Parallel Database

Parallel Database

• A parallel database system seeks to improve performance through
parallelization of various operations, such as loading data, building indexes
and evaluating queries. Although data may be stored in a distributed
fashion, the distribution is governed solely by performance considerations.
Parallel database improves processing and input/output speeds by using
multiple CPUs and disks in parallel. Centralized and client-server database
systems are not powerful enough to handle such applications. In parallel
processing, many operations are performed simultaneously, as opposed to
serial processing, in which the computational steps are performed
sequentially.

Parallel Computing
• Parallel computing is a form of computing in which many instructions are carried
out simultaneously. Parallel computing operates on the principle that large problems
can almost always be divided into smaller ones, which may be carried out
concurrently ("in parallel"). Parallel computing exists in several different forms: bitlevel
parallelism, instruction level parallelism, data parallelism, and task parallelism.
It has been used for many years, mainly in high performance computing, but interest
in it has become greater in recent years due to physical constraints preventing
frequency scaling. Parallel computing has recently become the dominant paradigm
in computer architecture, mainly in the form of multicore processors
Example parallel databases:

Objectivity/DB

Objectivity/DB is a commercial object oriented database management system
produced by Objectivity, Inc. It allows applications to make standard C, C++, Java,
Python or Smalltalk objects persistent without having to convert the data objects into
the rows and columns used by a relational database management system.
Objectivity/DB supports the most popular object oriented languages plus
SQL/ODBC and XML. It runs on Linux, LynxOS, UNIX and Windows platforms.
All of the languages and platforms interoperate, with the Objectivity/DB kernel
taking care of compiler and hardware platform differences.
• Objectivity/DB is a distributed database that provides a single logical view across a
federation of databases. It uses a distributed computing model that links a small
software library with the client application. The client transparently communicates
with remote servers that are functionally simpler than their equivalents in centralized
database server architectures. There are lock, remote data transfer and query agent
server processes. The distributed architecture helps make Objectivity/DB inherently
scalable and reliable. It has sustained ingest rates in excess of one terabyte per hour
while simultaneously supporting data fusion and query operations - Building a High
Throughput Data repository With High Query Performance.
• Objectivity/DB uses a hierarchy of storage constructs. Objects are stored in logical
clusters called containers. The containers are stored in databases that are cataloged
in a federated database. Every object has a unique 64-bit or 32-bit Object Identifier
[OID] that is a composite logical structure. The physical address space limitation for
a single federation is in the millions of Terabytes range. The largest publicized
Objectivity/DB installation (at Stanford Linear Accelerator Center) stored over a
Petabyte of objects.

Comments

Post a Comment

Popular posts from this blog

Handling of Skew

Handling of Skew 􀂄 The distribution of tuples to disks may be skewed — that is, some disks have many tuples, while others may have fewer tuples. 􀂄 Types of skew: 􀃌 Attribute-value skew. 􀂾 Some values appear in the partitioning attributes of many tuples; all the tuples with the same value for the partitioning attribute end up in the same partition. 􀂾 Can occur with range-partitioning and hash-partitioning. 􀃌 Partition skew. 􀂾 With range-partitioning, badly chosen partition vector may assign too many tuples to some partitions and too few to others. 􀂾 Less likely with hash-partitioning if a good hash-function is chosen. Handling Skew in Range-Partitioning 􀂄 To create a balanced partitioning vector (assuming partitioning attribute forms a key of the relation): 􀃌 Sort the relation on the partitioning attribute. 􀃌 Construct the partition vector by scanning the relation in sorted order as follows. 􀂾 After every 1/nth of the relation has been read, the value...
Read more

Fragment-and-Replicate Join

Fragment-and-Replicate Join 􀂄 Partitioning not possible for some join conditions 􀃌 e.g., non-equijoin conditions, such as r.A > s.B. 􀂄 For joins were partitioning is not applicable, parallelization can be accomplished by fragment and replicate technique 􀃌 Depicted on next slide 􀂄 Special case – asymmetric fragment-and-replicate: 􀃌 One of the relations, say r, is partitioned; any partitioning technique can be used. 􀃌 The other relation, s, is replicated across all the processors. 􀃌 Processor Pi then locally computes the join of ri with all of s using any join technique. 􀂄 General case: reduces the sizes of the relations at each processor. 􀃌 r is partitioned into n partitions,r0, r1, ..., r n-1;s is partitioned into m partitions, s0, s1, ..., sm-1. 􀃌 Any partitioning technique may be used. 􀃌 There must be at least m * n processors. 􀃌 Label the processors as 􀃌 P0,0, P0,1, ..., P0,m-1, P1,0, ..., Pn-1m-1. 􀃌 Pi,j computes the join of ri with sj. In ...
Read more

USER INTERFACE DESIGN FOR ANNA UNIVERSITY SYLLABUS

Unit – I Introduction Objective To Understand the definition and importance of User Interface Design To know about the concept, advantages and applications of GUI and Web interface User Interface Design Definition • User interface design is a subset of a field of study called human-computer interaction (HCI). Human-computer interaction is the study, planning, and design of how people and computers work together so that a person’s needs are satisfied in the most effective way. • The user interface is the part of a computer and its software that people can see, hear, touch, talk to, or otherwise understand or direct. The user interface has essentially two components: input and output. • Input is how people communicate his needs to the system using keyboard or any pointing device and output is how the system returns processing result to user through screen or sound. • The best interface is one which has proper design with combination of effective input and output mechanisms. Importance of...
Read more