Presto 325 Documentation

12.19. Release 307

12.19. Release 307

General Changes

  • Fix cleanup of spill files for queries using window functions or ORDER BY. (#543)
  • Optimize queries containing ORDER BY together with LIMIT over an OUTER JOIN by pushing ORDER BY and LIMIT to the outer side of the join. (#419)
  • Improve performance of table scans for data sources that produce tiny pages. (#467)
  • Improve performance of IN subquery expressions that contain a DISTINCT clause. (#551)
  • Expand support of types handled in EXPLAIN (TYPE IO). (#509)
  • Add support for outer joins involving lateral derived tables (i.e., LATERAL). (#390)
  • Add support for setting table comments via the COMMENT syntax. (#200)

Web UI Changes

  • Allow UI to work when opened as /ui (no trailing slash). (#500)

Security Changes

  • Make query result and cancellation URIs secure. Previously, an authenticated user could potentially steal the result data of any running query. (#561)

Server RPM Changes

  • Prevent JVM from allocating large amounts of native memory. The new configuration is applied automatically when Presto is installed from RPM. When Presto is installed another way, or when you provide your own jvm.config, we recommend adding -Djdk.nio.maxCachedBufferSize=2000000 to your jvm.config. See Deploying Presto for details. (#542)

CLI Changes

  • Always abort query in batch mode when CLI is killed. (#508, #580)

JDBC Driver Changes

  • Abort query synchronously when the ResultSet is closed or when the Statement is cancelled. Previously, the abort was sent in the background, allowing the JVM to exit before the abort was received by the server. (#580)

Hive Connector Changes

  • Add safety checks for Hive bucketing version. Hive 3.0 introduced a new bucketing version that uses an incompatible hash function. The Hive connector will treat such tables as not bucketed when reading and disallows writing. (#512)
  • Add support for setting table comments via the COMMENT syntax. (#200)

MySQL Connector Changes

See Base-JDBC Connector Library Changes.

PostgreSQL Connector Changes

See Base-JDBC Connector Library Changes.

Redshift Connector Changes

See Base-JDBC Connector Library Changes.

SQL Server Connector Changes

See Base-JDBC Connector Library Changes.

Base-JDBC Connector Library Changes

  • Fix reading and writing of timestamp values. Previously, an incorrect value could be read, depending on the Presto JVM time zone. (#495)
  • Add support for using a client-provided username and password. The credential names can be configured using the user-credential-name and password-credential-name configuration properties. (#482)

SPI Changes

  • LongDecimalType and IpAddressType now use Int128ArrayBlock instead of FixedWithBlock. Any code that creates blocks directly, rather than using the BlockBuilder returned from the Type, will need to be updated. (#492)
  • Remove FixedWidthBlock. Use one of the *ArrayBlock classes instead. (#492)
  • Add support for simple constraint pushdown into connectors via the ConnectorMetadata.applyFilter() method. (#541)