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  1. Core Server
  2. SERVER-17882

Update with key too large to index crashes WiredTiger/RockDB secondary

    Details

    • Backwards Compatibility:
      Fully Compatible
    • Operating System:
      ALL
    • Backport Completed:
    • Steps To Reproduce:
      Hide

      Initiate a replicaset with a 2.6 primary and a 3.0 WT secondary.

      //generate 2048 chars string
      var s="a"; for (i=0;i<11;i++) s+=s; print(s.length);
       
      //build index
      db.foo.ensureIndex({"doober": 1})
       
      //insert 
      db.foo.insert({_id: "hi", "doober": "doo"})
       
      //enable write failure on long index on PRIMARY and SECONDARY
      db.getSiblingDB('admin').runCommand( { setParameter: 1, failIndexKeyTooLong: true } )
       
      //expect update failure
      db.foo.update({_id: "hi" }, { $set: {"doober": s}})
       
      //disable write failure on long index on PRIMARY and SECONDARY
      db.getSiblingDB('admin').runCommand( { setParameter: 1, failIndexKeyTooLong: false } )
       
      //crash secondary
      db.foo.update({_id: "hi" }, { $set: {"doober": s}})
      

      Show
      Initiate a replicaset with a 2.6 primary and a 3.0 WT secondary. //generate 2048 chars string var s="a"; for (i=0;i<11;i++) s+=s; print(s.length);   //build index db.foo.ensureIndex({"doober": 1})   //insert db.foo.insert({_id: "hi", "doober": "doo"})   //enable write failure on long index on PRIMARY and SECONDARY db.getSiblingDB('admin').runCommand( { setParameter: 1, failIndexKeyTooLong: true } )   //expect update failure db.foo.update({_id: "hi" }, { $set: {"doober": s}})   //disable write failure on long index on PRIMARY and SECONDARY db.getSiblingDB('admin').runCommand( { setParameter: 1, failIndexKeyTooLong: false } )   //crash secondary db.foo.update({_id: "hi" }, { $set: {"doober": s}})
    • Sprint:
      Quint Iteration 3.1.2

      Description

      Issue Status as of Apr 29, 2015

      ISSUE SUMMARY
      MongoDB 3.0 secondaries running non-MMAPv1 storage engines (i.e.: WiredTiger, RocksDB) may fail to properly handle updates involving keys longer than 1024 bytes if the key is indexed.

      Setting failIndexKeyTooLong to false has no effect.

      USER IMPACT
      A secondary receiving an update involving a key longer than 1024 terminates if there's an index on that key. If enough secondaries are affected the replica set may become unavailable.

      WORKAROUNDS
      It is highly recommended that users do not use keys longer than 1024. When upgrading from 2.6, please upgrade directly to version 3.0.3 or higher.

      AFFECTED VERSIONS
      MongoDB versions 3.0.0, 3.0.1, and 3.0.2 are affected by this issue.

      FIX VERSION
      The fix is included in the 3.0.3 production release.

      Original description

      If you have a 2.6 PRIMARY and a WT or RocksDB SECONDARY, you can crash the SECONDARY by updating an indexed key with > 1024 characters.

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              • Created:
                Updated:
                Resolved: