Amazon Aurora Backtrack

Re:Amazon Aurora Backtrack by wpietri on Thursday May 10, 2018 @10:15AM (#17039011)

Very interesting. The describe it as a rewind. Does anybody know if it's really a rewind, where each log record is reversible? Or do they do the easier thing of saving snapshots and then replaying the log from snapshot to desired point?

[ Parent | on HN ]

Re:Amazon Aurora Backtrack by misframer on Thursday May 10, 2018 @10:33AM (#17039163)

Aurora uses a log-structured storage system, so they just point to a previous version that they haven't garbage collected.

[ Parent | on HN ]

Re:Amazon Aurora Backtrack by awgupta on Tuesday May 15, 2018 @10:07PM (#17079475)

that's correct.

[ Parent | on HN ]

Re:Amazon Aurora Backtrack by mmahemoff on Thursday May 10, 2018 @10:27AM (#17039111)

Probably reversible transactions where possible, but with original-state metadata attached to the transaction if it's required to reverse it (https://en.wikipedia.org/wiki/Memento_pattern).

[ Parent | on HN ]

Re:Amazon Aurora Backtrack by awgupta on Tuesday May 15, 2018 @10:09PM (#17079488)

no, we don't perform destructive writes so we are able to simply mark a region of the log as to be skipped. this approach also allows us to move back and forth within the time domain even after a backtrack.

[ Parent | on HN ]

Re:Amazon Aurora Backtrack by walru on Thursday May 10, 2018 @10:19AM (#17039044)

Every thing is recorded.

edit: And I'm being down voted because? Because HN does not enjoy the truth?

[ Parent | on HN ]

Re:Amazon Aurora Backtrack by freehunter on Thursday May 10, 2018 @10:36AM (#17039193)

The downvotes are probably because the answer wasn't helpful and doesn't mesh with Amazon's statements.

[ Parent | on HN ]

Re:Amazon Aurora Backtrack by walru on Thursday May 10, 2018 @10:39AM (#17039217)

How did that work for everyone deleting their FB account?

[ Parent | on HN ]

Re:Amazon Aurora Backtrack by freehunter on Thursday May 10, 2018 @10:40AM (#17039229)

How is this conversation helpful to this thread? The question is not "how much does Amazon keep" but "how long/much/granular can I restore".

[ Parent | on HN ]

Re:Amazon Aurora Backtrack by walru on Thursday May 10, 2018 @10:48AM (#17039294)

That sounded like the original question to me. It's an estranged statement to believe otherwise.

So, yes, they save snapshots and take you back to the time of your choosing based off that.

[ Parent | on HN ]

Re:Amazon Aurora Backtrack by matthewmacleod on Thursday May 10, 2018 @01:21PM (#17040943)

So, yes, they save snapshots and take you back to the time of your choosing based off that.

Okay, but you're most likely wrong with that. If you read about how Aurora works (https://www.allthingsdistributed.com/files/p1041-verbitski.p...) it seems likely that they will be using log entries to rollback database state, rather than retaining "snapshots".

[ Parent | on HN ]

Re:Amazon Aurora Backtrack by icebraining on Thursday May 10, 2018 @10:58AM (#17039388)

An estranged statement? What does that mean?

How do you know they use the snapshots method, rather than reversing the changes?

[ Parent | on HN ]

[dead]

Re:Amazon Aurora Backtrack by icebraining on Thursday May 10, 2018 @01:09PM (#17040792)

Well, as Bucephalus355 pointed out in another comment, Oracle has a similar feature and it's not implemented using snapshots.

[ Parent | on HN ]