[DOCS-5289] How is 2-phase commit done to update config servers? Created: 26/Apr/15 Updated: 24/Feb/16 Due: 15/May/15 Resolved: 04/May/15 |
|
| Status: | Closed |
| Project: | Documentation |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Mark Callaghan | Assignee: | Kay Kim (Inactive) |
| Resolution: | Done | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Participants: | |
| Days since reply: | 8 years, 41 weeks, 2 days ago |
| Description |
|
The manual claims that 2-phase commit is used for changes to config servers. A property that 2-phase commit provides is that changes are not visible on any of the servers until all servers have agreed to commit. From reading source in src/mongo/s and src/mongo/s/catalog I don't see how that is provided. Assuming I am correct, can the manual be updated to explain the behavior that is provided? What I do see is this pattern for updates which runs in two phases but isn't 2-phase commit: Two questions: 2) What is done to avoid inconsistent read after inconsistent write? If this were 2-phase commit then inconsistent read (read after inconsistent write) wouldn't be possible. Code I read to understand this includes:
|
| Comments |
| Comment by Githook User [ 04/May/15 ] |
|
Author: {u'username': u'kay-kim', u'name': u'kay', u'email': u'kay.kim@10gen.com'}Message: |
| Comment by Githook User [ 04/May/15 ] |
|
Author: {u'username': u'kay-kim', u'name': u'kay', u'email': u'kay.kim@10gen.com'}Message: |
| Comment by Githook User [ 04/May/15 ] |
|
Author: {u'username': u'kay-kim', u'name': u'kay', u'email': u'kay.kim@10gen.com'}Message: |
| Comment by Kay Kim (Inactive) [ 01/May/15 ] |
|
Hi Mark – Thanks so much for filing this ticket! Definitely need to update the docs. |
| Comment by Mark Callaghan [ 26/Apr/15 ] |
|
Claim from manual is at http://docs.mongodb.org/manual/core/sharded-cluster-config-servers/ Also spoke about this claim in a mongo-users group discussion. Other operations also write to the config servers, like replacing a shard server. "Read and Write Operations on Config Servers |