Amazon.com, Inc.
Dynamically switching between query and scan for optimizing table reads

Abstract:

Various embodiments of dynamically switching between query and scan for optimizing table reads are described. A particular client of a shared table can use various criteria in determining whether to query for individual entries in a table, or whether to scan the entire table. Criteria can be, in some embodiments, whether there are fewer than a threshold number of other clients accessing the same portion of the table as the particular client, or the size of the portion accessed by the client. If there are fewer than a threshold number of other clients accessing the same portion of the table, and the size of the portion is below a size threshold, for example, then querying individual entries in the table might be appropriate in those circumstances. By querying instead of scanning, for example, clients can reduce the total number of I/O operations per second on the shared table.