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MAUSDocumentCacheConfiguration » History » Revision 2

Revision 1 (Jackson, Mike, 01 December 2011 15:03) → Revision 2/15 (Jackson, Mike, 01 December 2011 15:21)

h1. Document Cache Configuration 

 MAUS can use a database to cache JSON documents until they are ready for processing. An example of this is caching the outputs from transforms (maps) until ready for merging (reduce). Two databases are currently supported - CouchDB and MongoDB. 

 h2. CouchDB 

 CouchDB (http://couchdb.apache.org/) is a document-oriented database. Each MongoDB server holds 0 or more databases. Each database holds a collection of 0 or more documents. CouchDB is schema free web site - the documents can be all of the same structure or of different structures. http://couchdb.apache.org/ 

 h3. Installing CouchDB 

 CouchDB can be installed using @yum@ as follows. 

  * Log in as root 
  * Run  
 <pre> 
 $ yum install couchdb 
  ... 
  couchdb            i386            1.0.1-2.el5.rf            rpmforge            749 k 
  ... 
 </pre> 
  * Start the server 
 <pre> 
 $ service couchdb start 
 Starting database server couchdb 
 $ service couchdb status 
 Apache CouchDB is running as process 6723, time to relax. 
 </pre> 
 (as an alternative to @service couchdb@ you can use @/etc/init.d/couchdb@) 

 By default CouchDB is available on http://localhost:5984/. 

 h3. CouchDB and Python 

 MAUS uses couchdb-python - http://code.google.com/p/couchdb-python/. This is installed when you build MAUS. 

 h3. CouchDB and MAUS 

 To use CouchDB with MAUS you need to provide the following configuration parameters: 

  * Document store class e src/common_py/ConfigurationDefaults.py 
 mongodb_host = "localhost" # Default MongoDB host name. This mandatory parameter specifies a Python module that will handle interaction with CouchDB. The parameter and value needs to be: Only needed if using Mon 
 <pre> goDBDocumentStore. 
 doc_store_class="CouchDBDocumentStore.CouchDBDocumentStore" mongodb_port = 27017 # Default MongoDB port. Only needed if using MongoDBDocumen 
 </pre> 
  * CouchDB URL. This optional parameter specifies the CouchDB URL. If omitted then the default of @localhost:5984@ is used. To override this value do: tStore. 
 <pre> 
 couchdb_url="http://maus.org.uk:5984" 
 </pre> 
  * CouchDB mongodb_database_name = "mausdb" # Default MongoDB database name. This optional parameter specifies the database within CouchDB to use. If omotted then the default of @mausdb@ is used. To override this value do: Only needed if 
  using MongoDBDocumentStore. 
 <pre> mongodb_collection_name = "spills" # Default MongoDB collection name. Only neede 
 couchdb_database_name="someotherdbname"  
 </pre> 
  ** Note that d if the database is not present in CouchDB it will be created automatically. 

 Here is an example of running the simple histogram example using CouchDB as the document cache: 
 <pre> 
 $ ./bin/examples/simple_histogram_example.py -type_of_dataflow=multi_process \ 
 -doc_store_class="CouchDBDocumentStore.CouchDBDocumentStore" 
 </pre> 

 MongoDBDocumentStore. 


 h2. MongoDB 

 MongoDB (http://www.mongodb.org/) is a document-oriented database. Each MongoDB server holds 0 or more databases. Each database holds 1 or more collections and each collection 0 or more documents. MongoDB is schema free web site - the documents can be all of the same structure or of different structures. http://www.mongodb.org/ 

 h3. Installing MongoDB  

 MongoDB can be installed using @yum@ as follows. 

  * Log in as root 
  * Edit @/etc/yum.repos.d/10gen.repo@ and add the lines 
 <pre> 
 [10gen] 
 name=10gen Repository 
 baseurl=http://downloads-distro.mongodb.org/repo/redhat/os/i686 
 gpgcheck=0 
 </pre> 
  * Run  
 <pre> 
 $ yum install mongo-10gen 
  ... 
  mongo-10gen           i686           2.0.1-mongodb_1             10gen            28 M 
  ... 
 $ yum install mongo-10gen-server 
  ... 
  mongo-10gen-server         i686         2.0.1-mongodb_1            10gen         5.4 M 
 ... 
 </pre> 
  * Start the server 
 <pre> 
 $ service mongod start 
 Starting mongod: forked process: 4357 
                                                            [    OK    ] 
 all output going to: /var/log/mongo/mongod.log 
 $ service mongod status 
 mongod (pid 4357) is running... 
 </pre> 
 (as an alternative to @service mongod@ you can use @/etc/init.d/mongod@) 

 By default MongoDB is available on http://localhost:27017/. 

 h3. MongoDB and Python 

 MAUS uses pymongo - http://api.mongodb.org/python/current/. This is installed when you build MAUS. 

 h3. MongoDB and MAUS 

 To use MongoDB with MAUS you need to provide the following configuration parameters: 

  * Document store class name. This mandatory parameter specifies a Python module that will handle interaction with MongoDB. The parameter and value needs to be: 
 <pre> 
 doc_store_class="MongoDBDocumentStore.MongoDBDocumentStore" 
 </pre> 
  * MongoDB host. This optional parameter specifies the MongoDB host. If omitted then the default of @localhost@ is used. To override this value do: 
 <pre> 
 mongodb_host="maus.org.uk" 
 </pre> 
  * MongoDB port. This optional parameter specifies the MongoDB port. If omitted then the default of @27017@ is used. To override this value do: 
 <pre> 
 mongodb_port=12345 
 </pre> 
  * MongoDB database name. This optional parameter specifies the database within MongoDB to use. If omotted then the default of @mausdb@ is used. To override this value do: 
 <pre> 
 mongodb_database_name="someotherdbname"  
 </pre> 
  ** Note that if the database is not present in MongoDB it will be created automatically. 
  * MongoDB collection name. This optional parameter specifies the collection within the MongoDB database to use. If omotted then the default of @spills@ is used. To override this value do: 
 <pre> 
 mongodb_collection_name="someothercollectionname"  
 </pre> 
  ** Note that if the database is not present in MongoDB it will be created automatically. 

 Here is an example of running the simple histogram example using MongoDB as the document cache: 
 <pre> 
 $ ./bin/examples/simple_histogram_example.py -type_of_dataflow=multi_process \ 
 -doc_store_class="MongoDBDocumentStore.MongoDBDocumentStore" 
 </pre>