منابع مشابه
Parametric Query Optimization for Linear and Piecewise Linear Cost Functions
The cost of a query plan depends on many parameters, such as predicate selectivities and available memory, whose values may not be known at optimization time. Parametric query optimization (PQO) optimizes a query into a number of candidate plans, each optimal for some region of the parameter space. We first propose a solution for the PQO problem for the case when the cost functions are linear i...
متن کاملDesign and Analysis of Parametric Query Optimization Algorithms
Query optimizers normally compile queries into one optimal plan by assuming complete knowledge of all cost parameters such as selectivity and resource availability. The execution of such plans could be sub-optimal when cost parameters are either unknown at compile time or change significantly between compile time and runtime [Loh89, GrW89]. Parametric query optimization [INS+92, CG94, GK94] opt...
متن کاملRelational Databases Query Optimization using Hybrid Evolutionary Algorithm
Optimizing the database queries is one of hard research problems. Exhaustive search techniques like dynamic programming is suitable for queries with a few relations, but by increasing the number of relations in query, much use of memory and processing is needed, and the use of these methods is not suitable, so we have to use random and evolutionary methods. The use of evolutionary methods, beca...
متن کاملGreen Query Optimization: Taming Query Optimization Overheads through Plan Recycling
PLASTIC [1] is a recently-proposed tool to help query optimizers significantly amortize optimization overheads through a technique of plan recycling. The tool groups similar queries into clusters and uses the optimizer-generated plan for the cluster representative to execute all future queries assigned to the cluster. An earlier demo [2] had presented a basic prototype implementation of PLASTIC...
متن کاملAniPQO: Almost Non-intrusive Parametric Query Optimization for Nonlinear Cost Functions
The cost of a query plan depends on many parameters, such as predicate selectivities and available memory, whose values may not be known at optimization time. Parametric query optimization (PQO) optimizes a query into a number of candidate plans, each optimal for some region of the parameter space. We propose a heuristic solution for the PQO problem for the case when the cost functions may be n...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The VLDB Journal The International Journal on Very Large Data Bases
سال: 1997
ISSN: 1066-8888,0949-877X
DOI: 10.1007/s007780050037