Uploaded image for project: 'Documentation'
  1. Documentation
  2. DOCS-13452

4.2 only: remove index metadata.infoObj fields from examples.

    XMLWordPrintableJSON

Details

    Description

      Description

      Downstream Change Summary

      In 4.2, just need to update example outputs that show this field in collStats pages.
      4.4 is already being done when updating output for another ticket.

      Description of Linked Ticket

      Since as far as I care to look back, mongodb has passed index "info objects" to the WT table's app_metadata. The index data is converted to a json string representation which contains the collection name.

      When this string is malformed and WT hits a parsing error, it's typically discovered via the primary and results in a uassert:

      test> db.createCollection("\x7F")
      {
      	"ok" : 0,
      	"errmsg" : "22: Invalid argument",
      	"code" : 2,
      	"codeName" : "BadValue"
      }
      

      However an existing collection can be renamed without renaming the ns field on an index entry:

      test> db.foo.renameCollection("\x7F")
      { "ok" : 1 }
      test> db["\x7F"].find()
      { "_id" : ObjectId("5cd472baae8328407ec23421") }
      

      With the new unique index format, indexes can have their metadata re-written to note the format the index is currently in. This can happen on an empty collMod command. There are cases where a primary will replicate this collMod without having hit the parsing error itself. A secondary processing this oplog entry will crash.

      Scope of changes

      Impact to Other Docs

      MVP (Work and Date)

      Resources (Scope or Design Docs, Invision, etc.)

      Attachments

        Activity

          People

            Unassigned Unassigned
            backlog-server-pm Backlog - Core Eng Program Management Team
            Votes:
            0 Vote for this issue
            Watchers:
            4 Start watching this issue

            Dates

              Created:
              Updated:
              1 year, 14 weeks, 2 days ago