RE: How does Oracle set the High Water Mark?
- From: Feighery Raymond <Raymond.Feighery@xxxxxxxxxxxxx>
- To: "'oracle-l@xxxxxxxxxxxxx'" <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 10 Mar 2004 14:43:37 -0000
Good answer.
On mine it's set to 0. I think this is a feature of Automatic Space Segment
Management (see other post).
Thanks
Ray
-----Original Message-----
From: Tim Gorman [mailto:tim@xxxxxxxxxxxxx]
Sent: Wednesday, March 10, 2004 2:13 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Re: How does Oracle set the High Water Mark?
Used to be controlled by a hidden parameter named:
PARAMETER DESCRIPTION DFLT
--------------------------------------- -------------------- -----
_bump_highwater_mark_count = 0 how many blocks TRUE
should we allocate
per free list on
advancing HW
And it used to default to 5. But, on my 9.2.0.1 database, it doesn't appear
to have a default value at all. If it is being calculated internally, then
on your database it seems to be 13, perhaps?
on 3/10/04 6:56 AM, Feighery Raymond at Raymond.Feighery@xxxxxxxxxxxxx
wrote:
> Oracle 9.2.0.4 Solaris 8
>
> How does Oracle set the HWM? In the example below, I create a table and
> insert one row. I would expect only one block to be used, instead Oracle
> seems to have pushed the HWM up to 13 blocks. I can imagine that this
might
> be done to "pre-mark" rows as used during bulk inserts, but how does
Oracle
> decide where to set the HWM?
>
> SQL> select * from dba_tablespaces where tablespace_name = 'EXAMPLE';
> TABLESPACE_NAME BLOCK_SIZE INITIAL_EXTENT NEXT_EXTENT MIN_EXTENTS
> ------------------------------ ---------- -------------- -----------
> -----------
> MAX_EXTENTS PCT_INCREASE MIN_EXTLEN STATUS CONTENTS LOGGING FOR EXTENT_MAN
> ----------- ------------ ---------- --------- --------- --------- ---
> ----------
> ALLOCATIO PLU SEGMEN DEF_TAB_
> --------- --- ------ --------
> EXAMPLE 4096 65536 1
> 2147483645 65536 ONLINE PERMANENT LOGGING NO LOCAL
> SYSTEM NO AUTO DISABLED
>
> SQL> create table t (col1 number(1));
> Table created.
> SQL> analyze table t compute statistics;
> Table analyzed.
> SQL> insert into t values(1);
> 1 row created.
> SQL> commit;
> Commit complete.
> SQL> select blocks, empty_blocks from user_tables where table_name = 'T';
> BLOCKS EMPTY_BLOCKS
> ---------- ------------
> 0 16
> SQL> analyze table t compute statistics;
> Table analyzed.
> SQL> select blocks, empty_blocks from user_tables where table_name = 'T';
> BLOCKS EMPTY_BLOCKS
> ---------- ------------
> 13 3
>
>
___________________________________________________________________________
>
>
> This email and any attached to it are confidential and intended only for
the
> individual or entity to which it is addressed. If you are not the
intended
> recipient, please let us know by telephoning or emailing the sender. You
> should also delete the email and any attachment from your systems and
should
> not copy the email or any attachment or disclose their content to any
other
> person or entity. The views expressed here are not necessarily those of
> Churchill Insurance Group plc or its affiliates or subsidiaries. Thank
you.
>
> Churchill Insurance Group plc. Company Registration Number - 2280426.
> England.
>
> Registered Office: Churchill Court, Westmoreland Road, Bromley, Kent BR1
> 1DP.
>
>
> ----------------------------------------------------------------
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> ----------------------------------------------------------------
> To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx
> put 'unsubscribe' in the subject line.
> --
> Archives are at //www.freelists.org/archives/oracle-l/
> FAQ is at //www.freelists.org/help/fom-serve/cache/1.html
> -----------------------------------------------------------------
----------------------------------------------------------------
Please see the official ORACLE-L FAQ: http://www.orafaq.com
----------------------------------------------------------------
To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx
put 'unsubscribe' in the subject line.
--
Archives are at //www.freelists.org/archives/oracle-l/
FAQ is at //www.freelists.org/help/fom-serve/cache/1.html
-----------------------------------------------------------------
___________________________________________________________________________
This email and any attached to it are confidential and intended only for the
individual or entity to which it is addressed. If you are not the intended
recipient, please let us know by telephoning or emailing the sender. You
should also delete the email and any attachment from your systems and should
not copy the email or any attachment or disclose their content to any other
person or entity. The views expressed here are not necessarily those of
Churchill Insurance Group plc or its affiliates or subsidiaries. Thank you.
Churchill Insurance Group plc. Company Registration Number - 2280426.
England.
Registered Office: Churchill Court, Westmoreland Road, Bromley, Kent BR1
1DP.
----------------------------------------------------------------
Please see the official ORACLE-L FAQ: http://www.orafaq.com
----------------------------------------------------------------
To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx
put 'unsubscribe' in the subject line.
--
Archives are at //www.freelists.org/archives/oracle-l/
FAQ is at //www.freelists.org/help/fom-serve/cache/1.html
-----------------------------------------------------------------
Other related posts:
