[Glass] Compacting extent as part of the daily cleanup/backup scripts? Re: Compact a extend0.dbf

[Dale Henrichs via Glass]

On Mon, Aug 18, 2014 at 10:58 AM, Mariano Martinez Peck <
marianopeck at gmail.com> wrote:

>
>
> On Sat, Jun 7, 2014 at 9:55 AM, Dale Henrichs <
> dale.henrichs at gemtalksystems.com> wrote:
>
>> Dario,
>>
>> The procedure for compacting extent files is:
>>
>>   1. make a full backup
>>   2. shut down stone
>>   3. cp a virgin extent ($GEMSTONE/bin/extent0.seaside.dbf) into your
>>       data directory
>>   4. start stone
>>   5 restore from backup
>>
>>
> Hi Dale,
>
> I had a similar scenario today. My extent is about 11GB and 9GB out of
> them are free. I get that doing   '(SystemRepository freeSpace / 1024 /
> 1024 ) asFloat  greaseString'.
> So...yes, yeah, I would like to compact this extent.
>
> Now...I have backup and cleanup strings every day which do a MFC and
> reclaim, make full backup, and remove unnecessary tranlogs according to
> last backup. Very much as the script you provided me from ss3.  So I was
> wondering if the compact of the extent could also be part of this scripts.
>  Would it be worth?  I guess I must measure myself right? I mean, I can
> compacting it a the beginning of a business day, and see how much free
> space I have again at night? Then regarding that answer, I can consider
> whether do this daily, or weekly or ...
>
> Another question is...I guess that when you make the extent bigger there
> is some cost associated. So...I don't want to be compacting frequently (say
> every day) if then the app will run slower because it is making bigger the
> extent all the time.
>

I think that the main consideration in extent size is how much disk space
you have available...

there really isn't much of a penalty for having free space in your extents.

On the other hand, there is a rall performance penalty for growing your
extents ... if you don't have enough free space in an extent the system
will have to allocate more disk space for the extent and that can add to
disk i/o load on your system while the extent is grown ...

So at the end of the day, you really only need to shrink your extents when
you are in danger of running out of disk space for tranlogs or other files
...

Dale
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.gemtalksystems.com/mailman/private/glass/attachments/20140902/3e7eadcb/attachment.html>