Files
mongo/db/repl/manager.cpp
Dwight 5c68591f64 rs
2010-07-22 15:28:02 -04:00

146 lines
4.7 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 "rs.h"
#include "../client.h"
namespace mongo {
enum {
NOPRIMARY = -2,
SELFPRIMARY = -1
};
/* check members OTHER THAN US to see if they think they are primary */
const Member * Manager::findOtherPrimary() {
Member *m = rs->head();
Member *p = 0;
while( m ) {
if( m->state() == RS_PRIMARY && m->hbinfo().up() ) {
if( p ) throw "twomasters"; // our polling is asynchronous, so this is often ok.
p = m;
}
m = m->next();
}
if( p )
noteARemoteIsPrimary(p);
return p;
}
Manager::Manager(ReplSetImpl *_rs) :
task::Server("rs Manager"), rs(_rs), busyWithElectSelf(false), _primary(NOPRIMARY)
{
}
void Manager::starting() {
Client::initThread("rs Manager");
}
void Manager::noteARemoteIsPrimary(const Member *m) {
if( rs->currentPrimary() == m )
return;
rs->_currentPrimary = m;
rs->_self->lhb() = "";
if( rs->iAmArbiterOnly() )
rs->changeState(RS_ARBITER);
else
rs->changeState(RS_RECOVERING);
}
/** called as the health threads get new results */
void Manager::msgCheckNewState() {
{
RSBase::lock lk(rs);
if( busyWithElectSelf ) return;
const Member *p = rs->currentPrimary();
if( p && !p->hbinfo().up() ) {
assert( p != rs->_self );
p = rs->_currentPrimary = 0;
}
const Member *p2;
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 2primary" << s << rsLog;
return;
}
if( p2 ) {
/* someone else thinks they are primary. */
if( p == p2 ) { // already match
return;
}
if( p == 0 ) {
noteARemoteIsPrimary(p2);
return;
}
// todo xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
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( !rs->iAmPotentiallyHot() ) // if not we never try to be primary
return;
/* TODO : CHECK PRIORITY HERE. can't be elected if priority zero. */
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() = "can't see a majority, won't consider electing self";
return;
}
rs->_self->lhb() = "";
busyWithElectSelf = true; // don't try to do further elections & such while we are already working on one.
}
try {
rs->elect.electSelf();
}
catch(RetryAfterSleepException&) {
/* we want to process new inbounds before trying this again. so we just put a checkNewstate in the queue for eval later. */
requeue();
}
catch(...) {
log() << "replSet error unexpected assertion in rs manager" << rsLog;
}
busyWithElectSelf = false;
}
}