[Drivers] ACID transaction description #143
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| ACID transactions guarantee atomicity, consistency, isolation, and durability so | ||||||||
| that database operations are executed safely, even when failures occur. ACID | ||||||||
| transactions are required in some industries where errors or partial updates | ||||||||
| could lead to serious financial, legal, or safety consequences. | ||||||||
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| By default, operations on single documents conform to ACID standards. For | ||||||||
| operations on multiple documents or collections, MongoDB supports multi-document | ||||||||
| ACID transactions using sessions. These transactions use the snapshot isolation | ||||||||
| level so applications see a consistent set of data while the transaction is | ||||||||
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Collaborator
There was a problem hiding this comment. This is a nit, but a small suggestion to possibly better explain what we mean by "snapshot isolation".
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| running and write concerns to ensure changes are safely saved. With these | ||||||||
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Collaborator
There was a problem hiding this comment. Re "write concerns to ensure changes are safely saved.", I'm not totally sure I understand what this means. Maybe something like: "changes to data are committed safely" ? |
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| features, MongoDB provides ACID guarantees that are comparable to those found in | ||||||||
| traditional relational databases. | ||||||||
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Collaborator
There was a problem hiding this comment. How important is this last sentence? I'm a little concerned that it could potentially read like we are "comparable", but maybe not as a good. But if this is a requirement from product or similar, I'm fine leaving. |
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who is the intended reader here? for readers who are technical, "conform to ACID standards" may be a bit too vague of a statement here.
Consistency - MongoDB offers causal consistency using sessions
Isolation - Any insert/update/delete of a single document is atomic and fully isolated; other clients never see a partial update to a document. MongoDB’s multi-document transaction protocol is designed to provide snapshot isolation: a transaction reads from a stable snapshot taken at (or just before) the transaction start, and other clients cannot see its in-progress writes.
Durability - as long as you have write concern: majority, your writes are durable though node failures.
It depends on how technical the reader is, but I would er on the side of including some of the nuance above.