102 lines
3.2 KiB
C++
102 lines
3.2 KiB
C++
/* @file manager.cpp
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*/
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/**
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* Copyright (C) 2008 10gen Inc.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License, version 3,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,b
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "pch.h"
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#include "rs.h"
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namespace mongo {
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enum {
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NOPRIMARY = -2,
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SELFPRIMARY = -1
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};
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/* check members OTHER THAN US to see if they think they are primary */
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const ReplSet::Member * ReplSet::Manager::findOtherPrimary() {
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Member *m = rs->head();
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Member *p = 0;
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while( m ) {
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if( m->state() == PRIMARY ) {
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if( p ) throw "twomasters"; // our polling is asynchronous, so this is often ok.
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p = m;
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}
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m = m->next();
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}
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if( p )
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noteARemoteIsPrimary(p);
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return p;
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}
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ReplSet::Manager::Manager(ReplSet *_rs) : task::Server("ReplSet::Manager"), rs(_rs), _primary(NOPRIMARY)
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{
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}
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void ReplSet::Manager::noteARemoteIsPrimary(const Member *m) {
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if( !rs->primary() )
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rs->_currentPrimary = m;
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rs->_self->lhb() = "";
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}
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/** called as the health threads get new results */
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void ReplSet::Manager::msgCheckNewState() {
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const Member *p = rs->currentPrimary();
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const Member *p2;
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try { p2 = findOtherPrimary(); }
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catch(string s) {
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/* two other nodes think they are primary (asynchronously polled) -- wait for things to settle down. */
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log() << "replSet warning DIAG TODO 2primary" << s << rsLog;
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return;
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}
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if( p == p2 && p ) return;
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if( p2 ) {
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/* someone else thinks they are primary. */
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if( p == p2 ) // already match
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return;
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if( p == 0 )
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noteARemoteIsPrimary(p2); return;
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if( p != rs->_self )
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noteARemoteIsPrimary(p2); return;
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/* we thought we were primary, yet now someone else thinks they are. */
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if( !rs->elect.aMajoritySeemsToBeUp() )
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noteARemoteIsPrimary(p2); return;
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/* ignore for now, keep thinking we are master */
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return;
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}
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if( p ) {
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/* we are already primary, and nothing significant out there has changed. */
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/* todo: if !aMajoritySeemsToBeUp, relinquish */
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assert( p == rs->_self );
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return;
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}
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/* no one seems to be primary. shall we try to elect ourself? */
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if( !rs->elect.aMajoritySeemsToBeUp() ) {
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rs->_self->lhb() = "can't see a majority, won't consider electing self";
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return;
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}
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rs->_self->lhb() = "";
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rs->elect.electSelf();
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}
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}
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