Pessimistic data reading in a dispersed storage network

1. A method comprises:

receiving a data retrieval request;

determining a read threshold number of encoded data slices in response to the data retrieval request;

sending read request messages regarding the read threshold number of encoded data slices to storage units of a dispersed storage network;

entering a loop, wherein the loop includes:

receiving encoded data slices of the read threshold number of encoded data slices within a time period to produce received encoded data slices;

when a number of received encoded data slices compares unfavorably to a decode threshold number:

determining an incremental number of encoded data slices based on the number of received encoded data slices and the decode threshold number;

sending a read request message regarding the incremental number of encoded data slices to other storage units of the dispersed storage network; and

repeating the loop; and

when the number of received encoded data slices compares favorably to the decode threshold number of encoded data slices, exiting the loop; and

dispersed storage error decoding the received encoded data slices to recapture a data segment of data.

2. The method of claim 1 , wherein the read threshold number comprises at least one of:

the read threshold number is equal to the decode threshold; and

the read threshold number is greater than the decode threshold and less than a pillar width.

3. The method of claim 1 , wherein the determining of the read threshold number of encoded data slices is based on at least one of:

a read threshold number;

a data identifier (ID);

a user ID;

error coding dispersal storage function parameters;

storage unit performance history;

one or more storage unit queries;

a virtual DSN address to physical location table lookup;

a list;

a vault lookup;

a command;

a predetermination;

a message;

a source name; and

a slice name.

4. The method of claim 1 , wherein the time period comprises:

a dynamic time duration that is based on at least one of a list, a performance indicator, and a reliability indicator.

5. The method of claim 1 , wherein the determining an incremental number of encoded data slices as at least one of:

the difference between the decode threshold number and the number of received encoded data slices;

the difference between the read threshold number and the number of received encoded data slices; and

the difference between a pillar width number and the number of received encoded data slices.

6. The method of claim 1 , wherein the determining of the incremental number of encoded data slice is based on at least one of:

identifying a previously responding storage unit;

identifying a previously non-responding storage unit;

identifying a storage unit associated with a timeout indication;

a list;

a vault lookup;

a command;

a predetermination;

a message;

a source name; and

a slice name.

7. A computer comprises:

an interface; and

a processing module operable to:

receive, via the interface, a data retrieval request;

determine a read threshold number of encoded data slices in response to the data retrieval request;

send read request messages regarding the read threshold number of encoded data slices to storage units of a dispersed storage network;

enter a loop, wherein the loop includes:

receive encoded data slices of the read threshold number of encoded data slices within a time period to produce received encoded data slices;

when a number of received encoded data slices compares unfavorably to a decode threshold number:

determine an incremental number of encoded data slices based on the number of received encoded data slices and the decode threshold number;

send a read request message regarding the incremental number of encoded data slices to other storage units of the dispersed storage network; and

repeat the loop; and

when the number of received encoded data slices compares favorably to the decode threshold number of encoded data slices, exit the loop; and

dispersed storage error decode the received encoded data slices to recapture a data segment of data.

8. The computer of claim 7 , wherein the read threshold number comprises at least one of:

the read threshold number is equal to the decode threshold; and

the read threshold number is greater than the decode threshold and less than a pillar width.

9. The computer of claim 7 , wherein the processing module further functions to determine the read threshold number of encoded data slices based on at least one of:

a read threshold number;

a data identifier (ID);

a user ID;

error coding dispersal storage function parameters;

storage unit performance history;

one or more storage unit queries;

a virtual DSN address to physical location table lookup;

a list;

a vault lookup;

a command;

a predetermination;

a message;

a source name; and

a slice name.

10. The computer of claim 7 , wherein the time period comprises:

a dynamic time duration that is based on at least one of a list, a performance indicator, and a reliability indicator.

11. The computer of claim 7 , wherein the processing module further functions to determine the incremental number of encoded data slices as at least one of:

the difference between the decode threshold number and the number of received encoded data slices;

the difference between the read threshold number and the number of received encoded data slices; and

the difference between a pillar width number and the number of received encoded data slices.

12. The computer of claim 7 , wherein the processing module determines the incremental number of encoded data slices based on at least one of:

identifying a previously responding storage unit;

identifying a previously non-responding storage unit;

identifying a storage unit associated with a timeout indication;

a list;

a vault lookup;

a command;

a predetermination;

a message;

a source name; and

a slice name.