Microsoft Technology Licensing, LLC

Sitaram C Raju

Kyle G Peltonen

Srikanth Shoroff

Bartosz Boleslaw Milewski

A system for performing transaction processing on user data maintains a transaction table. The transaction table holds the identities of structured storages that have been opened but not yet closed by each of the transactions that are accessing the structured storages. Each time that a stream holding user data is opened in a write mode, an internal copy of the stream is made. Changes are applied to the internal copy. At commit time, the following metadata operations are performed as a single atomic transaction. Each copy is renamed to have the name of the original stream. If no other transactions are accessing the stream, the original stream is deleted. However, if other transactions are accessing the stream, the original stream is renamed to have the name of the copy. The metadata transaction is implemented with write-ahead logging. Upon recovery from a system failure, any metadata transaction that was in progress at the time of the failure is undone. Then the transaction table is read to identify each of the structured storages that must be opened and processed to remove any remaining internal copies of streams. In summary, the system provides robust multiuser transacted access to user data through file system metadata transactions and uses a transaction table to optimize system recovery.

Recovering from a failure using a transaction table in connection with

A method and system for improved monitoring of document changes in a search engine by an indexing program. Once an indexing or other such monitoring program is halted, upon restart the monitoring program needs to update its own files and its indexes to reflect document changes that occurred while halted. A file system such as the Windows NT file system persistently logs document change information on disk in a monotonically increasing, uniquely-numbered persistent record, which further identifies the file that has changed. The method and system utilize the logged change information to efficiently maintain the indexes, and to rapidly update the indexes after a shutdown and subsequent restart.

Monitoring document changes in a file system of documents with the

Transaction processing for user data employing both logging and shadow

A method and mechanism for responding to a query in a hierarchically organized system of documents and folders. In response to the query, a set of documents is retrieved based on specified criteria. Only documents in that set which match a specified scope are returned in a result set. Scope testing is performed on each of the documents in the set by obtaining a document identifier of each document, and then using that document identifier to obtain a document identifier of the parent folder thereof. The document identifier of the parent folder is used as a key to a data structure, which stores flags indicative of whether parent folders are in the specified scope. If the flag for a given parent folder indicates that the parent folder is in scope, the document having that parent is returned in the result set. If the flag indicates that the current document is not in scope, that document is not returned. If there was not an entry in the data structure for that key, prefix matching is performed on the parent folder to determine whether it is in scope. The parent folder scope information is then added to the data structure as a flag indexed by the document identifier of the parent folder.

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Sitaram C Raju