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Tara2 |
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Advanced Member |
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Wednesday, November 8, 2017 |
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Monday, March 1, 2021 3:57:38 PM |
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thar wrote:you can look at this another way
not + ever = never
since no transaction ever waits
=
since transactions never wait
so it might not be helpful to look at 'ever' on its own here, but as the negative.
It would not be in this sentence on its own. It only exists here because this is a negative statement.
No + ever.
Many thanks. 
Sorry thar, I have [roblem with 'ever' in sentences like the below, how that mean 'at any time', it looks like 'until now':
a. At any time: Have you ever been to Europe?
Can you please explain?
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Wilmar (USA) 1M wrote:
from the definition for ever, here on TFD:
a. At any time: Have you ever been to Europe?
Many thanks!!!
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Can you please explain this use of 'ever'?
The protocol ensures freedom from deadlock, since no transaction ever waits.
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Can you please explain any differences it terms of meaning between 'randomized', 'nondeterministic' and 'uncertainty'?
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Aha, understand, not completely . Many thanks to you both!!!!
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Many thanks!!!
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FounDit wrote:
Well, cascadeless would be as I said before, having no regard or consideration for a cascade, so I don't think that is what you want.
Having a mechanism whereby a cascade cannot happen, would then fit the definition of being cascade-free. The mechanism prevents the possibility of a cascade, so the program is free from having a cascade occur ( if a cascade is a roll back).
Many thanks dear FoynDit for the great explanation!!!
Sorry :) , so from this, 'cascadeless' and 'cascade free' are similar, no, please?
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thar wrote:The word means both
Interested - intrigued, wanting to investigate,
And
Interesting - strange, odd, unexpected
Since a case can't want to investigate, it has to be that the case is odd.
People can be both meanings, but things can only be odd, because they can't feel the emotion of being curious about something.
Many thanks dear thar for the great explanation!!!
Sorry thar, you used 'interesting' and 'interested'. Does 'interese' also mean 'odd', please?
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What does 'curious' mean?
• If T30 uses the tuple newly inserted by T31 in computing count(*), then T30 reads
a value written by T31. Thus, in a serial schedule equivalent to S, T31 must come
before T30.
• If T30 does not use the tuple newly inserted by T31 in computing count(*), then in
a serial schedule equivalent to S, T30 must come before T31.
The second of these two cases is curious. T30 and T31 do not access any tuple in common,
yet they conflict with each other! In effect, T30 and T31 conflict on a phantom
tuple. If concurrency control is performed at the tuple granularity, this conflict would
go undetected. As a result, the system could fail to prevent a nonserializable schedule.
This problem is an instance of the phantom phenomenon.
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FounDit wrote:Tara2 wrote:Sorry FounDit, I s'v explained what casecade mean here.
It's about rolling back transactions, if we rollback a transaction all other transactions that used the data modified by this transaction should be rolled back too, this is meant casecade Right, but that would be a cascade(ing) rollback, correct? All the instructions that used the data now reverse what was done with the data.
Yes, may thanks!!!
They use mechanisms to avoid cascading rollbacks, now what is the difference if we say 'cascadeless' or 'cascade free', please?
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