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Accommodating WITH HOLD Cursors in a Transaction- bounded Processing Environment

IP.com Disclosure Number: IPCOM000014001D
Original Publication Date: 2001-Feb-01
Included in the Prior Art Database: 2003-Jun-19

Publishing Venue

IBM

Abstract

This disclosure shows a method to accommodate WITH HOLD cursors in an environment where the processing units, or database agent, of a relational database are only associated with a specific application for the length of a transaction (i.e. a unit of work). After the end of a transaction, the agent may be re-assigned to a different application which means that any information from the previous application stored with that agent is lost. This causes a problem for those SQL statements whose lifespan exceeds that of a transaction, in particular it causes a problem for open WITH HOLD cursors. For these statements, it is important that the application information and statement information not be lost at the end of a transaction; it needs to be stored in such a way that another, different agent can pick up processing where the first one left off. This problem can be addressed by organizing the application SQL working memory into two distinct areas: an Application Shared SQL Workspace and an Agent Private SQL Workspace. The Application Shared SQL Workspace will contain statements that live beyond the current unit of work while the Agent Private SQL Workspace will contain the others. This approach also requires the introduction of an Application SQL Context that maps which SQL statements are being executed by the application and in which workspace the statements are being executed. Application SQL Context Agent Private SQL Workspace Application