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In Memory DataBase

1. In Memory DataBase​

Technology​

The technology chosen for the in memory database is Redis, an in memory data structure store.

Functionality​

The Human_Detection_Module class instatiates a dictionary called "database" and this dictionary is sent as a parameter to the Human_Detection_Worker class when called. This dictionary will contain all the ordered frames sent from the camera. In the Human_Detection_Worker class the Redis database is instantiated on port 6379, self.redisDB = redis.Redis(host= 'localhost', port= '6379'). We flush database in case its carrying data from an old run using self.redisDB.flushdb().

On the create_database_entry funtion we get the updateded stored dictionary form the in memory databse, self.database = self.redisDB.hgetall("redisDB") decode it and equal it to the current dictionary. we than use this dictionary to add new values and after that it is stored back in the in memory database as a hashmap, using Redis's hmset funtion. 


        self.database = {key.decode('utf-8'):value.decode('utf-8') for key,value in self.database.items()}
        self.database[num_humans_key] = num_humans
        self.database[timestamp_key] = ts
        # Save the updated dictionary into Redis In-Memory Database
        self.redisDB.hmset("redisDB",self.database)

Lastly the in memory database is applied to the alarm_if_needed function, this is done by getting the stored dictionary from the in memory database (hgetall function) and decoding it (The result is a normal dictionary). The alarm_if_needed function then analises the frames in the dictionary.