Issue 2857 Repair Tool

Documentation for the repair tool developed in Issue #2857 to fix issue introduced in issues #2651.

Step: Determine if your Sync Gateway version is affected

If you have one of these versions, you might have been affected, depending on your revs_limit parameter value and exact usage.

• 1.3.1.2
• 1.4.1.1

To verify whether or not you are affected, use the Dry Run mechanism described below.

Step: Backup your data

Please backup your data before running this tool. If you run into errors please restore the data from your backup and contact support

Step: Enable CRUD log key

Make sure the Sync Gateway config has CRUD logging enabled.

Step: Perform a dry run

curl -X POST \
  http://localhost:4985/db/_repair \
  -H 'content-type: application/json' \
  -d '{
  "dry_run": true,
  "repair_jobs": [
     {
     	"type": "RepairRevTreeCycles"
     }	
  ]
}'

The response JSON will return the doc id's that would have been repaired by the dry run.

You can see the actual transformed docs Couchbase Server document named _sync:repair:dryrun:[key]. These docs will auto-delete in 24 hours.

Step: Repair Bucket

Assuming the dry run output looks good, repair the bucket using this command:

curl -X POST \
  http://localhost:4985/db/_repair \
  -H 'content-type: application/json' \
  -d '{
  "dry_run": false,
  "repair_jobs": [
     {
     	"type": "RepairRevTreeCycles"
     }	
  ]
}'

Expected JSON response:

[
    {
        "id": "data_for_test",
        "repair_job_type": [
            "RepairRevTreeCycles"
        ]
    }
]

Step: Verify

Verify that the doc no longer has cycles in the revtree by running:

curl http://{{host}}:{{port_admin}}/{{db}}/your_doc_id?revs=true

And replace your_doc_id with a doc that had known issues, and verify that you do not see the error: "reason": "Internal error: getHistory found cycle in revision tree

Step: Restart Sync Gateway

This is required to flush out any stale values that might be in the Revision Cache.

Step: (optional) Restore from backup

Repaired docs will be backed up in a temporary Couchbase Server document named _sync:repair:backup:[key] for 24 hours.

If something goes wrong, you can restore back to the original docs using these backup copies.