What is difference between a thread and a process?
A process is a collection of virtual memory space, code, data, and system resources. A thread is code that is to be serially executed within a process. A processor... Read more »
Archive for November, 2006
What is mutex?
Mutex is a program object that allows multiple program threads to share the same resource, such as file access, but not simultaneously. When a program is started... Read more »
What is a cluster Key?
The related columns of the tables are called the cluster key. The cluster key is indexed using a cluster index and its value is stored only once for multiple tables... Read more »
What is a deadlock?
Two processes waiting to update the rows of a table which are locked by the other process then deadlock arises. In a database environment this will often happen... Read more »
What is Read-Only Transaction?
A Read-Only transaction ensures that the results of each query executed in the transaction are consistent with respect to the same point in time. Read more »
Define Transaction?
A Transaction is a logical unit of work that comprises one or more SQL statements executed by a single user. Read more »
What is Rule-based approach to optimization?
Choosing an executing plan based on the access paths available and the ranks of these access paths. Read more »
What is Cost-based approach to optimization?
Considering available access paths and determining the most efficient execution plan based on statistics in the data dictionary for the tables accessed by the statement... Read more »
What does “Commit” do?
“Commit” makes permanent the changes resulting from all SQL statements in the transaction. The changes made by the SQL statements of a transaction become... Read more »