July 19, 2012 at 9:10 am
coldfusion244 (7/19/2012)
Luis Cazares (7/19/2012)
Why is everyone so upset about the answer? It's clear that the question is if you can restore the database without deleting the other snapshots. Otherwise you wouldn't have multiple snapshots and the scenario won't be the same.It's like if someone asked: "Can I restore a database if I don't have a valid backup?"
And you answered: "Yes, you just need to create a backup from which you want to restore".
I completely disagree. The question never states that you do or do not delete or keep anything. It literally asked if you could restore from any of them, of which the answer is yes with the caveat of the rest must be dropped. It's not like your scenario at all. In this scenario we have multiple valid points of which to start, in yours we don't.
The point is you can make it work, but you need to change the scenario first. I gave an example way out of proportion but it's still valid. The question says "you have multiple snapshots, can you restore from any of them?", the answer is "No" because you need to delete the snapshots so you remain with one and is no longer under the terms of the question.
July 19, 2012 at 9:17 am
Heh, perhaps it's because I haven't completely cleared my brain after studying for the MCITP. Because this question read very similar to some questions on that test. I just went into automatic answer mode. Lol.
+1 for me yayz!
July 19, 2012 at 9:24 am
Luis Cazares (7/19/2012)
coldfusion244 (7/19/2012)
Luis Cazares (7/19/2012)
Why is everyone so upset about the answer? It's clear that the question is if you can restore the database without deleting the other snapshots. Otherwise you wouldn't have multiple snapshots and the scenario won't be the same.It's like if someone asked: "Can I restore a database if I don't have a valid backup?"
And you answered: "Yes, you just need to create a backup from which you want to restore".
I completely disagree. The question never states that you do or do not delete or keep anything. It literally asked if you could restore from any of them, of which the answer is yes with the caveat of the rest must be dropped. It's not like your scenario at all. In this scenario we have multiple valid points of which to start, in yours we don't.
The point is you can make it work, but you need to change the scenario first.
No you don't. The scenario is a database with multiple snapshot. The restore procedure for that scenario is a two-step procedure:
1. Delete the other snapshots.
2. Restore to the remaining snapshot.
The original scenario hasn't changed.
I gave an example way out of proportion but it's still valid. The question says "you have multiple snapshots, can you restore from any of them?", the answer is "No" because you need to delete the snapshots so you remain with one and is no longer under the terms of the question.
But you can delete the other snapshots. The question doesn't rule that out as an action you can take. It doesn't limit you to a single-step restore process; it doesn't provide any constraints which would lead a solutions-oriented reader to believe that deleting the other snapshots is not an option. And for the answer to be "No", there must be a constraint that the other snapshots cannot be deleted.
"Can you?" is a question of possibility. If the requested action is possible in any plausible way within the constraints of the scenario, the answer is "Yes." And that's what we have here.
July 19, 2012 at 10:53 am
I, like Luis, assumed that the reason the additional snapshots were part of the question was to direct the reader to the correct answer. That being said, I also have empathy for those who took the wording as it was stated and picked a different answer even though they completely understood the technology and situation, just misinterpreted the intention because it wasn't clear to them. There have been many times where I've looked at a QOD, seen that it could go two ways and struggled to try and guess the intent. I'm still happy to have the QOD every day regardless of whether I get it right or not and regardless of whether I feel the question was well written or not. Thank you Igor for taking the time to draw up a question, work through it, and get it published. I've done it before and it's not easy. I'm glad you did it!
Thanks,
Chad
July 19, 2012 at 10:58 am
An iffy question at best. I guess I'm glad we don't mess around with snapshots just full backups with twice nightly test restores.
July 19, 2012 at 11:02 am
Learned something new, thanks for the question!
July 19, 2012 at 11:36 am
I got it wrong 🙁 but learnt something new. Thanks.
July 19, 2012 at 11:36 am
What the conversation doesn't mention is that a snapshot is a copy of changed records only, not a snapshot of the entire database. A record gets changed in db, the pre-change record is copied to the snapshot for snapshot consistency. The remaining unchanged records are only in the db, not the snapshot.
That being said, if there is database corruption, you may not have a full database for restoration from the snapshot.
*****
Give a man a fish, and you've given him a meal. Teach a man to fish and he'll ask to borrow your boat.:-P
July 19, 2012 at 11:38 am
Good Question. This kind of questions could be read carefully due to mistakes, the SQL manual say YES but not specifically say that must not be read only.
Regards
July 19, 2012 at 11:40 am
The given answer is absolutely incorrect. http://msdn.microsoft.com/en-us/library/ms189281.aspx states explicitly how to revert to a selected snapshot if multiple snapshots exist.
1. Select the snapshot you wish to restore.
2. Drop the other snapshots.
July 19, 2012 at 11:46 am
anthony.green (7/19/2012)
I also read it as being Yes as the question didnt specify needing to delete or not delete the other snapshots, so in theory Yes I can revert to any of the snapshots.
I see it that way. I also see it as "without doing anything else and leaving the snapshots in place"
Kind of a 50/50 split on how it can be interpreted in my mind.
Jason...AKA CirqueDeSQLeil
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July 19, 2012 at 11:51 am
tbailey 19088 (7/19/2012)
The given answer is absolutely incorrect. http://msdn.microsoft.com/en-us/library/ms189281.aspx states explicitly how to revert to a selected snapshot if multiple snapshots exist.1. Select the snapshot you wish to restore.
2. Drop the other snapshots.
Those are the prerequisites to be able to revert a database.
A most complete answer would be: "No, you need to drop all snapshots except one to revert the database" (More explained but still a negative answer)
July 19, 2012 at 12:54 pm
Good question on reverting to snapshots. I do not necessarily agree with the 'correct' answer.
July 19, 2012 at 1:25 pm
😛 Revert from a snapshot and Database Restore from a snapshot are two differant things covered by two differant BOL articles. 😛
Restore (includes how to restore from ANY snapshot)
http://msdn.microsoft.com/en-us/library/ms186858.aspx
<sorry since reverting the database to a database snapshot that predates the damage is main reason you have to do this part first/>
Back Up the Transaction Log When the Database Is Damaged
http://msdn.microsoft.com/en-us/library/ms189606.aspx
<then this can happen/>
Revert
http://msdn.microsoft.com/en-us/library/ms189281.aspx
Poor wording + Wrong Correct Answer = :crazy:
This teaches only one thing and makes only one point.
How to fact check pooor information.:hehe: Point is you should always fact check your data. 😎
July 19, 2012 at 1:45 pm
vk-kirov (7/19/2012)
Weird logic. I don't understand how the answer could be "No", while in fact the database can be restored from any of the snapshots (although not with a single RESTORE DATABASE command). Seems to be pure sophistry.
I have to agree with you on that. Although if the author understood this words meaning, maybe he could have phrased the QOTD better and not had a +70% fail rate. 😛
FYI -
http://en.wikipedia.org/wiki/Sophistry
a specious (deceptive) argument used for deceiving someone.
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