performance by using various optimization techniques during designing, querying, transactions etc. Database tuning aims to maximize use of system resources to perform work as efficiently and rapidly as possible. Doing performance tuning on the database is one of the most common and yet the most important activity that every database administrator (DBA) must perform on an ongoing and regular basis. Experts recommend that you regularly fine-tune databases to optimized performance. Fine-tuning helps users to run their reports and queries faster and get results quicker. Goals of database performance tuning are: To make application run faster. To improve (reduce) the response time of queries and transactions. How to avoid excessive lock contention, thereby increasing concurrency among transactions. How to minimize the overhead of logging and unnecessary dumping of data. How to optimize the buffer size and scheduling of processes. How to allocate resources such as disks, RAM, and processes for most efficient utilization. Database performance can be tuned by focusing on the following point. Tuning database performance by designing the efficient database schema. Normalize to database to appropriate normal form. Selecting the transactions involving less I/O operations by the query optimizer. Creating indices. Designing the efficient queries. Distributed relational systems and Data Replication A distributed database is a database in which storage devices are not all attached to a common processing unit such as the CPU and which is controlled by a distributed database
management system. It may be stored in multiple computers, located in the same physical location; or may be distributed over a network of interconnected computers. Distributed databases bring the advantages of distributed computing to the database management domain. It consists of a number of processing elements, not necessarily homogenous, that are interconnected by a computer network, and that cooperate in performing certain assigned tasks. As a general goal, distributed computing systems partition a big, unmanageable problem into smaller pieces and solve it effectively in a coordinated manner. Its main benefit is that computer power can be used to solve a complex task and each autonomous processing element can be managed independently and develop its own applications. A distributed database management system (DDBMS) is a centralized software system that manages a distributed database in a manner as if it were all stored in a single location. A distributed database is basically a database that is not limited to one system, it is spread over different sites, i.e, on multiple computers or over a network of computers. A distributed database system is located on various sited that don’t share physical components. This maybe required when a particular database needs to be accessed by various users globally. It needs to be managed such that for the users it looks like one single database.