摘要:
Providing cost model data for tuning query cache memory size in database systems. In one aspect, a query is received, and a query cache is checked for a stored query matching the received query. In response to a cache miss occurring, a token representing the received query is generated and checked for matching a token stored in a simulation area, each stored token representing a query object previously evicted from the query cache. A processing time saved by an avoidance of the cache miss is determined, and a cache size needed to avoid the cache miss is determined only when the generated token matches a stored token, by summing sizes of all query objects represented by the stored tokens. Each stored token is included in a stub that also includes the size of the represented query object and an identification number indicating a stored order.
摘要:
Methods and systems are provided for executing a simulation of an operation in a data processing system. In one implementation, the method includes executing an operation under a first set of conditions, determining a characteristic associated with the execution of the operation under the first set of conditions, and executing a simulation of the operation under a second set of conditions different from the first set of conditions. The simulation of the operation is constrained by the determined characteristic. The method can further include determining a cost/benefit of executing the operation under a set of conditions different from the first set of conditions based at least in part on the simulation.
摘要:
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.
摘要:
A method for reducing oscillations of an output value associated with a program to be operatively coupled to a data processing system. The program having an internal process configured to read an input value provided by the program, the input value adjusting a performance aspect of the internal process, the internal process configured to provide an output value reflecting changes in the internal process responsive to the input value, the output value readable by the program. The method including writing the output value to a queue stored in memory of the data processing system, selecting a portion of the queue, matching the selected portion of the queue with a predetermined pattern, selecting a type of adjustment to be made to the input value, the type of adjustment corresponding to the matched predetermined pattern, determining a new input value according to the selected type of adjustment, and providing the new value the internal process, the internal process providing a new output value having reduced oscillations responsive to the new input value.
摘要:
There are disclosed systems and computer program products for dynamically resizing memory pools used by database management systems. In one aspect, if a decrease in allocation to the memory pool is required, at least one page grouping that may be freed from the memory pool is identified as a candidate based on its position in a list of page groupings. If the page grouping contains any used memory blocks, the used memory blocks may be copied from a candidate page grouping to another page grouping in the list in order to free the candidate page grouping. Once the candidate page grouping is free of used memory blocks, the candidate page grouping may be freed from the memory pool. As an example, this system or computer program product may be used for dynamically resizing locklists or lock memory.
摘要:
Methods and systems are provided for tuning memory allocated among a plurality of applications in a data processing system. In one implementation, the method includes generating memory benefit data for the plurality of applications, comparing the generated memory benefit data associated with each of the plurality of applications, and dynamically reallocating memory from one or more of the plurality of applications to one or more other of the plurality of applications based on the comparison. A method and system is also provided for tuning memory allocated among a plurality of individual memory consumers for a given application.
摘要:
There are disclosed systems and computer program products for dynamically resizing memory pools used by database management systems. In one aspect, if a decrease in allocation to the memory pool is required, at least one page grouping that may be freed from the memory pool is identified as a candidate based on its position in a list of page groupings. If the page grouping contains any used memory blocks, the used memory blocks may be copied from a candidate page grouping to another page grouping in the list in order to free the candidate page grouping. Once the candidate page grouping is free of used memory blocks, the candidate page grouping may be freed from the memory pool. As an example, this system or computer program product may be used for dynamically resizing locklists or lock memory.
摘要:
There are disclosed methods for dynamically resizing memory pools used by database management systems. In one aspect, if a decrease in allocation to the memory pool is required, at least one page grouping that may be freed from the memory pool is identified as a candidate based on its position in a list of page groupings. If the page grouping contains any used memory blocks, the used memory blocks may be copied from a candidate page grouping to another page grouping in the list in order to free the candidate page grouping. Once the candidate page grouping is free of used memory blocks, the candidate page grouping may be freed from the memory pool. As an example, this method may be used for dynamically resizing locklists or lock memory.
摘要:
Systems and methods are provided for optimizing the performance and/or allocation of constrained resources in a dynamic computing environment using adaptive regulatory control methods. For example, systems and methods for providing constrained optimization in a dynamic computing system implement model-based adaptive (self-tuning) regulatory control schemes that are designed to handle the system dynamics and which take into consideration control costs (such as the overheads of changing resource allocations and performance degradation due to transient load imbalances) to find an optimal solution. To facilitate practical application, a dual control architecture is disclosed which combines a heuristic fixed step control process that is implemented when there is no valid system model for model-based control. A system model is continually obtained and validated during run-time to adapt control parameters to variations in system dynamics.
摘要:
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.