Problems may also occur with the locking mechanism within concurrency control, two examples of such problems are:
Deadlock can be the first of two problems which may occur, the second problem that may occur is live lock
a. Deadlock
When two resources are looking to be unlocked at the same time, however this cannot happen so it is necessary for them to wait for each other. If two or more processors are waiting for an item to be unlocked they are waiting in a circulating chain. This means that when they eventually become available they will unlock and the process can be completed.
Deadlock is very common and may occur during the processing of many items, it is most likely to happen when processors are waiting to see a specific type of exclusive resources. A very good example of this would be “Some computers, usually those intended for the time-sharing and/or real-time markets, are often equipped with a hardware lock, or hard lock, which guarantees exclusive access to processes, forcing serialization” Dead Lock, Introduction to Concurrency Control, 2006 .
A simple way to think of deadlock is to say that if the actions of two people cannot be satisfied a deadlock situation has basically occurred
b. Live lock.
This is very similar to deadlock however there is constantly change is happening with the processors however there is no progression on to the next stage of the process.
An example of how a live lock situation occurs is as follows:
“when numerous people arrive at a four way stop, and are not quite sure who should proceed next. If no one makes a solid decision to go, and all the cars just keep creeping into the intersection afraid that someone else will possibly hit them, then a kind of livelock can happen.”
c. basic time stampin...
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...s to happen and also it will give the user a trouble-shooter guide to facilitate the and help them to understand and assist the programme during its main task. This trouble-shooter feature has been included with the most recent versions of the Microsoft SQL database package.
Concurrency within an Oracle database
If there was a single user database the user can modify the data in the database without concern for other users modifying or changing the same data at the same time however the statements we have multiple simultaneous transactions can be obtained with all of the one time.
Within the Oracle database control of data concurrency and consistency is vital because it may be a multiuser environment.
Database researchers have defined serializability as a process which gives transactions behaviour which makes them appear as if they are all happening at the one time.
A serial bus system uses the same line to transfer different data bits of the same byte/word. Usually they have only one data line and the bits will flow one after the other, as a packet. An examples of series bus systems are The Universal Standard Bus (USB) and IEEE 1394 bus architecture. Parallel bus systems are more expensive than series bus systems, although, parallel bus systems have a much higher
Precedence constraints are confinements on the request in which the work components can be performed. A few components must be done before others.
3. Multi-threading occurs when multiple programs are processed at the same time or when several parts of a program are processed at the same time.
Consistency constraints may be violated despite proper integrity enforcement in each transaction. For example, incorrect bank balances might be reflected due to simultaneous withdrawals and deposits on the same account, and so
...a flood of packets. Therefore, the victim node or sometimes the whole network can get easily paralyzed [24].
Unknown / unintentional or un-covenanted movements this could be in the form of unpredictable movements whilst the equipment is being maintained or at the reinstatement of power. Other causes may be due to the corruption of software, or damage to the any of the peripherals or programmable electronics.
In politics, gridlock or deadlock or political stalemate refers to a situation when there is difficulty of passing laws in a legislature because the voters for and against a proposed law are evenly divided; or in which two legisl...
A piece of well-oiled machinery consists of an intricate and complex system: there are well-organized processes, mechanisms within the device work efficiently, and multiple processes function simultaneously to subsequently perform various functions. What happens when there is a glitch in the machine? When there is something wrong, such as connections between intricate processes, which do not follow through, the machine fails to function properly. In some cases, there are not any adjustment or fallback mechanisms. At that point, the damage can be irreversible and the machinery is no longer salvageable. [However, this can illustrate the interactions and processes within the complex machinery.]
Latency is the property shared by some viruses which allows them to persist indefinitely in
Some faculties and departments are already using Oracle applications in their day-to-day operations. As time goes by, more and more information users will be working with an application based on Oracle database technology. If you get the opportunity to be a member of an application development team, you will become familiar with the workings of Oracle and relational databases. Other users may have to learn about this popular database management system through their own experience. This article is for our readers who, as of yet, have no access to Oracle databases but have a yearning for learning what they're all about.
memory it is caused by having to slow of memory on to fast of a bus.
MySQL Workbench and SQL Server 2008 have the same common goal, but how each program approaches that goal is different. There are some things that MySQL Workbench can do that SQL Server cannot. But, of course, Oracle can do everything. There are some general differences between MySQL and SQL Server for example: look, feel, methods, security, backup and recovery. These are the things this paper will discuss.
Inconsistently storing organization data creates a lot of issues, a poor database design can cause security, integrity and normalization related issues. Majority of these issues are due to redundancy and weak data integrity and irregular storage, it is an ongoing challenge for every organization and it is important for organization and DBA to build logical, conceptual and efficient design for database. In today’s complex database systems Normalization, Data Integrity and security plays a key role. Normalization as design approach helps to minimize data redundancy and optimizes data structure by systematically and properly placing data in to appropriate groupings, a successful normalize designed follows “First Normalization Flow”, “Second Normalization Flow” and “Third Normalization flow”. Data integrity helps to increase accuracy and consistency of data over its entire life cycle, it also help keep track of database objects and ensure that each object is created, formatted and maintained properly. It is critical aspect of database design which involves “Database Structure Integrity” and “Semantic data Integrity”. Database Security is another high priority and critical issue for every organization, data breaches continue to dominate business and IT, building a secure system is as much important like Normalization and Data Integrity. Secure system helps to protect data from unauthorized users, data masking and data encryption are preferred technology used by DBA to protect data.
According to Microsoft, the simplest definition of a process is an executed program. A thread is “the basic unit to which the operating system allocates processor time”. A thread can “execute any part of the process code, including parts currently being executed by another thread”. In Windows, threads share its virtual address space and system resources. Unlike the conceptual model, each thread “maintains exception handlers, a scheduling priority, thread local storage, a unique thread identifier and a set of structures the system will use to save the thread context until it is scheduled”. Like the conceptual model of a thread, Windows’ threads do not share registers and stack resources. This is because the thread context includes “the thread’s set of machine registers, the kernel stack, a thread environment lock and a user stack in the address sp...
In our world, people rely heavily on the power of technology every day. Kids are learning how to operate an iPad before they can even say their first word. School assignments have become virtual, making it possible to do anywhere in the world. We can receive information from across the world in less than a second with the touch of a button. Technology is a big part of our lives, and without it life just becomes a lot harder. Just like our phones have such an importance to us in our daily lives, database management systems are the same for businesses. Without this important software, it would be almost impossible for companies to complete simple daily tasks with such ease.