Presto is an open source distributed SQL query engine. It is used to run interactive analytic queries.
- Supports American National Standards Institute (ANSI) SQL.
- Supports various data sources:
- SQL Server
- Local files
- Supports advanced data structures:
- Array and map data
- JSON data
- GIS data
- Color data
- Delivers strong scalability:
- Support for various data connectors
- Customization of data types
- Customization of SQL functions
- Uses a pipeline model to process data and return data in real time.
- Provides a monitoring interface:
- Provides a web UI, on which you can view the execution processes of queries.
- Supports Java Management Extensions (JMX) protocols.
- Receives and parses query requests, generates an execution plan, and delivers the execution plan to worker nodes for execution.
- Monitors the running status of worker nodes. Each worker node maintains a heartbeat connection with the coordinator node.
- Maintains metastore data.
Worker nodes run the tasks that are assigned by the coordinator node, use connectors to read data from external storage systems, process the data, and send the processing results to the coordinator node.
- Extract, transform, load (ETL)
- Ad hoc queries
- Analysis of large amounts of structured or semi-structured data
- Aggregation of large amounts of multidimensional data, and report analysis
- You can quickly deploy a Presto cluster that has hundreds of nodes.
- EMR Presto supports auto scaling. You can easily scale out a Presto cluster.
- EMR Presto can process data stored in OSS buckets.
- EMR Presto provides an end-to-end service that requires no O&M.
Data source model
A catalog contains multiple schemas and references an external data source, which can be accessed by using connectors. You execute an SQL statement in Presto to access one or more catalogs.
A schema is a database instance that contains multiple data tables.
A data table is the same as a general database table.
Presto uses connectors to connect to various external data sources. Presto provides a standard SPI, which allows you to develop your own connectors to access custom data sources.
A catalog is typically associated with a specific type of connector that is configured in the Properties file of the catalog. Presto contains multiple built-in connectors.
The Presto version depends on the EMR version that you select when you create a cluster. For the mapping between EMR versions and Presto versions, see Overview.