[SERVER-7780] downgrading 2.3 to 2.0 causes local.oplog.rs Assertion failure len * 5 > lastExtentSize Created: 27/Nov/12  Updated: 14/Oct/15  Resolved: 17/Dec/12

Status: Closed
Project: Core Server
Component/s: None
Affects Version/s: None
Fix Version/s: 2.3.2

Type: Bug Priority: Major - P3
Reporter: Greg Studer Assignee: Ben Becker
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Attachments: File multi_cluster.js     File multi_rs.js     Text File test_failure_filtered.txt     File upgrade_config_db.js    
Issue Links:
Related
related to DOCS-817 Need to doc multiVersion tests, at le... Closed
is related to SERVER-5285 Either disallow or fix capped collect... Closed
Operating System: ALL
Steps To Reproduce:

Run upgrade_config_db.js below.

Participants:

 Description   

At least with certain parameters (smallfiles, oplogsize : 40) restarting mongod 2.0 on data files created with mongod 2.3 can cause errors failures.

Discovered when running multi-version upgrade tests.



 Comments   
Comment by Ben Becker [ 04/Dec/12 ]

To clarify, the issue is choosing the maximum bound on the number of documents in a capped collection. To maintain backwards compatibility, we need to select a value to represent 'no max' (or as close as possible) in all versions of mongod. Because an on-disk format change is not possible at this time, the 'no max' value was decided to be 2^31 (2147483647) documents.

The caveat to this approach is that any collection with a max doc size of exactly 2147483647 documents will be treated as 'no max' in v2.3.2+. It should be noted that attempting to set the maximum number of documents on a capped collection to anything >= 2147483647 will result in no cap on the number of documents.

Comment by auto [ 04/Dec/12 ]

Author:

{u'date': u'2012-12-04T21:46:51Z', u'name': u'Ben Becker', u'email': u'ben.becker@10gen.com'}

Message: SERVER-7780: add test for explicit max doc count
Branch: master
https://github.com/mongodb/mongo/commit/ed810cab19d462ae99c07c40ee976fd680435245

Comment by auto [ 04/Dec/12 ]

Author:

{u'date': u'2012-12-04T19:59:39Z', u'email': u'ben.becker@10gen.com', u'name': u'Ben Becker'}

Message: SERVER-7780: fix backwards compatability for max docs in capped collection
Branch: master
https://github.com/mongodb/mongo/commit/62cf5ad3e3b2e2c52f55f9b06e4d094047307923

Generated at Thu Feb 08 03:15:35 UTC 2024 using Jira 9.7.1#970001-sha1:2222b88b221c4928ef0de3161136cc90c8356a66.