Release 0.69¶
Warning
The following config properties must be removed from the
etc/config.properties
file on both the coordinator and workers:
presto-metastore.db.type
presto-metastore.db.filename
Additionally, the datasources
property is now deprecated
and should also be removed (see Datasource Configuration).
Prevent Scheduling Work on Coordinator¶
We have a new config property, node-scheduler.include-coordinator
,
that allows or disallows scheduling work on the coordinator.
Previously, tasks like final aggregations could be scheduled on the
coordinator. For larger clusters, processing work on the coordinator
can impact query performance because the machine’s resources are not
available for the critical task of scheduling, managing and monitoring
query execution.
We recommend setting this property to false
for the coordinator.
See Config Properties for an example.
Datasource Configuration¶
The datasources
config property has been deprecated.
Please remove it from your etc/config.properties
file.
The datasources configuration is now automatically generated based
on the node-scheduler.include-coordinator
property
(see Prevent Scheduling Work on Coordinator).
Raptor Connector¶
Presto has an extremely experimental connector that was previously called
the native
connector and was intertwined with the main Presto code
(it was written before Presto had connectors). This connector is now
named raptor
and lives in a separate plugin.
As part of this refactoring, the presto-metastore.db.type
and
presto-metastore.db.filename
config properties no longer exist
and must be removed from etc/config.properties
.
The Raptor connector stores data on the Presto machines in a columnar format using the same layout that Presto uses for in-memory data. Currently, it has major limitations: lack of replication, dropping a table does not reclaim the storage, etc. It is only suitable for experimentation, temporary tables, caching of data from slower connectors, etc. The metadata and data formats are subject to change in incompatible ways between releases.
If you would like to experiment with the connector, create a catalog
properties file such as etc/catalog/raptor.properties
on both the
coordinator and workers that contains the following:
connector.name=raptor
metadata.db.type=h2
metadata.db.filename=var/data/db/MetaStore
Machine Learning Functions¶
Presto now has functions to train and use machine learning models (classifiers and regressors). This is currently only a proof of concept and is not ready for use in production. Example usage is as follows:
SELECT evaluate_classifier_predictions(label, classify(features, model))
FROM (
SELECT learn_classifier(label, features) AS model
FROM training_data
)
CROSS JOIN validation_data
In the above example, the column label
is a bigint
and the column
features
is a map of feature identifiers to feature values. The feature
identifiers must be integers (encoded as strings because JSON only supports
strings for map keys) and the feature values are numbers (floating point).
Variable Length Binary Type¶
Presto now supports the varbinary
type for variable length binary data.
Currently, the only supported function is length()
.
The Hive connector now maps the Hive BINARY
type to varbinary
.
General Changes¶
Add missing operator:
timestamp with time zone
-interval year to month
Support explaining sampled queries
Add JMX stats for abandoned and canceled queries
Add
javax.inject
to parent-first class list for pluginsImprove error categorization in event logging