International Business Machines Corporation

Kevin James Cherkauer

Scott David Lashley

Steven Robert Pearson

Kevin Leo Beck

Xun Xue

Jason Christopher Young

Roger L Q Zheng

Roger C Raphael

Effi Ofer

Jonathan Leffler

Dale Murray McInnis

Techniques for data replication from a primary system to a standby system. A first buffer portion of a transaction log buffer is allocated to a first transaction at a primary system. Upon determining that the first buffer portion is fully formed, before the log data is written to the storage on the primary system, and before the transaction log buffer is entirely full, the log data in the first buffer portion is transmitted to the standby system, from the primary system. Upon writing the log data to the storage on the primary system and after the log data in the first buffer portion is transmitted to the standby system, a notification is transmitted to the standby system, from the primary system, where the standby system is configured to process the received log data responsive to receiving the notification from the primary system.

Log-shipping data replication with early log record fetching

Methods, systems and program products for log-shipping data replication from a primary system to a communicatively-coupled standby system. Embodiments of the invention may receive transactional log data at a standby system, from the primary system, and before the transactional log data is written to storage on the primary system. Embodiments may then receive a notification from the primary system indicating that the corresponding log data was written to storage on the primary system, and responsive to receiving the notification, may process the received transactional log data.

The intermittent sampling of storage access frequency is performed by determining a duration of a collection window and a duration of an observation window within the collection window. A position of the observation window within the collection window is randomly selected, and frequencies of accesses of one or more storage objects during the observation window are observed. When a new access of a given storage object occurs, a delta time for the given storage object is calculated as the time of the observed access minus the timestamp of the most recent observed prior access of the given storage object. Optionally, the delta time of two sequential accesses of a given storage object in two different observation windows may be calculated as if the two different observation windows are immediately adjacent to each other.

Intermittent sampling of storage access frequency

In defining database objects for storage in a storage hierarchy, frequencies of accesses of a plurality of database objects over a predetermined time period are observed. A mean and standard deviation for the plurality of database objects are computed based on the observed frequencies of accesses of the plurality of database objects. A z-score for a given database object is determined based on a comparison of the frequency of access for the given database with the mean and standard deviation computed for the plurality of database objects by the computing processor; and a level in the storage hierarchy corresponding to the z-score of the given database object is determined. The given database object may then be stored at the level in the storage hierarchy corresponding to the z-score of the given database object.

Autonomically defining hot storage and heavy workloads

A storage manager and related method and computer program product manages client data on a data storage resource and includes the ability to utilize many different types of data stream filters that are neither built into the storage manager nor require a custom programming effort. A storage manager user may readily implement filtering by simply identifying a data stream filter the user wishes the storage manager to use for filtering the user's data. The filter can be an off-the-shelf program that is not part of the storage manager and which does not require client application or storage manager domain knowledge (e.g., knowledge of protocols or data types or formats used by the application or storage manager). The storage manager invokes the identified filter as part of a requested data stream operation and receives a data stream from a data stream source. The data stream is provided to the filter, which filters the data stream. Following filtering, the storage manager receives the data stream from the filter and sends it to a data stream destination.

Data stream filters and plug-ins for storage managers

A method, system, and computer usable program product for managing a security database in a computer memory by presenting a content delivery unit in a browser window on a computer display, identifying a plurality of domains associated with the content delivery unit wherein a first set of the plurality of domains is associated with hyperlinks in the content delivery unit, receiving user input selecting a security category for a second set of domains, and associating the second set of domains with the selected security category in the security database.

Managing security features of a browser

A system for limiting the amount of time for a database server to perform a crash recovery process. A maximum recovery time for the database server to perform the crash recovery process is specified. An estimated recovery time for the crash recovery process that is less than the maximum recovery time is calculated, based on at least one of a deterministic analysis of cost accumulation during prior instances of the crash recovery process or an empirical analysis of cost accumulation during regular transaction processing in the database server. The crash recovery process is then conformed to the estimated recovery time.

System for deterministic database recovery time

A log-shipping data replication system employs a primary server coupled to a standby server. In operation, the primary server concurrently flushes log data at the primary server and transmits the same log data from the primary server to the standby server. The primary server further transmits at least one buffer flush boundary indication to the standby server indicating the flushing status of the log data at the primary server. The standby server processes the log data as a function of receiving the log data from the primary server, and/or receiving the at least one buffer flush boundary indication from the primary server.

Log shipping data replication with parallel log writing and log shipping at the primary site

A method and system are provided for providing a consistent reintegration of a failed primary instance as a new secondary instance with implementation of truncation of log records. Upon failure of a primary instance, a secondary instance may be reassigned as the new primary instance. Prior to reintegration, any portion of the database log of the failed primary that is after the log position of the new primary instance may be truncated, followed by a comparison of the log positions of both the new primary instance and the new secondary instance. In limited circumstances, the truncation of the log data generated by the failed primary instance after the point of failure is possible, and supports reintegration of the failed primary as a new secondary instance with limited overhead.

Consistent reintegration of a failed primary instance

Sending log records from a first system instance's log buffer to a second system instance is disclosed. Both instances may be instances of a database system. A method may create a log record within the buffer. The record contains actual log information, such as descriptions of transactions. A flag corresponding to the record is set in memory other than the buffer. The flag indicates whether the record has been sent to the second instance, and/or whether the second instance has received the record. The method may further embed non-log information within a simulated log record having a format identical to the log record's format. The non-log information, which may not include actual transactions to be committed, is embedded in a body section of the simulated record. At least one otherwise unused bit of a metadata section of the simulated record is set, indicating that the simulated record is simulated.

Sending log records directly from log buffer

A system for data base management using memory devices holding a database containing tables of data occupying extents. A database engine reviews each query to determine an extents list of extents containing the data needed by that said query. A query monitor then re-orders the extents lists so that extents are retrieved and stored in a buffer cache for more efficient use when executing the queries. The database engine retrieves needed extents from the memory devices, as ordered in the extents lists, and stores those extents in the buffer cache. The database engine then executes one or more queries on the data in the extents in the buffer cache to determine respective results.

Shared scans utilizing query monitor during query execution to improve buffer cache utilization across multi-stream query environments

A system for data base management using memory devices holding a database containing tables of data occupying extents. A database engine reviews each query to determine an extents list of extents containing the data needed by that said query. A query monitor then re-orders the extents lists so that extents are retreived and stored in a buffer cache for more efficient use when executing the queries. The database engine retreives needed extents from the memory devices, as ordered in the extents lists, and stores those extents in the buffer cache. The database engine then executes one or more queries on the data in the extents in the buffer cache to determine respective results.

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Portland, OR, United States of America

Kevin James Cherkauer