Microsoft Technology Licensing, LLC

Other

David Bruce Lomet

Roger Shane Barga

Quetzalcoatl Bradley

Balendran Mugundan

Peter Gvozdjak

Raghu Ram

Matthew Alban Neerincx

Oleg Ignat

Justin Jon Levandoski

Chadwin James Mumford

Sudipta Sengupta

Michael T Massa

Rod N Gamache

Gor Nishanov

Rohit Jain

Philip Alan Bernstein

David Allen Dion

Sunita Shrivastava

Luiz F Santos

Rushabh A Doshi

Luiz Fernando Federico Dos Santos

Rajsekhar Das

Gerhard Weikum

Mark Rogers Tuttle

Michael James Zwilling

Philip A Bernstein

Raj Das

Ryan Stutsman

Alan David Fekete

Kostas Tzoumas

Mohamed Mokbel

Keliang Zhao

Sunita V Nishanov

Betty Joan Salzberg

Matthew A Neerincx

Chadwin J Mumford

A data manager may include a data opaque interface configured to provide, to an arbitrarily selected page-oriented access method, interface access to page data storage that includes latch-free access to the page data storage. In another aspect, a swap operation may be initiated, of a portion of a first page in cache layer storage to a location in secondary storage, based on initiating a prepending of a partial swap delta record to a page state associated with the first page, the partial swap delta record including a main memory address indicating a storage location of a flush delta record that indicates a location in secondary storage of a missing part of the first page. In another aspect, a page manager may initiate a flush operation of a first page in cache layer storage to a location in secondary storage, based on atomic operations with flush delta records.

Log-structured storage for data access

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 transaction engine includes a multi-version concurrency control (MVCC) module that accesses a latch-free hash table that includes respective hash table entries that include respective buckets of respective bucket items. The bucket items represent respective records, the respective bucket items each including a value indicating a temporal most recent read time of the item and a version list of descriptions that describe respective versions of the respective records, the MVCC module performing timestamp order concurrency control, using the latch-free hash table. Recovery log buffers may be used as cache storage for the transaction engine.

High performance transactions in database management systems

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.

Latch-free, log-structured storage for multiple access methods

Update requests that specify updates to a logical page associated with a key-value store are obtained. Updates to the logical page are posted using the obtained plurality of update requests, without accessing the logical page via a read operation.

High throughput data modifications using blind update operations

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

A request to modify an object in storage that is associated with one or more computing devices may be obtained, the storage organized based on a latch-free B-tree structure. A storage address of the object may be determined, based on accessing a mapping table that includes map indicators mapping logical object identifiers to physical storage addresses. A prepending of a first delta record to a prior object state of the object may be initiated, the first delta record indicating an object modification associated with the obtained request. Installation of a first state change associated with the object modification may be initiated via a first atomic operation on a mapping table entry that indicates the prior object state of the object. For example, the latch-free B-tree structure may include a B-tree like index structure over records as the objects, and logical page identifiers as the logical object identifiers.

Structuring storage based on latch-free B-trees

This patent application relates to enhanced logical recovery techniques for redo recovery operations of a system with an unbundled storage engine. These techniques can be implemented by utilizing an enhanced logical recovery approach in which a dirty page table (DPT) is constructed based on information logged during normal execution. The unbundled storage engine can include a transaction component (TC) that is architecturally independent of a data component (DC). These techniques can enhance redo recovery operations by mitigating the resources needed to determine whether previously executed operations sent from the TC to the DC are to be repeated in response to a recovery-initiating event. This can include using the DPT to avoid fetching every data page corresponding to every previously executed operation received by the DC during recovery and/or pre-fetching data pages and/or index pages that correspond to PIDs in the DPT.

Logical recovery with unbundled transaction services

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.

Automatic transaction retry after session failure

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Redmond, WA, United States of America

David Bruce Lomet