Retrieving data using an asynchronous buffer

• US 8,239,447 B2
• Filed: 12/28/2004
• Issued: 08/07/2012
• Est. Priority Date: 12/28/2004
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP AG (SAP SE)
• Inventors: Garg, Manish, Stein, Martin H., Steiner, Martin W.
• Primary Examiner(s): Patel, Haresh N
• Assistant Examiner(s): Shaw, Peter
• Application Number:
  US11/024,562
• Publication Number:
  US 20060140202A1
• Time in Patent Office: 2,779 Days
• Field of Search: 709/203, 709/231, 370/412, 711/100, 711/169
• US Class Current: 709/203
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/9031 Wraparound memory, e.g. overrun or underrun detection

Abstract

A mechanism for retrieving data over a network using an asynchronous buffer is described herein. According to one embodiment, an exemplary process includes, in response to a request for first data from a client via a first thread, determining whether a local circular buffer contains the requested first data, the local circular buffer having a head region and a tail region for identifying a head and a tail of the local circular buffer respectively, and the local circular buffer containing a portion of a data file maintained by a server over a network, generating a second thread to the server over the network to request the first data, if the local circular buffer does not contain the requested first data, and returning the first thread to the client while waiting for a result of the second thread from the server. Other methods and apparatuses are also described.

Claims

1. A computer implemented method, comprising:

in response to a request for first data from a client via a first thread, determining whether a local circular buffer contains the requested first data, the local circular buffer having a head region and a tail region for identifying a head and a tail of the local circular buffer respectively, the local circular buffer arranged to wrap around itself both past the tail and past the head thus allowing reading and writing of data past the tail and past the head responsive to a data scrolling activity at the client, the local circular buffer containing a portion of a data file maintained by a server over a network;

based on a determination that the local circular buffer does not contain the requested first data, generating a second thread to the server over the network to request the first data;

determining whether a location of a previous request for data associated with a request index is related to the head region of the local circular buffer;

adjusting a file pointer of the file of the server to a location substantially corresponding to a location associated with a tail index prior to generating the second thread; and

returning the first thread to the client while waiting for a result of the second thread from the server.

2. The method of claim 1, further comprising:

receiving a second data from the server over the network in response to the second thread, the second data including the requested first data;

storing the second data in the local circular buffer; and

notifying the client indicating arrival of the requested first data to enable the client to retrieve the requested first data from the local circular buffer.

3. The method of claim 2, wherein the second data includes additional data other than the requested first data, and wherein the additional data is anticipated that the client is to request subsequently.

4. The method of claim 1, further comprising returning the requested first data from the local circular buffer to the client via the first thread if the local circular buffer contains the requested first data.

5. The method of claim 1, wherein determining whether the first data is in the local circular buffer comprises:

determining whether the first data is within one of the head and tail regions of the local circular buffer; and

returning the requested first data from the local circular buffer to the client via the first thread if the first data is within one of the head and tail regions of the local circular buffer.

6. The method of claim 1, wherein the request for the first data is identified by a request index, wherein the head region and the tail region of the local circular buffer are identified by a head index and a tail index respectively, and wherein determining whether the first data is within one of the head and tail regions of the local circular buffer is performed based on the request index, head index, and tail index according to a mathematical formula.

7. The method of claim 6, further comprising determining whether the request index is beyond the tail region by comparing the request index with the tail index, wherein the second thread is generated if the request index is beyond the tail region of the local circular buffer.

8. The method of claim 1, further comprising:

determining whether a previous request for data associated with a request index has been made to the server via a third thread and a result of the third thread is still pending; and

returning the first thread indicating the first data is pending without generating the second thread if the result of the third thread is still pending.

9. The method of claim 8, further comprising:

maintaining a requested start index and a requested end index for the previous request while the third thread is pending; and

determining whether the request index is within the requested start index and the requested end index in order to determine whether a previous request has been made.

10. The method of claim 6, further comprising determining whether the request index is beyond the head region of the local circular buffer by comparing the request index with the head index, wherein the second thread is generated if the request index is beyond the head region.

11. The method of claim 6, further comprising:

determining whether a previous request for data associated with the request index has been made to the server via a third thread and a result of the third thread is still pending; and

returning the first thread indicating the first data is pending without generating the second thread if the result of the third thread is still pending.

12. The method of claim 6, further comprising:

determining whether a location of the previous request is related to the tail region of the local circular buffer; and

adjusting a file pointer of the file of the server to a location substantially corresponding to a location associated with the head index prior to generating the second thread.

13. The method of claim 11, further comprising:

maintaining a requested start index and a requested end index for the previous request while the third thread is pending; and

determining whether the request index is within the requested start index and the requested end index in order to determine whether a previous request has been made.

14. The method of claim 1, wherein the client includes a graphical user interface (GUI) that displays a portion of data maintained in the local circular buffer, and wherein the server is an enterprise server.

15. The method of claim 14, wherein the GUI is a part of a log viewer and the data file stored in the server is a part of a log file for logging enterprise transactions of the enterprise server.

16. A non-transitory machine-readable storage medium containing instructions that, when executed by a processor, causes the processor to perform a method for processing messages, the method comprising:

in response to a request for first data from a client via a first thread, determining whether a local-circular buffer contains the requested first data, the local circular buffer having a head region and a tail region for identifying a head and a tail of the local circular buffer respectively, the local circular buffer arranged to wrap around itself both past the tail and past the head thus allowing reading and writing of data past the tail and past the head responsive to a data scrolling activity at the client, the local circular buffer containing a portion of a data file maintained by a server over a network;

based on a determination that the local circular buffer does not contain the requested first data, generating a second thread to the server over the network to request the first data;

determining whether a location of a previous request for data associated with a request index is related to the head region of the local circular buffer;

adjusting a file pointer of the file of the server to a location substantially corresponding to a location associated with a tail index prior to generating the second thread; and

returning the first thread to the client while waiting for a result of the second thread from the server.

17. The non-transitory machine-readable storage medium of claim 16, wherein the method further comprises:

receiving a second data from the server over the network in response to the second thread, the second data including the requested first data;

storing the second data in the local circular buffer; and

notifying the client indicating arrival of the requested first data to enable the client to retrieve the requested first data from the local circular buffer.

18. The non-transitory machine-readable storage medium of claim 17, wherein the second data includes additional data other than the requested first data, and wherein the additional data is anticipated that the client is to request subsequently.

19. A data processing system, comprising:

a processor; and

a memory coupled to the processor for storing instructions, when executed from the memory, causes the processor to perform operations including;

in response to a request for first data from a client via a first thread, determine whether a local circular buffer contains the requested first data, the local circular buffer having a head region and a tail region for identifying a head and a tail of the local circular buffer respectively, the local circular buffer arranged to wrap around itself both past the tail and past the head thus allowing reading and writing of data past the tail and past the head responsive to a data scrolling activity at the client, the local circular buffer containing a portion of a data file maintained by a server over a network;

based on a determination that the local circular buffer does not contain the requested first data, generate a second thread to the server over the network to request the first data;

determine whether a location of a previous request for data associated with a request index is related to the head region of the local circular buffer;

adjust a file pointer of the file of the server to a location substantially corresponding to a location associated with a tail index prior to generating the second thread; and

return the first thread to the client while waiting for a result of the second thread from the server.