Checklist

• I have read the relevant section in the
  contribution guide
  on reporting bugs.
• I have checked the issues list
  for similar or identical bug reports.
• I have checked the pull requests list
  for existing proposed fixes.
• I have checked the commit log
  to find out if the bug was already fixed in the master branch.
• I have included all related issues and possible duplicate issues
  in this issue (If there are none, check this box anyway).

Mandatory Debugging Information

• I have included the output of celery -A proj report in the issue.
  (if you are not able to do this, then at least specify the Celery
  version affected).
• I have verified that the issue exists against the master branch of Celery.
• I have included the contents of pip freeze in the issue.
• I have included all the versions of all the external dependencies required
  to reproduce this bug.

Optional Debugging Information

• I have tried reproducing the issue on more than one Python version
  and/or implementation.
• I have tried reproducing the issue on more than one message broker and/or
  result backend.
• I have tried reproducing the issue on more than one version of the message
  broker and/or result backend.
• I have tried reproducing the issue on more than one operating system.
• I have tried reproducing the issue on more than one workers pool.
• I have tried reproducing the issue with autoscaling, retries,
  ETA/Countdown & rate limits disabled.
• I have tried reproducing the issue after downgrading
  and/or upgrading Celery and its dependencies.

Related Issues and Possible Duplicates

Related Issues

• None

Possible Duplicates

• None

Environment & Settings

Celery version:

celery -A celeryacl report

software -> celery:4.3.0 (rhubarb) kombu:4.5.0 py:3.6.8
billiard:3.6.0.0 py-amqp:2.4.2
platform -> system:Linux arch:64bit
kernel version:4.18.0-1013-azure imp:CPython
loader -> celery.loaders.app.AppLoader
settings -> transport:amqp results:db+mysql+pymysql://celery:**@X.X.X.X:XXXX/celeryresults

Steps to Reproduce

Required Dependencies

• Minimal Python Version: N/A or Unknown
• Minimal Celery Version: N/A or Unknown
• Minimal Kombu Version: N/A or Unknown
• Minimal Broker Version: N/A or Unknown
• Minimal Result Backend Version: N/A or Unknown
• Minimal OS and/or Kernel Version: N/A or Unknown
• Minimal Broker Client Version: N/A or Unknown
• Minimal Result Backend Client Version: N/A or Unknown

Python Packages

pip freeze
amqp==2.4.2
asn1crypto==0.24.0
bcrypt==3.1.6
billiard==3.6.0.0
celery==4.3.0
cffi==1.12.2
Click==7.0
cryptography==2.6.1
Flask==1.0.2
Flask-Cors==3.0.7
itsdangerous==1.1.0
Jinja2==2.10
kombu==4.5.0
MarkupSafe==1.1.1
mysql-connector-python==8.0.15
netmiko==2.3.3
paramiko==2.4.2
protobuf==3.7.1
pyasn1==0.4.5
pycparser==2.19
PyMySQL==0.9.3
PyNaCl==1.3.0
pyserial==3.4
pytz==2018.9
PyYAML==5.1
scp==0.13.2
six==1.12.0
SQLAlchemy==1.2.14
textfsm==0.4.1
vine==1.3.0
Werkzeug==0.15.2

Other Dependencies

Minimally Reproducible Test Case

Expected Behavior

With the following configured "result_extended" to true I expected to see more meta data in the backend results DB but I don't. I just see the standard results.

app = Celery('tasks',
backend='db+mysql+pymysql://XXX:XXX@X.X.X.X:XXXX/celeryresults',
broker='amqp://xxxx:xxxx@X.X.X.X/celery',
result_extended=True)

Actual Behavior