[ZODB-Dev] Remember date of last pack?

[Christian Zagrodnick]

On 2010-07-26 17:36:37 +0200, Jim Fulton said:

> On Mon, Jul 26, 2010 at 11:14 AM, Christian Zagrodnick <cz at gocept.com> wrote:
>> Hi,
>> 
>> for monitoring if a storage has been packed it would be handy if it
>> remembered the date of its last pack. An easy solution for file storage
>> would be to create a Data.fs.packed file.
>> 
>> Other ways do determine the date would be:
>> 
>> - Use age of Data.fs.old: very implicit; file is not available during
>> packing (thus monitoring becomes difficult); it is not required to keep
>> Data.fs.old
>> - Provide a wrapper script around zeopack which stores the information:
>> while that would work it is rather tedious to provide that again and
>> again for each buildout/installation.
>> 
>> Comments?
> 
> ZEO servers log when databases are packed.  I often look at the ZEO
> logs to verify that databases have been packed.

Sure. I was talking about automatic monitoring, though. That implies a 
rather cheap and simple way to determine the value to be checked.

> 
> File-storage packed database records have a status flag of "p", so you
> can determine the approximate (depending on how active your database
> is) date of last pack by scanning the transaction headers.

That sounds rather expensive. But then I don't know too much about that.

-- 
Christian Zagrodnick · cz at gocept.com
gocept gmbh & co. kg · forsterstraße 29 · 06112 halle (saale) · germany
http://gocept.com · tel +49 345 1229889 4 · fax +49 345 1229889 1
Zope and Plone consulting and development