[CAMEL-8063] Persistent tail tracking picks random tail tracker from mongoDB collection

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.13.1
• Fix Version/s: 2.15.0
• Component/s: camel-mongodb
• Estimated Complexity: Novice
• Assignee: Willem Jiang
• Reporter: Jörg Peschke
• Created: 19/Nov/14 12:28
• Updated: 13/Oct/17 12:24
• Resolved: 20/Nov/14 09:05

Description

There is a bug the method "initialize" in "MongoDbTailTrackingManager.java":

...
if (trackingObj == null)

{ dbCol.insert(filter, WriteConcern.SAFE); trackingObj = dbCol.findOne(); }

...

If no tail tracking object exists in the database, a new one will be inserted (that's okay), but the query "dbCol.findOne()" fetches ANY tail tracking object from the database (and not the one we've just inserted).

In my oppinition, this is a bug and should be corrected like this:
...
DBObject filter = new BasicDBObject("persistentId", config.persistentId);
trackingObj = dbCol.findOne(filter);
if (trackingObj == null)

{ dbCol.insert(filter, WriteConcern.SAFE); trackingObj = dbCol.findOne(filter); }

(not tested).

A workaround can be implemented by putting each persistent tail tracker in it's own collection, so I marked this issue as "minor".

More details: http://camel.465427.n5.nabble.com/MongoDB-Persistent-tail-tracking-with-concurrent-tailable-consumers-td5759131.html

Best regards,
Joerg Peschke