[SERVER-18022] Support "read committed" isolation level where "committed" means confirmed by the voting majority of a replica set Created: 13/Apr/15 Updated: 26/Jul/19 Resolved: 12/Aug/15 |
|
| Status: | Closed |
| Project: | Core Server |
| Component/s: | Querying, Replication |
| Affects Version/s: | None |
| Fix Version/s: | 3.1.7 |
| Type: | Improvement | Priority: | Major - P3 |
| Reporter: | Andy Schwerin | Assignee: | Mathias Stearn |
| Resolution: | Done | Votes: | 2 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
|
||||||||||||||||||||||||||||||||
| Backwards Compatibility: | Fully Compatible | ||||||||||||||||||||||||||||||||
| Sprint: | Quint Iteration 3, Quint Iteration 4, Quint Iteration 5, Quint Iteration 6, Quint Iteration 7, QuInt 8 08/28/15 | ||||||||||||||||||||||||||||||||
| Participants: | |||||||||||||||||||||||||||||||||
| Description |
|
Writes in MongoDB replica sets are "committed" when the majority of voting nodes in the replica set confirm the write (n.b., arbiters cannot confirm writes). This ticket is to add a feature to query-like operations (find, count, aggregate, etc) to restrict the data observed to data known to have been committed at the replica set level. It is an approximate but imperfect analog of "w: majority" writes. In MongoDB deployments using an MVCC storage engine, such as WiredTiger, this behavior could be implemented by having the replication subsystem retain the newest "known committed" version of data on each node, and have the query system serve "committed" reads from that version rather than the newest version. |
| Comments |
| Comment by Githook User [ 28/Aug/15 ] |
|
Author: {u'username': u'RedBeard0531', u'name': u'Mathias Stearn', u'email': u'mathias@10gen.com'}Message: |
| Comment by Githook User [ 29/Jul/15 ] |
|
Author: {u'username': u'milkie', u'name': u'Eric Milkie', u'email': u'milkie@10gen.com'}Message: |
| Comment by Githook User [ 29/Jun/15 ] |
|
Author: {u'username': u'RedBeard0531', u'name': u'Mathias Stearn', u'email': u'mathias@10gen.com'}Message: |
| Comment by Andy Schwerin [ 13/Apr/15 ] |
|
redbeard0531, I finally got around to creating a server ticket for this. Per prior conversation, we'll need to gracefully refuse to support this behavior in storage engines that don't offer the necessary underpinnings. |