[#125] Ensuring objects are deleted properly

[angeloprobst]

test.metta.gz

Steps to run:

1. Start Redis (port 29000) and Mongo (port 28000) and load them with the attached test.metta.gz file (use das-cli for that).
2. Ensure the following vars are set on your local env:

DAS_MONGODB_HOSTNAME=localhost
DAS_MONGODB_PASSWORD=dassecret
DAS_MONGODB_PORT=28000
DAS_MONGODB_USERNAME=dbadmin
DAS_REDIS_HOSTNAME=localhost
DAS_REDIS_PORT=29000

3. From the repo root, build all: make build-all
4. From the repo root, run AB: make run-attention-broker
5. In a separate terminal, from the repo root, run Query Agent: make run-query-agent
6. In a separate terminal, from the repo root, run the following query:

bash -x src/scripts/run.sh query \
  "localhost:31701" \
  "localhost:31700" \
  AND 2 \
    LINK_TEMPLATE Expression 3 \
      NODE Symbol Contains \
      VARIABLE sentence1 \
      LINK Expression 2 \
        NODE Symbol Word \
        NODE Symbol '"bbb"' \
    LINK_TEMPLATE Expression 3 \
      NODE Symbol Contains \
      VARIABLE sentence2 \
      LINK Expression 2 \
        NODE Symbol Word \
        NODE Symbol '"aaa"'

7. Check the amount of memory allocated by the Query Agent:

ps faux | grep 'query_broker 31700' | grep -Ev '(docker|grep|bash)'

Expected output (in this example, QA allocated ~311MB):

8. Execute the steps 6 and 7 multiple times to check if the memory grows continuously.

[angeloprobst]

This could be removed because the base class destructor is already doing the same.

[angeloprobst]

This could be removed because the base class destructor is already doing the same.