// ttl.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 .
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kIndex
#include "mongo/platform/basic.h"
#include "mongo/db/ttl.h"
#include "mongo/base/counter.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/auth/user_name.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/catalog/collection_catalog_entry.h"
#include "mongo/db/catalog/database_catalog_entry.h"
#include "mongo/db/catalog/database_holder.h"
#include "mongo/db/client.h"
#include "mongo/db/commands/fsync.h"
#include "mongo/db/commands/server_status_metric.h"
#include "mongo/db/concurrency/write_conflict_exception.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/dbdirectclient.h"
#include "mongo/db/operation_context_impl.h"
#include "mongo/db/ops/delete.h"
#include "mongo/db/repl/replication_coordinator_global.h"
#include "mongo/db/server_parameters.h"
#include "mongo/util/background.h"
#include "mongo/util/exit.h"
#include "mongo/util/log.h"
namespace mongo {
using std::set;
using std::endl;
using std::list;
using std::string;
using std::vector;
Counter64 ttlPasses;
Counter64 ttlDeletedDocuments;
ServerStatusMetricField ttlPassesDisplay("ttl.passes", &ttlPasses);
ServerStatusMetricField ttlDeletedDocumentsDisplay("ttl.deletedDocuments", &ttlDeletedDocuments);
MONGO_EXPORT_SERVER_PARAMETER( ttlMonitorEnabled, bool, true );
MONGO_EXPORT_SERVER_PARAMETER( ttlMonitorSleepSecs, int, 60 ); //used for testing
class TTLMonitor : public BackgroundJob {
public:
TTLMonitor(){}
virtual ~TTLMonitor(){}
virtual string name() const { return "TTLMonitor"; }
static string secondsExpireField;
virtual void run() {
Client::initThread( name().c_str() );
cc().getAuthorizationSession()->grantInternalAuthorization();
while ( ! inShutdown() ) {
sleepsecs( ttlMonitorSleepSecs );
LOG(3) << "TTLMonitor thread awake" << endl;
if ( !ttlMonitorEnabled ) {
LOG(1) << "TTLMonitor is disabled" << endl;
continue;
}
if ( lockedForWriting() ) {
// note: this is not perfect as you can go into fsync+lock between
// this and actually doing the delete later
LOG(3) << " locked for writing" << endl;
continue;
}
try {
doTTLPass();
}
catch ( const WriteConflictException& e ) {
LOG(1) << "Got WriteConflictException in TTL thread";
}
}
}
private:
void doTTLPass() {
// Count it as active from the moment the TTL thread wakes up
OperationContextImpl txn;
// if part of replSet but not in a readable state (e.g. during initial sync), skip.
if (repl::getGlobalReplicationCoordinator()->getReplicationMode() ==
repl::ReplicationCoordinator::modeReplSet &&
!repl::getGlobalReplicationCoordinator()->getMemberState().readable())
return;
set dbs;
dbHolder().getAllShortNames( dbs );
ttlPasses.increment();
for ( set::const_iterator i=dbs.begin(); i!=dbs.end(); ++i ) {
string db = *i;
vector indexes;
getTTLIndexesForDB(&txn, db, &indexes);
for ( vector::const_iterator it = indexes.begin();
it != indexes.end(); ++it ) {
BSONObj idx = *it;
try {
if ( !doTTLForIndex( &txn, db, idx ) ) {
break; // stop processing TTL indexes on this database
}
} catch (const DBException& dbex) {
error() << "Error processing ttl index: " << idx
<< " -- " << dbex.toString();
// continue on to the next index
continue;
}
}
}
}
/**
* Acquire an IS-mode lock on the specified database and for each
* collection in the database, append the specification of all
* TTL indexes on those collections to the supplied vector.
*
* The index specifications are grouped by the collection to which
* they belong.
*/
void getTTLIndexesForDB( OperationContext* txn, const string& dbName,
vector* indexes ) {
invariant( indexes && indexes->empty() );
ScopedTransaction transaction( txn, MODE_IS );
Lock::DBLock dbLock( txn->lockState(), dbName, MODE_IS );
Database* db = dbHolder().get( txn, dbName );
if ( !db ) {
return; // skip since database no longer exists
}
const DatabaseCatalogEntry* dbEntry = db->getDatabaseCatalogEntry();
list namespaces;
dbEntry->getCollectionNamespaces( &namespaces );
for ( list::const_iterator it = namespaces.begin();
it != namespaces.end(); ++it ) {
string ns = *it;
Lock::CollectionLock collLock( txn->lockState(), ns, MODE_IS );
CollectionCatalogEntry* coll = dbEntry->getCollectionCatalogEntry( ns );
if ( !coll ) {
continue; // skip since collection not found in catalog
}
vector indexNames;
coll->getAllIndexes( txn, &indexNames );
for ( size_t i = 0; i < indexNames.size(); i++ ) {
const string& name = indexNames[i];
BSONObj spec = coll->getIndexSpec( txn, name );
if ( spec.hasField( secondsExpireField ) ) {
indexes->push_back( spec.getOwned() );
}
}
}
}
/**
* Remove documents from the collection using the specified TTL index
* after a sufficient amount of time has passed according to its expiry
* specification.
*
* @return true if caller should continue processing TTL indexes of collections
* on the specified database, and false otherwise
*/
bool doTTLForIndex( OperationContext* txn, const string& dbName, const BSONObj& idx ) {
BSONObj key = idx["key"].Obj();
const string ns = idx["ns"].String();
if ( key.nFields() != 1 ) {
error() << "key for ttl index can only have 1 field" << endl;
return true;
}
if ( !idx[secondsExpireField].isNumber() ) {
log() << "ttl indexes require the " << secondsExpireField << " field to be "
<< "numeric but received a type of: "
<< typeName( idx[secondsExpireField].type() );
return true;
}
BSONObj query;
{
BSONObjBuilder b;
long long expireMs = 1000 * idx[secondsExpireField].numberLong();
b.appendDate( "$lt", curTimeMillis64() - expireMs );
query = BSON( key.firstElement().fieldName() << b.obj() );
}
LOG(1) << "TTL -- ns: " << ns << "key:" << key << " query: " << query << endl;
long long numDeleted = 0;
int attempt = 1;
while (1) {
ScopedTransaction scopedXact(txn, MODE_IX);
AutoGetDb autoDb(txn, dbName, MODE_IX);
Database* db = autoDb.getDb();
if (!db) {
return false;
}
Lock::CollectionLock collLock( txn->lockState(), ns, MODE_IX );
Collection* collection = db->getCollection( ns );
if ( !collection ) {
// collection was dropped
return true;
}
if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesForDatabase(dbName)) {
// we've stepped down since we started this function,
// so we should stop working as we only do deletes on the primary
return false;
}
if ( collection->getIndexCatalog()->findIndexByKeyPattern( txn, key ) == NULL ) {
// index not finished yet
LOG(1) << " skipping index because not finished";
return true;
}
try {
numDeleted = deleteObjects(txn,
db,
ns,
query,
PlanExecutor::YIELD_AUTO,
false,
true);
break;
}
catch (const WriteConflictException& dle) {
WriteConflictException::logAndBackoff(attempt++, "ttl", ns);
}
}
ttlDeletedDocuments.increment(numDeleted);
LOG(1) << "\tTTL deleted: " << numDeleted << endl;
return true;
}
};
void startTTLBackgroundJob() {
TTLMonitor* ttl = new TTLMonitor();
ttl->go();
}
string TTLMonitor::secondsExpireField = "expireAfterSeconds";
}