SERVER-26065 Write more generic optime comparator function

5 files changed, 251 insertions, 185 deletions

diff --git a/jstests/core/optime_cmp.js b/jstests/core/optime_cmp.js
new file mode 100644
index 00000000000..7ddd83bfc8e
--- /dev/null
+++ b/jstests/core/optime_cmp.js
@@ -0,0 +1,34 @@
+(function() {
+    'use strict';
+
+    // PV0
+    assert.eq(-1, rs.compareOpTimes(Timestamp(1, 0), Timestamp(2, 0)));
+    assert.eq(-1, rs.compareOpTimes(Timestamp(1, 0), Timestamp(1, 1)));
+
+    assert.eq(0, rs.compareOpTimes(Timestamp(2, 0), Timestamp(2, 0)));
+
+    assert.eq(1, rs.compareOpTimes(Timestamp(2, 0), Timestamp(1, 1)));
+    assert.eq(1, rs.compareOpTimes(Timestamp(1, 2), Timestamp(1, 1)));
+
+    // lhs PV0 rhs PV1
+    assert.throws(function() {
+        rs.compareOpTimes(Timestamp(1, 0), {ts: Timestamp(2, 0), t: 2});
+    });
+
+    // lhs PV1 rhs PV0
+    assert.throws(function() {
+        rs.compareOpTimes({ts: Timestamp(1, 0), t: 2}, Timestamp(2, 0));
+    });
+
+    // PV1
+    assert.eq(-1, rs.compareOpTimes({ts: Timestamp(2, 2), t: 2}, {ts: Timestamp(3, 1), t: 2}));
+    assert.eq(-1, rs.compareOpTimes({ts: Timestamp(2, 2), t: 2}, {ts: Timestamp(2, 4), t: 2}));
+    assert.eq(-1, rs.compareOpTimes({ts: Timestamp(3, 0), t: 2}, {ts: Timestamp(2, 0), t: 3}));
+
+    assert.eq(0, rs.compareOpTimes({ts: Timestamp(3, 0), t: 2}, {ts: Timestamp(3, 0), t: 2}));
+
+    assert.eq(1, rs.compareOpTimes({ts: Timestamp(3, 1), t: 2}, {ts: Timestamp(2, 2), t: 2}));
+    assert.eq(1, rs.compareOpTimes({ts: Timestamp(2, 4), t: 2}, {ts: Timestamp(2, 2), t: 2}));
+    assert.eq(1, rs.compareOpTimes({ts: Timestamp(2, 0), t: 3}, {ts: Timestamp(3, 0), t: 2}));
+
+})();
diff --git a/jstests/replsets/rslib.js b/jstests/replsets/rslib.js
index 6206a4a8168..d60f86462bf 100644
--- a/jstests/replsets/rslib.js
+++ b/jstests/replsets/rslib.js
@@ -10,6 +10,7 @@ var waitUntilAllNodesCaughtUp;
 var updateConfigIfNotDurable;
 var reInitiateWithoutThrowingOnAbortedMember;
 var awaitRSClientHosts;
+var getLastOpTime;
 
 (function() {
     "use strict";
@@ -356,4 +357,15 @@ var awaitRSClientHosts;
             return false;
         }, 'timed out waiting for replica set client to recognize hosts', timeout);
     };
+
+    /**
+     * Returns the last opTime of the connection based from replSetGetStatus. Can only
+     * be used on replica set nodes.
+     */
+    getLastOpTime = function(conn) {
+        var replSetStatus =
+            assert.commandWorked(conn.getDB("admin").runCommand({replSetGetStatus: 1}));
+        var connStatus = replSetStatus.members.filter(m => m.self)[0];
+        return connStatus.optime;
+    };
 }());
diff --git a/jstests/slow1/replsets_priority1.js b/jstests/slow1/replsets_priority1.js
index 4bbb856a4b6..dfd31173b6b 100644
--- a/jstests/slow1/replsets_priority1.js
+++ b/jstests/slow1/replsets_priority1.js
@@ -1,203 +1,205 @@
 // come up with random priorities and make sure that the right member gets
 // elected. then kill that member and make sure the next one gets elected.
 
-print("\n\n\nreplsets_priority1.js BEGIN\n");
+(function() {
 
-load("jstests/replsets/rslib.js");
+    "use strict";
 
-var rs = new ReplSetTest({name: 'testSet', nodes: 3, nodeOptions: {verbose: 2}});
-var nodes = rs.startSet();
-rs.initiate();
+    load("jstests/replsets/rslib.js");
 
-var master = rs.getPrimary();
+    var rs = new ReplSetTest({name: 'testSet', nodes: 3, nodeOptions: {verbose: 2}});
+    var nodes = rs.startSet();
+    rs.initiate();
 
-var everyoneOkSoon = function() {
-    var status;
-    assert.soon(function() {
-        var ok = true;
-        status = master.adminCommand({replSetGetStatus: 1});
+    var master = rs.getPrimary();
 
-        if (!status.members) {
-            return false;
-        }
+    var everyoneOkSoon = function() {
+        var status;
+        assert.soon(function() {
+            var ok = true;
+            status = master.adminCommand({replSetGetStatus: 1});
 
-        for (var i in status.members) {
-            if (status.members[i].health == 0) {
-                continue;
+            if (!status.members) {
+                return false;
             }
-            ok &= status.members[i].state == 1 || status.members[i].state == 2;
-        }
-        return ok;
-    }, tojson(status));
-};
 
-var checkPrimaryIs = function(node) {
+            for (var i in status.members) {
+                if (status.members[i].health == 0) {
+                    continue;
+                }
+                ok &= status.members[i].state == 1 || status.members[i].state == 2;
+            }
+            return ok;
+        }, tojson(status));
+    };
 
-    print("nreplsets_priority1.js checkPrimaryIs(" + node.host + ")");
+    var checkPrimaryIs = function(node) {
 
-    var status;
+        print("nreplsets_priority1.js checkPrimaryIs(" + node.host + ")");
 
-    assert.soon(function() {
-        var ok = true;
+        var status;
 
-        try {
-            status = master.adminCommand({replSetGetStatus: 1});
-        } catch (e) {
-            print(e);
-            print("nreplsets_priority1.js checkPrimaryIs reconnecting");
-            reconnect(master);
-            status = master.adminCommand({replSetGetStatus: 1});
-        }
+        assert.soon(function() {
+            var ok = true;
 
-        var str = "goal: " + node.host + "==1 states: ";
-        if (!status || !status.members) {
-            return false;
-        }
-        status.members.forEach(function(m) {
-            str += m.name + ": " + m.state + " ";
-
-            if (m.name == node.host) {
-                ok &= m.state == 1;
-            } else {
-                ok &= m.state != 1 || (m.state == 1 && m.health == 0);
+            try {
+                status = master.adminCommand({replSetGetStatus: 1});
+            } catch (e) {
+                print(e);
+                print("nreplsets_priority1.js checkPrimaryIs reconnecting");
+                reconnect(master);
+                status = master.adminCommand({replSetGetStatus: 1});
             }
-        });
-        print();
-        print(str);
-        print();
 
-        occasionally(function() {
-            print("\nstatus:");
-            printjson(status);
+            var str = "goal: " + node.host + "==1 states: ";
+            if (!status || !status.members) {
+                return false;
+            }
+            status.members.forEach(function(m) {
+                str += m.name + ": " + m.state + " ";
+
+                if (m.name == node.host) {
+                    ok &= m.state == 1;
+                } else {
+                    ok &= m.state != 1 || (m.state == 1 && m.health == 0);
+                }
+            });
+            print();
+            print(str);
             print();
-        }, 15);
 
-        return ok;
-    }, node.host + '==1', 240000, 1000);
+            occasionally(function() {
+                print("\nstatus:");
+                printjson(status);
+                print();
+            }, 15);
 
-    everyoneOkSoon();
-};
+            return ok;
+        }, node.host + '==1', 240000, 1000);
 
-everyoneOkSoon();
+        everyoneOkSoon();
+    };
 
-print("\n\nreplsets_priority1.js initial sync");
+    everyoneOkSoon();
 
-// intial sync
-master.getDB("foo").bar.insert({x: 1});
-rs.awaitReplication();
+    print("\n\nreplsets_priority1.js initial sync");
 
-print("\n\nreplsets_priority1.js starting loop");
+    // intial sync
+    master.getDB("foo").bar.insert({x: 1});
+    rs.awaitReplication();
 
-var n = 5;
-for (i = 0; i < n; i++) {
-    print("Round " + i + ": FIGHT!");
+    print("\n\nreplsets_priority1.js starting loop");
 
-    var max = null;
-    var second = null;
-    reconnect(master);
-    var config = master.getDB("local").system.replset.findOne();
+    var n = 5;
+    for (var i = 0; i < n; i++) {
+        print("Round " + i + ": FIGHT!");
 
-    var version = config.version;
-    config.version++;
+        var max = null;
+        var second = null;
+        reconnect(master);
+        var config = master.getDB("local").system.replset.findOne();
 
-    for (var j = 0; j < config.members.length; j++) {
-        var priority = Math.random() * 100;
-        print("random priority : " + priority);
-        config.members[j].priority = priority;
+        var version = config.version;
+        config.version++;
 
-        if (!max || priority > max.priority) {
-            max = config.members[j];
-        }
-    }
+        for (var j = 0; j < config.members.length; j++) {
+            var priority = Math.random() * 100;
+            print("random priority : " + priority);
+            config.members[j].priority = priority;
 
-    for (var j = 0; j < config.members.length; j++) {
-        if (config.members[j] == max) {
-            continue;
+            if (!max || priority > max.priority) {
+                max = config.members[j];
+            }
         }
-        if (!second || config.members[j].priority > second.priority) {
-            second = config.members[j];
+
+        for (var j = 0; j < config.members.length; j++) {
+            if (config.members[j] == max) {
+                continue;
+            }
+            if (!second || config.members[j].priority > second.priority) {
+                second = config.members[j];
+            }
         }
-    }
 
-    print("\n\nreplsets_priority1.js max is " + max.host + " with priority " + max.priority +
-          ", reconfiguring...");
+        print("\n\nreplsets_priority1.js max is " + max.host + " with priority " + max.priority +
+              ", reconfiguring...");
 
-    var count = 0;
-    while (config.version != version && count < 100) {
-        reconnect(master);
+        var count = 0;
+        while (config.version != version && count < 100) {
+            reconnect(master);
 
-        occasionally(function() {
-            print("version is " + version + ", trying to update to " + config.version);
-        });
+            occasionally(function() {
+                print("version is " + version + ", trying to update to " + config.version);
+            });
 
-        try {
-            master.adminCommand({replSetReconfig: config});
-            master = rs.getPrimary();
-            reconnect(master);
+            try {
+                master.adminCommand({replSetReconfig: config});
+                master = rs.getPrimary();
+                reconnect(master);
 
-            version = master.getDB("local").system.replset.findOne().version;
-        } catch (e) {
-            print("nreplsets_priority1.js Caught exception: " + e);
-        }
+                version = master.getDB("local").system.replset.findOne().version;
+            } catch (e) {
+                print("nreplsets_priority1.js Caught exception: " + e);
+            }
 
-        count++;
-    }
+            count++;
+        }
 
-    print("\nreplsets_priority1.js wait for 2 slaves");
+        print("\nreplsets_priority1.js wait for 2 slaves");
 
-    assert.soon(function() {
-        rs.getPrimary();
-        return rs.liveNodes.slaves.length == 2;
-    }, "2 slaves");
+        assert.soon(function() {
+            rs.getPrimary();
+            return rs.liveNodes.slaves.length == 2;
+        }, "2 slaves");
 
-    print("\nreplsets_priority1.js wait for new config version " + config.version);
+        print("\nreplsets_priority1.js wait for new config version " + config.version);
 
-    assert.soon(function() {
-        versions = [0, 0];
-        rs.liveNodes.slaves[0].setSlaveOk();
-        versions[0] = rs.liveNodes.slaves[0].getDB("local").system.replset.findOne().version;
-        rs.liveNodes.slaves[1].setSlaveOk();
-        versions[1] = rs.liveNodes.slaves[1].getDB("local").system.replset.findOne().version;
-        return versions[0] == config.version && versions[1] == config.version;
-    });
+        assert.soon(function() {
+            var versions = [0, 0];
+            rs.liveNodes.slaves[0].setSlaveOk();
+            versions[0] = rs.liveNodes.slaves[0].getDB("local").system.replset.findOne().version;
+            rs.liveNodes.slaves[1].setSlaveOk();
+            versions[1] = rs.liveNodes.slaves[1].getDB("local").system.replset.findOne().version;
+            return versions[0] == config.version && versions[1] == config.version;
+        });
 
-    print("replsets_priority1.js awaitReplication");
+        print("replsets_priority1.js awaitReplication");
 
-    // the reconfiguration needs to be replicated! the hb sends it out
-    // separately from the repl
-    rs.awaitReplication();
+        // the reconfiguration needs to be replicated! the hb sends it out
+        // separately from the repl
+        rs.awaitReplication();
 
-    print("reconfigured.  Checking statuses.");
+        print("reconfigured.  Checking statuses.");
 
-    checkPrimaryIs(max);
+        checkPrimaryIs(max);
 
-    // Wait for election oplog entry to be replicated, to avoid rollbacks later on.
-    rs.awaitReplication();
+        // Wait for election oplog entry to be replicated, to avoid rollbacks later on.
+        rs.awaitReplication();
 
-    print("rs.stop");
+        print("rs.stop");
 
-    rs.stop(max._id);
+        rs.stop(max._id);
 
-    var master = rs.getPrimary();
+        master = rs.getPrimary();
 
-    print("\nkilled max primary.  Checking statuses.");
+        print("\nkilled max primary.  Checking statuses.");
 
-    print("second is " + second.host + " with priority " + second.priority);
-    checkPrimaryIs(second);
+        print("second is " + second.host + " with priority " + second.priority);
+        checkPrimaryIs(second);
 
-    // Wait for election oplog entry to be replicated, to avoid rollbacks later on.
-    rs.awaitReplication();
+        // Wait for election oplog entry to be replicated, to avoid rollbacks later on.
+        rs.awaitReplication();
 
-    print("restart max " + max._id);
+        print("restart max " + max._id);
 
-    rs.restart(max._id);
-    master = rs.getPrimary();
+        rs.restart(max._id);
+        master = rs.getPrimary();
 
-    print("max restarted.  Checking statuses.");
-    checkPrimaryIs(max);
+        print("max restarted.  Checking statuses.");
+        checkPrimaryIs(max);
 
-    // Wait for election oplog entry to be replicated, to avoid rollbacks later on.
-    rs.awaitReplication();
-}
+        // Wait for election oplog entry to be replicated, to avoid rollbacks later on.
+        rs.awaitReplication();
+    }
 
-print("\n\n\n\n\nreplsets_priority1.js SUCCESS!\n\n");
+})();
diff --git a/src/mongo/shell/replsettest.js b/src/mongo/shell/replsettest.js
index bdb0980304f..2a5ec4b2227 100644
--- a/src/mongo/shell/replsettest.js
+++ b/src/mongo/shell/replsettest.js
@@ -302,17 +302,6 @@ var ReplSetTest = function(opts) {
     }
 
     /*
-     * Checks if given optime object conforms to Protocol Version 1 optime format.
-     *
-     * PV1 Format:
-     * {ts:Timestamp, t:NumberLong}
-     *
-     */
-    function _isOptimeV1(optime) {
-        return (optime.hasOwnProperty("ts") && optime.hasOwnProperty("t"));
-    }
-
-    /*
      * Compares Timestamp objects. Returns true if ts1 is 'earlier' than ts2, else false.
      */
     function _isEarlierTimestamp(ts1, ts2) {
@@ -322,34 +311,6 @@ var ReplSetTest = function(opts) {
         return ts1.getTime() < ts2.getTime();
     }
 
-    /*
-     * Compares optimes. Returns true if ot1 is 'earlier' than ot2, else false.
-     *
-     * Note: Since Protocol Version 1 was introduced for replication, 'optimes'
-     * can come in two different formats. This function checks for this and changes
-     * any timestamps of PV0 format to PV1 format, by adding a default term number of -1,
-     * to make comparison logic generic for both formats.
-     *
-     * Optime Formats:
-     * PV0: Timestamp
-     * PV1: {ts:Timestamp, t:NumberLong}
-     */
-    function _isEarlierOpTime(ot1, ot2) {
-        // Make sure both optimes have a timestamp and a term.
-        var ot1 = _isOptimeV1(ot1) ? ot1 : {ts: ot1, t: NumberLong(-1)};
-        var ot2 = _isOptimeV1(ot2) ? ot2 : {ts: ot2, t: NumberLong(-1)};
-
-        // If both optimes have a term that's not -1 and one has a lower term, return that optime.
-        if (!friendlyEqual(ot1.t, NumberLong(-1)) && !friendlyEqual(ot2.t, NumberLong(-1))) {
-            if (!friendlyEqual(ot1.t, ot2.t)) {
-                return ot1.t < ot2.t;
-            }
-        }
-
-        // Otherwise, choose the optime with the lower timestamp.
-        return _isEarlierTimestamp(ot1.ts, ot2.ts);
-    }
-
     /**
      * Returns list of nodes as host:port strings.
      */
@@ -724,7 +685,7 @@ var ReplSetTest = function(opts) {
                 if (friendlyEqual(rcmOpTime, {ts: Timestamp(0, 0), t: NumberLong(0)})) {
                     return false;
                 }
-                if (_isEarlierOpTime(rcmOpTime, masterOpTime)) {
+                if (rs.compareOpTimes(rcmOpTime, masterOpTime) < 0) {
                     return false;
                 }
             }
@@ -824,7 +785,7 @@ var ReplSetTest = function(opts) {
                         slaveOpTime = _getLastOpTime(slave);
                     }
 
-                    if (_isEarlierOpTime(masterLatestOpTime, slaveOpTime)) {
+                    if (rs.compareOpTimes(masterLatestOpTime, slaveOpTime) < 0) {
                         masterLatestOpTime = _getLastOpTime(master);
                         print("ReplSetTest awaitReplication: optime for " + slaveName +
                               " is newer, resetting latest primary optime to " +
diff --git a/src/mongo/shell/utils.js b/src/mongo/shell/utils.js
index a7c9fe4c9a8..dc6db851124 100644
--- a/src/mongo/shell/utils.js
+++ b/src/mongo/shell/utils.js
@@ -981,6 +981,26 @@ var Random = (function() {
 
 })();
 
+/**
+ * Compares Timestamp objects. Returns -1 if ts1 is 'earlier' than ts2, 1 if 'later'
+ * and 0 if equal.
+ */
+function timestampCmp(ts1, ts2) {
+    if (ts1.getTime() == ts2.getTime()) {
+        if (ts1.getInc() < ts2.getInc()) {
+            return -1;
+        } else if (ts1.getInc() > ts2.getInc()) {
+            return 1;
+        } else {
+            return 0;
+        }
+    } else if (ts1.getTime() < ts2.getTime()) {
+        return -1;
+    } else {
+        return 1;
+    }
+}
+
 Geo = {};
 Geo.distance = function(a, b) {
     var ax = null;
@@ -1296,6 +1316,43 @@ rs.debug.getLastOpWritten = function(server) {
     return s.oplog.rs.find().sort({$natural: -1}).limit(1).next();
 };
 
+/**
+ * Compares optimes. Returns -1 if ot1 is 'earlier' than ot2, 1 if 'later' and 0 if equal.
+ *
+ * Note: Since Protocol Version 1 was introduced for replication, 'optimes'
+ * can come in two different formats. This function will throw an error when the opTime
+ * passed do not have the same protocol version.
+ *
+ * Optime Formats:
+ * PV0: Timestamp
+ * PV1: {ts:Timestamp, t:NumberLong}
+ */
+rs.compareOpTimes = function(ot1, ot2) {
+    function _isOptimeV1(optime) {
+        return (optime.hasOwnProperty("ts") && optime.hasOwnProperty("t"));
+    }
+
+    // Make sure both optimes have a timestamp and a term.
+    var ot1 = _isOptimeV1(ot1) ? ot1 : {ts: ot1, t: NumberLong(-1)};
+    var ot2 = _isOptimeV1(ot2) ? ot2 : {ts: ot2, t: NumberLong(-1)};
+
+    if ((ot1.t == -1 && ot2.t != -1) || (ot1.t != -1 && ot2.t == -1)) {
+        throw Error('cannot compare optimes between different protocol versions');
+    }
+
+    if (!friendlyEqual(ot1.t, ot2.t)) {
+        if (ot1.t < ot2.t) {
+            return -1;
+        } else {
+            return 1;
+        }
+    }
+    // else equal terms, so proceed to compare timestamp component.
+
+    // Otherwise, choose the optime with the lower timestamp.
+    return timestampCmp(ot1.ts, ot2.ts);
+};
+
 help = shellHelper.help = function(x) {
     if (x == "mr") {
         print("\nSee also http://dochub.mongodb.org/core/mapreduce");