SERVER-43752 Fix prepare_conflict.js log check

Author: haleyConnelly

jstests/core/txns/prepare_conflict.js

@@ -12,14 +12,18 @@ const dbName = "test";
 const collName = "prepare_conflict";
 const testDB = db.getSiblingDB(dbName);
 const testColl = testDB.getCollection(collName);
-
-// Logs must be cleared each run.
-assert.commandWorked(testDB.adminCommand({clearLog: "global"}));
+const prepareConflictDurationLogMsg = "prepareConflictDuration";
 
 testColl.drop({writeConcern: {w: "majority"}});
 assert.commandWorked(testDB.runCommand({create: collName, writeConcern: {w: "majority"}}));
 
-function assertPrepareConflict(filter, clusterTime, count) {
+/**
+ * Asserts that a prepare read conflict occurs, and is recorded through the profiler and logs
+ * accordingly, by running a find command that uses the provided filter and clusterTime.
+ */
+const assertPrepareConflict = function assertPrepareReadConflict(filter, clusterTime) {
+    assert.commandWorked(testDB.adminCommand({clearLog: "global"}));
+
     // Uses a 5 second timeout so that there is enough time for the prepared transaction to
     // release its locks and for the command to obtain those locks.
     assert.commandFailedWithCode(
@@ -32,8 +36,7 @@ function assertPrepareConflict(filter, clusterTime, count) {
         }),
         ErrorCodes.MaxTimeMSExpired);
 
-    // Ensures prepareConflictDuration is logged each time a prepare conflict is encountered.
-    checkLog.containsWithCount(testDB, "prepareConflictDuration", count);
+    checkLog.contains(testDB, prepareConflictDurationLogMsg);
 
     let prepareConflicted = false;
     const cur =
@@ -46,15 +49,15 @@ function assertPrepareConflict(filter, clusterTime, count) {
         }
     }
     assert(prepareConflicted);
-}
+};
 
-// Inserts a document modified by the transaction.
+// Insert a document modified by the transaction.
 const txnDoc = {
     _id: 1,
     x: 1
 };
 assert.commandWorked(testColl.insert(txnDoc));
-// Inserts a document unmodified by the transaction.
+// Insert a document unmodified by the transaction.
 const otherDoc = {
     _id: 2,
     y: 2
@@ -77,24 +80,21 @@ assert.commandWorked(sessionDB.runCommand({
 }));
 const prepareTimestamp = PrepareHelpers.prepareTransaction(session);
 
-// Stores the number of times prepareConflictDuration should appear in the log.
-let conflictCount = 1;
-
 // Conflict on _id of prepared document.
-assertPrepareConflict({_id: txnDoc._id}, prepareTimestamp, conflictCount);
+assertPrepareConflict({_id: txnDoc._id}, prepareTimestamp);
 
 // Conflict on field that could be added to a prepared document.
-assertPrepareConflict({randomField: "random"}, prepareTimestamp, ++conflictCount);
+assertPrepareConflict({randomField: "random"}, prepareTimestamp);
 
 // No conflict on _id of a non-prepared document.
+assert.commandWorked(testDB.adminCommand({clearLog: "global"}));
 assert.commandWorked(testDB.runCommand({find: collName, filter: {_id: otherDoc._id}}));
+assert.eq(false, checkLog.checkContainsOnce(testDB, prepareConflictDurationLogMsg));
 
 // No conflict on indexed field of a non-prepared document.
+assert.commandWorked(testDB.adminCommand({clearLog: "global"}));
 assert.commandWorked(testDB.runCommand({find: collName, filter: {y: otherDoc.y}}));
-
-// Ensures that prepareConflictDuration is only logged when a prepare conflict is encountered. We
-// expect conflictCount to be 2.
-checkLog.containsWithCount(testDB, "prepareConflictDuration", conflictCount);
+assert.eq(false, checkLog.checkContainsOnce(testDB, prepareConflictDurationLogMsg));
 
 // At this point, we can guarantee all subsequent reads will conflict. Do a read in a parallel
 // shell, abort the transaction, then ensure the read succeeded with the old document.
@@ -105,7 +105,6 @@ const findAwait = startParallelShell(function() {
     const it = db.getSiblingDB(TestData.dbName)
                    .runCommand({find: TestData.collName, filter: {_id: TestData.txnDoc._id}});
 }, db.getMongo().port);
-
 assert.commandWorked(session.abortTransaction_forTesting());
 
 // The find command should be successful.