Abstract: Aspects of the disclosure are directed to a metadata cache for extending data warehouse features to data lakes. The metadata cache can accelerate query execution by directly accessing unmanaged data from the data lake rather than accessing the data through the data warehouse. The metadata cache can allow for filtering the unmanaged data to improve the speed of retrieving data for executing a query.

Abstract: A method for unstructured data analytics in data warehouses includes receiving an unstructured data query from a user, the unstructured data query requesting the data processing hardware determine one or more unstructured data files stored at a data repository that match query parameters. The method includes determining, using an object table, a set of unstructured data files stored at the data repository that matches the query parameters. The object table includes a plurality of rows, each row of the plurality of rows associated with a respective unstructured data file stored at the data repository, and a plurality of columns, each column of the plurality of columns comprising metadata associated with the respective unstructured data file of each row of the plurality of rows. The method includes returning, to the user, a structured data table including the determined set of unstructured data files.

Abstract: Systems and methods are disclosed to implement, in a multi-writer database system, a database engine node that optimistically sends queued purge operations to a backend storage system without waiting for acknowledgement of previous operations from the storage system. If a conflict is later detected for a particular operation, the database engine node may retry some portion of the purge operations in the queue. In embodiments, the purge operations are performed as part of a garbage collection phase of a multi-version concurrency control (MVCC) protocol, where unneeded versions of objects previously generated for isolated snapshots are deleted. In embodiments, the operations in the queue may be grouped so that a rejection of one operation in the group will cause the entire group to be retried. Because these purge operations are idempotent and directed to objects that are invisible, they may be freely retried in arbitrary order, without maintaining any rollback state.

Abstract: Queries to a consistent view of a data set across different types of query engines are performed. Portions of a query received at a first type of query engine that can be performed at a different type of a query engine can be identified. A consistent view of a data set stored in a common data store can be provided by the first type of query engine to the second query engine. When the different type of query engine performs the portion of the query, the different type of query engine applies the consistent view of the data set. A result for the query can be returned by the first type of query engine based on results from the different type of query engine.

Abstract: The present disclosure provides a storage engine that unifies data warehouses and lakes, by providing uniform fine-grained access control, performance acceleration across multi-cloud storage, and open formats. It provides an application programming interface (API) for query engines spanning across data warehouse and open source runtimes to access distributed data with consistent security and governance controls. Access is evaluated at the API layer, separate from the query engine, and is uniformly enforced across query engines.

Abstract: Systems and methods are disclosed to implement, in a database system, a database engine node that generates write tracking transactions to atomically enforce cross-page constraints for write operations. In embodiments, the database system may include multiple database engine nodes that optimistically perform page writes without checking for potential conflicts at a shared storage system. The storage system is configured to detect and report conflicting writes on the same page. To cause the storage system to report cross-page conflicts for a write, the database engine node creates a transaction that includes the write and a write tracker (WT) operation for a tracked page. The WT operation will cause the storage system to report any conflicting writes to the tracked page before the actual write is accepted by the storage system. If a reported conflict is not favorably resolved, the database engine node will abort the entire transaction, including the actual write.

Abstract: Batch processing of undo log records may be performed for rolling back a database transaction. When a rollback operation for a database transaction is performed, undo log records from an undo log to rollback the database transaction are divided into different groups of undo log records. Different requests for the different undo log records are sent to a storage system to be performed. If a conflict is detected for an undo log record in a group, an indication of the conflicting undo log record may be provided to indicate the conflict. The group of undo log records may be resent with a request to reapply the undo log records in the group. When all groups have been identified as successfully completed, then the rollback operation may be considered completed.

Abstract: 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.

Abstract: Systems and methods are disclosed to implement, in a database system, database engine nodes that implement multi-page writes as an atomic operation. In embodiments, the database system may include multiple database engine nodes that optimistically perform page writes locally without checking for potential conflicts at a shared storage system. The storage system will detect and report conflicting writes on a single page. To ensure that a group of writes to multiple pages occur atomically, the database engine node maintains a transaction context for the group, so that if a page conflict is later detected for any write in the group, the entire group will be rolled back at the database engine node and the storage system. In embodiments, the transaction context will track subsequent writes generated by the node to any page written by the group, so that these subsequent writes are also rolled back with the group.

Abstract: 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.

Abstract: 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.

Abstract: A current state of one or more entries in a mapping table that are associated with latch-free updates of a data structure that uses indirection mapping tables is accessed. A transformation of the current state of the one or more entries in the mapping table to a transformed state of the entries in the mapping table, is controlled. The controlling includes initiating an atomic multi-word compare-and-swap (MWCAS) operation on a plurality of words using a hardware transactional memory (HTM) resident in a device processor, and the MWCAS operation is performed using hardware primitive operations of the HTM, via the device processor. A transformation of a current state of the data structure to an updated state of the data structure, is controlled, via the transformation of the current state of the one or more entries in the mapping table to the transformed state of the entries in the mapping table.

Abstract: 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.

Abstract: 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.

Abstract: A current state of one or more entries in a mapping table that are associated with latch-free updates of a data structure that uses indirection mapping tables is accessed. A transformation of the current state of the one or more entries in the mapping table to a transformed state of the entries in the mapping table, is controlled. The controlling includes initiating an atomic multi-word compare-and-swap (MWCAS) operation on a plurality of words using a hardware transactional memory (HTM) resident in a device processor, and the MWCAS operation is performed using hardware primitive operations of the HTM, via the device processor. A transformation of a current state of the data structure to an updated state of the data structure, is controlled, via the transformation of the current state of the one or more entries in the mapping table to the transformed state of the entries in the mapping table.

Abstract: 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.

Abstract: 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.

Abstract: A distributed system with transaction support may have a transaction component and one or more data components. The transaction component may manage a transaction using a log sequence number for each operation, and then transmit operations to one or more data components with log sequence numbers. The data components may perform the data operations in an idempotent manner and return a reply. The transaction component may then write the operation, its log sequence number, and information from the reply message to its log. The transaction component is able to commit a transaction, as well as retry or undo portions of a transaction, by using the information stored on its log. This may be possible even when a single transaction uses multiple data components, which may be located on different devices or manage separate and independent data sources.

Abstract: 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.

Abstract: A distributed system with transaction support may have a transaction component and one or more data components. The transaction component may manage a transaction using a log sequence number for each operation, and then transmit operations to one or more data components with log sequence numbers. The data components may perform the data operations in an idempotent manner and return a reply. The transaction component may then write the operation, its log sequence number, and information from the reply message to its log. The transaction component is able to commit a transaction, as well as retry or undo portions of a transaction, by using the information stored on its log. This may be possible even when a single transaction uses multiple data components, which may be located on different devices or manage separate and independent data sources.