Files
mongo/db/repl/manager.cpp
Dwight Merriman 2f02e0c2f0 refactoring
2010-05-16 17:34:22 -04:00

104 lines
3.4 KiB
C++

/* @file manager.cpp
*/
/**
* Copyright (C) 2008 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,b
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "pch.h"
#include "replset.h"
namespace mongo {
enum {
NOPRIMARY = -2,
SELFPRIMARY = -1
};
/* check members OTHER THAN US to see if they think they are primary */
const ReplSet::Member * ReplSet::Manager::findOtherPrimary() {
Member *m = _rs->head();
Member *p = 0;
while( m ) {
if( m->m().state == PRIMARY ) {
if( p ) throw "twomasters"; // our polling is asynchronous, so this is often ok.
p = m;
}
m = m->next();
}
return p;
}
ReplSet::Manager::Manager(ReplSet *rs) : _rs(rs), _primary(NOPRIMARY)
{
}
void ReplSet::Manager::noteARemoteIsPrimary(const Member *m) {
_rs->_self->lhb().set("finish code #1");
log() << "replSet finish notearemoteisprimary " << m->fullName() << rsLog;
}
/** called as the health threads get new results */
void ReplSet::Manager::checkNewState() {
static mutex m;
{
scoped_lock lk(m);
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 == p2 && p ) 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;
}
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->lhb().set("can't see a majority, won't elect self");
return;
}
_rs->_self->lhb().set("");
}
_rs->elect.electSelf();
}
}