[SERVER-5042] Implement support for reliable change notifications Created: 22/Feb/12 Updated: 06/Dec/22 Resolved: 24/Jul/17 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Querying |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | New Feature | Priority: | Major - P3 |
| Reporter: | Yuri Finkelstein | Assignee: | Backlog - Query Team (Inactive) |
| Resolution: | Duplicate | Votes: | 28 |
| Labels: | pull-request | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
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| Assigned Teams: |
Query
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| Description |
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This features enables users to subscribe to change event stream (notifications) resulting from changes made to documents in a collection in mongodb. The user can specify a filter to be applied to change events. The resulting stream would go into a capped collection created specifically for this subscription. In addition, mongodb will keep a position in this capped collection reflecting the last message consumed by the client so that the client could resume reading the event stream where it left off. Here is a more detailed version of how this should work: This feature is basically very similar to how mongodb replication works. |
| Comments |
| Comment by Spencer Brody (Inactive) [ 24/Jul/17 ] |
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We are planning on releasing a change streams API in our upcoming 3.6 release. The exact implementation is a bit different than what is described in this ticket, but should provide similar functionality. The work for this project is spread out across multiple tickets, but you can follow |
| Comment by ijammy [X] [ 02/Oct/14 ] |
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Also, I'm implementing something else, which is similar to what I did in the pull-request, but leveraging rabbitmq, an AMQP implementation. |
| Comment by ijammy [X] [ 02/Oct/14 ] |
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Thanks Benety & Paul I don't know how the mongodb community like this feature enhancement (https://github.com/mongodb/mongo/pull/199) at this moment. but at Yottaa, we've been using this customized mongodb( https://github.com/ijammy/mongo ) in production to publish the changes to the subscribers who are interested in specific documents. and I also know a few people used the customized mongodb version as well. The only issue is that every time we upgrade mongodb, I have to apply the patch to the new version. So if there is a possibility to merge this kind of feature into the mainline, I would love to re-send the pull-request based on the mainline. |
| Comment by Paul Pedersen [ 09/May/13 ] |
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An interesting mongodb feature enhancement. I would like to revive the thread on this suggestion. |
| Comment by Scott Lyons [ 16/May/12 ] |
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My organization needs something just like this. So far I've been able to make use of https://github.com/mongodb/mongo/pull/199 with great effect. |
| Comment by Yuri Finkelstein [ 16/Apr/12 ] |
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Just to add bit more context as to why this is an important feature to have. Consider a typical pattern: a business transaction is performed in a database and several off-line applications need to be notified of this event asynchronously. A common solution to this problem is for the application committing a transaction with the DB to also post a message to a pub/sub message broker. Now, in reality this is easier said than done if certain degree of reliability is required. For one, how can one guarantee that notification event is never lost beween completion of DB transaction and posting it to the pub/sub broker? 2PC is rarely an option and Mongo siply does not support it. Another issue is the need to manage throughput capacity of the message broker as the number of DB transaction is growing. Since capacity management in DB and message brokers are rarely performed by the same team (in a large org) this presents logistical challenges. The feature proposed in this ticket would allow designers to completely eliminate the need for message broker in this pattern and reply on MongoDB for both business transactions and generation of related notifications. It solves both problems mentioned above nicely: Additional consideration: |