mailing list For webmasters
Welcome Guest
deadlock-free/deadlockless Options
Tara2
Posted: Monday, February 22, 2021 12:49:37 PM

Rank: Advanced Member

Joined: 11/8/2017
Posts: 3,400
Neurons: 12,458
Can you please explain the difference between these two (deadlock-free/deadlockless)?

The tree-locking protocol has an advantage over the two-phase locking protocol in that, unlike two-phase locking, it is deadlock-free, so no rollbacks are required.
FounDit
Posted: Monday, February 22, 2021 2:32:58 PM

Rank: Advanced Member

Joined: 9/19/2011
Posts: 15,184
Neurons: 72,704
Tara2 wrote:
Can you please explain the difference between these two (deadlock-free/deadlockless)?

The tree-locking protocol has an advantage over the two-phase locking protocol in that, unlike two-phase locking, it is deadlock-free, so no rollbacks are required.


These appear to be words that are created. Deadlock-free is a compound word that simply indicates freedom from being deadlocked. There is no deadlock.

Deadlockless would have a meaning similar to "regardless", that is, without regard or consideration for anything. So deadlockless would mean without regard or consideration for a deadlock, no regard or consideration for the state of being deadlocked. I can't imagine using such a word.
Tara2
Posted: Monday, February 22, 2021 3:40:02 PM

Rank: Advanced Member

Joined: 11/8/2017
Posts: 3,400
Neurons: 12,458
FounDit wrote:
Tara2 wrote:
Can you please explain the difference between these two (deadlock-free/deadlockless)?

The tree-locking protocol has an advantage over the two-phase locking protocol in that, unlike two-phase locking, it is deadlock-free, so no rollbacks are required.


These appear to be words that are created. Deadlock-free is a compound word that simply indicates freedom from being deadlocked. There is no deadlock.

Deadlockless would have a meaning similar to "regardless", that is, without regard or consideration for anything. So deadlockless would mean without regard or consideration for a deadlock, no regard or consideration for the state of being deadlocked. I can't imagine using such a word.

Many thanks for your great explanation dear FounDit. Angel Angel
I myself created the word 'deadlockless' haha
Sorry FounDit but these two words I really have seen both. What is your opinion about these two, please?

(cascadeless/cascade free)
cascadless schedules/cascade-free schedules

Recall from Section 17.7.2 that, in addition to being serializable, schedules should be cascadeless. Cascading rollback may occur under two-phase locking. As an illustration, consider the partial schedule of Figure 18.8. Each transaction observes the two-phase locking protocol, but the failure of T5 after the read(A) step of T7 leads to cascading rollback of T6 and T7.
Wilmar (USA) 1M
Posted: Monday, February 22, 2021 5:53:57 PM

Rank: Advanced Member

Joined: 6/4/2015
Posts: 5,744
Neurons: 1,282,752
Location: Vinton, Iowa, United States
You do understand I hope, that many of the words you ask about are part of the computer engineering vocabulary. You need to develop that vocabulary if you are serious about that field. Are you understanding the material you read, even with the vocabulary help you ask for here?

This is the the page for asking questions about English grammar. It isn't the right place to ask for help understanding basic computer engineering concepts, and I wonder if you need some help with that, instead. What do you think?
FounDit
Posted: Monday, February 22, 2021 8:07:29 PM

Rank: Advanced Member

Joined: 9/19/2011
Posts: 15,184
Neurons: 72,704
Tara2 wrote:
FounDit wrote:
Tara2 wrote:
Can you please explain the difference between these two (deadlock-free/deadlockless)?

The tree-locking protocol has an advantage over the two-phase locking protocol in that, unlike two-phase locking, it is deadlock-free, so no rollbacks are required.


These appear to be words that are created. Deadlock-free is a compound word that simply indicates freedom from being deadlocked. There is no deadlock.

Deadlockless would have a meaning similar to "regardless", that is, without regard or consideration for anything. So deadlockless would mean without regard or consideration for a deadlock, no regard or consideration for the state of being deadlocked. I can't imagine using such a word.

Many thanks for your great explanation dear FounDit. Angel Angel
I myself created the word 'deadlockless' haha
Sorry FounDit but these two words I really have seen both. What is your opinion about these two, please?

(cascadeless/cascade free)
cascadless schedules/cascade-free schedules
Cascadeless as it is used here means that a cascade should not occur. Cascading simply means one thing following another, so you can think of the execution of instructions as a cascade when one follows another. That, of course, is exactly what a program does. So if two or more instructions are executed, then they cascade. If two more instructions reverse the operation, then you could say they cascade in a rollback fashion. That is, the instructions reverse what was just done. A simple illustration would be two ADD instructions - a cascade. Two SUBTRACT instructions using the same data would be a cascade rollback. It's as if the two ADD instructions never happened.

Recall from Section 17.7.2 that, in addition to being serializable, schedules should be cascadeless. Cascading rollback may occur under two-phase locking. As an illustration, consider the partial schedule of Figure 18.8. Each transaction observes the two-phase locking protocol, but the failure of T5 after the read(A) step of T7 leads to cascading rollback of T6 and T7.
Tara2
Posted: Tuesday, February 23, 2021 4:55:43 AM

Rank: Advanced Member

Joined: 11/8/2017
Posts: 3,400
Neurons: 12,458
Many thanks!!!
What about 'cascade-free', please?
FounDit
Posted: Tuesday, February 23, 2021 11:08:00 AM

Rank: Advanced Member

Joined: 9/19/2011
Posts: 15,184
Neurons: 72,704
Tara2 wrote:
Many thanks!!!
What about 'cascade-free', please?


To be "cascade-free", would seem to really be impossible for a computer program. After all, one thing following another is a cascade, and that's what a program does. It is a cascade of instructions.

But, after saying that, there is a sense where you could apply it. If you think of a subroutine as a cascade event (a small set of instructions that may or may not be activated), then if your program has no subroutines, it might be said to be cascade-free in that respect. But that is really twisting the logic and language in order to get there...*laughing*

Another way to be "cascade-free" would be if a subroutine was called, but one of the first couple of instructions caused it to end before the whole subroutine was completed, you could say the "cascade" didn't finish. So in that respect, the program was "cascade-free". But again, that's really being kind of foolish about it.
Tara2
Posted: Wednesday, February 24, 2021 9:12:13 AM

Rank: Advanced Member

Joined: 11/8/2017
Posts: 3,400
Neurons: 12,458
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
FounDit
Posted: Wednesday, February 24, 2021 12:46:18 PM

Rank: Advanced Member

Joined: 9/19/2011
Posts: 15,184
Neurons: 72,704
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.
Tara2
Posted: Wednesday, February 24, 2021 2:02:49 PM

Rank: Advanced Member

Joined: 11/8/2017
Posts: 3,400
Neurons: 12,458
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?
FounDit
Posted: Wednesday, February 24, 2021 8:15:31 PM

Rank: Advanced Member

Joined: 9/19/2011
Posts: 15,184
Neurons: 72,704
Tara2 wrote:
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?


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).
Tara2
Posted: Thursday, February 25, 2021 3:40:14 PM

Rank: Advanced Member

Joined: 11/8/2017
Posts: 3,400
Neurons: 12,458
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?
FounDit
Posted: Thursday, February 25, 2021 10:38:21 PM

Rank: Advanced Member

Joined: 9/19/2011
Posts: 15,184
Neurons: 72,704
Tara2 wrote:
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?

Yes, there would be no cascade.
Tara2
Posted: Friday, February 26, 2021 5:06:32 AM

Rank: Advanced Member

Joined: 11/8/2017
Posts: 3,400
Neurons: 12,458
Many thanks!!!
Users browsing this topic
Guest


Forum Jump
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.