Multi-tier caching system

A method of responding to a data request in a computer system having multiple caches, the method comprising:

• receiving a first data request;
• identifying a relative level of processing that may be necessary, for said first data request, to identify a data item to be served in response to said data request;
• if said level of processing is relatively low, searching a first memory of the computer system for said data item, wherein contents of said first memory are managed by an operating system;
• and
• if said level of processing is relatively high, searching a second memory of the computer system for said data item, wherein contents of said second memory are managed by an application programs
• determining whether a cached version of said data item stored in one of said first memory and said second memory is invalid compared to a version of said data item stored on a storage device other than said first memory and said second memory;
• and
• if said cached version of said data item is determined to be invalid, determining whether a desired performance level is maintainable if an updated version of said data item is retrieved from said storage device for service and said first data request is held to await said updated version.

A method of caching data in a multi-tier caching system, comprising:

• receiving a first data request at a computer system having a memory;
• searching a first memory for a data item responsive to said first data request, wherein said first memory comprises a portion of the computer system memory configured to store contents managed by an operating system;
• searching a second memory for said data item, wherein said second memory comprises a portion of the computer system memory configured to store contents managed by an application program;
• receiving a second data request;
• serving, in response to said second data request, an invalid version of said data item from one of said first memory and said second memory:
• receiving said data item from a storage device other than said first memory and said second memory;
• serving said data item in response to said first data request;
• and
• storing said data item in one of said first memory and said second memory.

A computer readable storage medium storing instructions that, when executed by a computer, cause the computer to perform a method of caching data in a multi-tier caching system, the method comprising:

• receiving a first data request at a computer system having a memory;
• searching a first memory for a data item responsive to said first data request, wherein said first memory comprises a portion of the computer system memory configured to store contents managed by an operating system;
• searching a second memory for said data item, wherein said second memory comprises a portion of the computer system memory configured to store contents managed by an application program;
• receiving a second data request:
• serving, in response to said second data request, an invalid version of said data item from one of said first memory and said second memory,
• receiving said data item from a storage device other than said first memory and said second memory;
• serving said data item in response to said first data request;
• and
• storing said data item in one of said first memory and said second memory.

A multi-tier caching system for a computing device having a main memory, the caching system comprising:

• a first memory of the computing device, wherein contents of said first memory are managed by an operating system;
• a second memory of the computing device, wherein contents of said second memory are managed by an application;
• and
• a data analysis module configured to determine, for a first data item retrieved in response to a first data request, in which of said first memory and said second memory said first data item should be stored.

A method of operating a multi-tiered caching system in a single computer system, comprising:

• receiving a first data request at a computer system having a multi-tiered caching system comprising multiple caches;
• searching a first cache of the multiple caches for a data item responsive to said first data request, wherein contents of said first cache are managed by an operating system of the computer system;
• and
• if said searching of said first cache is unsuccessful, passing said first data request to a second cache of the multiple caches managed by an application program executing on the computer system.

A multi-tier caching system, comprising:

• a first caching means configured to cache a first set of data items for serving in response to data requests, wherein said first caching means comprises a portion of a computer memory managed by an operating system executing on the computer;
• a second caching means configured to cache a second set of data items for serving in response to data requests, wherein said second caching means comprises a portion of the computer memory managed by an application program executing on the computer;
• selection means configured to select one of said first caching means and said second caching means to cache a new data item retrieved from a storage device external to the computer;
• and
• serving means configured to serve, from one of said first caching means and said second caching means, an invalid version of a first data item in response to a request for the first data item;
• wherein a current version of the first data item is stored on the storage device.

A computer readable medium storing instructions that, when executed by a computer, cause the computer to perform a method of caching data in a multi-tier caching system, the method comprising:

• receiving a first data request from a user;
• searching a first memory for a first data item responsive to said first data request, wherein the contents of said first memory are managed by an operating system;
• searching a second memory for said first data item, wherein the contents of said second memory are managed by an application program;
• if said searches of said first memory and said second memory are unsuccessful:
• receiving said first data item from a storage device other than said first memory and said second memory;
• and
• identifying one of said first memory and said second memory in which to store said first data item for serving in response to a later data request;
• and serving said first data item to said user;
• wherein said data request comprises a parameter having a value, and wherein said identifying comprises storing said first data item in said second memory if a second data item different from said first data item must be served to a second data request having a different value for said parameter than said first data request.

A method of responding to a data request in a computer system having multiple caches, the method comprising:

• receiving a first data request from a user;
• searching a first memory for a first data item to be served in response to said first data request, wherein the contents of said first memory are managed by an operating system;
• searching a second memory for said first data item, wherein the contents of said second memory are managed by an application program;
• and
• if one or more of said searches of said first memory and said second memory is successful:
• determining whether said first data item is invalid compared to a version of said first data item stored on a storage device other than said first memory and said second memory;
• and
• if said first data item is determined to be invalid, determining whether a desired performance level of the computer system is maintainable if an updated version of said first data item is requested from said storage device to serve to said user in place of said invalid first data item;
• and serving said first data item to the user.

A computer readable medium storing instructions that, when executed by a computer, cause the computer to perform a method of responding to a data request in a computer system having multiple caches, the method comprising:

• receiving a first data request;
• identifying a relative level of processing that may be necessary, for said first data request, to identify a data item to be served in response to said data request;
• if said level of processing is relatively low, searching a first memory of the computer system for said data item, wherein contents of said first memory are managed by an operating system;
• if said level of processing is relatively high, searching a second memory of the computer system for said data item, wherein contents of said second memory are managed by an application program;
• determining whether a cached version of said data item stored in one of said first memory and said second memory is invalid compared to a version of said data item stored on a storage device other than said first memory and said second memory;
• and
• if said cached version of said data item is determined to be invalid, determining whether a desired performance level is maintainable if an updated version of said data item is retrieved from said storage device for service and said first data request is held to await said updated version.

A computer readable medium storing instructions that, when executed by a computer, cause the computer to perform a method of operating a multi-tiered caching system in a single computer system, comprising:

• receiving a first data request at a computer system having a multi-tiered caching system comprising multiple caches;
• searching a first cache of the multiple caches for a data item responsive to said first data request, wherein contents of said first cache are managed by an operating system of the computer system;
• and
• if said searching of said first cache is unsuccessful, passing said first data request to a second cache of the multiple caches managed by an application program executing on the computer system.

A computer readable medium storing instructions that, when executed by a computer, cause the computer to perform a method of responding to a data request in a computer system having multiple caches, the method comprising:

• receiving a first data request from a user;
• searching a first memory for a first data item to be served in response to said first data request, wherein the contents of said first memory are managed by an operating system;
• searching a second memory for said first data item, wherein the contents of said second memory are managed by an application program;
• and
• if one or more of said searches of said first memory and said second memory is successful:
• determining whether said first data item is invalid compared to a version of said first data item stored on a storage device other than said first memory and said second memory;
• and
• if said first data item is determined to invalid, determining whether a desired performance level of the computer system is maintainable if an updated version of said first data item is requested from said storage device to serve to said user in place of said invalid first data item;
• and serving said first data item to the user.