What is a TABLESPACE?

[Gil]

Hi,

I am a novice in the Database world. What is a TABLESPACE, and when do I
use it?

I was creating a Table in DB2 and it gave me two default choices for a
TABLESPACE name:
1. None
2. USERSPACE1
What is happening if I choose None or if I choose USERSPACE1? I noticed
this in Oracle as well, so image this is a DBMS thing.

Gil

[Greg Nash]

Hi Gil,
A tablespace is a place where tables are kept.
It could be a directory, using "System Managed Space" (SMS), ie the
operating system allocates space as required, and each table or index is a
file.
Or, it could be a file or disk, or a collection of files and/or disks that
are manually created / assigned by the system administrator, using "Database
Managed Space" (DMS). This way a large space can be allocated in one hit.
This way the database is responsible for allocating space, and you won't get
file-system fragmentation nor real-time file allocations interfering with
performance.

Userspace1 is usually created by default when you take all the easy options
in creating a database. When you create a table, you can specify which
tablespace to use, or don't specify and it will choose one for you.

You can also tune different tablespaces for different kinds of loads to
improve performance on a busy system.

For a little more info, look in the online documentation --> Administration
Guide --> Index --> Table Space --> Overview.

--Greg
Gil wrote:

> Hi,
>
> I am a novice in the Database world. What is a TABLESPACE, and when do I
> use it?
>
> I was creating a Table in DB2 and it gave me two default choices for a
> TABLESPACE name:
> 1. None
> 2. USERSPACE1
> What is happening if I choose None or if I choose USERSPACE1? I noticed
> this in Oracle as well, so image this is a DBMS thing.
>
> Gil