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/**
* 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 "mongo/pch.h"
#include "mongo/db/prefetch.h"
#include "mongo/db/dbhelpers.h"
#include "mongo/db/diskloc.h"
#include "mongo/db/index.h"
#include "mongo/db/index_update.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/namespace_details.h"
namespace mongo {
// prefetch for an oplog operation
void prefetchPagesForReplicatedOp(const BSONObj& op) {
const char *opField;
const char *opType = op.getStringField("op");
if ( *opType == 'i' )
opField = "o";
else if( *opType == 'u' )
opField = "o2";
else
// prefetch ignores other ops
return;
BSONObj obj = op.getObjectField(opField);
const char *ns = op.getStringField("ns");
prefetchIndexPages(ns, obj);
// do not prefetch the data for inserts; it doesn't exist yet
if (*opType == 'u') {
prefetchRecordPages(ns, obj);
}
}
void prefetchIndexPages(const char *ns, const BSONObj& obj) {
DiskLoc unusedDl; // unused
IndexInterface::IndexInserter inserter;
NamespaceDetails *nsd = nsdetails(ns);
// includes all indexes, including ones
// in the process of being built
int indexCount = nsd->nIndexesBeingBuilt();
BSONObjSet unusedKeys;
//vector<int> multi;
//vector<BSONObjSet> multiKeys;
for ( int indexNo = 0; indexNo < indexCount; indexNo++ ) {
// This will page in all index pages for the given object.
fetchIndexInserters(/*out*/unusedKeys, inserter, nsd, indexNo, obj, unusedDl);
// do something with multikeys later?
// if( keys.size() > 1 ) {
// multi.push_back(i);
// multiKeys.push_back(BSONObjSet());
// multiKeys[multiKeys.size()-1].swap(keys);
// }
unusedKeys.clear();
}
}
void prefetchRecordPages(const char* ns, const BSONObj& obj) {
BSONElement _id;
if( obj.getObjectID(_id) ) {
BSONObjBuilder builder;
builder.append(_id);
BSONObj result;
Client::ReadContext ctx( ns );
try {
if( Helpers::findById(cc(), ns, builder.done(), result) ) {
volatile char _dummy_char;
// Touch the first word on every page in order to fault it into memory
for (int i = 0; i < result.objsize(); i += g_minOSPageSizeBytes) {
_dummy_char += *(result.objdata() + i);
}
// hit the last page, in case we missed it above
_dummy_char += *(result.objdata() + result.objsize());
}
}
catch( AssertionException& ) {
log() << "ignoring assertion in prefetchRecord()" << endl;
}
}
}
}
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