Skip to main content

Temporary Tablespaces in ORACLE

Temporary Tablespaces

Temporary tablespaces are used for special operations, particularly for sorting data results on disk and for hash joins in SQL. For SQL with millions of rows returned, the sort operation is too large for the RAM area and must occur on disk. The temporary tablespace is where this takes place.

Each database should have one temporary tablespace that is created when the database is created. You create, drop and manage tablespaces with create temporary tablespace, drop temporary tablespace and alter temporary tablespace commands, each of which is like it?s create tablespace counterpart.
The only other difference is that a temporary tablespace uses temporary files (also called tempfiles) rather than regular datafiles. Thus, instead of using the datafiles keyword you use the tempfiles keyword when issuing a create, drop or alter tablespace command as you can see in these examples:

 CREATE TEMPORARY TABLESPACE temp
TEMPFILE ?/ora01/oracle/oradata/booktst_temp_01.dbf? SIZE 50m;
DROP TEMPORARY TABLESPACE temp INCLUDING CONTENTS AND DATAFILES;

Tempfiles are a bit different than datafiles in that you may not immediately see them grow to the size that they have been allocated (this particular functionality is platform dependent). Hence, don?t panic if you see a file that looks too small.

col allocated_bytes format 999,999,999,999,999

col free_bytes format 999,999,999,999,999

 select
a.tablespace_name,
a.file_name,
a.bytes c3,
b.free_bytes
FROM
dba_temp_files a,
(SELECT file_id, SUM(bytes) free_bytes
FROM dba_free_space b GROUP BY file_id) b
WHERE
a.file_id=b.file_id
ORDER BY
a.tablespace_name;
Labels:

Comments

Post a Comment

Popular posts from this blog

Hi! I'm Java...

Java is a computer programming language. It enables programmers to write computer instructions using English based commands, instead of having to write in numeric codes. It’s known as a “high-level” language because it can be read and written easily by humans. Like English, Java has a set of rules that determine how the instructions are written. These rules are known as its “syntax”. Once a program has been written, the high-level instructions are translated into numeric codes that computers can understand and execute. Who Created Java? In the early nineties, Java was created by a team led by James Gosling for Sun Microsystems. It was originally designed for use on digital mobile devices, such as cell phones. However, when Java 1.0 was released to the public in 1996, its main focus had shifted to use on the Internet. It provided more interactivity with users by giving developers a way to produce animated webpages . Over the years it has evolved as a successful language for
1 comment
Read more

I'm the Server Operating System

Server Operating System A server operating system is software that was especially developed to serve as a platform for running multi-user computer programs, applications that are networked and programs critical to business computing. This type of operating system (OS) often comes bundled with the most common types of applications deployed in the client-server model, a term used to indicate the exchange of information between computers. For example, a hypertext transfer protocol (HTTP) or web server hosts or "holds" the text files, images files and scripts that work together to form a website. When someone connects to the Internet and types in a web address, the server that holds the files of the site delivers or "serves" the requested pages to the client computer or the machine that made the request. Frequently used applications in the client-server model handle operations for sharing files and printers across a network, hosting and serving web pages via the
Post a Comment
Read more

A Hit Count Using Java Servlet's Session Tracking

import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class SessionTracker extends HttpServlet {         public void doGet(HttpServletRequest req,HttpServletResponse res)         throws ServletException,IOException         {                res.setContentType("text/html");                PrintWriter out=res.getWriter();                HttpSession session=req.getSession(true);                Integer count=(Integer)session.getValue("tracker.count");                if(count==null)                {                         count=new Integer(1);                }else{                         count=new Integer(count.intValue()+1);                }                session.putValue("tracker.count",count);                out.println("<HTML><BODY><H1>SESSION TRACKING DEMO</H1>");                out.println("You've visited this page "+count+((count.intValue()==1)?" time.":"times."
2 comments
Read more