QUERYING A SPECIFIED DATA STORAGE LAYER OF A DATA STORAGE SYSTEM

摘要

Technology is disclosed for retrieving data from a specific storage layer of a storage system (“the technology”). A query application programming interface (API) is provided that allows an application to specify a storage layer on which the query should be executed. The query API can be used in a multi-threaded environment which employs a combination of fast threads and slow threads to serve read/write requests from applications. The fast threads are configured to query on a first set of storage layers, e.g., storage layers in a primary storage, while the slow threads are configured to query on a second set of storage layers, e.g., storage layers in a secondary storage. If a fast thread does not find the requested data in the first set, the request is transferred to a slow thread and the fast thread is allocated to another request while the slow thread is serving the current request.

主权项

1. A method performed by a computing device, comprising:
receiving, at a server, a query to obtain a data item stored at a data storage system, the server having multiple threads for executing the query; assigning, by the server, the query to a first thread of the multiple threads, the first thread executing the query to retrieve the data item from a first storage layer of the data storage system; determining, by the first thread, whether the data item is available at the first data storage layer; and responsive to a determination that the data item is not available at the first storage layer, transferring the query to a second thread of the multiple threads, the second thread executing the query to retrieve the data item from a second data storage layer of the data storage system.