I’m trying to update my MongoDB installation from 3.6 to the latest version [4.4] on Ubuntu16.04 using apt-get. Going from 4.0 to 4.2 I faced a problem during the startup process after updating the binaries and mongo.log shows the exception below:
2020-08-07T14:58:26.205+0300 I STORAGE [initandlisten] exception in initAndListen: Location40415: BSON field 'MinValidDocument.oplogDeleteFromPoint' is an unknown field., terminating
I’m using WiredTiger and I checked the feature compatibility version and other prerequisites according to the installation and the compatibility docs and everything looks fine. I don’t have any clue on what could be the source of this problem and I’d be grateful if someone can help.
Can you start this instance in standalone mode (different port and no replication settings in config) and provide the following content when logged in as admin:
use local
db.replset.minvalid.find({}).pretty ();
For some reason I believe this document is malformed.
The field oplogDeleteFromPoint should not be there when the FCV is moved to 4.2 according to SERVER-30556
I forgot to mention that but I’m experimenting on a standalone instance. I guess that’s not possible because the server won’t start after the upgrade so, I downgraded mongo to 4.0.19 and started it and connected via mongoshell and this is the output:
> use local
switched to db local
> db.replset.minvalid.find({}).pretty ();
{
"_id" : ObjectId("57b18fb43040dc07cefc3235"),
"ts" : Timestamp(1505648110, 6),
"t" : NumberLong(-1),
"oplogDeleteFromPoint" : Timestamp(0, 0)
}
What do you suggest in this case? do you think modifying this document manually before the upgrade would be a wise move?
I ran your query before the upgrade and it solved my problem.
For clarification, the problem appeared after updating the binaries to version 4.2. When I start the mongo service, the service fails to start and the log shows this exception before it starts the shutdown procedure:
2020-08-07T14:58:26.205+0300 I STORAGE [initandlisten] exception in initAndListen: Location40415: BSON field 'MinValidDocument.oplogDeleteFromPoint' is an unknown field., terminating
The solution was to unset the oplogDeleteFromPoint like @Pavel_Duchovny advised. After that I updated the binaries and and the service started normally.