Nowadays, Exadata is a buzzword in a database world so i decided to put a light on this.
In simple words Exadata ==> a server with pre-installed and pre-optimized database so i can say that the hardware is designed in such a manner that each component in the hardware is tuned to work with database including memory, CPU.. etc.
Oracle Exadata is positioned as pre-configured clustered database server Here is i have used a term cluster so lets understand this concept.
> To avoid these problems a product came Exadata which provides bundled hardware and software to customer infact a hardware with intelligence.
> it is positioned as clustered as it contains bundle of database servers that hosts database software combining together serving a one purpose only and also it consists of storage servers that are having chunks of memory to hold the data from database servers.
As you can see the above image it is containing a database servers, a storage servers and infiniband switches which as a whole serving a one purpose.
Its becoming popular because of its main feature i’e Smart Scan
Lets understand this via a small example:
> In RAC env Database is stored at Shared Storage Server and to get output of any query data has to transfer from Shared Storage server to Database Node and then DB node will process data and provide results.
so if a query has to return 1 million rows and order table contains 100 million rows so all the 100 million rows will come from storage node to database node for processing and then output will be received. This will take a lot of time for DBA.
> To eliminate this Exadata smart scanning introduced where if a query has to return 1 million rows so only 1 million rows will be transferred to database node and not all the 100 million rows. This is something called as Filtering at Storage Level
Ofcourse, this is not its only feature but has many which makes it popular.
I hope you must have got the basic understanding of Exadata via above description.