/**
* Returns true if request is a query for sharded indexes.
*/
static bool doShardedIndexQuery(OperationContext* txn, Request& r, const QuerySpec& qSpec) {
// Extract the ns field from the query, which may be embedded within the "query" or
// "$query" field.
auto nsField = qSpec.filter()["ns"];
if (nsField.eoo()) {
return false;
}
const NamespaceString indexNSSQuery(nsField.str());
auto status = grid.catalogCache()->getDatabase(txn, indexNSSQuery.db().toString());
if (!status.isOK()) {
return false;
}
shared_ptr<DBConfig> config = status.getValue();
if (!config->isSharded(indexNSSQuery.ns())) {
return false;
}
// if you are querying on system.indexes, we need to make sure we go to a shard
// that actually has chunks. This is not a perfect solution (what if you just
// look at all indexes), but better than doing nothing.
ShardPtr shard;
ChunkManagerPtr cm;
config->getChunkManagerOrPrimary(indexNSSQuery.ns(), cm, shard);
if (cm) {
set<ShardId> shardIds;
cm->getAllShardIds(&shardIds);
verify(shardIds.size() > 0);
shard = grid.shardRegistry()->getShard(*shardIds.begin());
}
ShardConnection dbcon(shard->getConnString(), r.getns());
DBClientBase& c = dbcon.conn();
string actualServer;
Message response;
bool ok = c.call(r.m(), response, true, &actualServer);
uassert(10200, "mongos: error calling db", ok);
{
QueryResult::View qr = response.singleData().view2ptr();
if (qr.getResultFlags() & ResultFlag_ShardConfigStale) {
dbcon.done();
// Version is zero b/c this is deprecated codepath
throw RecvStaleConfigException(r.getns(),
"Strategy::doQuery",
ChunkVersion(0, 0, OID()),
ChunkVersion(0, 0, OID()));
}
}
r.reply(response, actualServer.size() ? actualServer : c.getServerAddress());
dbcon.done();
return true;
}
/**
* Returns true if request is a query for sharded indexes.
*/
static bool doShardedIndexQuery( Request& r, const QuerySpec& qSpec ) {
// Extract the ns field from the query, which may be embedded within the "query" or
// "$query" field.
string indexNSQuery(qSpec.filter()["ns"].str());
DBConfigPtr config = grid.getDBConfig( r.getns() );
if ( !config->isSharded( indexNSQuery )) {
return false;
}
// if you are querying on system.indexes, we need to make sure we go to a shard
// that actually has chunks. This is not a perfect solution (what if you just
// look at all indexes), but better than doing nothing.
ShardPtr shard;
ChunkManagerPtr cm;
config->getChunkManagerOrPrimary( indexNSQuery, cm, shard );
if ( cm ) {
set<Shard> shards;
cm->getAllShards( shards );
verify( shards.size() > 0 );
shard.reset( new Shard( *shards.begin() ) );
}
ShardConnection dbcon( *shard , r.getns() );
DBClientBase &c = dbcon.conn();
string actualServer;
Message response;
bool ok = c.call( r.m(), response, true , &actualServer );
uassert( 10200 , "mongos: error calling db", ok );
{
QueryResult *qr = (QueryResult *) response.singleData();
if ( qr->resultFlags() & ResultFlag_ShardConfigStale ) {
dbcon.done();
// Version is zero b/c this is deprecated codepath
throw RecvStaleConfigException( r.getns(),
"Strategy::doQuery",
ChunkVersion( 0, 0, OID() ),
ChunkVersion( 0, 0, OID() ));
}
}
r.reply( response , actualServer.size() ? actualServer : c.getServerAddress() );
dbcon.done();
return true;
}
void remove( const string& name ) {
scoped_lock lk( _mutex );
for ( ShardMap::iterator i = _lookup.begin(); i!=_lookup.end(); ) {
ShardPtr s = i->second;
if ( s->getName() == name ) {
_lookup.erase(i++);
}
else {
++i;
}
}
for ( ShardMap::iterator i = _rsLookup.begin(); i!=_rsLookup.end(); ) {
ShardPtr s = i->second;
if ( s->getName() == name ) {
_rsLookup.erase(i++);
}
else {
++i;
}
}
}
void _installHost( const string& host , const ShardPtr& s ) {
_lookup[host] = s;
const ConnectionString& cs = s->getAddress();
if ( cs.type() == ConnectionString::SET ) {
if ( cs.getSetName().size() ) {
scoped_lock lk( _rsMutex);
_rsLookup[ cs.getSetName() ] = s;
}
vector<HostAndPort> servers = cs.getServers();
for ( unsigned i=0; i<servers.size(); i++ ) {
_lookup[ servers[i].toString() ] = s;
}
}
}
bool run( const string& dbname,
BSONObj& cmdObj,
int,
string& errmsg,
BSONObjBuilder& result,
bool ) {
string ns;
if ( !FieldParser::extract( cmdObj, nsField, &ns, &errmsg ) ) {
return false;
}
if ( ns.size() == 0 ) {
errmsg = "no namespace specified";
return false;
}
vector<BSONObj> bounds;
if ( !FieldParser::extract( cmdObj, boundsField, &bounds, &errmsg ) ) {
return false;
}
if ( bounds.size() == 0 ) {
errmsg = "no bounds were specified";
return false;
}
if ( bounds.size() != 2 ) {
errmsg = "only a min and max bound may be specified";
return false;
}
BSONObj minKey = bounds[0];
BSONObj maxKey = bounds[1];
if ( minKey.isEmpty() ) {
errmsg = "no min key specified";
return false;
}
if ( maxKey.isEmpty() ) {
errmsg = "no max key specified";
return false;
}
ShardPtr mergeShard = guessMergeShard( NamespaceString( ns ), minKey );
if ( !mergeShard ) {
errmsg = (string)"could not find shard for merge range starting at "
+ minKey.toString();
return false;
}
BSONObjBuilder remoteCmdObjB;
remoteCmdObjB.append( cmdObj[ MergeChunksPassCommand::nsField() ] );
remoteCmdObjB.append( cmdObj[ MergeChunksPassCommand::boundsField() ] );
remoteCmdObjB.append( MergeChunksPassCommand::configField(),
configServer.getPrimary().getAddress().toString() );
remoteCmdObjB.append( MergeChunksPassCommand::shardNameField(),
mergeShard->getName() );
BSONObj remoteResult;
// Throws, but handled at level above. Don't want to rewrap to preserve exception
// formatting.
ScopedDbConnection conn( mergeShard->getAddress() );
bool ok = conn->runCommand( "admin", remoteCmdObjB.obj(), remoteResult );
conn.done();
// Always refresh our chunks afterwards
refreshChunkCache( NamespaceString( ns ) );
result.appendElements( remoteResult );
return ok;
}
// Useful for ensuring our shard data will not be modified while we use it
Shard findCopy( const string& ident ){
ShardPtr found = find( ident );
scoped_lock lk( _mutex );
massert( 13128 , (string)"can't find shard for: " + ident , found.get() );
return *found.get();
}
void Strategy::queryOp(OperationContext* txn, Request& request) {
verify(!NamespaceString(request.getns()).isCommand());
Timer queryTimer;
globalOpCounters.gotQuery();
QueryMessage q(request.d());
NamespaceString ns(q.ns);
ClientBasic* client = txn->getClient();
AuthorizationSession* authSession = AuthorizationSession::get(client);
Status status = authSession->checkAuthForFind(ns, false);
audit::logQueryAuthzCheck(client, ns, q.query, status.code());
uassertStatusOK(status);
LOG(3) << "query: " << q.ns << " " << q.query << " ntoreturn: " << q.ntoreturn
<< " options: " << q.queryOptions;
if (q.ntoreturn == 1 && strstr(q.ns, ".$cmd"))
throw UserException(8010, "something is wrong, shouldn't see a command here");
if (q.queryOptions & QueryOption_Exhaust) {
uasserted(18526,
string("the 'exhaust' query option is invalid for mongos queries: ") + q.ns +
" " + q.query.toString());
}
// Spigot which controls whether OP_QUERY style find on mongos uses the new ClusterClientCursor
// code path.
// TODO: Delete the spigot and always use the new code.
if (useClusterClientCursor) {
// Determine the default read preference mode based on the value of the slaveOk flag.
ReadPreference readPreferenceOption = (q.queryOptions & QueryOption_SlaveOk)
? ReadPreference::SecondaryPreferred
: ReadPreference::PrimaryOnly;
ReadPreferenceSetting readPreference(readPreferenceOption, TagSet());
BSONElement rpElem;
auto readPrefExtractStatus = bsonExtractTypedField(
q.query, LiteParsedQuery::kWrappedReadPrefField, mongo::Object, &rpElem);
if (readPrefExtractStatus.isOK()) {
auto parsedRps = ReadPreferenceSetting::fromBSON(rpElem.Obj());
uassertStatusOK(parsedRps.getStatus());
readPreference = parsedRps.getValue();
} else if (readPrefExtractStatus != ErrorCodes::NoSuchKey) {
uassertStatusOK(readPrefExtractStatus);
}
auto canonicalQuery = CanonicalQuery::canonicalize(q, WhereCallbackNoop());
uassertStatusOK(canonicalQuery.getStatus());
// If the $explain flag was set, we must run the operation on the shards as an explain
// command rather than a find command.
if (canonicalQuery.getValue()->getParsed().isExplain()) {
const LiteParsedQuery& lpq = canonicalQuery.getValue()->getParsed();
BSONObj findCommand = lpq.asFindCommand();
// We default to allPlansExecution verbosity.
auto verbosity = ExplainCommon::EXEC_ALL_PLANS;
const bool secondaryOk = (readPreference.pref != ReadPreference::PrimaryOnly);
rpc::ServerSelectionMetadata metadata(secondaryOk, readPreference);
BSONObjBuilder explainBuilder;
uassertStatusOK(ClusterFind::runExplain(
txn, findCommand, lpq, verbosity, metadata, &explainBuilder));
BSONObj explainObj = explainBuilder.done();
replyToQuery(0, // query result flags
request.p(),
request.m(),
static_cast<const void*>(explainObj.objdata()),
explainObj.objsize(),
1, // numResults
0, // startingFrom
CursorId(0));
return;
}
// Do the work to generate the first batch of results. This blocks waiting to get responses
// from the shard(s).
std::vector<BSONObj> batch;
// 0 means the cursor is exhausted and
// otherwise we assume that a cursor with the returned id can be retrieved via the
// ClusterCursorManager
auto cursorId =
ClusterFind::runQuery(txn, *canonicalQuery.getValue(), readPreference, &batch);
uassertStatusOK(cursorId.getStatus());
// TODO: this constant should be shared between mongos and mongod, and should
// not be inside ShardedClientCursor.
BufBuilder buffer(ShardedClientCursor::INIT_REPLY_BUFFER_SIZE);
// Fill out the response buffer.
int numResults = 0;
for (const auto& obj : batch) {
buffer.appendBuf((void*)obj.objdata(), obj.objsize());
numResults++;
}
replyToQuery(0, // query result flags
request.p(),
request.m(),
buffer.buf(),
buffer.len(),
numResults,
0, // startingFrom
cursorId.getValue());
return;
}
QuerySpec qSpec((string)q.ns, q.query, q.fields, q.ntoskip, q.ntoreturn, q.queryOptions);
// Parse "$maxTimeMS".
StatusWith<int> maxTimeMS = LiteParsedQuery::parseMaxTimeMSQuery(q.query);
uassert(17233, maxTimeMS.getStatus().reason(), maxTimeMS.isOK());
if (_isSystemIndexes(q.ns) && doShardedIndexQuery(txn, request, qSpec)) {
return;
}
ParallelSortClusteredCursor* cursor = new ParallelSortClusteredCursor(qSpec, CommandInfo());
verify(cursor);
// TODO: Move out to Request itself, not strategy based
try {
cursor->init(txn);
if (qSpec.isExplain()) {
BSONObjBuilder explain_builder;
cursor->explain(explain_builder);
explain_builder.appendNumber("executionTimeMillis",
static_cast<long long>(queryTimer.millis()));
BSONObj b = explain_builder.obj();
replyToQuery(0, request.p(), request.m(), b);
delete (cursor);
return;
}
} catch (...) {
delete cursor;
throw;
}
// TODO: Revisit all of this when we revisit the sharded cursor cache
if (cursor->getNumQueryShards() != 1) {
// More than one shard (or zero), manage with a ShardedClientCursor
// NOTE: We may also have *zero* shards here when the returnPartial flag is set.
// Currently the code in ShardedClientCursor handles this.
ShardedClientCursorPtr cc(new ShardedClientCursor(q, cursor));
BufBuilder buffer(ShardedClientCursor::INIT_REPLY_BUFFER_SIZE);
int docCount = 0;
const int startFrom = cc->getTotalSent();
bool hasMore = cc->sendNextBatch(q.ntoreturn, buffer, docCount);
if (hasMore) {
LOG(5) << "storing cursor : " << cc->getId();
int cursorLeftoverMillis = maxTimeMS.getValue() - queryTimer.millis();
if (maxTimeMS.getValue() == 0) { // 0 represents "no limit".
cursorLeftoverMillis = kMaxTimeCursorNoTimeLimit;
} else if (cursorLeftoverMillis <= 0) {
cursorLeftoverMillis = kMaxTimeCursorTimeLimitExpired;
}
cursorCache.store(cc, cursorLeftoverMillis);
}
replyToQuery(0,
request.p(),
request.m(),
buffer.buf(),
buffer.len(),
docCount,
startFrom,
hasMore ? cc->getId() : 0);
} else {
// Only one shard is used
// Remote cursors are stored remotely, we shouldn't need this around.
unique_ptr<ParallelSortClusteredCursor> cursorDeleter(cursor);
ShardPtr shard = grid.shardRegistry()->getShard(txn, cursor->getQueryShardId());
verify(shard.get());
DBClientCursorPtr shardCursor = cursor->getShardCursor(shard->getId());
// Implicitly stores the cursor in the cache
request.reply(*(shardCursor->getMessage()), shardCursor->originalHost());
// We don't want to kill the cursor remotely if there's still data left
shardCursor->decouple();
}
}
/**
* Updates the remote cached version on the remote shard host (primary, in the case of replica
* sets) if needed with a fully-qualified shard version for the given namespace:
* config server(s) + shard name + shard version
*
* If no remote cached version has ever been set, an initial shard version is sent.
*
* If the namespace is empty and no version has ever been sent, the config server + shard name
* is sent to the remote shard host to initialize the connection as coming from mongos.
* NOTE: This initialization is *best-effort only*. Operations which wish to correctly version
* must send the namespace.
*
* Config servers are special and are not (unless otherwise a shard) kept up to date with this
* protocol. This is safe so long as config servers only contain unversioned collections.
*
* It is an error to call checkShardVersion with an unversionable connection (isVersionableCB).
*
* @return true if we contacted the remote host
*/
bool checkShardVersion(DBClientBase* conn_in,
const string& ns,
ChunkManagerPtr refManager,
bool authoritative,
int tryNumber) {
// TODO: cache, optimize, etc...
// Empty namespaces are special - we require initialization but not versioning
if (ns.size() == 0) {
return initShardVersionEmptyNS(conn_in);
}
auto status = grid.catalogCache()->getDatabase(nsToDatabase(ns));
if (!status.isOK()) {
return false;
}
shared_ptr<DBConfig> conf = status.getValue();
DBClientBase* conn = getVersionable(conn_in);
verify(conn); // errors thrown above
unsigned long long officialSequenceNumber = 0;
ShardPtr primary;
ChunkManagerPtr manager;
if (authoritative)
conf->getChunkManagerIfExists(ns, true);
conf->getChunkManagerOrPrimary(ns, manager, primary);
if (manager) {
officialSequenceNumber = manager->getSequenceNumber();
}
const auto shard = grid.shardRegistry()->getShard(conn->getServerAddress());
uassert(ErrorCodes::ShardNotFound,
str::stream() << conn->getServerAddress() << " is not recognized as a shard",
shard);
// Check this manager against the reference manager
if (manager) {
if (refManager && !refManager->compatibleWith(*manager, shard->getId())) {
const ChunkVersion refVersion(refManager->getVersion(shard->getId()));
const ChunkVersion currentVersion(manager->getVersion(shard->getId()));
string msg(str::stream()
<< "manager (" << currentVersion.toString() << " : "
<< manager->getSequenceNumber() << ") "
<< "not compatible with reference manager (" << refVersion.toString()
<< " : " << refManager->getSequenceNumber() << ") "
<< "on shard " << shard->getId() << " (" << shard->getConnString().toString()
<< ")");
throw SendStaleConfigException(ns, msg, refVersion, currentVersion);
}
} else if (refManager) {
string msg(str::stream() << "not sharded ("
<< ((manager.get() == 0) ? string("<none>") : str::stream()
<< manager->getSequenceNumber())
<< ") but has reference manager ("
<< refManager->getSequenceNumber() << ") "
<< "on conn " << conn->getServerAddress() << " ("
<< conn_in->getServerAddress() << ")");
throw SendStaleConfigException(
ns, msg, refManager->getVersion(shard->getId()), ChunkVersion::UNSHARDED());
}
// Do not send setShardVersion to collections on the config servers - this causes problems
// when config servers are also shards and get SSV with conflicting names.
// TODO: Make config servers regular shards
if (primary && primary->getId() == "config") {
return false;
}
// Has the ChunkManager been reloaded since the last time we updated the shard version over
// this connection? If we've never updated the shard version, do so now.
unsigned long long sequenceNumber = 0;
if (connectionShardStatus.getSequence(conn, ns, &sequenceNumber)) {
if (sequenceNumber == officialSequenceNumber) {
return false;
}
}
ChunkVersion version = ChunkVersion(0, 0, OID());
if (manager) {
version = manager->getVersion(shard->getId());
}
LOG(1) << "setting shard version of " << version << " for " << ns << " on shard "
<< shard->toString();
LOG(3) << "last version sent with chunk manager iteration " << sequenceNumber
<< ", current chunk manager iteration is " << officialSequenceNumber;
BSONObj result;
if (setShardVersion(*conn,
ns,
grid.catalogManager()->connectionString().toString(),
version,
manager.get(),
authoritative,
result)) {
LOG(1) << " setShardVersion success: " << result;
connectionShardStatus.setSequence(conn, ns, officialSequenceNumber);
return true;
}
LOG(1) << " setShardVersion failed!\n" << result << endl;
if (result["need_authoritative"].trueValue())
massert(10428, "need_authoritative set but in authoritative mode already", !authoritative);
if (!authoritative) {
// use the original connection and get a fresh versionable connection
// since conn can be invalidated (or worse, freed) after the failure
checkShardVersion(conn_in, ns, refManager, 1, tryNumber + 1);
return true;
}
if (result["reloadConfig"].trueValue()) {
if (result["version"].timestampTime() == Date_t()) {
warning() << "reloading full configuration for " << conf->name()
<< ", connection state indicates significant version changes";
// reload db
conf->reload();
} else {
// reload config
conf->getChunkManager(ns, true);
}
}
const int maxNumTries = 7;
if (tryNumber < maxNumTries) {
LOG(tryNumber < (maxNumTries / 2) ? 1 : 0)
<< "going to retry checkShardVersion shard: " << shard->toString() << " " << result;
sleepmillis(10 * tryNumber);
// use the original connection and get a fresh versionable connection
// since conn can be invalidated (or worse, freed) after the failure
checkShardVersion(conn_in, ns, refManager, true, tryNumber + 1);
return true;
}
string errmsg = str::stream() << "setShardVersion failed shard: " << shard->toString() << " "
<< result;
log() << " " << errmsg << endl;
massert(10429, errmsg, 0);
return true;
}
void Strategy::queryOp( Request& r ) {
verify( !NamespaceString( r.getns() ).isCommand() );
Timer queryTimer;
QueryMessage q( r.d() );
NamespaceString ns(q.ns);
ClientBasic* client = ClientBasic::getCurrent();
AuthorizationSession* authSession = client->getAuthorizationSession();
Status status = authSession->checkAuthForQuery(ns, q.query);
audit::logQueryAuthzCheck(client, ns, q.query, status.code());
uassertStatusOK(status);
LOG(3) << "query: " << q.ns << " " << q.query << " ntoreturn: " << q.ntoreturn
<< " options: " << q.queryOptions << endl;
if ( q.ntoreturn == 1 && strstr(q.ns, ".$cmd") )
throw UserException( 8010 , "something is wrong, shouldn't see a command here" );
if (q.queryOptions & QueryOption_Exhaust) {
uasserted(18526,
string("the 'exhaust' query option is invalid for mongos queries: ") + q.ns
+ " " + q.query.toString());
}
QuerySpec qSpec( (string)q.ns, q.query, q.fields, q.ntoskip, q.ntoreturn, q.queryOptions );
// Parse "$maxTimeMS".
StatusWith<int> maxTimeMS = LiteParsedQuery::parseMaxTimeMSQuery( q.query );
uassert( 17233,
maxTimeMS.getStatus().reason(),
maxTimeMS.isOK() );
if ( _isSystemIndexes( q.ns ) && doShardedIndexQuery( r, qSpec )) {
return;
}
ParallelSortClusteredCursor * cursor = new ParallelSortClusteredCursor( qSpec, CommandInfo() );
verify( cursor );
// TODO: Move out to Request itself, not strategy based
try {
cursor->init();
if ( qSpec.isExplain() ) {
BSONObjBuilder explain_builder;
cursor->explain( explain_builder );
explain_builder.appendNumber( "executionTimeMillis",
static_cast<long long>(queryTimer.millis()) );
BSONObj b = explain_builder.obj();
replyToQuery( 0 , r.p() , r.m() , b );
delete( cursor );
return;
}
}
catch(...) {
delete cursor;
throw;
}
// TODO: Revisit all of this when we revisit the sharded cursor cache
if (cursor->getNumQueryShards() != 1) {
// More than one shard (or zero), manage with a ShardedClientCursor
// NOTE: We may also have *zero* shards here when the returnPartial flag is set.
// Currently the code in ShardedClientCursor handles this.
ShardedClientCursorPtr cc (new ShardedClientCursor( q , cursor ));
BufBuilder buffer( ShardedClientCursor::INIT_REPLY_BUFFER_SIZE );
int docCount = 0;
const int startFrom = cc->getTotalSent();
bool hasMore = cc->sendNextBatch(q.ntoreturn, buffer, docCount);
if ( hasMore ) {
LOG(5) << "storing cursor : " << cc->getId() << endl;
int cursorLeftoverMillis = maxTimeMS.getValue() - queryTimer.millis();
if ( maxTimeMS.getValue() == 0 ) { // 0 represents "no limit".
cursorLeftoverMillis = kMaxTimeCursorNoTimeLimit;
}
else if ( cursorLeftoverMillis <= 0 ) {
cursorLeftoverMillis = kMaxTimeCursorTimeLimitExpired;
}
cursorCache.store( cc, cursorLeftoverMillis );
}
replyToQuery( 0, r.p(), r.m(), buffer.buf(), buffer.len(), docCount,
startFrom, hasMore ? cc->getId() : 0 );
}
else{
// Only one shard is used
// Remote cursors are stored remotely, we shouldn't need this around.
scoped_ptr<ParallelSortClusteredCursor> cursorDeleter( cursor );
ShardPtr shard = cursor->getQueryShard();
verify( shard.get() );
DBClientCursorPtr shardCursor = cursor->getShardCursor(*shard);
// Implicitly stores the cursor in the cache
r.reply( *(shardCursor->getMessage()) , shardCursor->originalHost() );
// We don't want to kill the cursor remotely if there's still data left
shardCursor->decouple();
}
}
