Query Engine Setup
The Spark Datasource API is a popular way of authoring Spark ETL pipelines. Hudi tables can be queried via the Spark datasource with a simple
See the Spark Quick Start for more examples of Spark datasource reading queries.
If your Spark environment does not have the Hudi jars installed, add
--jars <path to jar>/hudi-spark-bundle_2.11-<hudi version>.jar to the classpath of drivers
and executors. Alternatively, hudi-spark-bundle can also fetched via the
--packages options (e.g:
PrestoDB is a popular query engine, providing interactive query performance. One can use both Hive or Hudi connector (Presto version 0.275 onwards) for querying Hudi tables. Both connectors currently support snapshot querying on COPY_ON_WRITE tables, and snapshot and read optimized queries on MERGE_ON_READ Hudi tables.
Since PrestoDB-Hudi integration has evolved over time, the installation instructions for PrestoDB would vary based on versions. Please check the below table for query types supported and installation instructions for different versions of PrestoDB.
|PrestoDB Version||Installation description||Query types supported|
|< 0.233||Requires the ||Snapshot querying on COW tables. Read optimized querying on MOR tables.|
|>= 0.233||No action needed. Hudi (0.5.1-incubating) is a compile time dependency.||Snapshot querying on COW tables. Read optimized querying on MOR tables.|
|>= 0.240||No action needed. Hudi 0.5.3 version is a compile time dependency.||Snapshot querying on both COW and MOR tables.|
|>= 0.268||No action needed. Hudi 0.9.0 version is a compile time dependency.||Snapshot querying on bootstrap tables.|
|>= 0.272||No action needed. Hudi 0.10.1 version is a compile time dependency.||File listing optimizations. Improved query performance.|
|>= 0.275||No action needed. Hudi 0.11.0 version is a compile time dependency.||All of the above. Native Hudi connector that is on par with Hive connector.|
To learn more about the usage of Hudi connector, please checkout prestodb documentation.
Incremental queries and point in time queries are not supported either through the Hive connector or Hudi connector. However, it is in our roadmap and you can track the development under HUDI-3210.
There is a known issue (HUDI-4290) for a clustered Hudi table. Presto query using version 0.272 or later
may contain duplicates in results if clustering is enabled. This issue has been fixed in Hudi version 0.12.0 and we need to upgrade
in presto to version 0.12.0. It is tracked in HUDI-4605.
- Configure Presto according to the Presto configuration document.
- Configure hive catalog in
- Alternatively, configure hudi catalog in
Beginning query by connecting hive metastore with presto client. The presto client connection command is as follows:
# The presto client connection command where <catalog_name> is either hudi or hive,
# and <schema_name> is the database name used in hive sync.
./presto --server xxx.xxx.xxx.xxx:9999 --catalog <catalog_name> --schema <schema_name>
Trino (formerly PrestoSQL) was forked off of PrestoDB a few years ago. Hudi supports 'Snapshot' queries for Copy-On-Write tables and 'Read Optimized' queries for Merge-On-Read tables. This is through the initial input format based integration in PrestoDB (pre forking). This approach has known performance limitations with very large tables, which has been since fixed on PrestoDB. We are working on replicating the same fixes on Trino as well.
To query Hudi tables on Trino, please place the
hudi-trino-bundle jar into the Hive connector installation
In order for Hive to recognize Hudi tables and query correctly,
- the HiveServer2 needs to be provided with the
hudi-hadoop-mr-bundle-x.y.z-SNAPSHOT.jarin its aux jars path. This will ensure the input format classes with its dependencies are available for query planning & execution.
- For MERGE_ON_READ tables, additionally the bundle needs to be put on the hadoop/hive installation across the cluster, so that queries can pick up the custom RecordReader as well.
In addition to setup above, for beeline cli access, the
hive.input.format variable needs to be set to the fully qualified path name of the
org.apache.hudi.hadoop.HoodieParquetInputFormat. For Tez, additionally the
hive.tez.input.format needs to be set
org.apache.hadoop.hive.ql.io.HiveInputFormat. Then proceed to query the table like any other Hive table.
Copy on Write Tables in Apache Hudi versions 0.5.2, 0.6.0, 0.7.0, 0.8.0, 0.9.0, 0.10.x, 0.11.x and 0.12.0 can be queried via Amazon Redshift Spectrum external tables. To be able to query Hudi versions 0.10.0 and above please try latest versions of Redshift.
Hudi tables are supported only when AWS Glue Data Catalog is used. It's not supported when you use an Apache Hive metastore as the external catalog.
Please refer to Redshift Spectrum Integration with Apache Hudi for more details.
Copy on Write tables in Apache Hudi 0.10.0 and above can be queried via StarRocks external tables from StarRocks version 2.2.0. Only snapshot queries are supported currently. In future releases Merge on Read tables will also be supported. Please refer to StarRocks Hudi external table for more details on the setup.