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 );
}
}
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 );
}
}