System Connector
The System connector provides information and metrics about the currently running openLooKeng cluster. It makes this available via normal SQL queries.
Configuration
The System connector doesn't need to be configured: it is automatically available via a catalog named system.
Using the System Connector
List the available system schemas:
SHOW SCHEMAS FROM system;
List the tables in one of the schemas:
SHOW TABLES FROM system.runtime;
Query one of the tables:
SELECT * FROM system.runtime.nodes;
Kill a running query:
CALL system.runtime.kill_query(query_id => '20151207_215727_00146_tx3nr', message => 'Using too many resources');
System Connector Tables
metadata.catalogs
The catalogs table contains the list of available catalogs.
metadata.schema_properties
The schema properties table contains the list of available properties that can be set when creating a new schema.
metadata.table_properties
The table properties table contains the list of available properties that can be set when creating a new table.
metadata.table_comments
The table comments table contains the list of table comment.
runtime.nodes
The nodes table contains the list of visible nodes in the openLooKeng cluster along with their status.
runtime.queries
The queries table contains information about currently and recently running queries on the openLooKeng cluster. From this table you can find out the original query text (SQL), the identity of the user who ran the query and performance information about the query including how long the query was queued and analyzed.
runtime.tasks
The tasks table contains information about the tasks involved in a openLooKeng query including where they were executed and and how many rows and bytes each task processed.
runtime.transactions
The transactions table contains the list of currently open transactions and related metadata. This includes information such as the create time, idle time, initialization parameters, and accessed catalogs.
System Connector Procedures
runtime.kill_query(query_id, message)
Kill the query identified by query_id. The query failure message will include the specified message.
