12.10. Memory Connector
The Memory connector stores all data and metadata in RAM on workers and both are discarded when Presto restarts.
This connector is in early experimental stage it is not recommended to use it in a production environment. The intended use of this connector at this point is purely for testing.
DROP TABLE memory is not released immediately. It is released
after next write access to memory connector.
When one worker fails/restarts all data that were stored in it’s memory will be lost forever. In other words in case of worker crash/stop/restart there will be partial and silent data loss. If all worker nodes fail/restart when coordinator is keep running tables will end up empty.
When coordinator fails/restarts all metadata about tables will be lost, but tables’ data will be still present on the workers however they will be inaccessible.
This connector will not work properly with multiple coordinators, since each coordinator will have a different metadata.
To configure the Memory connector, create a catalog properties file
/etc/opt/prestoadmin/connector/memory.properties with the following contents:
presto-admin to deploy the connector file. See Adding a Connector.
Create a table using the Memory connector:
CREATE TABLE memory.default.nation AS SELECT * from tpch.tiny.nation;
Insert data into a table in the Memory connector:
INSERT INTO memory.default.nation SELECT * FROM tpch.tiny.nation;
Select from the Memory connector:
SELECT * FROM memory.default.nation;
DROP TABLE memory.default.nation;