Abstract: A storage appliance system is disclosed which may include at least one application server for locally executing an application, and one or more storage servers in communication with the application server for I/O transmission therebetween. Also disclosed are an application server, a method, and a computer program product.

Abstract: A method, computer program product, and system for detecting and fencing off a failed entity instance so that failover time in the computing system is reduced. Upon detection of a failed entity, for example a failed process, a signal handler invokes an operating system interface to fence off the failed instance from modifying its persistent state, so that the entity may be re-instantiated prior to termination of the failed instance. This approach reduces failover time and eliminates split-brain problems without compromising access to the failed instance to obtain diagnostic information, core dumps, and the like.

Abstract: According to one embodiment of the present invention, a method of detecting and correcting hot pages in a database system includes monitoring transactions involving pages in a database and determining if one of the transactions had to wait for access to one of the pages; incrementing a page contention counter each time one of the transactions had to wait for access to one of the pages. The method then determines if the page contention counter exceeds a predetermined threshold and monitors transactions on one of the pages for which the page contention count was exceeded. The method then determines if a row was accessed in the page for which the page contention count was exceeded and increments a reference count for the accessed row. The accessed rows are flagged when the reference count exceeds a second predetermined threshold. The flagged rows are moved to another page in the database.

Abstract: A storage appliance system is disclosed which may include at least one application server for locally executing an application, and one or more storage servers in communication with the application server for I/O transmission therebetween. Also disclosed are an application server, a method, and a computer program product.

Abstract: Provided are a method, system, and program for handling access requests to a page while copying an updated page of data to storage. An update to a page in a memory is received and indication is made that the page has an exclusive lock. The update is applied to the page and an operation is initiated to copy the updated page to a physical log in a storage in response to applying the update to the page. Reads and writes are allowed to proceed against the page while the operation to copy the updated page to the physical log in the storage is occurring.

Abstract: A system is provided that includes processing logic and a memory management module. The memory management module is configured to allocate a portion of memory space for a thread stack unit and to partition the thread stack unit to include a stack and a thread-local storage region. The stack is associated with a thread that is executable by the processing logic and the thread-local storage region is adapted to store data associated with the thread. The portion of memory space allocated for the thread stack unit is based on a size of the thread-local storage region that is determined when the thread is generated and a size of the stack.

Abstract: A method, computer program product, and system for detecting and fencing off a failed entity instance so that failover time in the computing system is reduced. Upon detection of a failed entity, for example a failed process, a signal handler invokes an operating system interface to fence off the failed instance from modifying its persistent state, so that the entity may be re-instantiated prior to termination of the failed instance. This approach reduces failover time and eliminates split-brain problems without compromising access to the failed instance to obtain diagnostic information, core dumps, and the like.

Abstract: A method and system for enabling dynamic matching of storage utilization characteristics of a host system application with the characteristics of the available storage pools of an attached distributed storage system, in order to provide an optimal match between the application and selected storage pool. An abstraction manager is provided, enhanced with a storage device configuration utility/module, which performs a series of tasks to (1) obtain/collect the correct configuration information from each connected storage device or storage pools and/or (2) calculate the configuration information when the information is not readily available. The storage device configuration module then normalizes, collates and matches the configuration information to the various applications running on the host system and/or outputs the information to a user/administrator of the host system via a software interface.

Abstract: According to one embodiment of the present invention, a method for detecting and correcting hot pages in a database system is provided. According to one embodiment of the present invention, a method includes monitoring transactions involving pages in a database and determining if one of the transactions had to wait for access to one of the pages; incrementing a page contention counter each time one of the transactions had to wait for access to one of the pages. The method then determines if the page contention counter exceeds a predetermined threshold and monitors transactions on one of the pages for which the page contention count was exceeded. The method then determines if a row was accessed in the page for which the page contention count was exceeded and increments a reference count for the accessed row. the accessed rows are flagged when the reference count exceeds a second predetermined threshold. The flagged rows are moved to another page in the database.

Abstract: A method for committing transactions in a distributed system are provided. The method provides for receiving a request from a client to commit a transaction at a coordinator node in the distributed system, tracking a tail log sequence number for every other node in the distributed system, determining a max log sequence number associated with the transaction for each participant node in the distributed system, and committing the transaction at the coordinator node when the tail log sequence number for each participant node is greater than or equal to the max log sequence number associated with the transaction at the respective participant node.

Abstract: There are disclosed systems, computer program products, and methods for self-tuning memory. In an embodiment, a method for self-tuning memory comprises setting a tuning interval and a target range for free memory for a memory pool. If memory consumption falls outside of the set target range for free memory during a tuning interval, a new target size for the memory pool is set based on the target range for free memory. Memory allocation for the memory pool is increased or decreased for the next tuning interval, such that the new target size for the memory pool is reached. A decrement rate may be used to provide a controlled decrease of the memory pool over a plurality of tuning intervals if necessary, until the new target size for the memory pool is reached.

Abstract: A system is provided that includes processing logic and a memory management module. The memory management module is configured to allocate a portion of memory space for a thread stack unit and to partition the thread stack unit to include a stack and a thread-local storage region. The stack is associated with a thread that is executable by the processing logic and the thread-local storage region is adapted to store data associated with the thread. The portion of memory space allocated for the thread stack unit is based on a size of the thread-local storage region that is determined when the thread is generated and a size of the stack.

Abstract: A method, apparatus, and computer program product for storage pools with write atomicity. An abstraction manager enforces write atomicity and disallows options which are inconsistent with write atomicity. The abstraction manager constructs through a physical device interface a logical continuous view of a storage pool in a manner consistent with write atomicity. Applications collect information specific to write atomicity from the abstraction manager through an application interface.

Abstract: A computer program product and system for committing transactions in a distributed system are provided. The method, computer program product, and system provide for receiving a request from a client to commit a transaction at a coordinator node in the distributed system, tracking a tail log sequence number for every other node in the distributed system, determining a max log sequence number associated with the transaction for each participant node in the distributed system, and committing the transaction at the coordinator node when the tail log sequence number for each participant node is greater than or equal to the max log sequence number associated with the transaction at the respective participant node.

Abstract: A method to enhance relational database management system resiliency and query operations by minimizing CPU overhead and database page access latency and by facilitating database restoration and query efficiency. The method includes creating a clean database page in a buffer pool of a relational database management system, granting exclusive access to the clean database page within the buffer pool to an application that transitions the clean database page to a dirty database page by altering data store thereon, immediately downgrading exclusive access to the dirty database page to shared access in response to receiving an exclusive access termination request from the application, writing the dirty database page to a physical log, and releasing share access to the dirty database page.

Abstract: A method, apparatus, and computer program product for storage pools with write atomicity. An abstraction manager enforces write atomicity and disallows options which are inconsistent with write atomicity. The abstraction manager constructs through a physical device interface a logical continuous view of a storage pool in a manner consistent with write atomicity. Applications collect information specific to write atomicity from the abstraction manager through an application interface.

Abstract: A method and system for improving memory access patterns of software systems on NUMA systems discovers NUMA system resources where the NUMA system resources comprises a plurality of NUMA nodes; determines a plurality of database threads, processes, and objects for a database configuration; and generates a policy which assigns the plurality of database threads, processes, and objects to the plurality of NUMA nodes, wherein the generating of the policy is performed prior to initialization of the plurality of database threads, processes, and objects. The assignment of the database threads, processes, or objects to NUMA nodes is such that the amount of remote memory accesses is reduced. When the database thread, process, or object initializes, the database server queries the policy for its assigned NUMA node(s). The database thread, process, or object is then bound to the assigned NUMA node(s).

Abstract: A technique for recovering a dropped table is provided. One or more table spaces are specified prior to one or more tables being dropped from the specified one or more table spaces. When a table is to be dropped from the one or more specified table spaces, a table identifier, a time stamp, and table definition attributes are stored for the dropped table in a data structure and the table is dropped. Upon receiving a request to restore a table space from the one or more specified table spaces, each of the one or more tables in the table space being restored is recovered using the data structure.

Abstract: The use of a centralized version table allows for efficient object switching. Rather than synchronizing all database agents to recognize a newly created file as containing the most recent version of a given object, database agents requiring access to the given object need only consult the centralized version table to learn file identity information. That is, the database agents consult the centralized version table to determine which of the files associated with a given object contain the most recent version of the given object. Mechanisms associated with the use of the centralized version table also provide for efficient recovery from a failure that has occurred during an object switching transaction.

Abstract: A system and an associated method selectively process log files for enhancing performance of tablespace recovery by processing only those log files required, and for selecting which log file to process during recovery for both redo and rollback phases of recovery. The system and method skip the processing of log files that do not contain records of interest for the tablespace being recovered and determines whether a log file contains anything that needs to be played, in particular for the recovery of a subsystem in the database, such as a tablespace. Pre processing of the log files is not done, rather including tablespace ID correlated with log file ID information is collected while the log files are created. The cross-correlated information is used during tablespace recovery to selectively determine which of the log files to process. Some log files may be skipped in cases where not all of the database system is being recovered.