[HIVE-15277] Teach Hive how to create/delete Druid segments

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.2.0
• Fix Version/s: 2.2.0
• Component/s: Druid integration
• Labels: TODOC2.2
• Assignee: Slim Bouguerra
• Reporter: Slim Bouguerra
• Created: 24/Nov/16 00:02
• Updated: 27/Feb/24 22:24
• Resolved: 15/Dec/16 20:52

Description

We want to extend the DruidStorageHandler to support CTAS queries.
In this implementation Hive will generate druid segment files and insert the metadata to signal the handoff to druid.

The syntax will be as follows:

CREATE TABLE druid_table_1
STORED BY 'org.apache.hadoop.hive.druid.DruidStorageHandler'
TBLPROPERTIES ("druid.datasource" = "datasourcename")
AS <select `timecolumn` as `___time`, `dimension1`,`dimension2`,  `metric1`, `metric2`....>;

This statement stores the results of query <input_query> in a Druid datasource named 'datasourcename'. One of the columns of the query needs to be the time dimension, which is mandatory in Druid. In particular, we use the same convention that it is used for Druid: there needs to be a the column named '__time' in the result of the executed query, which will act as the time dimension column in Druid. Currently, the time column dimension needs to be a 'timestamp' type column.
metrics can be of type long, double and float while dimensions are strings. Keep in mind that druid has a clear separation between dimensions and metrics, therefore if you have a column in hive that contains number and need to be presented as dimension use the cast operator to cast as string.
This initial implementation interacts with Druid Meta data storage to add/remove the table in druid, user need to supply the meta data config as --hiveconf hive.druid.metadata.password=XXX --hiveconf hive.druid.metadata.username=druid --hiveconf hive.druid.metadata.uri=jdbc:mysql://host/druid

Issue Links

• contains: HIVE-15303 Upgrade to Druid 0.9.2
• is related to: HIVE-15809 Typo in the PostgreSQL database name for druid service
• is related to: HIVE-18196 Druid Mini Cluster to run Qtests integrations tests.
• supercedes: HIVE-14474 Create datasource in Druid from Hive
• links to: GitHub Pull Request #120