[Info-vax] SpiraLog revisited (was: OpenVMS x64 Atom project)

[Norm Raphael]

>-----Original Message-----
>From: kemain.nospam--- via Info-vax <info-vax at info-vax.com>
>To: info-vax at info-vax.com
>Cc: kemain.nospam at gmail.com
>Sent: Sat, Jun 12, 2021 8:11 am
>Subject: Re: [New Info-vax] OpenVMS x64 Atom project
>
>
>>-----Original Message-----
>>From: Info-vax <info-vax-bounces at rbnsn.com> On Behalf Of Arne Vajhøj via
>>Info-vax
>>Sent: June-06-21 8:58 PM
>>To: info-vax at rbnsn.com
>>Cc: Arne Vajhøj <arne at vajhoej.dk>
>>Subject: Re: [Info-vax] OpenVMS x64 Atom project
>>
>>>On 6/6/2021 12:45 PM, Jan-Erik Söderholm wrote:
>>> Den 2021-06-06 kl. 17:36, skrev Arne Vajhøj:
>>>> But the rule is still that either the database will be unavailable
>>>> for significant time or one need a snapshot capability where updates
>>>> can be done but the backup sees the snapshot data at the time of the
>>>> snapshot.
>>>>
>>>> Storage or file system or database - the basic problem is the same.
>>>
>>> Yes. Rdb solves that using a "quiet point". As can be seen from the
>>> log file above, that took 2 sec (freezing and waiting for active
>>> transactions to finish). EFter that 2 sec delay, all update activity
>>> are back to normal while the backup continues to run. The data backed
>>> up is the data that was there at the point in time of the "quiet point lock>>>release".>>>
>>> And any "snapshot" data is only saved to the "snapshot file" in the
>>> case that some process request to update it. If not, there is no
>>> reason to copy any data, of course. 99% of the database will be
>>> untouched during the backup and thus not copied to the snapshot file.
>>>
>>> So most of the data backed up is "real" data, not snapshot data.
>>
>>Yes.
>>
>>I think that is common as well.
>>
>>I believe that SpiraLog would have worked similarly - if anyone still remembers>>that.
>>
>>Arne
>>
>
>Fyi - Spiralog technical overview:
><https://www.hpl.hp.com/hpjournal/dtj/vol8num2/vol8num2art1.pdf>
>
>Regards,
>
>Kerry Main
>Kerry dot main at starkgaming dot com
>

Kerry, Remind me why SpiraLog was abandoned, please.


Please reply to norman.raphael at ieee.org
 Norman F. Raphael"Everything worthwhile eventuallydegenerates into real work." -Murphy