Composing a Presto Query¶
See Presto for more information about using Presto on QDS.
Presto queries run on Presto clusters. See Mapping of Cluster and Command Types for more information. Presto supports querying tables backed by the storage handlers.
QDS uses the Presto Ruby client, which provides better overall performance, processing DDL queries much faster and quickly reporting errors that a Presto cluster generates. For more information, see the Presto Ruby Client in QDS blog.
Perform the following steps to compose a Presto query:
Run only Hive DDL commands on a Presto cluster. Running Hive DML commands on a Presto cluster is not supported.
Navigate to the Workbench (beta) page. Select Presto from the command composer tabs.
Enter the Presto query in the text field.
Click Run to execute the query.
The query result is displayed in the Results tab and the query logs in the Logs tab. The Logs tab has the Errors and Warnings filter. For more information on how to download command results and logs, see Downloading Results and Logs.
For a given Presto query, a new Presto Query Tracker is displayed in the Logs tab when:
- A cluster instance that ran the query is still up.
- The query info is still present in the Presto server in that cluster instance. The query information is periodically purged from the server.
If any of the above 2 conditions is not met, the older Presto Query Tracker is displayed in the Logs tab.