Black Hole Connector

During table creation, a desired rows number can be specified. In such case, writes will behave in the same way, but reads will always return specified number of some constant rows. You shouldn’t rely on the content of such rows.

Warning

This connector will not work properly with multiple coordinators, since each coordinator will have a different metadata.

Examples

Create a table using the blackhole connector:

CREATE TABLE blackhole.test.nation AS
SELECT * from tpch.tiny.nation;

Insert data into a table in the blackhole connector:

Select from the blackhole connector:

Create a table with constant number of rows (500 * 1000 * 2000):

Now query it:

SELECT count(*) FROM blackhole.test.nation;

The above query will return 1,000,000,000.

The consuming and producing rate can be slowed down using the page_processing_delay table property. Setting this property to 5s will lead to a 5 second delay before consuming or producing a new page:

CREATE TABLE blackhole.test.delay (
)
  split_count = 1,
  pages_per_split = 1,
  rows_per_page = 1,