Yan Leshinsky

A storage engine may implement dynamic splitting of contentious data pages. Data pages may store data for a table of a data store as part of an indexing structure for the table. Access to the table may be provided by locating the corresponding data pages via the indexing structure. Access contention for different data pages may be monitored. Data pages may be identified for splitting based on the monitoring. A split operation for an identified data page may be formed to store the data on the… Show more

A storage engine may implement dynamic splitting of contentious data pages. Data pages may store data for a table of a data store as part of an indexing structure for the table. Access to the table may be provided by locating the corresponding data pages via the indexing structure. Access contention for different data pages may be monitored. Data pages may be identified for splitting based on the monitoring. A split operation for an identified data page may be formed to store the data on the identified data page on two different data pages so that subsequent access requests for the data are divided between the two data pages. Monitoring of access contention may also be performed to identify data pages for merging in order to consolidate access requests to a single data page. Show less

A data store may implement variable data replication and quorum-based durability schemes. Write requests may be maintained in complete views of the data or incomplete views of the data at storage nodes in a quorum set in the data store. Write requests may be received at different storage nodes sufficient to establish a write quorum, and stored in the replicas of the data at the storage nodes where they are received. Storage nodes maintaining incomplete views of the data may determine that each… Show more

A data store may implement variable data replication and quorum-based durability schemes. Write requests may be maintained in complete views of the data or incomplete views of the data at storage nodes in a quorum set in the data store. Write requests may be received at different storage nodes sufficient to establish a write quorum, and stored in the replicas of the data at the storage nodes where they are received. Storage nodes maintaining incomplete views of the data may determine that each of the storage nodes maintaining a complete view of the data in the quorum set stores certain write requests, and in response, may reclaim storage space for those write requests included in the incomplete views of the data in order to store other data at the storage node. Show less

A database system may receive a write request that specifies a modification to be made to a particular data record stored by the database system. A log record representing the modification to be made to the particular data record may be sent to a storage service of the database system. An indication (e.g., log record or other indication) that indicates a cached version of the particular data record stored in a read replica's cache is stale may be sent to a read replica. For a subsequent read of… Show more

A database system may receive a write request that specifies a modification to be made to a particular data record stored by the database system. A log record representing the modification to be made to the particular data record may be sent to a storage service of the database system. An indication (e.g., log record or other indication) that indicates a cached version of the particular data record stored in a read replica's cache is stale may be sent to a read replica. For a subsequent read of the particular data record received by the read replica, the read replica may request the particular data record from the storage service. Show less

A distributed data store may provide continuous backup for data stored in the distributed data store. Updates to data may be replicated amongst storage nodes according to a peer-to-peer replication scheme. A backup node may participate in the peer-to-peer replication scheme to identify additional updates to be applied to a backup version of the data in a separate data store. The backup node may obtain the updates according to the peer-to-peer replication scheme and update the backup version of… Show more

A distributed data store may provide continuous backup for data stored in the distributed data store. Updates to data may be replicated amongst storage nodes according to a peer-to-peer replication scheme. A backup node may participate in the peer-to-peer replication scheme to identify additional updates to be applied to a backup version of the data in a separate data store. The backup node may obtain the updates according to the peer-to-peer replication scheme and update the backup version of the data. In some embodiments, configuration changes to the data in the distributed data store may be detected via the peer-to-peer replication scheme such that a backup node can adapt performance of backup operations in conformity with the configuration change. Show less

A distributed data store may implement passive distribution encryption keys to enable access to encrypted data stored in the distributed data store. Keys to encrypt a data volume stored in the distributed data store may be encrypted according to a distribution key and provided to a client of the distributed data store. Storage nodes that maintain portions of the data volume may receive the encrypted key from a client to enable access to the data volume. The storage nodes may decrypt the key… Show more

A distributed data store may implement passive distribution encryption keys to enable access to encrypted data stored in the distributed data store. Keys to encrypt a data volume stored in the distributed data store may be encrypted according to a distribution key and provided to a client of the distributed data store. Storage nodes that maintain portions of the data volume may receive the encrypted key from a client to enable access to the data volume. The storage nodes may decrypt the key according to the distribution key and enable access to the data volume at the storage nodes. In to some embodiments, a key hierarchy may be implemented to encrypt the keys that provide access to the encrypted data. The key hierarchy may include a user key.

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A database management system may utilize a log-structured storage system instead of a conventional storage system. The log-structured storage system may store a baseline of an object and a series of log entries describing changes to the object. At various positions in the log, a combined record may be written to contain a description of a change to the object and a copy of the corresponding version of the object. Combined records may be used to employ alternative strategies for constructing or… Show more

A database management system may utilize a log-structured storage system instead of a conventional storage system. The log-structured storage system may store a baseline of an object and a series of log entries describing changes to the object. At various positions in the log, a combined record may be written to contain a description of a change to the object and a copy of the corresponding version of the object. Combined records may be used to employ alternative strategies for constructing or transmitting a version of an object. Embodiments may employ these alternative strategies for replication and data caches.

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A log-structured distributed storage system may implement individual write quorums. Log records may be sent to different storage nodes of a quorum set storing data for a storage client sufficient to satisfy a write quorum requirement. For each log record, acknowledgments from storage nodes are received, and a determination is made whether the write quorum requirement is satisfied for the log record. Different log records may be maintained at different storage nodes, and still satisfy the write… Show more

A log-structured distributed storage system may implement individual write quorums. Log records may be sent to different storage nodes of a quorum set storing data for a storage client sufficient to satisfy a write quorum requirement. For each log record, acknowledgments from storage nodes are received, and a determination is made whether the write quorum requirement is satisfied for the log record. Different log records may be maintained at different storage nodes, and still satisfy the write quorum requirement such that in some embodiments no one storage node may maintain all of the log records sent to storage nodes in the quorum set.

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A distributed database system may implement dynamic quorum group membership changes. In various embodiments, a quorum set may maintain a replica of a data object among group members according to a protection group policy for the data object. A group member may be identified as to be replaced. In response, a new quorum set may be created from the remaining group members and a new group member. The protection group policy may be updated to include the new group members such that subsequently… Show more

A distributed database system may implement dynamic quorum group membership changes. In various embodiments, a quorum set may maintain a replica of a data object among group members according to a protection group policy for the data object. A group member may be identified as to be replaced. In response, a new quorum set may be created from the remaining group members and a new group member. The protection group policy may be updated to include the new group members such that subsequently received updates are maintained at both the previous quorum set and the new quorum set. Previously received updates may be replicated on the new group member. Upon completion of replicating the previously received updates, the protection group policy for the data object may be revised such that subsequently received updates are maintained at the new quorum set. Show less

A data store maintaining data may implement reducing input/output (I/O) operations for on-demand data page generation. Log records may be maintained for data pages of data describing changes to the data pages. A coalesce operation may be performed when log records for a data page exceed a coalesce threshold for the data page, applying the log records for the data page to a version of the data page and creating a new version that includes the changes indicated by the log records. An indication… Show more

A data store maintaining data may implement reducing input/output (I/O) operations for on-demand data page generation. Log records may be maintained for data pages of data describing changes to the data pages. A coalesce operation may be performed when log records for a data page exceed a coalesce threshold for the data page, applying the log records for the data page to a version of the data page and creating a new version that includes the changes indicated by the log records. An indication may be received to increase the coalesce threshold for a particular data page, delaying a coalesce operation for the data page according to the increased coalesce threshold. The indication may be received from a storage engine that identifies a delay for the particular data page.

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Self-describing data blocks of a minimum atomic write size may be stored for a data store. Data may be received for storage in a data block at a persistent storage device. Metadata may be generated for the data that includes an error detection code which is generated for the data and the metadata together. An individual atomic write operation may write together the data and the metadata in the data block. When accessed, the error detection code is applicable to detect errors and the metadata… Show more

Self-describing data blocks of a minimum atomic write size may be stored for a data store. Data may be received for storage in a data block at a persistent storage device. Metadata may be generated for the data that includes an error detection code which is generated for the data and the metadata together. An individual atomic write operation may write together the data and the metadata in the data block. When accessed, the error detection code is applicable to detect errors and the metadata may also be applicable to determine whether the data is stored for a currently assigned purpose or a previously assigned purpose of the data block.

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A data store maintaining data may implement memory-based on-demand data page generation. Log records may be maintained in system memory according to a version threshold for data pages of data stored in persistent storage. When a request for a version of a particular data page is received that is within the version threshold, the data page may be obtained from persistent storage and log records associated with the data page may be applied to the data page to generate the requested version of the… Show more

A data store maintaining data may implement memory-based on-demand data page generation. Log records may be maintained in system memory according to a version threshold for data pages of data stored in persistent storage. When a request for a version of a particular data page is received that is within the version threshold, the data page may be obtained from persistent storage and log records associated with the data page may be applied to the data page to generate the requested version of the data page. The version threshold for the data pages may change, and log records in system memory may be identified for coalesce operations. The coalesce operations may be efficiently performed (e.g., in the background), updating the data pages in persistent storage to include the changes of the identified log records and space in system memory for the identified log records may be reclaimed. Show less

A log-structured data store implementing data backup may implement variable data replication. Write requests may be received at different storage nodes maintaining respective replicas of a portion of a log for data maintained in the log-structured data store. Log records indicating the write requests may be stored in the respective replicas of the log portions at the different storage nodes. The log records may be sent to a backup data store to be durability persisted as part of an archived… Show more

A log-structured data store implementing data backup may implement variable data replication. Write requests may be received at different storage nodes maintaining respective replicas of a portion of a log for data maintained in the log-structured data store. Log records indicating the write requests may be stored in the respective replicas of the log portions at the different storage nodes. The log records may be sent to a backup data store to be durability persisted as part of an archived version of the log. At some of the storage nodes, in response to determining that the log records have been durably persisted in the backup data store, storage space for the log records may be reclaimed. In other remaining storage nodes, the log records may be retained and made accessible for servicing read requests. Show less

Hybrid quorum policies may be implemented for access requests to state maintained in a distributed system. An update to state maintained in a distributed system may be sent to multiple nodes in the distributed system maintain the state in order to satisfy a hybrid quorum policy for updating the state in the distributed system. The hybrid quorum policy may include individual quorum policies for multiple quorum sets including nodes of the distributed system. Acknowledgments received from nodes in… Show more

Hybrid quorum policies may be implemented for access requests to state maintained in a distributed system. An update to state maintained in a distributed system may be sent to multiple nodes in the distributed system maintain the state in order to satisfy a hybrid quorum policy for updating the state in the distributed system. The hybrid quorum policy may include individual quorum policies for multiple quorum sets including nodes of the distributed system. Acknowledgments received from nodes in the distributed system indicating that the update is performed may be evaluated according to the individual quorum policies to determine whether the hybrid quorum policy is satisfied. If the hybrid quorum policy is satisfied, then the update to the state may be considered durable. Show less

A storage client and a quorum-based distributed storage system may implement dynamic utilization of bandwidth for a quorum-based distributed storage system. An update at a storage client may be received, and storage nodes of a protection group may be sent a write request indicating the update. In some embodiment, storage nodes that receive the write request may determine whether other storage nodes have not received the update and send the write request to be completed at those other storage… Show more

A storage client and a quorum-based distributed storage system may implement dynamic utilization of bandwidth for a quorum-based distributed storage system. An update at a storage client may be received, and storage nodes of a protection group may be sent a write request indicating the update. In some embodiment, storage nodes that receive the write request may determine whether other storage nodes have not received the update and send the write request to be completed at those other storage nodes. In some embodiments, if a latency threshold is exceeded other storage nodes in the protection group not previously sent the write request may be identified and sent the write request. Based on acknowledgements received from storage nodes in the distributed storage system, it may be determined whether a write quorum requirement is met for a write request.

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A distributed database system may implement log-structured distributed storage using a single log sequence number space. A log for a data volume may be maintained in a log-structured distributed storage system. The log may be segmented across multiple protection groups according to a partitioning of user data for the data volume. Updates to the log may be assigned a log sequence number from a log sequence number space for the data volume. A protection group may be determined for an update… Show more

A distributed database system may implement log-structured distributed storage using a single log sequence number space. A log for a data volume may be maintained in a log-structured distributed storage system. The log may be segmented across multiple protection groups according to a partitioning of user data for the data volume. Updates to the log may be assigned a log sequence number from a log sequence number space for the data volume. A protection group may be determined for an update according to which partition of user data space the update pertains. Metadata to be included with the log record may indicate a previous log sequence number of a log record maintained at the protection group. The log record may be sent to the protection group and identified as committed based on acknowledgments received from storage nodes implementing the protection group. Show less

A log-structured data store may implement efficient garbage collection. Log records may be maintained in data blocks according to a log record sequence. Based, at least in part, on a log reclamation point, the log records may be evaluated to identify data blocks to reclaim that have log records in the log sequence prior to the log reclamation point. New versions of data pages updated by log records in the identified data blocks may be generated and stored in base page storage for the log… Show more

A log-structured data store may implement efficient garbage collection. Log records may be maintained in data blocks according to a log record sequence. Based, at least in part, on a log reclamation point, the log records may be evaluated to identify data blocks to reclaim that have log records in the log sequence prior to the log reclamation point. New versions of data pages updated by log records in the identified data blocks may be generated and stored in base page storage for the log structured data store. The identified data blocks may then be reclaimed for storing new data.

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A computing system recovers volumes in a distributed computing environment while reducing downtime of storage servers. In an embodiment, a storage server contacts a control plane after a storage failure has occurred. If the storage server hosts an authoritative copy of an offline volume, the storage server is requested to restore the volume. Non-authoritative volumes are removed from the storage server and the storage server provides read access to the restored volume while resuming storage… Show more

A computing system recovers volumes in a distributed computing environment while reducing downtime of storage servers. In an embodiment, a storage server contacts a control plane after a storage failure has occurred. If the storage server hosts an authoritative copy of an offline volume, the storage server is requested to restore the volume. Non-authoritative volumes are removed from the storage server and the storage server provides read access to the restored volume while resuming storage services. Show less

A log-structured data store may implement optimized log storage for asynchronous log updates. In some embodiments, log records may be received indicating updates to data stored for a storage client and indicating positions in a log record sequence. The log records themselves may not be guaranteed to be received according to the log record sequence. Received log records may be stored in a hot log portion of a block-based storage device according to an order in which they are received. Log… Show more

A log-structured data store may implement optimized log storage for asynchronous log updates. In some embodiments, log records may be received indicating updates to data stored for a storage client and indicating positions in a log record sequence. The log records themselves may not be guaranteed to be received according to the log record sequence. Received log records may be stored in a hot log portion of a block-based storage device according to an order in which they are received. Log records in the hot log portion may then be identified to be moved to a cold log portion of the block-based storage device in order to complete a next portion of the log record sequence. Log records may be modified, such as compressed, or coalesced, before being stored together in a data block of the cold log portion according to the log record sequence. Show less

Application program data stored in system memory may be selectively persisted. An indication may be provided to an application program that an application data object or a range of application data stored in system memory may be treated as persistent. Data backup may be enabled for the application data object or range of application data in the event of a system failure, copying the application data object or range of application data from system memory to non-volatile data storage. Upon… Show more

Application program data stored in system memory may be selectively persisted. An indication may be provided to an application program that an application data object or a range of application data stored in system memory may be treated as persistent. Data backup may be enabled for the application data object or range of application data in the event of a system failure, copying the application data object or range of application data from system memory to non-volatile data storage. Upon recovery from a system failure, further data backup for the application data object or the range of application data may be disabled. In some embodiments, at least some of the application data object or range of application data may be recovered for the application program to access. Data backup for the application data object or the range of application data may also be re-enabled. Show less

A data volume may be shelved based at least in part on statistical triggers associated with the data, a user of the data, or a system configured to store and/or manage the data. Upon receiving a request to detach a data volume from a computing device, a determination of whether the data volume should be shelved may be made. In some aspects, the data volume may be shelved by moving the data to another storage system, storing an identifier of the data volume, and de-allocating space associated… Show more

A data volume may be shelved based at least in part on statistical triggers associated with the data, a user of the data, or a system configured to store and/or manage the data. Upon receiving a request to detach a data volume from a computing device, a determination of whether the data volume should be shelved may be made. In some aspects, the data volume may be shelved by moving the data to another storage system, storing an identifier of the data volume, and de-allocating space associated with the shelved data such that the shelved data is no longer maintained in the storage system. Further, in some aspects, upon a request to attach the data volume, the data may be moved back, the original identifier may be re-assigned to the data volume, and the data volume may be re-attached to the computing device. Show less

A system that implements a scalable data storage service may maintain tables in a data store on behalf of storage service clients. The service may maintain table data in multiple replicas of partitions that are stored on respective computing nodes in the system. In response to detecting an anomaly in the system, detecting a change in data volume on a partition or service request traffic directed to a partition, or receiving a service request from a client to split a partition, the data storage… Show more

A system that implements a scalable data storage service may maintain tables in a data store on behalf of storage service clients. The service may maintain table data in multiple replicas of partitions that are stored on respective computing nodes in the system. In response to detecting an anomaly in the system, detecting a change in data volume on a partition or service request traffic directed to a partition, or receiving a service request from a client to split a partition, the data storage service may create additional copies of a partition replica using a physical copy mechanism. The data storage service may issue a split command defined in an API for the data store to divide the original and additional replicas into multiple replica groups, and to configure each replica group to maintain a respective portion of the table data that was stored in the partition before the split.
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Self-describing data blocks of a minimum atomic write size may be stored for a data store. Data may be received for storage in a data block of a plurality of data blocks at a persistent storage device that are equivalent to a minimum atomic write size for the persistent storage device. Metadata may be generated for the data that includes an error detection code which is generated for the data and the metadata together. The data and the metadata are sent to the persistent storage device to store… Show more

Self-describing data blocks of a minimum atomic write size may be stored for a data store. Data may be received for storage in a data block of a plurality of data blocks at a persistent storage device that are equivalent to a minimum atomic write size for the persistent storage device. Metadata may be generated for the data that includes an error detection code which is generated for the data and the metadata together. The data and the metadata are sent to the persistent storage device to store together in the data block. An individual atomic write operation may write together the data and the metadata in the data block. When accessed, the error detection code is applicable to detect errors. The metadata may also be applicable to determine whether the data is stored for a currently assigned purpose or a previously assigned purpose of the data block. Show less

The claimed subject matter provides a system and/or a method that facilitates seamless integration of a data storage service within an operating system (OS). An online safe deposit box can store a portion of data, wherein the online safe deposit box is hosted by a data storage service provider. A local operating system associated with a device can leverage a graphic user interface (GUI) to interact with a portion of data associated with the device. A map component can create a mapped drive that… Show more

The claimed subject matter provides a system and/or a method that facilitates seamless integration of a data storage service within an operating system (OS). An online safe deposit box can store a portion of data, wherein the online safe deposit box is hosted by a data storage service provider. A local operating system associated with a device can leverage a graphic user interface (GUI) to interact with a portion of data associated with the device. A map component can create a mapped drive that integrates the online safe deposit box within the local operating system to enable seamless data interaction between the local operating system and the online safe deposit box, wherein the data interaction is at least one of a data upload from the local operating system to the online safe deposit box or a data download from the online safe deposit box to the local operating system.
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The claimed subject matter provides a system and/or a method that facilitates employing a safe deposit box that allows perpetual archiving of data. An online safe deposit box can store a portion of data, wherein the online safe deposit box is hosted by a data storage service provider. An archival model component can implement the online safe deposit box for perpetual archival of the portion of data. The archival model component can ensure at least one of the following: the online safe deposit… Show more

The claimed subject matter provides a system and/or a method that facilitates employing a safe deposit box that allows perpetual archiving of data. An online safe deposit box can store a portion of data, wherein the online safe deposit box is hosted by a data storage service provider. An archival model component can implement the online safe deposit box for perpetual archival of the portion of data. The archival model component can ensure at least one of the following: the online safe deposit retains the portion of data for a pre-defined duration; the portion of data within the online safe deposit box is accessible solely by an authorized entity; or the integrity of the portion of data is maintained, wherein the integrity is modified solely by an authorized user. Show less

The claimed subject matter relates to systems and/or methodologies that facilitate distributed storage of data. A distributed file system can be implemented on storage nodes such that the system places multiple copies of data (e.g., replicas) on a variety of disparate storage nodes to guarantee availability of the data and minimize loss of the data. Storage nodes are dynamically evaluated to identify respective characteristics. In one example, the characteristics can include availability of a… Show more

The claimed subject matter relates to systems and/or methodologies that facilitate distributed storage of data. A distributed file system can be implemented on storage nodes such that the system places multiple copies of data (e.g., replicas) on a variety of disparate storage nodes to guarantee availability of the data and minimize loss of the data. Storage nodes are dynamically evaluated to identify respective characteristics. In one example, the characteristics can include availability of a storage node, capacity of a storage node, data storage cost associated with a storage node, data transfer costs associated with a storage node, locality of a storage node, network topology, or user preferences associated with a storage node. The characteristics can be employed to generate optimal placements decisions. Show less

The claimed subject matter relates to an architecture that can determine costs associated with updating file formats. In particular, the architecture can interface with a network-accessible data storage service in order to determine a cost-benefit to the data storage service for a wide variety of conversion scenarios applicable to the particular topology of the data storage service. For example, the cost-benefit can differ for storage services configured according to a client-server model… Show more

The claimed subject matter relates to an architecture that can determine costs associated with updating file formats. In particular, the architecture can interface with a network-accessible data storage service in order to determine a cost-benefit to the data storage service for a wide variety of conversion scenarios applicable to the particular topology of the data storage service. For example, the cost-benefit can differ for storage services configured according to a client-server model relative to storage services configured according to a distributed topology. Regardless, the architecture can identify a legacy format, select a converter for converting the legacy format to the updated format, and then determine the cost-benefit for a variety of conversion or migration scenarios.
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The claimed subject matter relates to a network-accessible, online data archival service with a data store for archiving data for clients of the archival service. The archival service can include an architecture that can facilitate perpetual sustainability and accessibility of data by conforming to a model. In particular, the model can describe or define a minimum set of extensible or pluggable components or modules needed to facilitate and guarantee sustainability of and accessibility to the… Show more

The claimed subject matter relates to a network-accessible, online data archival service with a data store for archiving data for clients of the archival service. The archival service can include an architecture that can facilitate perpetual sustainability and accessibility of data by conforming to a model. In particular, the model can describe or define a minimum set of extensible or pluggable components or modules needed to facilitate and guarantee sustainability of and accessibility to the data in perpetuity. Show less

The subject invention pertains to a system and method of extending programming languages to enable static inheritance. In particular, static subclasses can be defined which extend class functionality and/or behaviors without extending base class state. The subclasses can be specified to include static fields as well as static or instance methods and/or properties that provide a more specific interpretation of an object without extending the state thereof. Furthermore, a static subclass can be… Show more

The subject invention pertains to a system and method of extending programming languages to enable static inheritance. In particular, static subclasses can be defined which extend class functionality and/or behaviors without extending base class state. The subclasses can be specified to include static fields as well as static or instance methods and/or properties that provide a more specific interpretation of an object without extending the state thereof. Furthermore, a static subclass can be specified to provide for type aliasing. Casting is also enabled in both directions between base class type and derived class type in a convenient manner without run-time performance penalties. According to one aspect of the invention, the disclosed systems and methods can be employed to create specific programmatic context, for instance for accessing, manipulating, and type checking external data (e.g., XML).
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The subject invention pertains to a system and method of incorporating collation information into data types. In particular, the subject invention provides for parameterizing data types with collation information such that a comparison between two different collations generates a static-type error rather than a run-time error. Additionally, the invention affords for conveniently working with localized data types to allow generic parameterization over collations as well as ordinary types. In the… Show more

The subject invention pertains to a system and method of incorporating collation information into data types. In particular, the subject invention provides for parameterizing data types with collation information such that a comparison between two different collations generates a static-type error rather than a run-time error. Additionally, the invention affords for conveniently working with localized data types to allow generic parameterization over collations as well as ordinary types. In the context of strings, the present invention enables concurrent use of strings in multiple languages and facilitates the correct handling thereof.
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An application program interface (API) provides a set of functions for application developers who build Web applications on Microsoft Corporation's .NET.TM. platform.

A method and system that facilitates automatic software updates from an online source such as the Internet, wherein a connection to determine whether an update (e.g., a driver or software component) is available online is no longer necessary during detection time. Information stored for updates corresponding to driver and other software component detection is locally cached, whereby update information is available when no connection exists, eliminating potentially wasted connections and being… Show more

A method and system that facilitates automatic software updates from an online source such as the Internet, wherein a connection to determine whether an update (e.g., a driver or software component) is available online is no longer necessary during detection time. Information stored for updates corresponding to driver and other software component detection is locally cached, whereby update information is available when no connection exists, eliminating potentially wasted connections and being particularly advantageous if occurring before the connection can be made. When a device is installed or software components are detected, instead of requiring a connection to enable updates, the cached information is evaluated to determine whether the update is available online. If so, the update is made when a connection is made and otherwise desired by the user. The user may defer making the connection, and the update may happen automatically and/or in the background on the next connection. Show less

An application program interface (API) provides a set of functions that make available support for processing XML documents for application developers who build Web applications on Microsoft Corporation's .NET.TM. platform.