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// shard.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,
* 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 "shard.h"
#include "config.h"
#include "request.h"
#include <set>
namespace mongo {
class StaticShardInfo {
public:
StaticShardInfo() : _mutex("StaticShardInfo") { }
void reload(){
list<BSONObj> all;
{
ScopedDbConnection conn( configServer.getPrimary() );
auto_ptr<DBClientCursor> c = conn->query( ShardNS::shard , Query() );
assert( c.get() );
while ( c->more() ){
all.push_back( c->next().getOwned() );
}
conn.done();
}
scoped_lock lk( _mutex );
// We use the _lookup table for all shards and for the primary config DB. The config DB info,
// however, does not come from the ShardNS::shard. So when cleaning the _lookup table we leave
// the config state intact. The rationale is that this way we could drop shards that
// were removed without reinitializing the config DB information.
map<string,Shard>::iterator i = _lookup.find( "config" );
if ( i != _lookup.end() ){
Shard config = i->second;
_lookup.clear();
_lookup[ "config" ] = config;
} else {
_lookup.clear();
}
for ( list<BSONObj>::iterator i=all.begin(); i!=all.end(); ++i ){
BSONObj o = *i;
string name = o["_id"].String();
string host = o["host"].String();
long long maxSize = 0;
BSONElement maxSizeElem = o[ ShardFields::maxSize.name() ];
if ( ! maxSizeElem.eoo() ){
maxSize = maxSizeElem.numberLong();
}
bool isDraining = false;
BSONElement isDrainingElem = o[ ShardFields::draining.name() ];
if ( ! isDrainingElem.eoo() ){
isDraining = isDrainingElem.Bool();
}
Shard s( name , host , maxSize , isDraining );
_lookup[name] = s;
_lookup[host] = s;
}
}
bool isMember( const string& addr ){
scoped_lock lk( _mutex );
map<string,Shard>::iterator i = _lookup.find( addr );
return i != _lookup.end();
}
const Shard& find( const string& ident ){
{
scoped_lock lk( _mutex );
map<string,Shard>::iterator i = _lookup.find( ident );
if ( i != _lookup.end() )
return i->second;
}
// not in our maps, re-load all
reload();
scoped_lock lk( _mutex );
map<string,Shard>::iterator i = _lookup.find( ident );
uassert( 13129 , (string)"can't find shard for: " + ident , i != _lookup.end() );
return i->second;
}
void set( const string& name , const string& addr , bool setName = true , bool setAddr = true ){
Shard s(name,addr);
scoped_lock lk( _mutex );
if ( setName )
_lookup[name] = s;
if ( setAddr )
_lookup[addr] = s;
}
void remove( const string& name ){
scoped_lock lk( _mutex );
for ( map<string,Shard>::iterator i = _lookup.begin(); i!=_lookup.end(); ){
Shard s = i->second;
if ( s.getName() == name ){
_lookup.erase(i++);
} else {
++i;
}
}
}
void getAllShards( vector<Shard>& all ){
scoped_lock lk( _mutex );
std::set<string> seen;
for ( map<string,Shard>::iterator i = _lookup.begin(); i!=_lookup.end(); ++i ){
Shard s = i->second;
if ( s.getName() == "config" )
continue;
if ( seen.count( s.getName() ) )
continue;
seen.insert( s.getName() );
all.push_back( s );
}
}
private:
map<string,Shard> _lookup;
mongo::mutex _mutex;
} staticShardInfo;
void Shard::setAddress( const string& addr , bool authoritative ){
assert( _name.size() );
_addr = addr;
if ( authoritative )
staticShardInfo.set( _name , _addr , true , false );
}
void Shard::reset( const string& ident ){
const Shard& s = staticShardInfo.find( ident );
uassert( 13128 , (string)"can't find shard for: " + ident , s.ok() );
_name = s._name;
_addr = s._addr;
_maxSize = s._maxSize;
_isDraining = s._isDraining;
}
void Shard::getAllShards( vector<Shard>& all ){
staticShardInfo.getAllShards( all );
}
BSONObj Shard::runCommand( const string& db , const BSONObj& cmd ) const {
ScopedDbConnection conn( this );
BSONObj res;
bool ok = conn->runCommand( db , cmd , res );
if ( ! ok ){
stringstream ss;
ss << "runCommand (" << cmd << ") on shard (" << _name << ") failed : " << res;
throw UserException( 13136 , ss.str() );
}
res = res.getOwned();
conn.done();
return res;
}
ShardStatus Shard::getStatus() const {
return ShardStatus( *this , runCommand( "admin" , BSON( "serverStatus" << 1 ) ) );
}
void Shard::reloadShardInfo(){
staticShardInfo.reload();
}
bool Shard::isMember( const string& addr ){
return staticShardInfo.isMember( addr );
}
void Shard::removeShard( const string& name ){
staticShardInfo.remove( name );
}
Shard Shard::pick(){
vector<Shard> all;
staticShardInfo.getAllShards( all );
if ( all.size() == 0 ){
staticShardInfo.reload();
staticShardInfo.getAllShards( all );
if ( all.size() == 0 )
return EMPTY;
}
ShardStatus best = all[0].getStatus();
for ( size_t i=1; i<all.size(); i++ ){
ShardStatus t = all[i].getStatus();
if ( t < best )
best = t;
}
log(1) << "picking shard: " << best << endl;
return best.shard();
}
ShardStatus::ShardStatus( const Shard& shard , const BSONObj& obj )
: _shard( shard ) {
_mapped = obj.getFieldDotted( "mem.mapped" ).numberLong();
_writeLock = 0; // TODO
}
}
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