルシステムやオブジェクトストレージに対応しています。これらのストレージにはそれぞれ独自のAPIやSDKが用意されていますが、それらを最適な形で個別に使い分けるため、Apache Iceberg、Apache Hudi、Delta Lake、Apache Paimonはそれぞれどのようにストレージ層を抽象化しているか説明します。

1. © LY Corporation Open Table Formatにおける ストレージ抽象化の⽐較 2026-02-13 Open Table Formats Study Group Tokyo #5 Akira Ajisaka
2. © LY Corporation Todayʼs Agenda 2 How? Azure Data Lake Storage Gen2 https://iceberg.apache.org/spec/#overview Hadoop HDFS Apache Ozone Amazon S3 Google Cloud Storage
3. © LY Corporation 3 Before OTF era… Hadoop FileSystem API is the abstraction layer Hadoop FileSystem API Azure Data Lake Storage Gen2 ・・・・ hdfs:// webhdfs:// ofs:// s3a:// gs:// abfs:// Hadoop MapReduce Hadoop HDFS Apache Ozone Amazon S3 Google Cloud Storage Apache Tez Apache Spark
4. © LY Corporation 4 Before OTF era… Hadoop FileSystem API is the abstraction layer Hadoop FileSystem API Azure Data Lake Storage Gen2 ・・・・ Distributed FileSystem WebHDFS FileSystem Ozone FileSystem S3A FileSystem GoogleHadoop FileSystem AzureBlob FileSystem Hadoop MapReduce Hadoop HDFS Apache Ozone Amazon S3 Google Cloud Storage Apache Tez Apache Spark
5. © LY Corporation 5 Abstraction in OTF Apache Hudi, Delta Lake, and Apache Paimon leverage Hadoop FileSystem API Hadoop FileSystem API Azure Data Lake Storage Gen2 ・・・・ Delta LogStore Paimon FileIO Apache Hudi Delta Lake Apache Paimon Hadoop HDFS Apache Ozone Amazon S3 Google Cloud Storage
6. © LY Corporation Hudi storage schemes (name, isWriteTransactional, supportAtomicCreation, storageLockClass) isWriteTransactional • If true, skip block corrupt check Atomic writes • If supportAtomicCreation is true, FileSystemLockProvider can be used • If storageLockClass is true, StorageBasedLockProvider can be used • Otherwise, coordinator (such as ZooKeeper, DynamoDB) is required
7. © LY Corporation FileSystem-specific implementations in Hudi Custom seek handling for GCS Custom EOF handling for Tencent CHDFS (Cloud HDFS) https://github.com/apache/hudi/blob/63275b32fdead4da9fdd4235fd540d80f46ea7ea/hudi-hadoop-common/sr c/main/java/org/apache/hudi/hadoop/fs/HadoopFSUtils.java#L230
8. © LY Corporation Delta Lake LogStore https://github.com/delta-io/delta/blob/2068a5bd7fd5b5a0cc9a5130822d7b586742c257/kernel/kernel-defaults/ src/main/java/io/delta/kernel/defaults/internal/logstore/LogStoreProvider.java#L67
9. © LY Corporation HDFS-specific implementation in Delta Call msync API for HDFS • HDFS with Observer NameNode setup is read-after-write consistency https://github.com/delta-io/delta/pull/769
10. © LY Corporation S3-specific implementation in Delta Use S3AFileSystem internal API if available • Use startAfter parameter in S3 ListObjectV2 API https://github.com/delta-io/delta/pull/1210
11. © LY Corporation GCS-specific implementation in Delta Use a separate thread to write to GCS • Avoid incomplete file due to thread interruption https://github.com/delta-io/delta/pull/782
12. © LY Corporation Apache Paimon Former Apache Flink Table Store • https://cwiki.apache.org/confluence/display/FLINK/FLIP-188%3A+Introduce+B uilt-in+Dynamic+Table+Storage File Layouts • LSM-tree (Log-Structured Merge-tree) for faster updates/deletes https://paimon.apache.org/docs/1.1/concepts/basic-concepts/
13. © LY Corporation Paimon FileIO interface isObjectStore() • If true, rename is not atomic and external lock is required to commit snapshots newTwoPhaseOutputStream(Path, boolean) • Default: Create a temp file and rename it • S3, Alibaba Cloud Object Storage Service (OSS): Multipart upload and commit https://github.com/apache/paimon/pull/6287
14. © LY Corporation Abstraction in Iceberg Hadoop FileSystem API Iceberg FileIO S3FileIO GCSFileIO Azure Data Lake Storage Gen2 ・・・・ ADLSFileIO HadoopFileIO Apache Iceberg has its own abstraction layer Apache Iceberg Amazon S3 Google Cloud Storage
15. © LY Corporation Iceberg FileIO history • 2018: File I/O Submodule for TableOperation ◦ FileIO interface ▪ newInputFile ▪ newOutputFile ▪ deleteFile • 2022: Add interface for FileIO prefix operations and implementations ◦ SupportsPrefixOperation interface ▪ listPrefix ▪ deletePrefix • 2022: Add SupportBulkOperation interface ◦ SupportsBulkOperation interface ▪ deleteFiles ◦ Used in expire snapshots and remove orphan files ◦ 2 years earlier than BulkDelete in Hadoop FileSystem API
16. © LY Corporation Optimize multi-object deletion in S3 • Before ◦ Call DeleteObject API for each file • After ◦ Call DeleteObjects API for each batch
17. © LY Corporation Summary • Introduce storage abstraction layer and their differences among OTFs • Dive-deep into storage-specific implementations and optimizations ◦ This presentation does not cover all of them ◦ You can go further by reading source code or let AI to do ▪ Example: “Read the source code, please teach me FileIO in Paimon and its implementation, especially please teach me any specific implementation for a specific storage.” • Improvements in an OTF can be ported to other OTFs?
18. © LY Corporation References • HadoopのファイルシステムAPI⼊⾨
19. © LY Corporation