Portal | Manuals | References | Downloads | Info | Programs | JCLs | Master the Mainframes
IBM Mainframe Computers Forums Index
 
Register
 
IBM Mainframe Computers Forums Index Mainframe: Search IBM Mainframe Forum: FAQ Memberlist Usergroups Profile Log in to check your private messages Log in
 

 

Table space extents > 1 , Table contains 0 Rows.

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> DB2
View previous topic :: :: View next topic  
Author Message
gylbharat

Active Member


Joined: 31 Jul 2009
Posts: 565
Location: Bangalore

PostPosted: Mon Oct 22, 2012 2:30 pm    Post subject: Table space extents > 1 , Table contains 0 Rows.
Reply with quote

Hi,

I have created a segmented tablesspace with only One table in that that tablespace.

However I observed something strange, Tablespace has extents 5 even if the table is empty (Zero Rows).

Can any one explain this?
Back to top
View user's profile Send private message

enrico-sorichetti

Global Moderator


Joined: 14 Mar 2007
Posts: 10201
Location: italy

PostPosted: Mon Oct 22, 2012 4:12 pm    Post subject: Reply to: Table space extents > 1 , Table contains 0 Rows
Reply with quote

probably an allocation <feature> ...
is the total space allocated equal to the initial space request
if yes then the volume has a fragmentation issue

generally , unless specifically requested, there is no guarantee that the initial allocation will be satisfied with a <single> extent
Back to top
View user's profile Send private message
gylbharat

Active Member


Joined: 31 Jul 2009
Posts: 565
Location: Bangalore

PostPosted: Mon Oct 22, 2012 4:24 pm    Post subject:
Reply with quote

Sorry... I didnot get you completely... Are you saying... say I request Primary Quantity as 100 Cyls , there was not enough space in any volume (STORAGE Group) which could allocate 100 Cyls in Single Extent?

Please let me know if this understanding is correct. In such cases how do I make sure it spans in 1 Extent?
Back to top
View user's profile Send private message
enrico-sorichetti

Global Moderator


Joined: 14 Mar 2007
Posts: 10201
Location: italy

PostPosted: Mon Oct 22, 2012 4:36 pm    Post subject: Reply to: Table space extents > 1 , Table contains 0 Rows
Reply with quote

Yes, I do not remember the exact sequence for the choice of eligible volumes

1) search for a volume with the total space requested available
2) search for a volume with the total space requested available in a single extent
at a certain point as many extents needed will be allocated

if <requested> and no contiguous space is available You will get IIRC a jcl error

are You defining the CLUSTER or are You letting DB2 do it under the covers ?
Back to top
View user's profile Send private message
gylbharat

Active Member


Joined: 31 Jul 2009
Posts: 565
Location: Bangalore

PostPosted: Mon Oct 22, 2012 4:38 pm    Post subject:
Reply with quote

Quote:
are You defining the CLUSTER or are You letting DB2 do it under the covers ?


We are not defining the table index to be clustered. As by default 1st index will act as clustering index.

How we can make it to 1 Extent?
Back to top
View user's profile Send private message
enrico-sorichetti

Global Moderator


Joined: 14 Mar 2007
Posts: 10201
Location: italy

PostPosted: Mon Oct 22, 2012 4:49 pm    Post subject: Reply to: Table space extents > 1 , Table contains 0 Rows
Reply with quote

Quote:
We are not defining the table index to be clustered. As by default 1st index will act as clustering index.


CLUSTER as per VSAM definition

a VSAM object is not called a file ...
is called a CLUSTER ...
with a DATA component and when needed an INDEX component

the relations between CLUSTER DATA INDEX ( primary/alternate ) PATH are called ASSOCIATIONS

the big entity consisting of
BASE CLUSTER, ALTERNATE INDEXES, PATH
is sometimes called a SPHERE

all is explained ..

here
z/OS V1R13.0 MVS JCL User's Guide
http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/iea2b570/CCONTENTS?SHELF=all13be9&DN=SA22-7598-07&DT=20110610095749
z/OS V1R13.0 MVS JCL Reference
http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/iea2b6b1/CCONTENTS?SHELF=all13be9&DN=SA22-7597-16&DT=20120814180937

and ...
z/OS V1R13.0 DFSMS Introduction
http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/DGT2DI40/CCONTENTS?SHELF=dgt2bkb1&DN=SC26-7397-04&DT=20110525151606
z/OS V1R13.0 DFSMSdfp Storage Administration
http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/DGT2S2A1/CCONTENTS?SHELF=dgt2bkb1&DN=SC26-7402-16&DT=20120126150025
z/OS V1R13 DFSMS Using Data Sets
http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/DGT2D4A0/CCONTENTS?SHELF=dgt2bkb1&DN=SC26-7410-11&DT=20110606092005


but also in the IBM REDBOOKS
here
http://www.redbooks.ibm.com/abstracts/sg246366.html

and in the series
ABCs of z/OS System Programming
( link to the first of it )
http://www.redbooks.ibm.com/abstracts/sg246981.html
Back to top
View user's profile Send private message
gylbharat

Active Member


Joined: 31 Jul 2009
Posts: 565
Location: Bangalore

PostPosted: Mon Oct 22, 2012 5:14 pm    Post subject:
Reply with quote

I am creating DB2 managed tablespaces. No I dont have control on defining LDS.
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> DB2 All times are GMT + 6 Hours
Page 1 of 1

 

Search our Forum:

Similar Topics
Topic Author Forum Replies Posted
This topic is locked: you cannot edit posts or make replies. Db2 SQL query to convert rows into co... subratarec DB2 5 Thu Nov 17, 2016 4:51 pm
No new posts Row-Numbers of distinct rows? Auryn DB2 1 Thu Oct 20, 2016 4:38 pm
No new posts Need Rexx Program to Load in to DB2 T... Hareesh Verma CLIST & REXX 22 Tue Sep 20, 2016 2:59 pm
No new posts Command UNIQUE CONSTRAINT on any tabl... rohanthengal DB2 2 Thu Aug 18, 2016 3:48 pm
No new posts Updating online Db2 table kishpra DB2 3 Fri Aug 12, 2016 2:44 pm


Facebook
Back to Top
 
Mainframe Wiki | Forum Rules | Bookmarks | Subscriptions | FAQ | Tutorials | Contact Us