Amazon Technologies, Inc.

Nirmal Mehta

Allan Henry Vermeulen

Wei Xiao

Kiran Kumar Muniswamy Reddy

Pejus Manoj Das

Xianglong Huang

A data storage system may implement locking item ranges for creating a secondary index of an online table. A secondary index may be generated for a table of items stored in a non-relational data store. Different ranges of items in the data store may be locked while a corresponding portion of the secondary index is generated. Upon generating the corresponding portion of the secondary index, a range of items may be unlocked. While generating the secondary index, the table may be made available for servicing access requests. For a request to update the table received during the generation of the secondary index, a determination may be made as to whether the update is included within a locked range of the table. If locked, the request may be delayed until the range is unlocked.

Locking item ranges for creating a secondary index from an online table

Distributed systems that maintain data items or state on multiple server nodes (e.g., a storage system or lock service) may receive transaction requests from clients that include read requests and/or write requests. If a transaction request includes a read request, a server node may determine a node staleness value for the requested data from the server's perspective, and may return a transaction response to the client that includes the requested data and the node staleness value. The client may compute a client staleness value for the requested data dependent on the node staleness value in the transaction response, rather than on a separate heartbeat process. If the transaction also includes a write request, the server may return the transaction response for the read request before the write commits. In this case, the client may not use the requested data until it receives another response indicating that the write committed.

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Nirmal Mehta