International Business Machines Corporation

Netezza Corporation

Sunil Sarin

Oliver Koeth

Foster D Hinshaw

James L Finnie

Gordon Andrew Booman

Craig S Harris

Knut Stolze

Namik Hrle

Chandrasekaran Mohan

Daniel Martin

James D Spyker

Dirk Alexander Seelemann, Ii

Yongfeng Yao

Glenn P Steffler

Praveen Mohandas

Lawrence Stabile

Krishnan Seetharaman

Thomas P Boldt

Venkat K Chandra

Prasad G Parulekar

David L Shepard

Adam J Storm

Ronen Grosman

Optimizing database table scans in presence of SMDO records is provided. An SMDO record corresponding to a most recent span of rows for a column associated with a query predicate is read. It is determined whether a condition for excluding a span of rows is true for the SMDO record based on a type of the query predicate. In response to determining that a condition for excluding a span of rows is not true for the SMDO record, the most recent span of rows is added to a list of spans of rows to scan. It is determined whether a condition for excluding all preceding spans of rows is true for the SMDO record based on the type of the query predicate. In response to determining that a condition for excluding all preceding spans of rows is true for the SMDO record, reading the set of SMDO records is stopped.

Optimizing database table scans in the presence of ordered data

In an approach to storing data elements in a database, a database management unit provides a table-mapping file for enabling access to a table of a plurality of tables in a storage medium, the table-mapping file comprising a plurality of map records of a single table, a map record comprising information indicative of the table, a column of the table, a data section of the table, and a range of values of data elements included in the data section of the column. The unit receives a data element at the database via a communication interface, determines the table, column, and data section the data element is to be stored in, and stores the data element in the section file corresponding to the determined table, column and data section. The unit then updates the table-mapping file corresponding to the table, columns and data section the data element has been stored in.

Method for storing data elements in a database

The present invention provides a method, system and computer program product for replication control using eventually consistent meta-data. In an embodiment of the invention, a method for replication control using eventually consistent meta-data is provided. The method includes replicating data in a replication data processing system of nodes coupled to one another over a computer communications network. The method also includes replicating meta-data representing the state of the replication data processing system into a data structure of eventually consistent meta-data. Finally, the method includes managing the replication of the data according to the replicated meta-data.

Replication control using eventually consistent meta-data

A method, a processing device, and a computer program product are provided. A truncate table command for truncating all or a subset of one or more rows of a database table is received from a first transaction executing on a processing device. At least one read operation on the truncated database table is performed for at least one transaction concurrent with the first transaction, wherein the truncated rows are visible to the at least one concurrent transaction and invisible to subsequent transactions. Storage units that store the truncated rows are reclaimed in response to completion of the at least one concurrent transaction.

Transactional table truncation for concurrent transactions

According to an aspect, a database management system (DBMS) is operated to perform data replication. The DBMS includes a source database and a target database. The source database includes a plurality of first tables respectively comprising one or more first columns, and the target database includes a plurality of second tables respectively comprising one or more second columns. Each of multiple ones of the first columns is mapped to one of the second columns, and each one of the second columns is adapted to store replicated data changes of the first column mapped to the second column. Each of the second columns has an assigned update time, the update time being a moment in time when the second column most recently received incremental data changes from its mapped first column. The DBMS operates to process requested database statements while providing data replication.

Data replication in a database management system

Consistency of replicated data copies with statement-based replication is provided without requiring transaction serializability. At a subordinate replication node, a transaction start message, replicated data modification statements, and a transaction commit message are received for a next committed transaction from a master replication node, wherein the transaction start message carries a master transaction identifier, an invisibility list consisting of identifiers of other master transactions that had started and not yet committed when this master transaction started, and an earliest invisible master transaction identifier. The master transaction identifier, invisibility list, and earliest invisible transaction identifier are mapped to subordinate transaction identifiers to preserve an order of transaction identifiers from the master replication node. A subordinate transaction is started with the mapped subordinate transaction identifier and with an invisibility list consisting of the mapped subordinate transaction identifiers for the master invisibility list for execution of the received data modification statements.

Relaxing transaction serializability with statement-based data replication

A multi-version database system controls visibility of data during transaction processing. A transaction includes a transaction identifier that identifies the transaction and an invisibility list of transactions whose effects are invisible to the transaction. Changes made by other transactions are visible to the transaction based on the isolation level of the transaction. Records are visible to a transaction based on a creator identifier stored in the record that identifies the transaction that created the record.

Controlling visibility in multi-version database systems

A mechanism controls concurrency among database transactions through the use of serial ordering relations. The ordering relations are computed dynamically in response to patterns of use. An embodiment of the present invention serializes a transaction that accesses a resource before a transaction that modifies the resource, even if the accessor starts after the modifier starts or commits after the modifier commits. A method of concurrency control for a database transaction in a distributed database system stores an intended use of a database system resource by the database transaction in a serialization graph. A serialization ordering is asserted between the database transaction and other database transactions based on the intended use of the database system resource by the database transaction. The serialization ordering is then communicated to a node in the distributed database system that needs to know the serialization ordering to perform concurrency control. Cycles in the serialization graph are detected based on the asserted serialization order and in order to break such cycles and ensure transaction serializability a database transaction is identified that is a member of a cycle in the serialization graph.

Distributed concurrency control using serialization ordering

Computer method and system for concurrency control using dynamic serialization ordering

Growing community of inventors

Newton, MA, United States of America

Sunil Sarin