[SERVER-1512] backup objects deleted by rollback (WAS: Repl set: Behavior when resyncing -> deleting documents) Created: 29/Jul/10  Updated: 12/Jul/16  Resolved: 03/Aug/10

Status: Closed
Project: Core Server
Component/s: Replication
Affects Version/s: 1.5.6
Fix Version/s: 1.5.8

Type: Improvement Priority: Major - P3
Reporter: nosh petigara Assignee: Eliot Horowitz (Inactive)
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Participants:

 Description   

Just looking through docs + code:

F = node that failed and coming back.
P = node that took over, new primary
From documentation and code in rs_rollback.cpp, appears we are deleting (or overwrite) data from 'F' that was when it comes back online after being down

In addition to deleting/updating, should we be copy the deleted versions of documents somewhere (e.g. some temp collection)
so that a manual re-application of the data is possible, if necessary?

(sorry if this behavior is already there and I missed it)



 Comments   
Comment by Michael Dirolf [ 12/Aug/10 ]

Giving a bit more details on what happens here, since we're linking to this case to explain (Eliot please correct if I'm wrong):

When a document needs to be rolled back it first gets written/appended to a flat file in the data directory, in a subdirectory called "rollback". The document gets written to a file named <current_ns>.<current_time>.<ordinal>.bson, and is written as a raw BSON document. The file should be treated as a sequence of raw BSON documents, much like the files generated by mongodump.

Comment by auto [ 03/Aug/10 ]

Author:

{'login': 'erh', 'name': 'Eliot Horowitz', 'email': 'eliot@10gen.com'}

Message: fix rollback saving SERVER-1512
http://github.com/mongodb/mongo/commit/625115721c13c93c2b17bab9bc0d686322fa9546

Comment by auto [ 03/Aug/10 ]

Author:

{'login': 'erh', 'name': 'Eliot Horowitz', 'email': 'eliot@10gen.com'}

Message: store rolled back info in flat files SERVER-1512
http://github.com/mongodb/mongo/commit/7207fe34dcb37bf0e284fa3d451ae6e858659b16

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