Presto

New Features

  • PRES-2080: The Presto 0.193 version is generally available. Detailed information around the 0.193 release are available as a blog post at Introducing Presto 0.193 in QDS .

  • PRES-1351: The Qubole Presto Server Bootstrap is an alternative to Node Bootstrap Script to install external jars such as presto-udfs before the Presto Server is started. This prevents the additional restart of the Presto Server that happens when you install such jars through the Node Bootstrap Script which causes query failures during the node startup. It is only supported in Presto 0.180 and later versions. Disabled

  • PRES-1862: Qubole Presto now supports providing full access to the S3 bucket owner for files written to the bucket by other users. When it is enabled, the S3 bucket owner gets complete permissions over the files written into the bucket. Disabled Cluster Restart Required

    The configuration is:

    catalog/hive.properties:

    hive.bucket-owner-full-control=true

  • PRES-2028: A new FastPath for queries executed by the QDS Drivers. The FastPath minimizes the QDS level time for Presto queries. It is only supported on Presto 0.180. With the Presto FastPath, the overall command latencies within QDS should come down to around 1.5 seconds when the cluster is active. Beta, Via Support Cluster Restart Required

Bug Fixes

  • PRES-1443: In Presto autoscaling, the spot ratio was maintained in all nodes. The Presto autoscaling logic is fixed to maintain the spot ratio only within the autoscaled nodes.

  • PRES-1567: The Hive authorization check was not available for SHOW COLUMNS when the Hive authorization is enabled. Qubole has introduced the authorization check for SHOW COLUMNS.

  • PRES-1760: There was an incorrect conversion of the timestamp fields. A new configuration property to automatically convert timestamp fields from the server timezone to the client timezone is added. The client timezone can be specified through the cluster configuration property, client-session-time-zone. Disabled Cluster Restart Required

    Example:

    config.properties:

    client-session-time-zone=Asia/Kolkata

    It is helpful when you are in a different timezone than the Presto Server in which case the timestamp fields in the output would be displayed in the server timezone if this configuration is not set.

  • PRES-1778: Some queries might show failed status in the Qubole UI without a stack trace in logs. The Presto client is fixed to bubble up errors in the commit phase.

  • PRES-1850: Error- inputFormat should not be accessed from a null StorageFormat. Presto can query tables backed by the storage handlers.

  • PRES-2014: The queries with brackets around them combined results for some columns. It has been resolved now.

Enhancements

  • PRES-1477: Backported the OS Fix for handling the complex type in the optimized Parquet reader to Qubole Presto 0.193.

  • PRES-1523: A fix is back-ported to honor skip.header.line.count and skip.footer.line.count in the SELECT queries from the Hive tables for the Text and Avro files.

  • PRES-1783: A Datadog alert is added to monitor Presto query planning time, which gets triggered if it exceeds two minutes. Beta, Via Support

  • PRES-1829: Presto can extract the username from the source name header for the authentication purpose.

  • PRES-1915: Changes in the file-based authentication:

    • The file-based authentication feature has been enhanced to accept only the hashed passwords for each user. Earlier, the plain passwords were accepted and stored as-is on the cluster which posed a security threat. MD5, SHA1, Unix Crypt, and BCrypt hashed passwords are supported. Qubole recommends using MD5 and BCrypt as SHA1 and Unix Crypt are less secure.

    • The file-based authentication accepts the input file as a collection of the username:password lines rather than a JSON.

  • PRES-1928: Qubole ensures that Presto would not start if the Qubole Presto Server bootstrap is specified through bootstrap.properties or the bootstrap-file-path in Presto overrides and when running the Qubole Presto Server bootstrap fails.

  • PRES-1939: Qubole Presto supports a customer delimiter in the INSERT OVERWRITE DIRECTORY syntax while writing results to S3. The customer delimiter must be an ASCII value.