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  1. Core Server
  2. SERVER-71862

Creating a unique index that should fail can return OK occasionally from createIndexes

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    • Type: Icon: Bug Bug
    • Resolution: Fixed
    • Priority: Icon: Major - P3 Major - P3
    • 6.3.0-rc0
    • Affects Version/s: None
    • Component/s: None
    • Labels:
      None
    • Storage Execution
    • Fully Compatible
    • ALL
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      Create this file:

      jstests/concurrency/fsm_workloads/unique_index_duplicate_key.js

      Paste this in:

      "use strict";

var $config = (function() {
    var states = (function() {
        function createIndex(db, collName) {
            assert.commandFailedWithCode(db[collName].createIndex({x: 1}, {unique: true}),
                                         ErrorCodes.DuplicateKey);
        }

        function init(db, collName) {
            assert.commandWorked(db[collName].insert({x: 1}));
            assert.commandWorked(db[collName].insert({x: 1}));
        }

        return {init: init, createIndex: createIndex};
    })();

    var transitions = {
        init: {createIndex: 1},
        createIndex: {createIndex: 1},
    };

    return {
        threadCount: 25,
        iterations: 1000,
        states: states,
        transitions: transitions,
    };
})();

      Run it:

      resmoke --suites=concurrency_replication jstests/concurrency/fsm_workloads/unique_index_duplicate_key.js

       

      Show
      Create this file: jstests/concurrency/fsm_workloads/unique_index_duplicate_key.js Paste this in: "use strict" ; var $config = (function() { var states = (function() { function createIndex(db, collName) { assert .commandFailedWithCode(db[collName].createIndex({x: 1}, {unique: true }), ErrorCodes.DuplicateKey); } function init(db, collName) { assert .commandWorked(db[collName].insert({x: 1})); assert .commandWorked(db[collName].insert({x: 1})); } return {init: init, createIndex: createIndex}; })(); var transitions = { init: {createIndex: 1}, createIndex: {createIndex: 1}, }; return { threadCount: 25, iterations: 1000, states: states, transitions: transitions, }; })(); Run it: resmoke --suites=concurrency_replication jstests/concurrency/fsm_workloads/unique_index_duplicate_key.js  
    • Execution Team 2023-02-06

      I wrote a concurrency test where multiple clients try to build the same unique index, all of which should fail due to documents with a duplicate key.

      Occasionally (once every 5 minutes), the test will return OK:

      Foreground jstests/concurrency/fsm_workloads/unique_index_duplicate_key.js
Error: command worked when it should have failed: {
 "numIndexesBefore" : 2,
 "numIndexesAfter" : 2,
 "createdCollectionAutomatically" : false,
 "commitQuorum" : "votingMembers",
 "note" : "all indexes already exist",
 "ok" : 1,
 "$clusterTime" : {
         "clusterTime" : Timestamp(1670274510, 21),
         "signature" : {
                 "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
                 "keyId" : NumberLong(0)
         }
 },
 "operationTime" : Timestamp(1670274510, 21)
}

      We should only have one index (_id) in this workload, but it's reporting numIndexesBefore/numIndexesAfter as 2, which results in this returning OK. The index was not actually built as seen by validate:

      [j0:prim] {"t":{"$date":"2022-12-05T21:47:05.459+00:00"},"s":"I",  "c":"COMMAND",  "id":20514,   "ctx":"conn194","msg":"CMD: validate","attr":{"namespace":"test0_fsmdb0.fsmcoll0","background":false,"full":true,"enforceFastCount":true,"checkBSONConformance":false,"repair":false}}
[j0:prim] {"t":{"$date":"2022-12-05T21:47:05.460+00:00"},"s":"I",  "c":"INDEX",    "id":20295,   "ctx":"conn194","msg":"Validating internal structure","attr":{"index":"_id_","namespace":"test0_fsmdb0.fsmcoll0"}}
[j0:prim] {"t":{"$date":"2022-12-05T21:47:05.465+00:00"},"s":"I",  "c":"INDEX",    "id":20303,   "ctx":"conn194","msg":"validating collection","attr":{"namespace":"test0_fsmdb0.fsmcoll0","uuid":{"uuid":{"$uuid":"b868fd78-5ddb-4db2-aaf2-511b3325e25e"}}}}
[j0:prim] {"t":{"$date":"2022-12-05T21:47:05.468+00:00"},"s":"I",  "c":"INDEX",    "id":20296,   "ctx":"conn194","msg":"Validating index consistency","attr":{"index":"_id_","namespace":"test0_fsmdb0.fsmcoll0"}}
[j0:prim] {"t":{"$date":"2022-12-05T21:47:05.469+00:00"},"s":"I",  "c":"INDEX",    "id":20306,   "ctx":"conn194","msg":"Validation complete for collection. No corruption found","attr":{"namespace":"test0_fsmdb0.fsmcoll0","uuid":{"uuid":{"$uuid":"b868fd78-5ddb-4db2-aaf2-511b3325e25e"}}}}

            Assignee:
            gregory.noma@mongodb.com Gregory Noma
            Reporter:
            gregory.wlodarek@mongodb.com Gregory Wlodarek
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              Created:
              Updated:
              Resolved: