Fallback delegates for modification of an index structure

Abstract

A method includes identifying a fallback delegate device of a plurality of delegate devices for changing one or more nodes of a plurality of nodes of a hierarchical index structure, where a primary delegate device of the plurality of delegate devices is responsible for changing the one or more nodes and where each delegate device of a plurality of delegate devices is assigned an individual global namespace address that is partially based on a location within the DSN. The method further includes determining to process a change to a node of the one or more nodes using the fallback delegate device.

What is claimed is: 
     
         1 . A method for execution by a device of a dispersed storage network (DSN), the method comprises:
 identifying a fallback delegate device of a plurality of delegate devices for changing one or more nodes of a plurality of nodes of a hierarchical index structure, wherein a primary delegate device of the plurality of delegate devices is responsible for changing the one or more nodes, wherein each delegate device of a plurality of delegate devices is assigned an individual global namespace address that is partially based on a location within the DSN, and wherein the hierarchical index structure is used to identify particular data stored in the DSN; and   determining to process a change to a node of the one or more nodes using the fallback delegate device.   
     
     
         2 . The method of  claim 1 , wherein the identifying the fallback delegate device comprises:
 performing a first modification of a global namespace address of the primary delegate device to produce a first modified address identifier;   determining whether another delegate device of the plurality of delegate devices has the global namespace address corresponding to the first modified address identifier; and   when the global namespace address of other delegate device corresponds to the first modified address identifier, identifying the other delegate device as the fallback delegate device for the one or more nodes.   
     
     
         3 . The method of  claim 2  further comprises:
 when the global namespace address of the other delegate device does not correspond to the first modified address identifier:
 performing a second modification to the first modified address identifier to produce a second modified address identifier; 
 determining whether a second other delegate device of the plurality of delegate devices has the global namespace address corresponding to the second modified address identifier; and 
 when the global namespace address of the second other delegate device corresponds to the second modified address identifier, identifying the second other delegate device as the fallback delegate device for the one or more nodes. 
 
 
     
     
         4 . The method of  claim 3  further comprises:
 when the global namespace address of the second other delegate device does not correspond to the second modified address identifier: 
 continuing to perform modifications of a current modified address identifier until one of the plurality of delegate devices is identified as the fallback delegate device or until the modifications have been exhausted; and 
 when the modifications have been exhausted, determining the device is to process the change to the node of the one or more nodes. 
 
     
     
         5 . The method of  claim 1  further comprises:
 modifying most significant bits (MSB) of a global namespace address of the primary delegate device to produce a modified MSB; 
 determining whether the MSB of the global namespace address of the other delegate device substantially matches the modified MSB; and 
 when the MSB of the global namespace address of the other delegate device substantially matches the modified MSB, identifying the other delegate device as the fallback delegate device for the one or more nodes. 
 
     
     
         6 . The method of  claim 1 , wherein the individual global namespace address comprises:
 most significant bits (MSB) corresponding to a geographic region of the DSN that is partially based on the location within the DSN; and   less significant bits (LSB) corresponding to a unique identifier of a particular delegate device within the geographic region.   
     
     
         7 . The method of  claim 1  further comprises:
 sending, by the device, a request to the fallback delegate device regarding the change to the node of the one or more nodes; 
 determining, by the fallback delegate device, whether the fallback delegate device is responsible for executing the change request; and 
 when the fallback delegate device is responsible for executing the request: 
 sending, by the fallback delegate device, a response message to the device indicating that the fallback delegate device is responsible for executing the request; and 
 executing, by the fallback delegate device, the change to the node of the one or more nodes. 
 
     
     
         8 . The method of  claim 7 , wherein the determining whether the fallback delegate device is responsible for executing the change request comprises:
 performing a first modification of a global namespace address of the primary delegate device to produce a first modified address identifier; and   determining that the fallback delegate device has the global namespace address corresponding to the first modified address identifier.   
     
     
         9 . The method of  claim 1 , wherein the identifying the fallback delegate device includes using one or more of:
 a deterministic function;   a default; and   a predetermination.   
     
     
         10 . The method of  claim 1 , wherein the plurality of nodes includes a root index node, a plurality of index nodes, and a plurality of leaf index nodes arranged in a related hierarchical manner. 
     
     
         11 . A computer readable memory comprises:
 a first memory element that stores operational instructions that, when executed by a device of a dispersed storage network (DSN), causes the device to:
 identify a fallback delegate device of a plurality of delegate devices for changing one or more nodes of a plurality of nodes of a hierarchical index structure, wherein a primary delegate device of the plurality of delegate devices is responsible for changing the one or more nodes, wherein each delegate device of a plurality of delegate devices is assigned an individual global namespace address that is partially based on a location within the DSN, and wherein the hierarchical index structure is used to identify particular data stored in the DSN; and 
   a second memory element that stores operational instructions that, when executed by the device, causes the device to:
 determine to process a change to a node of the one or more nodes using the fallback delegate device. 
   
     
     
         12 . The computer readable memory of  claim 11 , wherein the first memory element further stores operational instructions that, when executed by the device, causes the device to the identify the fallback delegate device by:
 performing a first modification of a global namespace address of the primary delegate device to produce a first modified address identifier;   determining whether another delegate device of the plurality of delegate devices has the global namespace address corresponding to the first modified address identifier; and   when the global namespace address of other delegate device corresponds to the first modified address identifier, identifying the other delegate device as the fallback delegate device for the one or more nodes.   
     
     
         13 . The computer readable memory of  claim 12  further comprises:
 a third memory element that stores operational instructions that, when executed by the device, causes the device to:
 when the global namespace address of the other delegate device does not correspond to the first modified address identifier:
 perform a second modification to the first modified address identifier to produce a second modified address identifier; 
 determine whether a second other delegate device of the plurality of delegate devices has the global namespace address corresponding to the second modified address identifier; and 
 when the global namespace address of the second other delegate device corresponds to the second modified address identifier, identify the second other delegate device as the fallback delegate device for the one or more nodes. 
 
 
 
     
     
         14 . The computer readable memory of  claim 13  further comprises:
 a fourth memory element that stores operational instructions that, when executed by the device, causes the device to:
 when the global namespace address of the second other delegate device does not correspond to the second modified address identifier:
 continue to perform modifications of a current modified address identifier until one of the plurality of delegate devices is identified as the fallback delegate device or until the modifications have been exhausted; and 
 
 when the modifications have been exhausted, determine the device is to process the change to the node of the one or more nodes. 
 
 
     
     
         15 . The computer readable memory of  claim 11  further comprises:
 a fifth memory element that stores operational instructions that, when executed by the device, causes the device to: 
 modify most significant bits (MSB) of a global namespace address of the primary delegate device to produce a modified MSB; 
 determine whether the MSB of the global namespace address of the other delegate device substantially matches the modified MSB; and 
 when the MSB of the global namespace address of the other delegate device substantially matches the modified MSB, identify the other delegate device as the fallback delegate device for the one or more nodes. 
 
     
     
         16 . The computer readable memory of  claim 11 , wherein the individual global namespace address comprises:
 most significant bits (MSB) corresponding to a geographic region of the DSN that is partially based on the location within the DSN; and   less significant bits (LSB) corresponding to a unique identifier of a particular delegate device within the geographic region.   
     
     
         17 . The computer readable memory of  claim 11  further comprises:
 the second memory element further stores operational instructions that, when executed by the device, causes the device to determine to process the change to the node of the one or more nodes using the fallback delegate device by: 
 sending, by the device, a request to the fallback delegate device regarding the change to the node of the one or more nodes; and 
 a sixth memory element that stores operational instructions that, when executed by the fallback delegate device, causes the fallback delegate device to:
 determine whether the fallback delegate device is responsible for executing the change request; and 
 when the fallback delegate device is responsible for executing the request:
 send a response message to the device indicating that the fallback delegate device is responsible for executing the request; and 
 execute the change to the node of the one or more nodes. 
 
 
 
     
     
         18 . The computer readable memory of  claim 17 , wherein the sixth memory element stores further operational instructions that, when executed by the fallback delegate device, causes the fallback delegate device to determine whether the fallback delegate device is responsible for executing the change request by:
 performing a first modification of a global namespace address of the primary delegate device to produce a first modified address identifier; and   determining that the fallback delegate device has the global namespace address corresponding to the first modified address identifier.   
     
     
         19 . The computer readable memory of  claim 11 , wherein the first memory element stores further operational instructions that, when executed by the device, causes the device to the identify the fallback delegate device using one or more of:
 a deterministic function;   a default; and   a predetermination.   
     
     
         20 . The computer readable memory of  claim 11 , wherein the plurality of nodes includes a root index node, a plurality of index nodes, and a plurality of leaf index nodes arranged in a related hierarchical manner.