Created question in FIWARE Q/A platform on 14-01-2017 at 22:01
Please, ANSWER this question AT http://stackoverflow.com/questions/41655134/fiware-cygnus-always-wants-to-create-a-new-mongodb-collection-when-it-receives-a

Question:
Fiware Cygnus always wants to create a new MongoDB collection when it receives a notification

Description:
I want to save historical data into MongoDB using Fiware Cygnus. But whenever Cygnus receives a notification it wants to create a new collection instead of adding a document if the collection already exists. I get this error message from Cygnus:

time=2017-01-14T20:58:11.785Z | lvl=WARN | corr=28eca6a8-da9c-11e6-841b-0242ac120009 | trans=9fa2d345-9aa1-4ff6-84df-75de5829a449 | srv=itg | subsrv=/building1 | comp=cygnus-ngsi | op=processNewBatches | msg=com.telefonica.iot.cygnus.sinks.NGSISink[590] : Command failed with error 48: 'a collection 'sth_itg.sth_/building1_TemperatureRoom1_room' already exists' on server iot-mongo:27017. The full response is

This is my agent.conf file:

cygnus-ngsi.sources = http-source
cygnus-ngsi.sinks = mongo-sink
cygnus-ngsi.channels = mongo-channel

cygnus-ngsi.sources.http-source.type = org.apache.flume.source.http.HTTPSource
cygnus-ngsi.sources.http-source.channels = mongo-channel
cygnus-ngsi.sources.http-source.port = 5050
cygnus-ngsi.sources.http-source.handler = com.telefonica.iot.cygnus.handlers.NGSIRestHandler
cygnus-ngsi.sources.http-source.handler.notification_target = /notify
cygnus-ngsi.sources.http-source.handler.default_service = default
cygnus-ngsi.sources.http-source.handler.default_service_path = /
cygnus-ngsi.sources.http-source.interceptors = ts gi
cygnus-ngsi.sources.http-source.interceptors.ts.type = timestamp
cygnus-ngsi.sources.http-source.interceptors.gi.type = com.telefonica.iot.cygnus.interceptors.NGSIGroupingInterceptor$Builder
cygnus-ngsi.sources.http-source.interceptors.gi.grouping_rules_conf_file = /opt/apache-flume/conf/grouping_rules.conf

cygnus-ngsi.sinks.mongo-sink.type = com.telefonica.iot.cygnus.sinks.NGSIMongoSink
cygnus-ngsi.sinks.mongo-sink.channel = mongo-channel
#cygnus-ngsi.sinks.mongo-sink.enable_encoding = false
#cygnus-ngsi.sinks.mongo-sink.enable_grouping = false
#cygnus-ngsi.sinks.mongo-sink.enable_name_mappings = false
#cygnus-ngsi.sinks.mongo-sink.enable_lowercase = false
#cygnus-ngsi.sinks.mongo-sink.data_model = dm-by-entity
#cygnus-ngsi.sinks.mongo-sink.attr_persistence = row
cygnus-ngsi.sinks.mongo-sink.mongo_hosts = iot-mongo:27017
cygnus-ngsi.sinks.mongo-sink.mongo_username =
cygnus-ngsi.sinks.mongo-sink.mongo_password =
#cygnus-ngsi.sinks.mongo-sink.db_prefix = sth_
#cygnus-ngsi.sinks.mongo-sink.collection_prefix = sth_
#cygnus-ngsi.sinks.mongo-sink.batch_size = 1
#cygnus-ngsi.sinks.mongo-sink.batch_timeout = 30
#cygnus-ngsi.sinks.mongo-sink.batch_ttl = 10
#cygnus-ngsi.sinks.mongo-sink.data_expiration = 0
#cygnus-ngsi.sinks.mongo-sink.collections_size = 0
#cygnus-ngsi.sinks.mongo-sink.max_documents = 0
#cygnus-ngsi.sinks.mongo-sink.ignore_white_spaces = true

cygnus-ngsi.channels.mongo-channel.type = com.telefonica.iot.cygnus.channels.CygnusMemoryChannel
cygnus-ngsi.channels.mongo-channel.capacity = 1000
cygnus-ngsi.channels.mongo-channel.transactionCapacity = 100

Am I doing something wrong? Can someone help with this?

Thank you in advance.