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Bulk Logged recovery model Expand / Collapse
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Posted Tuesday, April 17, 2012 1:19 PM
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L' Eomot Inversé (4/17/2012)
Ernie Schlangen (4/17/2012)
sknox (4/16/2012)

I would say that since the question read "...could you see a log file bigger than usual?" the only logical answer is yes. While the bulk-logged recovery model is a feature designed to reduce log file growth, it does not constrain log file growth. Therefore you certainly could see a larger log file in some circumstances.

However, I would also say that that does not seem to be the intent of the question. The question was poorly worded, but the explanation is correct. So, poor wording of the question has given us a "If False then True" situation -- which, if my memory of basic logic serves me properly, is still True. So much for logic.


This is pretty much the way I looked at this question. The key word to me was could as well, which pretty much forces the answer to be yes because it is such an open-ended question. I'm thinking along the lines of Arthur C. Clarke's first law:
When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.

The trouble is that to many people (including me) it looks as if the question means "is it at all likely that the decision to switch to bulk mode increases the size of" whatever it refers to. If it refers to the log file (which is what it says) the answer is clearly NO. If it refers to the backup file (which is what the question author says he intended) the answer is clearly YES.

And yes, regardless of Clark's law I will state that it is extremely unlikely that a switch to bulk logging will cause an increase in the log file size, and that it's equally unlikely that it won't cause an increase in the log backup size. If you believe Clarke's law you will probably want to claim that when I (an elderly scientist - on whether distinguished or not I make no comment) say that it is impossible that switching to bulk logged mode then doing a bulk operation then switching back to full mode and then doing a backup will lead to a smaller backup file that doing all the same except that the recovery mode switches are omitted I am likely to be talking from the wrong orifice, and that probable mistake on your part just goes to show that Clarke's law is (exactly as he intended) a broad generalisation that can't be used to determine specific outcomes although it can be used to indcate that unvalidated theories (as opposed to empirical knowledge) are often a waste of space.

Edit: eliminate double negatives (Cha toigh leam a' bheurla shasunnach - I hate the English gibberish).


I understand (and agree with) your point about the unlikeliness of the log file increasing in size. However, if it is possible for the log file size to increase, then the answer is "yes" to the question as stated (in my opinion, of course). And, for the record, I consider you to be "distinguished". I've certainly learned some things just from following up on references that you've made.
Post #1285226
Posted Tuesday, April 17, 2012 3:00 PM


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Ernie Schlangen (4/17/2012)
I understand (and agree with) your point about the unlikeliness of the log file increasing in size. However, if it is possible for the log file size to increase, then the answer is "yes" to the question as stated (in my opinion, of course).


Yes, on a literal interpretation of the words the answer is "yes"; the trouble with that interpretation is we would be reading the question as "is it false that selecting the bulk recovery model guarantee that it is impossible for the log file to grow" and given the words chosen to pose the question is looked very unlikely that that was the author's intention (and indeed he has said it was not his intention - he meant to ask about the backup file, not the log file).

And, for the record, I consider you to be "distinguished".

Oh dear, something else we disagree on.
I've certainly learned some things just from following up on references that you've made.

thanks for telling me that - I'm glad to know that someone is following up the links/references I provide.


Tom
Post #1285303
Posted Monday, April 23, 2012 8:18 PM
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Good question. Thanks for submitting.

http://brittcluff.blogspot.com/
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Posted Wednesday, April 25, 2012 3:31 AM


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I misread the question initially and made the assumption the question was referring to the log backup as opposed to the file. It was only after I clicked Submit that I saw the reference to log file so was expecting to get an incorrect answer.

I've never been so pleased to have misread a question and made an assumption!
Post #1289675
Posted Monday, July 30, 2012 7:19 AM


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Although I got the point because I assumed that you are talking about huge log backup file size (because that is something to note when you use bulk logged recovery model) however the question has been poorly worded.


Sujeet Singh
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Posted Friday, May 10, 2013 7:33 AM
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As mentioned, fix this question T_T
change to "could you see a log file backup bigger than usual?" -- I knew the backup would be bigger; from the wording I thought it was a trick Q

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