Pre-fetching data segments stored in a dispersed storage network

1. A method comprises:

receiving a data segment retrieval request regarding a data segment of a plurality of data segments, wherein the data segment is encoded in accordance with a dispersed storage error coding function to produce a set of encoded data slices, which is stored in a set of dispersed storage (DS) units of a dispersed storage network (DSN) memory; and

in response to the data segment retrieval request:

processing the data segment retrieval request;

determining pre-fetch segment buffering information based on the data segment, content of a pre-fetch segment buffer, a data consumption rate, and DS unit response rate; and

when the pre-fetch segment buffering information indicates pre-fetching one or more other data segments of the plurality of data segments:

generating one or more pre-fetch segment retrieval requests for the one or more other data segments;

receiving, in response to the one or more pre-fetch segment retrieval requests, one or more sets of at least a decode threshold number of encoded data slices;

decoding, in accordance with the dispersed storage error coding function, the one or more sets of at least the decode threshold number of encoded data slices to reproduce the one or more other data segments; and

updating the pre-fetch segment buffer with the one or more other data segments.

2. The method of claim 1 , wherein the processing the data segment retrieval request comprises:

determining whether the data segment is stored in the pre-fetch segment buffer; and

when the data segment is not stored in the pre-fetch segment buffer:

determining whether the data segment is identified in previous pre-fetch segment buffering information;

when the data segment is identified in the previous pre-fetch segment buffering information, retrieving the data segment from the pre-fetch segment buffer when the data segment is stored in the pre-fetch segment buffer; and

when the data segment is not identified in the previous pre-fetch segment buffering information:

generating a set of at least a decode threshold number of encoded data slice retrieval requests regarding at least a decode threshold number of the set of encoded data slices; and

decoding the at least the decode threshold number of the set of encoded data slices to reproduce the data segment.

3. The method of claim 1 , wherein the processing the data segment retrieval request comprises:

determining whether the data segment is stored in the pre-fetch segment buffer; and

when the data segment is stored in the pre-fetch segment buffer, retrieving the data segment from the pre-fetch segment buffer.

4. The method of claim 1 , wherein the pre-fetch segment buffering information comprises one or more of:

identity of the one or more other data segments;

a number of encoded data slices to retrieve for each of the one or more other data segments;

pillar identifiers (IDs) corresponding to encoded data slices of the number of encoded data slices to retrieve;

a set of DS unit IDs associated with the pillar IDs; and

a data segment retrieval performance goal.

5. The method of claim 1 , wherein generating one or more pre-fetch segment retrieval requests comprises:

for a pre-fetch segment retrieval request of the one or more pre-fetch segment retrieval requests, generating at least a decode threshold number of encoded data slices retrieval requests.

6. The method of claim 1 , wherein the DS unit response rate comprises:

a plurality of DS response characteristics for a plurality of DS units, wherein the plurality of DS units includes the set of DS units and wherein a DS response characteristic includes one or more of: a pillar identifier (ID), response latency information, processing consumption, network traffic, response history, and reliability information.

7. The method of claim 1 , wherein the determining the pre-fetch segment buffering information further comprises:

determining a data segment retrieval trend of the plurality of data segments; and

determining the pre-fetch segment buffering information further based on the data segment retrieval trend.

8. A module comprises:

a first module operable to receive a data segment retrieval request regarding a data segment of a plurality of data segments, wherein the data segment is encoded in accordance with a dispersed storage error coding function to produce a set of encoded data slices, which is stored in a set of dispersed storage (DS) units of a dispersed storage network (DSN) memory; and

in response to the data segment retrieval request:

a second module operable to process the data segment retrieval request;

a third module operable to determine pre-fetch segment buffering information based on the data segment, content of a pre-fetch segment buffer, a data consumption rate, and DS unit response rate; and

when the pre-fetch segment buffering information indicates pre-fetching one or more other data segments of the plurality of data segments, a fourth module operable to:

generate one or more pre-fetch segment retrieval requests for the one or more other data segments;

receive, in response to the one or more pre-fetch segment retrieval requests, one or more sets of at least a decode threshold number of encoded data slices;

decode, in accordance with the dispersed storage error coding function, the one or more sets of at least the decode threshold number of encoded data slices to reproduce the one or more other data segments; and

update the pre-fetch segment buffer with the one or more other data segments.

9. The module of claim 8 , wherein the second module functions to process the data segment retrieval request by:

determining whether the data segment is stored in the pre-fetch segment buffer; and

when the data segment is not stored in the pre-fetch segment buffer:

determining whether the data segment is identified in previous pre-fetch segment buffering information;

when the data segment is identified in the previous pre-fetch segment buffering information, retrieving the data segment from the pre-fetch segment buffer when the data segment is stored in the pre-fetch segment buffer; and

when the data segment is not identified in the previous pre-fetch segment buffering information:

generating a set of at least a decode threshold number of encoded data slice retrieval requests regarding at least a decode threshold number of the set of encoded data slices; and

decoding the at least the decode threshold number of the set of encoded data slices to reproduce the data segment.

10. The module of claim 8 , wherein the second module further functions to process the data segment retrieval request by:

determining whether the data segment is stored in the pre-fetch segment buffer; and

when the data segment is stored in the pre-fetch segment buffer, retrieving the data segment from the pre-fetch segment buffer.

11. The module of claim 8 , wherein the pre-fetch segment buffering information comprises one or more of:

identity of the one or more other data segments;

a number of encoded data slices to retrieve for each of the one or more other data segments;

pillar identifiers (IDs) corresponding to encoded data slices of the number of encoded data slices to retrieve;

a set of DS unit IDs associated with the pillar IDs; and

a data segment retrieval performance goal.

12. The module of claim 8 , wherein the fourth module functions to generate one or more pre-fetch segment retrieval requests by:

for a pre-fetch segment retrieval request of the one or more pre-fetch segment retrieval requests, generating at least a decode threshold number of encoded data slices retrieval requests.

13. The module of claim 8 , wherein the DS unit response rate comprises:

a plurality of DS response characteristics for a plurality of DS units, wherein the plurality of DS units includes the set of DS units and wherein a DS response characteristic includes one or more of: a pillar identifier (ID), response latency information, processing consumption, network traffic, response history, and reliability information.

14. The module of claim 8 , wherein the third module functions to determine the pre-fetch segment buffering information further by:

determining a data segment retrieval trend of the plurality of data segments; and

determining the pre-fetch segment buffering information further based on the data segment retrieval trend.