Bufferpool coherency for identifying and retrieving versions of workfile data using a producing DBMS and a consuming DBMS

A producing database management system (DBMS), comprising:

• a local memory;
• a location identifier to identify a location in said local memory of one or more data buffer pages of a workfile;
• a workfile version identifier for uniquely identifying a version of said data buffer pages of said workfile;
• flushing means for writing said data buffer pages of said workfile from said local memory to a storage device according to said location identifier;
• notifying means for sending a notify message to a consuming DBMS indicating that said workfile is written to said storage device, wherein said notify message includes said workfile version identifier;
• receiving means for receiving a reply message from said consuming DBMS indicating that said consuming DBMS retrieved said work file from said storage device;
• and
• disposing means for deleting said workfile from said local memory.

A consuming database management system (DBMS), comprising:

• receiving means for receiving a notify message from a producing DBMS indicating that a workfile is available for retrieval on a storage device, said workfile comprising one or more data buffer pages wherein each data buffer page contains a page version identifier to identify a version of said each data buffer page, wherein said notify message includes a workfile version identifier to identify a version of said workfile;
• retrieving means for retrieving said workfile from said storage device based on said workfile version identifier;
• and
• replying means for sending a reply message to said producing DBMS indicating that said consuming DBMS retrieved said workfile from said storage device.

A method for a producing data base management system (DBMS) to produce one or more workfiles and a consuming DBMS to consume the workfiles, each workfile comprising a plurality of data buffer pages, comprising the following steps that are performed by the producing DBMS:

• (1) identifying, with a location identifier, the data buffer pages located in a local memory of the producing DBMS that comprise saids one of the workflies;
• (2) identifying, with a workfile version identifier, a version of the data buffer pages of said one of the workfiles;
• (3) flushing the data buffer pages of the workfile from said local memory of the producing DBMS to a storage device according to said location identifier;
• (4) sending a notify message to the consuming DBMS indicating that said one of the workfiles is written to said storage device, wherein said notify message includes said workfile version identifier;
• (5) receiving a reply message from the consuming DBMS indicating that the consuming DBMS retrieved said one of the workfiles from said storage device;
• and
• (6) deleting said one of the workfiles from said local memory of the producing DBMS.

A method for a consuming database management system (DBMS) to consume one or more workfiles produced by a producing DBMS, each workfile comprising a plurality of data buffer pages, comprising the steps of:

• (1) receiving a notify message from the producing DBMS indicating that one of the workfiles is available for retrieval on a storage device, wherein each data buffer page of said one of the workfiles includes a page version identifier, wherein said notify message includes a workfile version identifier;
• (2) retrieving said one of the workfiles from said storage device based on said workfile version identifier;
• and
• (3) sending a reply message indicating that said one of the workfiles was retrieved from said storage device.

A computer program product for use with a computer system, comprising:

• a computer usable medium having computer readable program code means embodied in said medium for enabling a producing database management system (DBMS) to produce one or more workfiles, each of said workfiles comprising a plurality of data buffer pages, said program code means having:
• first computer readable program code means for enabling said producing DBMS to access a local memory;
• second computer readable program code means for enabling said producing DBMS to create and manage a location identifier to identify a location in said local memory of one or more of said data buffer pages of said each of said workfiles;
• third computer readable program code means for enabling said producing DBMS to create and manage a workfile version identifier for uniquely identifying a version of said data buffer pages of said each of said workfiles;
• fourth computer readable program code means for enabling said producing DBMS to write said data buffer pages of said each of said workfiles from said local memory to a storage device according to said location identifier;
• fifth computer readable program code means for enabling said producing DBMS to send a notify message to a consuming DBMS indicating that said each of said workfiles is written to said storage device, wherein said notify message includes said workfile version identifier;
• sixth computer readable program code means for enabling said producing DBMS to receive a reply message from said consuming DBMS indicating that said consuming DBMS retrieved said each of said workfiles from said storage device;
• and
• seventh computer readable program code means for enabling said producing DBMS to delete said each of said workfiles from said local memory.

A computer program product for use with a computer system, comprising:

• a computer usable medium having computer readable program code means embodied in said medium for enabling a consuming database management system (DBMS) to consume one or more workfiles, each of said workfiles comprising a plurality of data buffer pages, said program code means having:
• first computer readable program code means for enabling said consuming DBMS to receive a notify message from a producing DBMS indicating that said each of said workfiles is available for retrieval on a storage device, said each of said workfiles comprising one or more data buffer pages wherein each data buffer page contains a page version identifier to identify a version of said each data buffer page, wherein said notify message includes a workfile version identifier to identify a version of said one of said workfiles;
• second computer readable program code means for enabling said consuming DBMS to retrieve said each of said workfiles from said storage device based on said workfile version identifier;
• and
• third computer readable program code means for enabling said consuming DBMS to send a reply message to said producing DBMS indicating that said consuming DBMS retrieved said each of said workfiles from said storage device.

A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform method steps for a producing database management system (DBMS) to produce one or more workfiles and a consuming DBMS to consume the workfiles, each workfile comprising a plurality of data buffer pages, the method including the following steps that are performed by the producing DBMS:

• (1) identifying, with a location identifier, the data buffer pages located in a local memory of the producing DBMS that comprise one of the workfiles;
• (2) identifying, with a workfile version identifier, a version of the data buffer pages of said one of the workfiles;
• (3) flushing the data buffer pages of said one of the workfiles from said local memory of the producing DBMS to a storage device according to said location identifier;
• (4) sending a notify message to the consuming DBMS indicating that said one of the workfiles is written to said storage device, wherein said notify message includes said workfile version identifier;
• (5) receiving a reply message from the consuming DBMS indicating that the consuming DBMS retrieved said one of the workfiles from the storage device;
• and
• (6) deleting said one of the workfiles from said local memory of the producing DBMS.

A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform method steps for a consuming database management system (DBMS) to consume one or more workfiles produced by a producing DBMS, each workfile comprising a plurality of data buffer pages, the method including the steps of:

• (1) receiving a notify message from the producing DBMS indicating that one of the workfiles is available for retrieval on a storage device, wherein each data buffer page of said one of the workfiles includes a page version identifier, wherein said notify message includes a workfile version identifier;
• (2) retrieving said one of the workfiles from said storage device based on said workfile version identifier;
• and
• (3) sending a reply message indicating that said one of the workfiles was retrieved from the storage device.