Abstract: In some example embodiments, a method comprises: receiving, by a first node of a plurality of nodes in a distributed database system on a shared disk cluster infrastructure, a transaction request to perform a user database transaction a data item in a user database on a shared disk; acquiring, by the first node, a transaction lock for the data item; storing a lock file for the user database transaction in a lock information database on the shared disk, the lock file comprising lock information for the transaction lock and an indication of a status of the user database transaction, and the lock information comprising an identification of a location of the data item; and storing a transaction record of the user database transaction in the user database on the shared disk subsequent to the storing of the lock file in the lock information database on the shared disk.

Abstract: Disclosed herein are system, method, and computer program product embodiments for performing garbage collection in a database management system with a multi-version concurrency control. An embodiment operate by qualifying a multi-version concurrency control (MVCC) block for garbage collection, where the MVCC block includes multiple cells, each cell corresponding to a row of a table that was acted on by a transaction. Determining that the MVCC block can be garbage collected based on MVCC information in the MVCC block, where the MVCC information includes information that determines whether changes made to rows in the multiple cells are visible in a database management system. Based on the determining, garbage collecting the MVCC block.

Abstract: Disclosed herein are system, method, and computer program product embodiments for performing garbage collection in a database management system with a multi-version concurrency control. An embodiment operate by qualifying a multi-version concurrency control (MVCC) block for garbage collection, where the MVCC block includes multiple cells, each cell corresponding to a row of a table that was acted on by a transaction. Determining that the MVCC block can be garbage collected based on MVCC information in the MVCC block, where the MVCC information includes information that determines whether changes made to rows in the multiple cells are visible in a database management system. Based on the determining, garbage collecting the MVCC block.

Abstract: An operation on a row of a table of a database is initiated. Thereafter, a multi-version concurrency control (MVCC) object is accessed to identify blocks associated with the row position of the row using bitwise operations. Subsequently, a row state block computed based on the row position of the row is accessed to determine a row state for the row. At least one other block is accessed, based in part on the row state, to obtain at least one timestamp from the computed offset based on the row. Next, the at least one timestamp is stored or retrieved. Related apparatus, systems, techniques and articles are also described.

Abstract: Lockless allocation of a block from a page is initiated by computing a needed block size from an original block header value. Thereafter, a currently used block size and a capacity of the page are determined. A new block size is then computed based on the currently used block size and the needed block size and a remaining capacity of the page. A new block header value is subsequently generated that includes the determined new block size and the determined remaining capacity of the page The original block header value is then replaced with the new block header value. Related apparatus, systems, techniques and articles are also described.

Abstract: System, method, computer program product embodiments and combinations and sub-combinations thereof for managing data storage as an in-memory database in a database management system (DBMS) are provided. In an embodiment, a specialized database type is provided as a parameter of a native DBMS command. A database hosted entirely in-memory of the DBMS is formed when the specialized database type is specified.

Abstract: Embodiments include a method, apparatus and computer program product for providing access to a database data source during database maintenance. The method includes initiating maintenance of the database data source and managing the database maintenance to allow concurrent access to the database data source.

Abstract: System, method, computer program product embodiments and combinations and sub-combinations thereof for managing data storage as an in-memory database in a database management system (DBMS) are provided. In an embodiment, a specialized database type is provided as a parameter of a native DBMS command. A database hosted entirely in-memory of the DBMS is formed when the specialized database type is specified.