ChunkManager::ChunkManager(const CollectionType& coll)
: _ns(coll.getNs().ns()),
_keyPattern(coll.getKeyPattern()),
_unique(coll.getUnique()),
_sequenceNumber(NextSequenceNumber.addAndFetch(1)),
_chunkRanges() {
// coll does not have correct version. Use same initial version as _load and createFirstChunks.
_version = ChunkVersion(0, 0, coll.getEpoch());
}
Status _findAllCollections(const ConnectionString& configLoc,
bool optionalEpochs,
OwnedPointerMap<string, CollectionType>* collections)
{
scoped_ptr<ScopedDbConnection> connPtr;
try {
connPtr.reset(ScopedDbConnection::getInternalScopedDbConnection(configLoc, 30));
ScopedDbConnection& conn = *connPtr;
scoped_ptr<DBClientCursor> cursor(_safeCursor(conn->query(CollectionType::ConfigNS,
Query())));
while (cursor->more()) {
BSONObj collDoc = cursor->nextSafe();
CollectionType* coll = new CollectionType();
string errMsg;
coll->parseBSON(collDoc, &errMsg);
// Needed for the v3 to v4 upgrade
bool epochNotSet = !coll->isEpochSet() || !coll->getEpoch().isSet();
if (optionalEpochs && epochNotSet) {
// Set our epoch to something here, just to allow
coll->setEpoch(OID::gen());
}
if (errMsg != "" || !coll->isValid(&errMsg)) {
return Status(ErrorCodes::UnsupportedFormat,
stream() << "invalid collection " << collDoc
<< " read from the config server" << causedBy(errMsg));
}
if (coll->isDroppedSet() && coll->getDropped()) {
continue;
}
if (optionalEpochs && epochNotSet) {
coll->setEpoch(OID());
}
collections->mutableMap().insert(make_pair(coll->getNS(), coll));
}
}
catch (const DBException& e) {
return e.toStatus();
}
connPtr->done();
return Status::OK();
}
Status MetadataLoader::_initCollection(CatalogManager* catalogManager,
const string& ns,
const string& shard,
CollectionMetadata* metadata) const {
auto coll = catalogManager->getCollection(ns);
if (!coll.isOK()) {
return coll.getStatus();
}
CollectionType collInfo = coll.getValue();
if (collInfo.getDropped()) {
return Status(ErrorCodes::NamespaceNotFound,
str::stream() << "could not load metadata, collection "
<< ns << " was dropped");
}
metadata->_keyPattern = collInfo.getKeyPattern().toBSON();
metadata->fillKeyPatternFields();
metadata->_shardVersion = ChunkVersion(0, 0, collInfo.getEpoch());
metadata->_collVersion = ChunkVersion(0, 0, collInfo.getEpoch());
return Status::OK();
}
/**
* Upgrade v3 to v4 described here.
*
* This upgrade takes a config server without collection epochs (potentially) and adds
* epochs to all mongo processes.
*
*/
bool doUpgradeV3ToV4(const ConnectionString& configLoc,
const VersionType& lastVersionInfo,
string* errMsg)
{
string dummy;
if (!errMsg) errMsg = &dummy;
verify(lastVersionInfo.getCurrentVersion() == UpgradeHistory_NoEpochVersion);
if (lastVersionInfo.isUpgradeIdSet() && lastVersionInfo.getUpgradeId().isSet()) {
//
// Another upgrade failed, so cleanup may be necessary
//
BSONObj lastUpgradeState = lastVersionInfo.getUpgradeState();
bool inCriticalSection;
if (!FieldParser::extract(lastUpgradeState,
inCriticalSectionField,
&inCriticalSection,
errMsg))
{
*errMsg = stream() << "problem reading previous upgrade state" << causedBy(errMsg);
return false;
}
if (inCriticalSection) {
// Manual intervention is needed here. Somehow our upgrade didn't get applied
// consistently across config servers.
*errMsg = cannotCleanupMessage;
return false;
}
if (!_cleanupUpgradeState(configLoc, lastVersionInfo.getUpgradeId(), errMsg)) {
// If we can't cleanup the old upgrade state, the user might have done it for us,
// not a fatal problem (we'll just end up with extra collections).
warning() << "could not cleanup previous upgrade state" << causedBy(errMsg) << endl;
*errMsg = "";
}
}
//
// Check the versions of other mongo processes in the cluster before upgrade.
// We can't upgrade if there are active pre-v2.2 processes in the cluster
//
Status mongoVersionStatus = checkClusterMongoVersions(configLoc,
string(minMongoProcessVersion));
if (!mongoVersionStatus.isOK()) {
*errMsg = stream() << "cannot upgrade with pre-v" << minMongoProcessVersion
<< " mongo processes active in the cluster"
<< causedBy(mongoVersionStatus);
return false;
}
VersionType newVersionInfo;
lastVersionInfo.cloneTo(&newVersionInfo);
// Set our upgrade id and state
OID upgradeId = OID::gen();
newVersionInfo.setUpgradeId(upgradeId);
newVersionInfo.setUpgradeState(BSONObj());
// Write our upgrade id and state
{
scoped_ptr<ScopedDbConnection> connPtr;
try {
connPtr.reset(ScopedDbConnection::getInternalScopedDbConnection(configLoc, 30));
ScopedDbConnection& conn = *connPtr;
verify(newVersionInfo.isValid(NULL));
conn->update(VersionType::ConfigNS,
BSON("_id" << 1 << VersionType::version_DEPRECATED(3)),
newVersionInfo.toBSON());
_checkGLE(conn);
}
catch (const DBException& e) {
*errMsg = stream() << "could not initialize version info for upgrade"
<< causedBy(e);
return false;
}
connPtr->done();
}
//
// First lock all collection namespaces that exist
//
OwnedPointerMap<string, CollectionType> ownedCollections;
const map<string, CollectionType*>& collections = ownedCollections.map();
Status findCollectionsStatus = findAllCollectionsV3(configLoc, &ownedCollections);
if (!findCollectionsStatus.isOK()) {
*errMsg = stream() << "could not read collections from config server"
<< causedBy(findCollectionsStatus);
return false;
}
//
// Acquire locks for all sharded collections
// Something that didn't involve getting thousands of locks would be better.
//
OwnedPointerVector<ScopedDistributedLock> collectionLocks;
log() << "acquiring locks for " << collections.size() << " sharded collections..." << endl;
// WARNING - this string is used programmatically when forcing locks, be careful when
// changing!
// TODO: Add programmatic "why" field to lock collection
string lockMessage = str::stream() << "ensuring epochs for config upgrade"
<< " (" << upgradeId.toString() << ")";
if (!_acquireAllCollectionLocks(configLoc,
collections,
lockMessage,
20 * 60 * 1000,
&collectionLocks,
errMsg))
{
*errMsg = stream() << "could not acquire all namespace locks for upgrade"
<< " (" << upgradeId.toString() << ")"
<< causedBy(errMsg);
return false;
}
// We are now preventing all splits and migrates for all sharded collections
// Get working and backup suffixes
string workingSuffix = genWorkingSuffix(upgradeId);
string backupSuffix = genBackupSuffix(upgradeId);
log() << "copying collection and chunk metadata to working and backup collections..."
<< endl;
// Get a backup and working copy of the config.collections and config.chunks collections
Status copyStatus = copyFrozenCollection(configLoc,
CollectionType::ConfigNS,
CollectionType::ConfigNS + workingSuffix);
if (!copyStatus.isOK()) {
*errMsg = stream() << "could not copy " << CollectionType::ConfigNS << " to "
<< (CollectionType::ConfigNS + workingSuffix)
<< causedBy(copyStatus);
return false;
}
copyStatus = copyFrozenCollection(configLoc,
CollectionType::ConfigNS,
CollectionType::ConfigNS + backupSuffix);
if (!copyStatus.isOK()) {
*errMsg = stream() << "could not copy " << CollectionType::ConfigNS << " to "
<< (CollectionType::ConfigNS + backupSuffix) << causedBy(copyStatus);
return false;
}
copyStatus = copyFrozenCollection(configLoc,
ChunkType::ConfigNS,
ChunkType::ConfigNS + workingSuffix);
if (!copyStatus.isOK()) {
*errMsg = stream() << "could not copy " << ChunkType::ConfigNS << " to "
<< (ChunkType::ConfigNS + workingSuffix) << causedBy(copyStatus);
return false;
}
copyStatus = copyFrozenCollection(configLoc,
ChunkType::ConfigNS,
ChunkType::ConfigNS + backupSuffix);
if (!copyStatus.isOK()) {
*errMsg = stream() << "could not copy " << ChunkType::ConfigNS << " to "
<< (ChunkType::ConfigNS + backupSuffix) << causedBy(copyStatus);
return false;
}
//
// Go through sharded collections one-by-one and add epochs where missing
//
for (map<string, CollectionType*>::const_iterator it = collections.begin();
it != collections.end(); ++it)
{
// Create a copy so that we can change the epoch later
CollectionType collection;
it->second->cloneTo(&collection);
log() << "checking epochs for " << collection.getNS() << " collection..." << endl;
OID epoch = collection.getEpoch();
//
// Go through chunks to find epoch if we haven't found it or to verify epoch is the same
//
OwnedPointerVector<ChunkType> ownedChunks;
const vector<ChunkType*>& chunks = ownedChunks.vector();
Status findChunksStatus = findAllChunks(configLoc, collection.getNS(), &ownedChunks);
if (!findChunksStatus.isOK()) {
*errMsg = stream() << "could not read chunks from config server"
<< causedBy(findChunksStatus);
return false;
}
for (vector<ChunkType*>::const_iterator chunkIt = chunks.begin();
chunkIt != chunks.end(); ++chunkIt)
{
const ChunkType& chunk = *(*chunkIt);
// If our chunk epoch is set and doesn't match
if (epoch.isSet() && chunk.getVersion().epoch().isSet()
&& chunk.getVersion().epoch() != epoch)
{
*errMsg = stream() << "chunk epoch for " << chunk.toString() << " in "
<< collection.getNS() << " does not match found epoch "
<< epoch;
return false;
}
else if (!epoch.isSet() && chunk.getVersion().epoch().isSet()) {
epoch = chunk.getVersion().epoch();
}
}
//
// Write collection epoch if needed
//
if (!collection.getEpoch().isSet()) {
OID newEpoch = OID::gen();
log() << "writing new epoch " << newEpoch << " for " << collection.getNS()
<< " collection..." << endl;
scoped_ptr<ScopedDbConnection> connPtr;
try {
connPtr.reset(ScopedDbConnection::getInternalScopedDbConnection(configLoc, 30));
ScopedDbConnection& conn = *connPtr;
conn->update(CollectionType::ConfigNS + workingSuffix,
BSON(CollectionType::ns(collection.getNS())),
BSON("$set" << BSON(CollectionType::DEPRECATED_lastmodEpoch(newEpoch))));
_checkGLE(conn);
}
catch (const DBException& e) {
*errMsg = stream() << "could not write a new epoch for " << collection.getNS()
<< causedBy(e);
return false;
}
connPtr->done();
collection.setEpoch(newEpoch);
}
epoch = collection.getEpoch();
verify(epoch.isSet());
//
// Now write verified epoch to all chunks
//
log() << "writing epoch " << epoch << " for " << chunks.size() << " chunks in "
<< collection.getNS() << " collection..." << endl;
{
scoped_ptr<ScopedDbConnection> connPtr;
try {
connPtr.reset(ScopedDbConnection::getInternalScopedDbConnection(configLoc, 30));
ScopedDbConnection& conn = *connPtr;
// Multi-update of all chunks
conn->update(ChunkType::ConfigNS + workingSuffix,
BSON(ChunkType::ns(collection.getNS())),
BSON("$set" << BSON(ChunkType::DEPRECATED_epoch(epoch))),
false,
true); // multi
_checkGLE(conn);
}
catch (const DBException& e) {
*errMsg = stream() << "could not write a new epoch " << epoch.toString()
<< " for chunks in " << collection.getNS() << causedBy(e);
return false;
}
connPtr->done();
}
}
//
// Paranoid verify the collection writes
//
{
scoped_ptr<ScopedDbConnection> connPtr;
try {
connPtr.reset(ScopedDbConnection::getInternalScopedDbConnection(configLoc, 30));
ScopedDbConnection& conn = *connPtr;
// Find collections with no epochs
BSONObj emptyDoc =
conn->findOne(CollectionType::ConfigNS + workingSuffix,
BSON("$unset" << BSON(CollectionType::DEPRECATED_lastmodEpoch() << 1)));
if (!emptyDoc.isEmpty()) {
*errMsg = stream() << "collection " << emptyDoc
<< " is still missing epoch after config upgrade";
connPtr->done();
return false;
}
// Find collections with empty epochs
emptyDoc = conn->findOne(CollectionType::ConfigNS + workingSuffix,
BSON(CollectionType::DEPRECATED_lastmodEpoch(OID())));
if (!emptyDoc.isEmpty()) {
*errMsg = stream() << "collection " << emptyDoc
<< " still has empty epoch after config upgrade";
connPtr->done();
return false;
}
// Find chunks with no epochs
emptyDoc =
conn->findOne(ChunkType::ConfigNS + workingSuffix,
BSON("$unset" << BSON(ChunkType::DEPRECATED_epoch() << 1)));
if (!emptyDoc.isEmpty()) {
*errMsg = stream() << "chunk " << emptyDoc
<< " is still missing epoch after config upgrade";
connPtr->done();
return false;
}
// Find chunks with empty epochs
emptyDoc = conn->findOne(ChunkType::ConfigNS + workingSuffix,
BSON(ChunkType::DEPRECATED_epoch(OID())));
if (!emptyDoc.isEmpty()) {
*errMsg = stream() << "chunk " << emptyDoc
<< " still has empty epoch after config upgrade";
connPtr->done();
return false;
}
}
catch (const DBException& e) {
*errMsg = stream() << "could not verify epoch writes" << causedBy(e);
return false;
}
connPtr->done();
}
//
// Double check that our collections haven't changed
//
Status idCheckStatus = checkIdsTheSame(configLoc,
CollectionType::ConfigNS,
CollectionType::ConfigNS + workingSuffix);
if (!idCheckStatus.isOK()) {
*errMsg = stream() << CollectionType::ConfigNS
<< " was modified while working on upgrade"
<< causedBy(idCheckStatus);
return false;
}
idCheckStatus = checkIdsTheSame(configLoc,
ChunkType::ConfigNS,
ChunkType::ConfigNS + workingSuffix);
if (!idCheckStatus.isOK()) {
*errMsg = stream() << ChunkType::ConfigNS << " was modified while working on upgrade"
<< causedBy(idCheckStatus);
return false;
}
//
// ENTER CRITICAL SECTION
//
newVersionInfo.setUpgradeState(BSON(inCriticalSectionField(true)));
{
scoped_ptr<ScopedDbConnection> connPtr;
try {
connPtr.reset(ScopedDbConnection::getInternalScopedDbConnection(configLoc, 30));
ScopedDbConnection& conn = *connPtr;
verify(newVersionInfo.isValid(NULL));
conn->update(VersionType::ConfigNS,
BSON("_id" << 1 << VersionType::version_DEPRECATED(3)),
newVersionInfo.toBSON());
_checkGLE(conn);
}
catch (const DBException& e) {
// No cleanup message here since we're not sure if we wrote or not, and
// not dangerous either way except to prevent further updates (at which point
// the message is printed)
*errMsg = stream()
<< "could not update version info to enter critical update section"
<< causedBy(e);
return false;
}
// AT THIS POINT ANY FAILURE REQUIRES MANUAL INTERVENTION!
connPtr->done();
}
log() << "entered critical section for config upgrade" << endl;
Status overwriteStatus = overwriteCollection(configLoc,
CollectionType::ConfigNS + workingSuffix,
CollectionType::ConfigNS);
if (!overwriteStatus.isOK()) {
error() << cleanupMessage << endl;
*errMsg = stream() << "could not overwrite collection " << CollectionType::ConfigNS
<< " with working collection "
<< (CollectionType::ConfigNS + workingSuffix)
<< causedBy(overwriteStatus);
return false;
}
overwriteStatus = overwriteCollection(configLoc,
ChunkType::ConfigNS + workingSuffix,
ChunkType::ConfigNS);
if (!overwriteStatus.isOK()) {
error() << cleanupMessage << endl;
*errMsg = stream() << "could not overwrite collection " << ChunkType::ConfigNS
<< " with working collection "
<< (ChunkType::ConfigNS + workingSuffix)
<< causedBy(overwriteStatus);
return false;
}
//
// Finally update the version to latest and add clusterId to version
//
OID newClusterId = OID::gen();
// Note: hardcoded versions, since this is a very particular upgrade
// Note: DO NOT CLEAR the config version unless bumping the minCompatibleVersion,
// we want to save the excludes that were set.
newVersionInfo.setMinCompatibleVersion(UpgradeHistory_NoEpochVersion);
newVersionInfo.setCurrentVersion(UpgradeHistory_MandatoryEpochVersion);
newVersionInfo.setClusterId(newClusterId);
// Leave critical section
newVersionInfo.unsetUpgradeId();
newVersionInfo.unsetUpgradeState();
log() << "writing new version info and clusterId " << newClusterId << "..." << endl;
{
scoped_ptr<ScopedDbConnection> connPtr;
try {
connPtr.reset(ScopedDbConnection::getInternalScopedDbConnection(configLoc, 30));
ScopedDbConnection& conn = *connPtr;
verify(newVersionInfo.isValid(NULL));
conn->update(VersionType::ConfigNS,
BSON("_id" << 1 << VersionType::version_DEPRECATED(UpgradeHistory_NoEpochVersion)),
newVersionInfo.toBSON());
_checkGLE(conn);
}
catch (const DBException& e) {
error() << cleanupMessage << endl;
*errMsg = stream() << "could not write new version info "
<< "and exit critical upgrade section" << causedBy(e);
return false;
}
connPtr->done();
}
//
// END CRITICAL SECTION
//
return true;
}
Status MetadataLoader::initCollection( const string& ns,
const string& shard,
CollectionMetadata* metadata )
{
//
// Bring collection entry from the config server.
//
BSONObj collObj;
{
try {
ScopedDbConnection conn( _configLoc.toString(), 30 );
collObj = conn->findOne( CollectionType::ConfigNS, QUERY(CollectionType::ns()<<ns));
conn.done();
}
catch ( const DBException& e ) {
string errMsg = str::stream() << "could not query collection metadata"
<< causedBy( e );
// We deliberately do not return conn to the pool, since it was involved
// with the error here.
return Status( ErrorCodes::HostUnreachable, errMsg );
}
}
CollectionType collDoc;
string errMsg;
if ( !collDoc.parseBSON( collObj, &errMsg ) || !collDoc.isValid( &errMsg ) ) {
return Status( ErrorCodes::FailedToParse, errMsg );
}
//
// Load or generate default chunks for collection config.
//
if ( collDoc.isKeyPatternSet() && !collDoc.getKeyPattern().isEmpty() ) {
metadata->_keyPattern = collDoc.getKeyPattern();
metadata->_shardVersion = ChunkVersion( 0, 0, collDoc.getEpoch() );
metadata->_collVersion = ChunkVersion( 0, 0, collDoc.getEpoch() );
return Status::OK();
}
else if ( collDoc.isPrimarySet() && collDoc.getPrimary() == shard ) {
if ( shard == "" ) {
warning() << "shard not verified, assuming collection " << ns
<< " is unsharded on this shard" << endl;
}
metadata->_keyPattern = BSONObj();
metadata->_shardVersion = ChunkVersion( 1, 0, collDoc.getEpoch() );
metadata->_collVersion = metadata->_shardVersion;
return Status::OK();
}
else {
errMsg = str::stream() << "collection " << ns << " does not have a shard key "
<< "and primary " << ( collDoc.isPrimarySet() ? collDoc.getPrimary() : "" )
<< " does not match this shard " << shard;
return Status( ErrorCodes::RemoteChangeDetected, errMsg );
}
}
bool MetadataLoader::initCollection(const string& ns,
const string& shard,
const CollectionManager* oldManager,
CollectionManager* manager,
string* errMsg) {
//
// Bring collection entry from the config server.
//
BSONObj collObj;
{
scoped_ptr<ScopedDbConnection> connPtr;
try {
connPtr.reset(
ScopedDbConnection::getInternalScopedDbConnection(_configLoc.toString(), 30));
ScopedDbConnection& conn = *connPtr;
collObj = conn->findOne(CollectionType::ConfigNS, QUERY(CollectionType::ns()<<ns));
}
catch (const DBException& e) {
*errMsg = str::stream() << "caught exception accessing the config servers "
<< causedBy(e);
// We deliberately do not return connPtr to the pool, since it was involved
// with the error here.
return false;
}
connPtr->done();
}
CollectionType collDoc;
if (!collDoc.parseBSON(collObj, errMsg) || !collDoc.isValid(errMsg)) {
return false;
}
//
// Load or generate default chunks for collection config.
//
if (!collDoc.getKeyPattern().isEmpty()) {
manager->_key = collDoc.getKeyPattern();
if(!initChunks(collDoc, ns, shard, oldManager, manager, errMsg)){
return false;
}
}
else if(collDoc.getPrimary() == shard) {
if (shard == "") {
warning() << "shard not verified, assuming collection "
<< ns << " is unsharded on this shard" << endl;
}
manager->_key = BSONObj();
manager->_maxShardVersion = ChunkVersion(1, 0, collDoc.getEpoch());
manager->_maxCollVersion = manager->_maxShardVersion;
}
else {
*errMsg = str::stream() << "collection " << ns << " does not have a shard key "
<< "and primary " << collDoc.getPrimary()
<< " does not match this shard " << shard;
return false;
}
return true;
}
bool MetadataLoader::initChunks(const CollectionType& collDoc,
const string& ns,
const string& shard,
const CollectionManager* oldManager,
CollectionManager* manager,
string* errMsg) {
map<string,ChunkVersion> versionMap;
manager->_maxCollVersion = ChunkVersion(0, 0, collDoc.getEpoch());
// Check to see if we should use the old version or not.
if (oldManager) {
ChunkVersion oldVersion = oldManager->getMaxShardVersion();
if (oldVersion.isSet() && oldVersion.hasCompatibleEpoch(collDoc.getEpoch())) {
// Our epoch for coll version and shard version should be the same.
verify(oldManager->getMaxCollVersion().hasCompatibleEpoch(collDoc.getEpoch()));
versionMap[shard] = oldManager->_maxShardVersion;
manager->_maxCollVersion = oldManager->_maxCollVersion;
// TODO: This could be made more efficient if copying not required, but
// not as frequently reloaded as in mongos.
manager->_chunksMap = oldManager->_chunksMap;
LOG(2) << "loading new chunks for collection " << ns
<< " using old chunk manager w/ version "
<< oldManager->getMaxShardVersion()
<< " and " << manager->_chunksMap.size() << " chunks" << endl;
}
}
// Exposes the new 'manager's range map and version to the "differ," who
// would ultimately be responsible of filling them up.
SCMConfigDiffTracker differ(shard);
differ.attach(ns, manager->_chunksMap, manager->_maxCollVersion, versionMap);
try {
scoped_ptr<ScopedDbConnection> connPtr(
ScopedDbConnection::getInternalScopedDbConnection(_configLoc.toString(), 30));
ScopedDbConnection& conn = *connPtr;
auto_ptr<DBClientCursor> cursor = conn->query(ChunkType::ConfigNS,
differ.configDiffQuery());
if (!cursor.get()) {
// 'errMsg' was filled by the getChunkCursor() call.
manager->_maxCollVersion = ChunkVersion();
manager->_chunksMap.clear();
connPtr->done();
return false;
}
// Diff tracker should *always* find at least one chunk if collection exists.
int diffsApplied = differ.calculateConfigDiff(*cursor);
if (diffsApplied > 0) {
LOG(2) << "loaded " << diffsApplied
<< " chunks into new chunk manager for " << ns
<< " with version " << manager->_maxCollVersion << endl;
manager->_maxShardVersion = versionMap[shard];
manager->fillRanges();
connPtr->done();
return true;
}
else if(diffsApplied == 0) {
*errMsg = str::stream() << "no chunks found when reloading " << ns
<< ", previous version was "
<< manager->_maxCollVersion.toString();
warning() << *errMsg << endl;
manager->_maxCollVersion = ChunkVersion();
manager->_chunksMap.clear();
connPtr->done();
return false;
}
else{
// TODO: make this impossible by making sure we don't migrate / split on this
// shard during the reload. No chunks were found for the ns.
*errMsg = str::stream() << "invalid chunks found when reloading " << ns
<< ", previous version was "
<< manager->_maxCollVersion.toString()
<< ", this should be rare";
warning() << errMsg << endl;
manager->_maxCollVersion = ChunkVersion();
manager->_chunksMap.clear();
connPtr->done();
return false;
}
}
catch (const DBException& e) {
*errMsg = str::stream() << "caught exception accessing the config servers"
<< causedBy(e);
// We deliberately do not return connPtr to the pool, since it was involved
// with the error here.
return false;
}
}
Status MetadataLoader::initCollection( const string& ns,
const string& shard,
CollectionMetadata* metadata ) const
{
//
// Bring collection entry from the config server.
//
BSONObj collDoc;
{
try {
ScopedDbConnection conn( _configLoc.toString(), 30 );
collDoc = conn->findOne( CollectionType::ConfigNS, QUERY(CollectionType::ns()<<ns));
conn.done();
}
catch ( const DBException& e ) {
string errMsg = str::stream() << "could not query collection metadata"
<< causedBy( e );
// We deliberately do not return conn to the pool, since it was involved
// with the error here.
return Status( ErrorCodes::HostUnreachable, errMsg );
}
}
string errMsg;
if ( collDoc.isEmpty() ) {
errMsg = str::stream() << "could not load metadata, collection " << ns << " not found";
warning() << errMsg << endl;
return Status( ErrorCodes::NamespaceNotFound, errMsg );
}
CollectionType collInfo;
if ( !collInfo.parseBSON( collDoc, &errMsg ) || !collInfo.isValid( &errMsg ) ) {
errMsg = str::stream() << "could not parse metadata for collection " << ns
<< causedBy( errMsg );
warning() << errMsg << endl;
return Status( ErrorCodes::FailedToParse, errMsg );
}
if ( collInfo.isDroppedSet() && collInfo.getDropped() ) {
errMsg = str::stream() << "could not load metadata, collection " << ns
<< " was dropped";
warning() << errMsg << endl;
return Status( ErrorCodes::NamespaceNotFound, errMsg );
}
if ( collInfo.isKeyPatternSet() && !collInfo.getKeyPattern().isEmpty() ) {
// Sharded collection, need to load chunks
metadata->_keyPattern = collInfo.getKeyPattern();
metadata->_shardVersion = ChunkVersion( 0, 0, collInfo.getEpoch() );
metadata->_collVersion = ChunkVersion( 0, 0, collInfo.getEpoch() );
return Status::OK();
}
else if ( collInfo.isPrimarySet() && collInfo.getPrimary() == shard ) {
// A collection with a non-default primary
// Empty primary field not allowed if set
dassert( collInfo.getPrimary() != "" );
metadata->_keyPattern = BSONObj();
metadata->_shardVersion = ChunkVersion( 1, 0, collInfo.getEpoch() );
metadata->_collVersion = metadata->_shardVersion;
return Status::OK();
}
else {
// A collection with a primary that doesn't match this shard or is empty, the primary
// may have changed before we loaded.
errMsg = // br
str::stream() << "collection " << ns << " does not have a shard key "
<< "and primary "
<< ( collInfo.isPrimarySet() ? collInfo.getPrimary() : "" )
<< " does not match this shard " << shard;
warning() << errMsg << endl;
metadata->_collVersion = ChunkVersion( 0, 0, OID() );
return Status( ErrorCodes::RemoteChangeDetected, errMsg );
}
}
