Huge memory consumption during hot backup

From: Paolo <borghesi_at_libero.it>
Date: 16 Sep 2004 07:36:07 -0700
Message-ID: <63aec3d1.0409160636.7422939e@posting.google.com>

Hi,
I'm using Oracle 8.1.7.4.1 on Windows 2000 Advanced Server SP 3. The DB is in archive log mode, and I use the following script to perform an hot backup:

---

spool temp_bk_res
$SET backup=x:\backup

connect user/password_at_mydb as sysdba
$mkdir x:\backup\today

alter tablespace GENESYS_CFG begin backup;
$copy Y:\ORACLE\ORADATA\MYDB\USERS01.DBF x:\backup\today
alter tablespace GENESYS_CFG end backup; alter tablespace GENESYS_LOG begin backup;
$copy Y:\ORACLE\ORADATA\MYDB\USERS02.ORA x:\backup\today
$copy Y:\ORACLE\ORADATA\MYDB\USERS02.ORA x:\backup\today
$copy Y:\ORACLE\ORADATA\MYDB\USERS02.ORA x:\backup\today
alter tablespace GENESYS_LOG end backup; [...]

---

My problem is that when I begin the backup the available physical memory decreases by around 400-500Mb, and if my system have less free memory than requested it begins to swap a lot, making the database unable to reply to the application (which hang).

I've tried also by replacing the "$copy" commands with the "$start /wait /low ocopy" commands, but the memory consumption has not changed; besides, I tried to change Windows' file cache usage, by setting the "File and Printer Sharing for Microsoft Networks" properties to "Maximize data throughput for network applications", but with no success.

Do you have something to suggest?

Best regards,

Paolo Borghesi Received on Thu Sep 16 2004 - 09:36:07 CDT