From 803c4e15142f55445b7806a829139115d64cee9a Mon Sep 17 00:00:00 2001
From: Dwight Merriman <dwight@10gen.com>
Date: Sat, 15 May 2010 18:20:55 -0400
Subject: [PATCH] rs

---
 db/repl/consensus.cpp | 23 ++++++++++---
 db/repl/manager.cpp   | 80 +++++++++++++++++++++----------------------
 db/repl/replset.h     | 13 +++----
 3 files changed, 66 insertions(+), 50 deletions(-)

diff --git a/db/repl/consensus.cpp b/db/repl/consensus.cpp
index da782dd5191..adfddc5f2de 100644
--- a/db/repl/consensus.cpp
+++ b/db/repl/consensus.cpp
@@ -64,7 +64,7 @@ namespace mongo {
 
     static const int VETO = -10000;
 
-    bool ReplSet::Consensus::electSelf() {
+    void ReplSet::Consensus::_electSelf() {
         ReplSet::Member& me = *rs._self;
         electCmd = BSON(
                "replSetElect" << 1 <<
@@ -96,11 +96,26 @@ namespace mongo {
             if( time(0) - start > 30 ) {
                 // defensive; should never happen as we have timeouts on connection and operation for our conn
                 log() << "replSet too much time passed during election, ignoring result" << rsLog;
-                return false;
             }
-            return true;
+            /* succeeded. */
+            rs._myState = PRIMARY;
+            log() << "replSet elected self as primary" << rsLog;
+            return;
         } 
-        return false;
+    }
+
+    void ReplSet::Consensus::electSelf() {
+        static mutex m;
+        {
+            scoped_lock lk(m);
+            if( inprog ) return;
+            inprog = true;
+        }
+        try { _electSelf(); } catch(...) { }
+        {
+            scoped_lock lk(m);
+            inprog = false;
+        }
     }
 
 }
diff --git a/db/repl/manager.cpp b/db/repl/manager.cpp
index c5ec2f700c7..cbbbc2c0c22 100644
--- a/db/repl/manager.cpp
+++ b/db/repl/manager.cpp
@@ -53,51 +53,51 @@ namespace mongo {
     /** called as the health threads get new results */
     void ReplSet::Manager::checkNewState() {
         static mutex m;
-        scoped_lock lk(m);
+        {
+            scoped_lock lk(m);
 
-        //log() << "replSet checkNewState " << rsLog;
-
-        const Member *p = _rs->currentPrimary();
-        const Member *p2 = findOtherPrimary();
-        try { p2 = findOtherPrimary(); }
-        catch(string s) { 
-            log() << "replSet warning DIAG TODO " << s << rsLog;
-            return;
-        }
-
-        if( p == p2 && p ) return;
-
-        if( p2 ) { 
-            /* someone else thinks they are primary. */
-            if( p == p2 ) 
+            const Member *p = _rs->currentPrimary();
+            const Member *p2 = findOtherPrimary();
+            try { p2 = findOtherPrimary(); }
+            catch(string s) { 
+                /* two other nodes think they are primary (asynchronously polled) -- wait for things to settle down. */
+                log() << "replSet warning DIAG TODO " << s << rsLog;
                 return;
-            if( p == 0 )
-                noteARemoteIsPrimary(p2); return;
-            if( p != _rs->_self )
-                noteARemoteIsPrimary(p2); return;
-            /* we thought we were primary, yet now someone else thinks they are. */
-            if( !_rs->elect.aMajoritySeemsToBeUp() )
-                noteARemoteIsPrimary(p2); return;
-            /* ignore for now, keep thinking we are master */
-            return;
-        }
+            }
 
-        if( p ) { 
-            /* we are already primary, and nothing significant out there has changed. */\
-            /* todo: if !aMajoritySeemsToBeUp, relinquish */
-            assert( p == _rs->_self );
-            return;
-        }
+            if( p == p2 && p ) return;
 
-        /* no one seems to be primary.  shall we try to elect ourself? */
-        if( !_rs->elect.aMajoritySeemsToBeUp() ) { 
-            _rs->_self->_lastHeartbeatErrMsg.set("can't see a majority, won't elect self");
-            return;
-        }
+            if( p2 ) { 
+                /* someone else thinks they are primary. */
+                if( p == p2 ) // already match
+                    return;
+                if( p == 0 )
+                    noteARemoteIsPrimary(p2); return;
+                if( p != _rs->_self )
+                    noteARemoteIsPrimary(p2); return;
+                /* we thought we were primary, yet now someone else thinks they are. */
+                if( !_rs->elect.aMajoritySeemsToBeUp() )
+                    noteARemoteIsPrimary(p2); return;
+                /* ignore for now, keep thinking we are master */
+                return;
+            }
 
-        log() << "replSet todo elect self as primary primary" << rsLog;
-        _rs->_self->_lastHeartbeatErrMsg.set("todo code #2");
+            if( p ) { 
+                /* we are already primary, and nothing significant out there has changed. */
+                /* todo: if !aMajoritySeemsToBeUp, relinquish */
+                assert( p == _rs->_self );
+                return;
+            }
+
+            /* no one seems to be primary.  shall we try to elect ourself? */
+            if( !_rs->elect.aMajoritySeemsToBeUp() ) { 
+                _rs->_self->_lastHeartbeatErrMsg.set("can't see a majority, won't elect self");
+                return;
+            }
+
+            _rs->_self->_lastHeartbeatErrMsg.set("");
+        }
+        _rs->elect.electSelf();
     }
 
-
 }
diff --git a/db/repl/replset.h b/db/repl/replset.h
index 077aafb6653..28fe9f9030b 100644
--- a/db/repl/replset.h
+++ b/db/repl/replset.h
@@ -54,7 +54,6 @@ namespace mongo {
         State _myState;
 
     public:
-
         void fatal();
         bool isMaster(const char *client);
         void fillIsMaster(BSONObjBuilder&);
@@ -66,8 +65,7 @@ namespace mongo {
            replsetname/host1,host2:port,...
            where :port is optional.
 
-           throws exception if a problem initializing.
-        */
+           throws exception if a problem initializing. */
         ReplSet(string cfgString);
 
         /* call after constructing to start - returns fairly quickly after launching its threads */
@@ -90,12 +88,15 @@ namespace mongo {
         void loadConfig();
         void initFromConfig(ReplSetConfig& c);//, bool save);
 
-        struct Consensus {
+        class Consensus {
             ReplSet &rs;
-            Consensus(ReplSet *t) : rs(*t) { }
+            bool inprog;
+            void _electSelf();
+        public:
+            Consensus(ReplSet *t) : rs(*t),inprog(false) { }
             int totalVotes() const;
             bool aMajoritySeemsToBeUp() const;
-            bool electSelf();
+            void electSelf();
         } elect;
 
     public: