> ## Documentation Index > Fetch the complete documentation index at: https://docs.risingwave.com/llms.txt > Use this file to discover all available pages before exploring further. # Iceberg feature support > Current support matrix for Apache Iceberg sources, sinks, internal tables, catalogs, storage, and maintenance in RisingWave. RisingWave supports Apache Iceberg in three main workflows: * **Read external Iceberg tables** with `CREATE SOURCE`, ad hoc queries, materialized views, or refreshable `CREATE TABLE`. * **Write to external Iceberg tables** with `CREATE SINK`. * **Create internal Iceberg tables** with `CREATE TABLE ... ENGINE = iceberg`, where RisingWave manages the table lifecycle and stores data in Iceberg format. This page summarizes the current feature support. For syntax and examples, follow the linked pages in each section. ## Support overview | Area | Support | Notes | | :---------------------------------- | :-------- | :------------------------------------------------------------------------------------------------------------------------------------- | | External Iceberg sources | Supported | Use `CREATE SOURCE` for continuous ingestion from append-only tables. Schema is inferred from Iceberg metadata. | | Refreshable external Iceberg tables | Supported | Use `CREATE TABLE ... WITH (connector = 'iceberg', refresh_mode = 'FULL_RELOAD')` for on-demand or scheduled full reloads. | | External Iceberg sinks | Supported | Use `CREATE SINK` to write append-only or upsert streams to Iceberg tables. | | Internal Iceberg tables | Supported | Use `CREATE TABLE ... ENGINE = iceberg` to store RisingWave-managed tables in Iceberg format. | | Automatic Iceberg maintenance | Supported | Available for Iceberg sinks and internal Iceberg tables when a dedicated Iceberg compactor is deployed. | | Manual maintenance | Supported | Use `VACUUM` to expire snapshots and `VACUUM FULL` to compact files and expire snapshots. | | Built-in catalog | Supported | Uses RisingWave's metastore as a JDBC-compatible Iceberg catalog. PostgreSQL or MySQL metastore is required. | | External catalogs | Supported | Supports storage, REST, Glue, JDBC, Hive, S3 Tables, Lakekeeper, Snowflake, and Databricks Unity Catalog with catalog-specific limits. | ## Reading from Iceberg | Capability | Support | Notes | | :------------------------------------------- | :------------------------------------------ | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Schema inference | Supported | Iceberg source schemas are inferred automatically. Do not define columns in `CREATE SOURCE`. | | Ad hoc snapshot queries | Supported | Query an Iceberg source directly to read the current table snapshot. | | One-time loading | Supported | Append-only and mutable Iceberg tables are supported. RisingWave applies Iceberg equality deletes and position deletes when reading mutable tables. | | Continuous ingestion from append-only tables | Supported | Use `CREATE SOURCE` and build materialized views on top of the source. | | Continuous ingestion from mutable tables | Not supported for update/delete propagation | `CREATE SOURCE` is designed for append-only continuous ingestion. For mutable Iceberg tables, use refreshable `CREATE TABLE` with `FULL_RELOAD` when downstream results must reflect updates and deletes. | | On-demand full reload | Supported | Use `REFRESH TABLE` on a refreshable Iceberg table. | | Scheduled full reload | Supported | Set `refresh_interval_sec` together with `refresh_mode = 'FULL_RELOAD'`. | | Equality deletes | Supported | Supported when reading mutable tables in snapshot/full-reload paths. | | Position deletes | Supported | Supported when reading mutable tables in snapshot/full-reload paths. | | Predicate pushdown | Supported | Filters can be pushed into Iceberg scans where applicable. | | Time travel | Supported | Query committed Iceberg snapshots by timestamp or snapshot ID where the target object supports time travel. | For configuration details, see [Ingest data from Iceberg tables](/iceberg/ingest-from-iceberg). ## Writing to Iceberg | Capability | Support | Notes | | :------------------------ | :------------------------ | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Append-only sink | Supported | Set `type = 'append-only'`. Append-only sinks must use merge-on-read mode. | | Upsert sink | Supported | Set `type = 'upsert'` and provide `primary_key`. | | Force append-only | Supported | Set `force_append_only = 'true'` to write an upsert stream as inserts while ignoring deletes. | | Exactly-once delivery | Supported | Iceberg sinks default to exactly-once in the normal sink-decoupled mode. If `sink_decouple` is disabled, exactly-once is disabled automatically unless configured otherwise. | | Commit frequency | Supported | Use `commit_checkpoint_interval`. The default is `60`. | | Commit retry | Supported | Use `commit_retry_num`. The default is `8`. | | Auto-create target table | Supported | Set `create_table_if_not_exists = 'true'`. | | Partitioning | Supported | Use `partition_by` with column names or Iceberg transforms such as `bucket`, `truncate`, `year`, `month`, `day`, and `hour`. | | Sort order keys | Supported | Use `order_key` when creating the sink. | | Merge-on-read | Supported | Default write mode for Iceberg sinks and tables. | | Copy-on-write | Supported for upsert only | Append-only sinks and tables must use merge-on-read. | | Additive schema evolution | Supported | `auto.schema.change = 'true'` can propagate upstream `ADD COLUMN` changes for exactly-once Iceberg sinks. | | Iceberg format v2 | Supported | Default format version. | | Parquet writer settings | Supported | Configure output file size and compression with parameters such as `compaction.target_file_size_mb`, `compaction.write_parquet_compression`, and `compaction.write_parquet_max_row_group_bytes`. | For configuration details, see [Deliver data to Iceberg tables](/iceberg/deliver-to-iceberg) and [Iceberg write modes](/iceberg/write-modes). ## Internal Iceberg tables | Capability | Support | Notes | | :-------------------------------------------- | :-------- | :----------------------------------------------------------------------------------------------------------------- | | `CREATE TABLE ... ENGINE = iceberg` | Supported | Creates a RisingWave-managed table backed by Iceberg storage. | | Primary-key tables | Supported | Upsert semantics are written to Iceberg through the table's internal sink. | | Append-only tables | Supported | Use `APPEND ONLY` with `ENGINE = iceberg`. | | Inserts and streaming writes | Supported | Write with `INSERT` or stream data into the table with `CREATE SINK ... INTO`. | | Materialized views on internal Iceberg tables | Supported | Use internal Iceberg tables as inputs to materialized views. | | Partitioning | Supported | Use `partition_by` in table `WITH (...)` options. The partition key must be compatible with the table primary key. | | Commit frequency | Supported | Use `commit_checkpoint_interval`; the default is `60`. | | Time travel | Supported | Query committed snapshots with `FOR SYSTEM_TIME AS OF` or `FOR SYSTEM_VERSION AS OF`. | | Query storage selection | Supported | Use `iceberg_query_storage_mode` to choose Iceberg columnar reads, Hummock row reads, or optimizer-selected mode. | | Built-in catalog | Supported | Set `hosted_catalog = true` in the Iceberg connection. | | Automatic maintenance | Supported | `enable_compaction` controls background compaction and snapshot expiration. | | Manual maintenance | Supported | Use `VACUUM` or `VACUUM FULL` on the table. | For configuration details, see [Create and manage internal Iceberg tables](/iceberg/internal-iceberg-tables). ## Catalog and storage support | Catalog or storage | Support | Notes | | :------------------------------- | :---------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------ | | Storage catalog | Supported | Uses the warehouse path directly. Supports object stores such as S3, GCS, and Azure Blob where configured. | | REST catalog | Supported | Works with REST-compatible catalogs. Supports OAuth2-style credentials, bearer tokens, custom headers, SigV4 signing, and vended credentials. | | Lakekeeper | Supported | Use Lakekeeper as a self-hosted REST catalog. | | Amazon S3 Tables | Supported | Uses the REST catalog path with SigV4 signing. | | AWS Glue | Supported | Supports separate Glue credentials and assuming IAM roles. | | JDBC catalog | Supported | Can be used for external catalogs and for RisingWave's built-in catalog. | | Hive Metastore | Supported | Available as an external Iceberg catalog. | | Snowflake catalog | Supported for Iceberg sources | Use Snowflake-managed Iceberg tables as read-only sources. | | Databricks Unity Catalog | Supported for Iceberg sinks | Use Unity Catalog for Databricks-managed external Iceberg tables. `CREATE SOURCE` and `CREATE CONNECTION` are not supported for this integration. | | S3 and S3-compatible storage | Supported | Configure S3 credentials, endpoint, region, path-style access, or config loading. | | Google Cloud Storage | Supported | Configure GCS credentials directly or use REST catalog credential vending where applicable. | | Azure Blob Storage and ADLS Gen2 | Supported | Supported through Iceberg storage/catalog configuration where applicable. | For complete catalog parameters, see [Iceberg catalog configuration](/iceberg/catalogs). For storage parameters, see [Object storage configuration](/iceberg/object-storage). ## Maintenance support | Capability | Support | Notes | | :--------------------------- | :-------- | :----------------------------------------------------------------------------------- | | Automatic compaction | Supported | Set `enable_compaction = true`. Requires a dedicated Iceberg compactor node. | | Snapshot expiration | Supported | Controlled by `enable_snapshot_expiration` and snapshot expiration parameters. | | `VACUUM` | Supported | Expires old snapshots for an Iceberg sink or internal Iceberg table. | | `VACUUM FULL` | Supported | Runs compaction and then expires old snapshots. | | Full compaction | Supported | Rewrites all data files. | | Small-files compaction | Supported | Set `compaction.type = 'small-files'`. | | Files-with-delete compaction | Supported | Set `compaction.type = 'files-with-delete'`. | | Dynamic maintenance updates | Supported | Many compaction and snapshot-expiration parameters can be updated with `ALTER SINK`. | For setup and sizing, see [Deploy a dedicated Iceberg compactor](/iceberg/deploy-iceberg-compactor) and [Iceberg table maintenance](/iceberg/maintenance). ## Important limitations * `CREATE SOURCE` for Iceberg is intended for append-only continuous ingestion. Use refreshable `CREATE TABLE` with `FULL_RELOAD` for mutable external Iceberg tables. * Do not define columns in an Iceberg `CREATE SOURCE`; RisingWave infers the schema from Iceberg metadata. * `refresh_mode` is supported for `CREATE TABLE`, not `CREATE SOURCE`. * Append-only Iceberg sinks and append-only internal Iceberg tables must use merge-on-read mode. * Additive schema evolution currently covers `ADD COLUMN`; column drops, renames, and type changes require separate handling. * Catalog integrations can have role-specific limits. For example, Snowflake catalog is read-only in RisingWave, while the Databricks Unity Catalog integration is documented for Iceberg sinks.