Upgrading to 1.5.0 and beyond from a pre-1.5.0 version

This procedure has to be done only if your DB contains attributes with ID metadata.

Stop contextBroker
Remove previous contextBroker version
```
yum remove contextBroker
```
Take a backup of your DBs (this is just a safety measure in case any problem occurs, e.g some script gets interrupted before finished and your database data ends in an incoherent state)
Download the following script:
- change_attr_id_separator.py
Install pymongo (it is a script dependency) in case you don't have it previously installed
```
pip-python install pymongo
```
Apply the change_attr_id_separator.py script to your DBs, using the following command (where 'db' is the database name). Note that if you are using multitenant/multiservice you need to apply the procedure to each per-tenant/service database. The script can take a while, so an interactive progress counter is shown.
```
python change_attr_id_separator.py orion
```
If you get any of the following messages, there is some problem that needs to be solved before going to the next step. Check the "Troubleshooting mdsvector2mdsobject" section below.
```
WARNING: some problem was found during the process.
ERROR: document ... change attempt failed
```
Install new contextBroker version (Sometimes the commands fails due to yum cache. In that case, run "yum clean all" and try again)
```
yum install contextBroker
```
Start contextBroker

Note that the rpm command demands superuser privileges, so you have to run it as root or using the sudo command.

Troubleshooting

Three different kinds of problems may happen:

You get the following error message:

OperationFailed: Sort operation used more than the maximum 33554432 bytes of RAM. Add an index, or specify a smaller limit.

Try to create a suitable index with the following command in the mongo shell, then run the script again.

db.entities.createIndex({"_id.id": 1, "_id.type": -1, "_id.servicePath": 1})

Once migration has ended, you can remove the index with the following command:

db.entities.dropIndex({"_id.id": 1, "_id.type": -1, "_id.servicePath": 1})

Due to some unexpected problem during DB updating. The symptom of this problem is getting errors like this one:
```
- <n>: ERROR: document <...> change attempt failed!
```
There is no a general solution for this problem, it has to be analyzed case by case. If this happens to you, please have a look at the existing questions in StackOverflow about fiware-orion in order to check whether your problem is solved there. Otherwise create your own question (don't forget to include the "fiware-orion" tag and the exact error message in your case).