lowering HWM

[db2admin]

hello,

I am working on bringing HWM down. what is the best way to do this ? i
know db2dart but i am afraid if this locks database or tablespace etc.
i am thinking of exporting all data, dropping tables, recreating
tables and loading data back in. is there anyone who has worked with
similar situation ? what is the best way to do this ?
regards,
db2admin

[Sanjuro]

On Sep 11, 3:47*pm, db2admin <[e-mail]:

hello,

I am working on bringing HWM down. what is the best way to do this ? i
know db2dart but i am afraid if this locks database or tablespace etc.
i am thinking of exporting all data, dropping tables, recreating
tables and loading data back in. is there anyone who has worked with
similar situation ? what is the best way to do this ?

regards,
db2admin

Try an offline REORG first.

[Eric.Jones]

db2admin wrote:

hello,

I am working on bringing HWM down. what is the best way to do this ?

Let DB2 try to reduce the container allocations for the tablespace(s):

Alter tablespace TS_XXXX reduce (ALL nnnn)

As Sanjuro suggests, best to REORG first... then the freespace is
contiguous and the HWM can reduced further.
Eric

[w.l.fischer]

Hi,

the only way I can think of reliably reducing the HWM is to use
db2dart or drop the tablespace after all tables are dropped... The
latter is not better than the former.

What I did (in a test environment) is to reorg, then use

db2dart prestodb /rhwm /tsi <tbspaceid>,

then stop DB2 from requiring an offline backup:

db2dart prestodb /chst /what dbbp off

then backup the tablespace

db2 backup db prestodb tablespace <tbspacenameto /dev/null

After that, the DB is reusable. However, I'm not sure now if an online
backup is enough of the tablespace to bring it out of check pending
mode, I did an offline backup.

db2admin wrote:

hello,

I am working on bringing HWM down. what is the best way to do this ? i
know db2dart but i am afraid if this locks database or tablespace etc.
i am thinking of exporting all data, dropping tables, recreating
tables and loading data back in. is there anyone who has worked with
similar situation ? what is the best way to do this ?
regards,
db2admin

[w.l.fischer]

db2dart prestodb /rhwm /tsi <tbspaceid>,

I forgot to mention that you're not only concerned about the high
water mark, but also about the highest control page, which won't
automatically be removed by reorg'ing the tablespace. That's why I
used db2dart, to remove the control pages.