225 results about "Database transaction" patented technology

An incrementally-scalable database system and method. The system architecture enables database servers to be scaled by adding resources, such as additional servers, without requiring that the system be taken offline. Such scaling includes both adding one or more computer servers to a given server cluster, which enables an increase in database read transaction throughput, and adding one or more server clusters to the system configuration, which provides for increased read and write transaction throughput. The system also provides for load balancing read transactions across each server cluster, and load balancing write transactions across a plurality of server clusters. The system architecture includes an application server layer including one or more computers on which an application program(s) is running, a database server layer comprising two or more server clusters that each include two or more computer servers with replicated data, and an intermediate "virtual transaction" layer that includes at least two computers that facilitate database transactions with one or more databases operating in the database server layer. Data in the database(s) are evenly distributed across the server clusters in fragmented mutually exclusive subsets of data based on a hashing function. An application program interface is provided so as to enable application programs to perform a full range of database transactions without regard for where data is stored, or what database(s) is operating in the database server layer.

A computer readable medium storing executable instructions includes executable instructions to: receive a continuous stream of database transactions; form batches of database transactions from the continuous stream of database transactions; combine batches of database transactions with similar operations to form submission groups; identify dependencies between submission groups to designate priority submission groups; and apply priority submission groups to a database target substantially synchronously with the receipt of the continuous stream of database transactions.

A heterogeneous information system such as a digital library often uses a database manager together with other data resource manager(s), such as an object server or a video server, to manage digital content. Such a system often needs to maintain an application-specific database and/or to handle application-specific operational requirements. To facilitate system integration and application development, an application-independent reusable product is created which generates a custom system component or utility, such as a loader, according to a specification provided by a system integrator or an application developer.

A system and method avoids anomalies in presence of data manipulation language (DML) plans maintaining dependent objects and snapshot isolation. An anomaly due to using a snapshot isolation level within the transaction is detected within a database transaction and the transaction is aborted based upon that detection. Involved in making the anomaly detection is determining whether a view of particular data accessed during the transaction under a snapshot isolation view to ensure read consistency differs from a view of the data under another isolation level, such as the read committed isolation level. Then a detection is made that an anomaly may occur if it is determined that the view of the data accessed during the transaction under the snapshot isolation differs from the view of the data under the other isolation level. Such anomaly avoidance prevents an indexed view being maintained nor a referential integrity constraint validated based on incorrect data.

Systems and methods for reslicing data in a representation of a relational database are disclosed. In one embodiment, the database includes a representation including a first slice. The database system creates a plurality of new slice and to create a plurality of write queues. The database system copies units of data in the first slice to the new slices according to a distribution function. The distribution function determines, for each unit of data in the first slice, one of the new slices into which to copy the unit of data. The database system asynchronously writes one or more actions of a set of one or more asynchronous database transactions to the first slice when copying the data in the first slice to the new slices. The database asynchronously enqueues the one or more actions of the set of asynchronous database transactions in the write queues according to the distribution function.

A computer system includes an SSD as swap space for a database management system that comprises a primary database engine and at least one clone database engine. A queued database transaction is sent to the clone database engine for pre-processing while the primary database engine is processing a current database transaction and if data needed to process the queued database transaction is not currently cached in the computer system, the clone database engine fetches the data and caches it into a buffer accessible by the primary database engine. When the primary database engine is ready to process the queued database transaction, it will be able to access the needed data without accessing the SSD, thereby avoiding delays resulting from accessing the SSD.

In one exemplary embodiment, a method of a distributed database system includes the step of receiving a database transaction with a node of the distributed database system. A priority of the database transaction is determined. A load of a transaction queue of the node is determined. The execution of a database transaction is delayed if the load of the transaction queue is greater than a first-water mark. The database transaction is delayed for a specified period. A portion of the database transaction is execution after the specified period. It is determined if the load of the queue is below a second-water mark after the specified period. A remaining portion of the database transaction can be processed if the load of the queue is below the second-water mark.

Systems and methods are disclosed for monitoring and managing data transactions, such as SQL transactions. In certain examples, a management subsystem generates an alert identifying degrading database transactions to facilitate preventative tuning or other maintenance. In particular, a monitor module tracks performance measurements (e.g., logical reads) of select transactions. A modeler correlates the performance measurements and assigns first performance model(s) to represent the performance measurements and predicted performance measurements of a particular transaction. A trend change module detects a significant change in a trend and/or variance of the performance measurements and can cause the modeler module to generate a second performance model to represent at least a portion of the performance measurements and the predicted performance measurements of the particular transaction. An interface module triggers an alert when the second performance model indicates that the predicted performance measurements of the particular transaction are degrading at or above a threshold rate.

A system, method, computer program and article of manufacture for updating a disk that moves updates for a specific database object into available contiguous free data blocks, and writes the multiple updates to disk using a single disk access, maintaining database transactional and durability semantics semantics.

A method and system for achieving highly available, fault-tolerant execution of components in a distributed computing system, without requiring the writer of these components to explicitly write code (such as entity beans or database transactions) to make component state persistent. It is achieved by converting the intrinsically non-deterministic behavior of the distributed system to a deterministic behavior, thus enabling state recovery to be achieved by advantageously efficient checkpoint-replay techniques. The method comprises: adapting the execution environment for enabling message communication amongst and between the components; automatically associating a deterministic timestamp in conjunction with a message to be communicated from a sender component to a receiver component during program execution, the timestamp representative of estimated time of arrival of the message at a receiver component. At a component, tracking state of that component during program execution, and periodically checkpointing the state in a local storage device. Upon failure of a component, the component state is restored by recovering a recent stored checkpoint and re-executing the events occurring since the last checkpoint. The system is deterministic by repeating the execution of the receiving component by processing the messages in the same order as their associated timestamp.

A method and system (200) for message handling in a messaging system by: receiving messages from applications associated with transactions and placing the received messages in a queue (230) for subsequent retrieval; receiving requests of prepare, commit and abort for the transactions; deferring retrieval of messages from the queue so as to occur in the same sequence as the prepare requests of the transactions with which the respective messages are associated; and retrieving from the queue messages associated with a transaction in the order in which the messages were put by the application. Preferably deferral is achieved by deferring completion of transaction commits as required to occur in the same order as the prepare message requests. Deferral may be implemented by (i) using a three phase commit protocol having Prepare, Commit, and Release phases and by implementing the Release phase within the Commit phase of the same or a different transaction so that a standard two-phase coordinator may be used, or (ii) by completing a first part of a commit phase as requested and deferring a second part of the commit phase as required. This permits appropriate message ordering in a transactional system, and in particular permits the correct implementation of a database replication system (220) using coordinated message transport that is fed the changes during database transactions.

An in-memory database management system (DBMS) in a virtual machine (VM) preserves the durability property of the ACID model for database management without significantly slowing performance due to accesses to disk. Input data relating to a database transaction is recorded into a replay log and forwarded to the VM for processing by the DBMS. An indication of a start of processing by the DBMS of the database transaction is received after receipt of the input data by the VM and an indication of completion of processing of the database transaction by the DBMS is subsequently received, upon which outgoing output data received from the VM subsequent to the receipt of the completion indication is delayed. The delayed outgoing output data is ultimately released upon a confirmation that all input data received prior to the receipt of the start indication has been successfully stored into the replay log, thereby preserving durability for the database transaction.

Embodiments of the present invention include in-memory processing for data warehouse applications. In one embodiment, data records from a data warehouse application are stored in a data storage structure of an in-memory database. Data received from the data warehouse may be stored in a queue and loaded into the data storage structure according to predefined rules. Stored data records are associated with in-memory database transactions that caused the stored data record to be stored, and may further be associated with transactions that caused the stored data records to be changed. A mapping is generated to associate requests from the data warehouse application with in-memory database transactions. The data warehouse application may retrieve data in a change data format calculated on-the-fly.

A database audit system monitors database activity, providing a complete record of access to data and database structure. A database audit may be performed by collecting data from database transaction logs and traces, exporting the collected data into a repository, and analyzing the data in the repository to create data audit reports and to provide data audit browsing capabilities. A separation between audit side and audited data side is maintained through limited access permissions.

A computer readable storage medium includes executable instructions to store load data in new rows of an append only table within a data warehouse, without updating or deleting existing rows in the append only table. The new rows are added in a database transaction that guarantees that the distributed reads and writes of all transactions are processed reliably and that the transactions obey snapshot isolation rules. Data changes associated with the load data are maintained in a separate update table. Data from the append only table is merged with data changes from the update table to supply read data.

Systems, methods and computer program product embodiments for providing a locking protocol for partitioned and distributed database tables are disclosed herein. A locking method includes executing, by at least one processor, a first database transaction on a second node, attempting to acquire and acquiring a lock on the second node in intentional exclusive mode, executing, by the at least one processor, a second database transaction on a first node, acquiring a lock on the first node in exclusive mode and waiting to acquire a lock on the second node in exclusive mode, routing, by the at least one processor, the first database transaction to the first node and unsuccessfully trying to acquire a lock on the first node and committing, by the at least one processor, the first database transaction.

A method is provided for consistent reading of a number of objects (1O, 2O, 3O) within a database. The method is adapted for use with a database in which transactions are managed by two-phase locking. A first phase (A) includes a request for access to objects (1O, 2O, 3O) affected by the transaction and locking of these objects as soon as access thereto has been granted. A second phase (B) includes committing the transaction and releasing all locks that were set in the first phase. The actual work performed in a transaction may be summarized as object changing actions and/or object non-changing actions. A change, or an update, of the content of an object is performed by writing the new content into a new version of the object, where the current version of the object prior to the transaction is retained until no further transactions make use of this version. The transaction performs all changing actions within the first phase (A). The transaction is adapted to retain access to the objects (1O, 2O, 3O) after the second phase (B). The transaction is also adapted to perform the largest possible number of non-changing actions in a third phase (C), after the second phase (B), whereafter the transaction closes access to the objects. Thus, the transaction is provided with a consistent snapshot of effected objects (1O, 2O, 3O) in the database after the locks have been released, with regard to non-changing actions.

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.

The invention discloses a deadlock detection method and a device of a database transaction lock mechanism, which is characterized by predefining an adjacency matrix for storing cross-thread waiting relation messages. The method comprises the following steps: a locking thread records the cross-thread waiting relation messages generated in the process of locking in the adjacency matrix; an unlocking thread updates corresponding waiting relation messages in the adjacency matrix in the process of unlocking according to the requirements; a deadlock detection thread detects and calculates the thread by adopting the adjacency matrix and principles of graph theory so as to judge whether deadlock exists. The device comprises a message storage module, a deadlock detection module, and a message record module and a message update module. The technical proposal of the invention has extremely high deadlock detection speed, can fully utilize useful messages obtained in the processes of locking and unlocking to assist subsequent deadlock detection and saves calculation resources.

The present invention discloses a method and an arrangement for using a platform independent model comprising one or more state machines, and a generic middleware platform for orthogonally mapping the platform independent model to a source code and/or byte code platform, where an asynchronic behaviour is shown on the modelling level, and the source code or byte code level is achieved using message oriented middleware application API adapted for message exchange between clients both in point to point and publish/subscribe messaging regime and, persistency for one or more state machines is achieved using one or more modules adapted for database transactions, where the modules may handle concurrent access from multiple clients to the database.

The invention discloses a heterogeneous-database-replication parallel execution system and method based on synchronization of commit-point timelines. The system includes a source database, a target database and a replication system. The system and method have the advantages that for preventing destination-end events from execution failure, a traditional data replication system based on logs serially executes logs of various events according to the time sequences (LSN numbers) of the logs and does not consider the probability of the parallel execution of events. According to the system and method, commit-point timelines are adopted to form fences, the characteristic that all upload operations between two timelines do not colloid with one another is adopted, the operations are executed at the destination end in parallel, the replication efficiency is greatly improved, and the technical problem of the low replication efficiency caused by the serial execution of events in the target database is solved.