Preventing pauses in algorithms requiring pre-image information concerning modifications during data replication

• US 9,128,997 B1
• Filed: 02/03/2014
• Issued: 09/08/2015
• Est. Priority Date: 01/09/2009
• Status: Active Grant

• Current Assignee: Pivotal Software, Inc. (Broadcom, Inc.)
• Original Assignee: Pivotal Software, Inc. (Broadcom, Inc.)
• Inventors: Schuchardt, Bruce
• Primary Examiner(s): Beausoliel, Jr., Robert
• Assistant Examiner(s): Pham, Michael
• Application Number:
  US14/171,424
• Time in Patent Office: 582 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1658 Data re-synchronization of a redundant component, or initial sync of replacement, additional or spare unit
• CPC Class Codes: G06F 16/2365 Ensuring data consistency and integrity
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: G06F 16/275 Synchronous replication
• CPC Class Codes: G06F 16/955 using information identifiers, e.g. uniform resource locators [URL]

Abstract

Data accessible to a first process is replicated for use by a second process. Modifications to the data during the replication process may cause algorithms requiring the values of data both before and after replication to pause. Sending the values of the datum, before and after modification, to a process that will access the replicated data enables algorithms that use both values to initiate execution without waiting for the replication process to be completed.

Claims

1. A method of replicating data, comprising:

executing each process of a plurality of processes on a corresponding node of a plurality of nodes of a distributed computing system, each process of the plurality of processes using data stored in a data region, the plurality of processes being designated as a group of processes that are permitted to make changes to the data, wherein each process in the group is configured to perform actions comprising;

upon performing an action altering the data of the data region, transmitting changes of the data to the data region through a respective communication channel of one or more communication channels that interconnect the processes in the group to the data region, wherein the one or more communication channels are monitored by a transmission monitor of the distributed computing system configured to monitor transmissions of changes by the processes and by a reception monitor of the distributed computing system configured to monitor receptions of the changes by the data region, the transmission monitor including a transmission metric indicating a count of the transmissions of changes by the processes, the reception monitor including a reception metric indicating a count of the receptions of the changes by the data region;

receiving, by the distributed computing system, a request to replicate the data of the data region for use by a new process that is originally outside of the group;

transmitting, by the distributed computing system, a notice of intention to replicate the data and a state marker message to each process in the group, the state marker message directing each process in the group to communicate, to the new process, changes to the data resulting from actions of the respective process performed subsequent to receiving, by the respective process, the notice of intention to replicate the data; and

storing, by the new process, the changes to the data received from each process in the group as post image data that will be incorporated, after data stored in the data region is replicated, into replicated data.

2. The method of claim 1, further comprising:

upon determining that the changes to the data transmitted by each process in the group to the data region before receiving the notice of intention to replicate have been received by the data region, designating the one or more communication channels as having been stabilized and notifying the new process of the stabilization of the one or more communication channels;

replicating the data stored in the data region for the new process upon the stabilization; and

upon completion of replication of the data, updating the replicated data from the stored post image data by the new process and notifying the completion of the replication by the new process to the processes in the group.

3. The method of claim 2, wherein determining that the changes to the data transmitted by each process in the group to the data region have been received by the data region is performed by the transmission monitor and the reception monitor using the transmission metric and the reception metric.

4. The method of claim 2, wherein notifying the completion of the replication by the new process to the processes in the group triggers communication of subsequent changes to the data by the processes in the group to the replicated data.

5. A distributed computing system comprising:

one or more processors; and

a non-transitory computer-readable medium storing instructions that, when executed by the one or more processors, cause the one or more processors to perform operations comprising;

executing each process of a plurality of processes on a corresponding node of a plurality of nodes of the distributed computing system, each process of the plurality of processes using data stored in a data region, the plurality of processes being designated as a group of processes that are permitted to make changes to the data, wherein each process in the group is configured to perform actions comprising;

upon performing an action altering the data of the data region, transmitting changes of the data to the data region through a respective communication channel of one or more communication channels that interconnect the processes in the group to the data region, wherein the one or more communication channels are monitored by a transmission monitor of the distributed computing system configured to monitor transmissions of changes by the processes and by a reception monitor of the distributed computing system configured to monitor receptions of the changes by the data region, the transmission monitor including a transmission metric indicating a count of the transmissions of changes by the processes, the reception monitor including a reception metric indicating a count of the receptions of the changes by the data region;

receiving, by the distributed computing system, a request to replicate the data of the data region for use by a new process that is originally outside of the group;

transmitting, by the distributed computing system, a notice of intention to replicate the data and a state marker message to each process in the group, the state marker message directing each of the processes in the group to communicate, to the new process, changes to the data resulting from actions of the respective process performed subsequent to receiving, by the respective process, the notice of intention to replicate the data; and

storing, by the new process, the changes to the data received from each process in the group as post image data that will be incorporated, after data stored in the data region is replicated, into replicated data.

6. The system of claim 5, the operations further comprising:

upon determining that the changes to the data transmitted by each process in the group to the data region before receiving the notice of intention to replicate have been received by the data region, designating the one or more communication channels as having been stabilized and notifying the new process of the stabilization of the one or more communication channels;

replicating the data stored in the data region for the new process upon the stabilization; and

upon completion of replication of the data, updating the replicated data from the stored post image data by the new process and notifying the completion of the replication by the new process to the processes in the group.

7. The system of claim 6, wherein determining that the changes to the data transmitted by each process in the group to the data region have been received by the data region is performed by the transmission monitor and the reception monitor using the transmission metric and the reception metric.

8. The system of claim 6, wherein notifying the completion of the replication by the new process to the processes in the group triggers communication of subsequent changes to the data by the processes in the group to the replicated data.

9. A non-transitory computer-readable medium storing instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising:

executing each process of a plurality of processes on a corresponding node of a plurality of nodes of the distributed computing system, each process of the plurality of processes using data stored in a data region, the plurality of processes being designated as a group of processes that are permitted to make changes to the data, wherein each process in the group is configured to perform actions comprising;

upon performing an action altering the data of the data region, transmitting changes of the data to the data region through a respective communication channel of one or more communication channels that interconnect the processes in the group to the data region, wherein the one or more communication channels are monitored by a transmission monitor of the distributed computing system configured to monitor transmissions of changes by the processes and by a reception monitor of the distributed computing system configured to monitor receptions of the changes by the data region, the transmission monitor including a transmission metric indicating a count of the transmissions of changes by the processes, the reception monitor including a reception metric indicating a count of the receptions of the changes by the data region;

receiving, by the distributed computing system, a request to replicate the data of the data region for use by a new process that is originally outside of the group;

transmitting, by the distributed computing system, a notice of intention to replicate the data and a state marker message to process in the group, the state marker message directing process in the group to communicate, to the new process, changes to the data resulting from actions of the respective process performed subsequent to receiving, by the respective process, the notice of intention to replicate the data; and

storing, by the new process, the changes to the data received from each process in the group as post image data that will be incorporated, after data stored in the data region is replicated, into replicated data.

10. The non-transitory computer-readable medium of claim 9, the operations further comprising:

upon determining that the changes to the data transmitted by each process in the group to the data region before receiving the notice of intention to replicate have been received by the data region, designating the one or more communication channels as having been stabilized and notifying the new process of the stabilization of the one or more communication channels;

replicating the data stored in the data region for the new process upon the stabilization; and

upon completion of replication of the data, updating the replicated data from the stored post image data by the new process and notifying the completion of the replication by the new process to the processes in the group.

11. The non-transitory computer-readable medium of claim 10, wherein determining that the changes to the data transmitted by each process in the group to the data region have been received by the data region is performed by the transmission monitor and the reception monitor using the transmission metric and the reception metric.

12. The non-transitory computer-readable medium of claim 10, wherein notifying the completion of the replication by the new process to the processes in the group triggers communication of subsequent changes to the data by the processes in the group to the replicated data.