Managing memory utilization in a distributed storage and task network

A nontransitory computer readable storage device comprises:

• a first storage section that stores operational instructions that, when executed by a computing device, causes the computing device to:
• encode data into pluralities of sets of encoded data slices, wherein a set of encoded data slices of the pluralities of sets of encoded data slices corresponds to a data chunk of a data chunkset, wherein a plurality of sets of encoded data slices of the pluralities of sets of encoded data slices corresponds to the data chunkset, and wherein a decode threshold number of encoded data slices of the set of encoded data slices are needed to recover the data chunk;
• output the pluralities of sets of encoded data slices to distributed storage and task (DST) units of the distributed computing system, wherein a number of the DST units corresponds to a number of encoded data slices in a set of encoded data slices, and wherein each of the DST units stores a slice grouping of encoded data slices of the plurality of sets of encoded data slices of the corresponding data chunkset;
• divide the task into a decode threshold number of partial tasks;
• send a slice deletion policy to the DST units;
• a second storage section that stores operational instructions that, when executed by the computing device, causes the computing device to, on a data chunkset by data chunkset basis:
• select a decode threshold number of DST units from the DST units;
• assign the decode threshold number of partial tasks to the decode threshold number of DST units;
• a third storage section that stores operational instructions that, when executed by a DST unit of the decode threshold number of DST units, causes the DST unit to, on a data chunkset by data chunkset basis:
• execute a corresponding one of the decode threshold number of partial tasks on the corresponding slice grouping of encoded data slices for a given data chunkset to produce a partial result;
• and
• delete the slice grouping of the plurality of sets of encoded data slices of the given data chunkset in accordance with the slice deletion policy.