Supporting INSERT and CREATE TABLE AS

Примечание

Ниже приведена оригинальная документация Trino. Скоро мы ее переведем на русский язык и дополним полезными примерами.

To support INSERT, a connector must implement:

• beginInsert() and finishInsert() from the ConnectorMetadata interface;

• a ConnectorPageSinkProvider that receives a table handle and returns a ConnectorPageSink.

When executing an INSERT statement, the engine calls the beginInsert() method in the connector, which receives a table handle and a list of columns. It should return a ConnectorInsertTableHandle, that can carry any connector specific information, and it’s passed to the page sink provider. The PageSinkProvider creates a page sink, that accepts Page objects.

When all the pages for a specific split have been processed, Trino calls ConnectorPageSink.finish(), which returns a Collection<Slice> of fragments representing connector-specific information about the processed rows.

When all pages for all splits have been processed, Trino calls ConnectorMetadata.finishInsert(), passing a collection containing all the fragments from all the splits. The connector does what is required to finalize the operation, for example, committing the transaction.

To support CREATE TABLE AS, the ConnectorPageSinkProvider must also return a page sink when receiving a ConnectorOutputTableHandle. This handle is returned from ConnectorMetadata.beginCreateTable().