问题描述
我在这个领域很新。在阅读70x的材料时，我在这个学期遇到了
，但是无法理解它的准确含义。谁能帮我？谢谢
advance：）〜
I''m pretty new in this field. when reading some 70x material, I met with
this term but cannot catch its accurate meaning. who can help me? thanks in
advance:)~
推荐答案
无共享架构是指并行处理，其中一个表是
分为多个分区，以便数据库可以并行地在每个分区上同时工作
。为了获得最佳结果和最大的b $ b b可扩展性，每个分区不会与其他
节点共享硬件资源。这些硬件资源包括内存，磁盘驱动器，磁盘，b $ b控制器，处理器等。因此这个术语，没有共享。
真正的共享 - 没有体系结构，每个数据库分区都在一个独立的计算机（物理节点）上，它们之间有一个高速互连。这种架构是由Teradata发明的，它在20世纪80年代早期使用了多台Intel
386 PC和专有操作系统。
今天随着SMP（对称多处理）机器的出现，一台
单台计算机可以拥有多个CPU，多个磁盘和控制器，以及
OS可以在同一台计算机上同时运行的多个
进程之间有效共享内存和其他资源。然而
share-nothing仍然提供了对大型数据库具有线性可扩展性的能力，而SMP的可扩展性并不是非常线性的和
达到某个级别的饱和点。
大多数使用DB2的并行实现是无共享和/ b $ b SMP的混合，其中有多个物理节点，但每个都是SMP机器。
所以在这种情况下，你可能有6个节点（计算机），每个节点有4个CPU，而
总计24个数据库分区（每个节点4个）。真正的共享 - 什么都不会是每个物理节点的一个数据库分区。
Share-nothing也用于区分DB2和Teradata与其他的分区
并行实现，比如Oracle，即使每个节点有一个分区，也无法真正实现
无共享，因为这样的方式
Oracle并行数据库在内部工作。尽管Oracle不具备真正的无共享能力，但它适用于数据仓库的中等规模并行处理，但不如DB2和Teradata好。
Oracle多节点实现，因为它们不是真的
无共享，实际上增强了它实现故障转移的能力
能力，明确是因为它没有真正的分享 - 没有什么
架构。
Share-nothing architecture refers to parallel processing where a table is
divided into multiple partitions so that the database can work
simultaneously on each partition in parallel. For best results and the most
scalability, each partition would not share hardware resources with other
nodes. These hardware resources include memory, disk drives, disk
controllers, processors, etc. Hence the term, share-nothing.
In a true share-nothing architecture, each database partition is on a
separate computer (physical node) with a high-speed interconnect between
them. This architecture was invented by Teradata, which used multiple Intel
386 PC''s and a proprietary operating system in the early 1980''s.
Today, with the advent of SMP (Symmetrical Multi-Processing) machines, a
single computer can have multiple CPU''s, multiple disks and controllers, and
OS which can effective share memory and other resources among multiple
processes running on a single computer at the same time. However
share-nothing still provides the ability to have linear scalability to very
large databases, whereas the scalability of SMP is not quite linear and
reaches a saturation point at some level.
Most parallel implementations with DB2 are a hybrid of share-nothing and
SMP, where there are multiple physical nodes, but each one is SMP machine.
So in this case, you might have 6 nodes (computers) each with 4 CPU''s, and a
total of 24 database partitions (4 per node). True share-nothing would be
one database partition per physical node.
Share-nothing is also used to distinguish DB2 and Teradata from other
parallel implementations such as Oracle, which is not capable of true
share-nothing, even if you had one partition per node, because of the way
the Oracle parallel database works internally. Even though Oracle is not
capable of true share-nothing, it works well for moderate sized parallel
processing of data warehouses, but not quite as good as DB2 and Teradata.
Oracle multiple node implementations, because they are not true
share-nothing, actually enhances its ability to implement failover
capability, expressly because of its lack of a true share-nothing
architecture.
你试过谷歌吗？令人惊讶的是人们如何不使用谷歌。
输入无共享一词
did you try google? It amazes me how people don''t use google.
http://www.google.com
Put in the word "shared-nothing"
http://db.cs.berkeley.edu/papers/hpts85-nothing.pdf
在我达到这一段之前，我会忽略这一点。甲骨文是没有无法真正共享 - 没有......它的设计与
完全不同的架构，并没有兴趣尝试共享
什么都没有。
实际上，Oracle在第5版或第6版中没有共享，但由于我们遇到的问题，因此b / b
拒绝了它死亡多次
次，所以我再也不会讨论这个问题了。
只需说Oracle，就像大型机上的DB2一样，是
共享 - 所有一切建筑都是通过意图和没有人我知道
经验共享 - 一切都表明有任何愿望返回
到过去的糟糕日子。
-
Daniel Morgan
（将''x''替换为''u'''回复）
I was going to ignore this until I got to this paragraph. Oracle is
not ''incapable of true shared-nothing'' ... it is designed with an
entirely different architecture and has no interest in trying shared
nothing.
Well actually Oracle was shared-nothing through version 5 or 6 but
rejected it because of the very issues we have beaten to death multiple
times so I''ll no belabor the point again.
Suffice it to say that Oracle, like DB2 on mainframes, is a
shared-everything architecture by intent and no-one I am aware of with
experience with shared-everything has indicated any desire to return
to the bad old days.
--
Daniel Morgan
http://www.outreach.washington.edu/e...ad/oad_crs.asp
http://www.outreach.washington.edu/e...oa/aoa_crs.asp
da******@x.washington.edu
(replace ''x'' with a ''u'' to reply)
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