[DOCS-2908] That we run READ_UNCOMMITTED should be documented Created: 13/Mar/14 Updated: 16/Mar/15 Resolved: 04/Apr/14 |
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| Status: | Closed |
| Project: | Documentation |
| Component/s: | manual |
| Affects Version/s: | None |
| Fix Version/s: | v1.3.3 |
| Type: | Task | Priority: | Major - P3 |
| Reporter: | Andrew Erlichson | Assignee: | Sam Kleinman (Inactive) |
| Resolution: | Done | Votes: | 1 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Participants: | |
| Days since reply: | 9 years, 45 weeks, 6 days ago |
| Description |
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We should update this page: http://docs.mongodb.org/manual/reference/write-concern/ and this: http://docs.mongodb.org/manual/faq/fundamentals/#does-mongodb-support-acid-transactions to reflect the question posed here if the observed behavior is true: http://smalldatum.blogspot.com/2014/03/when-does-mongodb-make-transaction.html That is, if we consider the write fully committed only after it hits the journal, when j=true, then we should warn that another reader may see the write before it is fully committed. In the event of a failure and rollback, later readers may not see the write. This problem may also affect w=majority writes. In general, we want to guarantee the behavior that once a majority of members have seen the write, it is durable, even across the loss the primary. The problem is, if a majority of replica set nodes don't ack the write, and it's rolled back, someone on the primary may have already seen it. Essentially, we run READ_UNCOMMITTED. We should document this fact to avoid user confusion. |
| Comments |
| Comment by Sam Kleinman (Inactive) [ 04/Apr/14 ] |
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https://github.com/mongodb/docs/commit/db0172f7786bca6eb33200dd66c0c2366209facf |