Microsoft Technology Licensing, LLC

Oleg Ignat

David Bruce Lomet

Quetzalcoatl Bradley

Balendran Mugundan

Peter Gvozdjak

Raghu Ram

Matthew Alban Neerincx

Chadwin James Mumford

Luiz F Santos

Luiz Fernando Federico Dos Santos

Matthew A Neerincx

Chadwin J Mumford

Systems and methods are described that facilitate idempotent execution of commands generated by a client for execution by a database server. Each command transmitted to the server includes a command ID generated by the client. The server attempts to execute each command and subsequently stores the command ID associated therewith in a repository along with an indication of whether the command executed successfully. When a new command is received by the server, it determines if the command ID associated therewith has already been stored in the repository. If the command ID associated with the new command has not already been stored in the repository, then the server executes the new command. If the command ID associated with the new command has already been stored in the repository and a previously-received command associated with the command ID has been executed successfully, then the server will not execute the new command.

Idempotent command execution

Techniques for recovering from session failures between clients and database servers are described herein. A session may be established between a client and a first database server to handle a database query for the client. A command of the session may be received by the first database server from the client. Data requested by the command may be retrieved. Prior to responding to the command, the data is spooled to a session state stored in a repository of the first database server, and the session state is replicated to one or more additional database servers. The session state stored in the repository of the first database server enables the first database server and client to recover from a failure of the session. The replicated session state enables the additional database server(s) to reestablish the session and respond to the command, instead of the first database server, if the session fails.

Automatic data request recovery after session failure

A database server includes logic that is operable to monitor and analyze at least events occurring within an environment of the database server and/or execution errors generated by the database server in order to detect whether a problem condition exists. The database server further includes logic that is operable to send one or more commands to a database driver of a client that is communicatively connected to the database server, the one or more commands specifying one or more actions to be taken by the database driver in response to the existence of the problem condition. The database driver includes logic that is operable to receive the one or more commands from the database server and logic that is operable to cause the one or more commands to be executed.

Smart error recovery for database applications

Techniques for recovering from session failures between clients and database servers are described herein. A first session may be established between a client and a first database server to handle a database query for the client. A request for data associated with the first session may be received by the first database server from the client, and the data retrieved. Prior to responding to the request, the data is spooled to a first session state stored in a repository made accessible by at least one computing device. The computing device(s) controls access to session states in the repository that correspond to sessions between clients and database servers. The computing device(s) enables sessions to be reestablished between the clients and database servers by accessing data of the session states in the repository and transmitting the data in response to messages received from the database servers containing session identifiers.

Systems and methods are described that establish and maintain a virtual session between a client and one or more database servers. A database server establishes a first session with a client wherein establishing the virtual session with the client comprises associating a virtual session identifier (ID) with the first session, generates state information in association with the first session, and stores the state information in a repository in association with the virtual session ID. After the first session fails, a same or different database server establishes a second session with the client wherein establishing the second session with the client comprises receiving the virtual session ID from the client, accesses the state information that was stored in the repository in association with the virtual session ID, and associates the state information with the second session.

Virtual session management and reestablishment

Techniques for recovering from session failures between clients and database servers are described herein. A session may be established between a client and a first database server, and a transaction may be opened to process a plurality of database commands. One or more commands associated with the transaction may be received from the client at the database server. Each received command has an associated command identifier. A transaction log stores the command identifier associated with each received command and indicates whether each received command has been successfully executed at the database server. After a session failure, the session is reestablished, and a command identifier for a further command is received from the client. If the command identifier associated with the further command is determined to have been stored in the transaction log, the command does not need to be executed, and the transaction may continue.

Growing community of inventors

Bellevue, WA, United States of America

Oleg Ignat