Caching for unique combination reads in a dispersed storage network

A processing system of a dispersed storage and task (DST) execution unit comprises:

• at least one processor;
• a memory that stores operational instructions, that when executed by the at least one processor cause the processing system to:
• receive a first access request via a network that indicates a first data object, wherein the first data object is stored as a plurality of encoded slices in a plurality of storage units;
• select a first desired slice set based on an identifier of a first requesting module from which the first access request was received, wherein the first desired slice set includes a first subset of the plurality of encoded slices of the first data object;
• generate first absent slice data based on searching a local cache, wherein the first absent slice data indicates at least one encoded slice of the first desired slice set that is not present in the local cache;
• transmit via the network at least one read request to read the at least one encoded slice indicated by the first absent slice data from at least one storage unit of the plurality of storage units;
• receive the at least one encoded slice indicated by the first absent slice data from the at least one storage unit via the network;
• update the local cache to include the at least one encoded slice received from the at least one storage unit;
• regenerate the first data object for transmission via the network, wherein regenerating the first data object includes decoding the first subset of the plurality of encoded slices in the first desired slice set
• receive a second access request via a network that indicates the first data object;
• select a second desired slice set based on an identifier of a second requesting module from which the first access request was received, wherein the second desired slice set includes a second subset of the plurality of encoded slices of the first data object that includes the at least one encoded slice and wherein the first subset of the plurality of encoded slices is different from the second subset of the plurality of encoded slices;
• generate second absent slice data based on searching a local cache, wherein the second absent slice data indicates the second subset of the plurality of encoded slices is present in the local cache as a result of updating the local cache to include the at least one encoded slice received from the at least one storage unit;
• and
• regenerate the first data object for transmission t via the network, wherein regenerating the first data object includes decoding the second subset of the plurality of encoded slices in the second desired slice set by utilizing the second subset of the plurality of encoded slices stored in the local cache.

A non-transitory computer readable storage medium comprises:

• at least one memory section that stores operational instructions that, when executed by a processing system of a dispersed storage network (DSN) that includes a processor and a memory, causes the processing system to:
• receive a first access request from a first requesting module via a network that indicates a first data object, wherein the first data object is stored as a plurality of encoded slices in a plurality of storage units;
• select a first desired slice set based on an identifier of the first requesting module, wherein the first desired slice set includes a first subset of the plurality of encoded slices of the first data object;
• generate first absent slice data based on searching a local cache, wherein the first absent slice data indicates at least one encoded slice of the first desired slice set that is not present in the local cache;
• transmit via the network at least one read request to read the at least one encoded slice indicated by the first absent slice data from at least one storage unit of the plurality of storage units;
• receive the at least one encoded slice indicated by the first absent slice data from the at least one storage unit via the network;
• update the local cache to include the at least one encoded slice received from the at least one storage unit;
• regenerate the first data object for transmission to the first requesting module via the network, wherein regenerating the first data object includes decoding the first subset of the plurality of encoded slices in the first desired slice set
• receive a second access request from a second requesting module via a network that indicates the first data object;
• select a second desired slice set based on an identifier of the second requesting module, wherein the second desired slice set includes a second subset of the plurality of encoded slices of the first data object that includes the at least one encoded slice and wherein the first subset of the plurality of encoded slices is different from the second subset of the plurality of encoded slices;
• generate second absent slice data based on searching a local cache, wherein the second absent slice data indicates the second subset of the plurality of encoded slices is present in the local cache as a result of updating the local cache to include the at least one encoded slice received from the at least one storage unit;
• and
• regenerate the first data object for transmission to the second requesting module via the network, wherein regenerating the first data object includes decoding the second subset of the plurality of encoded slices in the second desired slice set by utilizing the second subset of the plurality of encoded slices stored in the local cache.