Abstract: Disclosed herein are system, method, and computer program product embodiments for adaptive caching for hybrid columnar databases with heterogeneous page sizes. An embodiment operates by scanning one or more pools comprising one or more pages of the same size in a buffer cache. The embodiment determines an increment of a reuse rate for the pools in the buffer cache within a time interval. The embodiment determines a cumulative reuse rate that is the sum of the increments of the reuse rate over several time intervals. The embodiment determines a gliding average reuse rate of the cumulative reuse rate over several time intervals. The embodiment compares the average reuse rates of the plurality of the pools to a threshold to dynamically determine whether a pool should reuse memory from the existing pages of the same pool or rebalance memory from one or more victim pools.

Abstract: A system for managing database logging, the comprises a processor; and a user task executing in a database server process and executable by the processor, the user task to: receive in a database management system on a database server, a command to manipulate a portion of a database managed by the database management system; obtain a lock on the portion of the database; create a first log record in a first private log cache associated with the user task, the first log record recording a data manipulation to the portion of the database; enqueue the first log record to a queue; and release the lock on the portion of the database after copying the first log record to the queue.

Abstract: Disclosed herein are system, method, and computer program product embodiments for adaptive caching for hybrid columnar databases with heterogeneous page sizes. An embodiment operates by receiving a request to load a new page of memory from a disk in a buffer cache. The embodiment scans one or more pools comprising one or more pages of the same size in a buffer cache. The embodiment determines an increment of a reuse rate for the pools in the buffer cache within a time interval. The embodiment determines a cumulative reuse rate that is the sum of the increments of the reuse rate over several time intervals. The embodiment determines a gliding average reuse rate of the cumulative reuse rate over several time intervals. The embodiment compares the average reuse rates of the plurality of the pools to a threshold to dynamically determine whether a pool should reuse memory from the existing pages of the same pool or rebalance memory from one or more victim pools.

Abstract: Disclosed herein are system, method, and computer program product embodiments for performing fair prefetching. An embodiment operates by splitting a data vector into a first subrange and a second subrange. The embodiment performs a first chance prefetch operation on the first subrange based on a fixed number of pages, thereby loading a set of pages of the first subrange into a main memory. The embodiment performs the first chance prefetch operation on the second subrange based on the fixed number of pages, thereby loading a first set of pages of the second subrange into the main memory. The embodiment performs a second chance prefetch operation on the second subrange based on the performing the first chance prefetch operation on the second subrange, thereby loading a second set of pages of the second subrange into the main memory. The embodiment then executes the query.

Abstract: A computer implemented method for manipulating data comprises receiving log transaction information from a primary database system at a secondary database system and parsing the log transaction information to identify data objects that have been modified on the primary database system. The secondary database system determines whether the data objects are present in main memory on the secondary database system and whether the log transaction corresponds to a data manipulation language (DML) query or a data definition language (DDL) query. If the data objects are not in the main memory and the query is a DML query, they are copied from persistence data volumes to the main memory. The data objects in main memory are modified by replaying the log transactions on the data objects in the main memory. Then, the data objects in the persistence data volumes are modified. Related apparatus, systems, techniques and articles are also described.

Abstract: Disclosed herein are system, method, and computer program product embodiments for performing fair prefetching. An embodiment operates by splitting a data vector into a first subrange and a second subrange. The embodiment performs a first chance prefetch operation on the first subrange based on a fixed number of pages, thereby loading a set of pages of the first subrange into a main memory. The embodiment performs the first chance prefetch operation on the second subrange based on the fixed number of pages, thereby loading a first set of pages of the second subrange into the main memory. The embodiment performs a second chance prefetch operation on the second subrange based on the performing the first chance prefetch operation on the second subrange, thereby loading a second set of pages of the second subrange into the main memory. The embodiment then executes the query.

Abstract: A system for managing database logging, the comprises a processor; and a user task executing in a database server process and executable by the processor, the user task to: receive in a database management system on a database server, a command to manipulate a portion of a database managed by the database management system; obtain a lock on the portion of the database; create a first log record in a first private log cache associated with the user task, the first log record recording a data manipulation to the portion of the database; enqueue the first log record to a queue; and release the lock on the portion of the database after copying the first log record to the queue.

Abstract: A system for managing database logging, the comprises a processor; and a user task executing in a database server process and executable by the processor, the user task to: receive in a database management system on a database server, a command to manipulate a portion of a database managed by the database management system; obtain a lock on the portion of the database; create a first log record in a first private log cache associated with the user task, the first log record recording a data manipulation to the portion of the database; enqueue the first log record to a queue; and release the lock on the portion of the database after copying the first log record to the queue.

Abstract: Objects across multiple database manipulation language (DML) redo log records are cached, during continuous replay of redo log records on a secondary system, for the same table partition to enable reuse of such cached objects. Later, these cached objects can be reused as they are accessed during the sequential processing of DML redo records for a specific table partition.

Abstract: Objects across multiple database manipulation language (DML) redo log records are cached, during continuous replay of redo log records on a secondary system, for the same table partition to enable reuse of such cached objects. Later, these cached objects can be reused as they are accessed during the sequential processing of DML redo records for a specific table partition.

Abstract: A computer implemented method for manipulating data comprises receiving log transaction information from a primary database system at a secondary database system and parsing the log transaction information to identify data objects that have been modified on the primary database system. The secondary database system determines whether the data objects are present in main memory on the secondary database system and whether the log transaction corresponds to a data manipulation language (DML) query or a data definition language (DDL) query. If the data objects are not in the main memory and the query is a DML query, they are copied from persistence data volumes to the main memory. The data objects in main memory are modified by replaying the log transactions on the data objects in the main memory. Then, the data objects in the persistence data volumes are modified. Related apparatus, systems, techniques and articles are also described.

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: 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: A system for managing database logging, the comprises a processor; and a user task executing in a database server process and executable by the processor, the user task to: receive in a database management system on a database server, a command to manipulate a portion of a database managed by the database management system; obtain a lock on the portion of the database; create a first log record in a first private log cache associated with the user task, the first log record recording a data manipulation to the portion of the database; enqueue the first log record to a queue; and release the lock on the portion of the database after copying the first log record to the queue.