Block sync failure on a custom blockchain

[h4x3rotab]

We are trying to deploy a polkascan open source version. However we encountered some problems after connected to our node.

Traceback (most recent call last):
  File "/usr/src/app/app/tasks.py", line 115, in accumulate_block_recursive
    block = harvester.add_block(block_hash)
  File "/usr/src/app/app/processors/converters.py", line 469, in add_block
    self.process_metadata(parent_spec_version, parent_hash)
  File "/usr/src/app/app/processors/converters.py", line 210, in process_metadata
    runtime = Runtime.query(self.db_session).get(spec_version)
  File "/usr/local/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 959, in get
    return self._get_impl(ident, loading.load_on_pk_identity)
  File "/usr/local/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 1069, in _get_impl
    return db_load_fn(self, primary_key_identity)
  File "/usr/local/lib/python3.6/site-packages/sqlalchemy/orm/loading.py", line 282, in load_on_pk_identity
    return q.one()
  File "/usr/local/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3292, in one
    ret = self.one_or_none()
  File "/usr/local/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3261, in one_or_none
    ret = list(self)
  File "/usr/local/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3334, in __iter__
    return self._execute_and_instances(context)
  File "/usr/local/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3356, in _execute_and_instances
    querycontext, self._connection_from_session, close_with_result=True
  File "/usr/local/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3371, in _get_bind_args
    mapper=self._bind_mapper(), clause=querycontext.statement, **kw
  File "/usr/local/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3349, in _connection_from_session
    conn = self.session.connection(**kw)
  File "/usr/local/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 1124, in connection
    execution_options=execution_options,
  File "/usr/local/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 1130, in _connection_for_bind
    engine, execution_options
  File "/usr/local/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 408, in _connection_for_bind
    self._assert_active()
  File "/usr/local/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 299, in _assert_active
    "This session is in 'inactive' state, due to the "
sqlalchemy.exc.InvalidRequestError: This session is in 'inactive' state, due to the SQL transaction being rolled back; no further SQL can be emitted within this transaction.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/celery/app/trace.py", line 375, in trace_task
    R = retval = fun(*args, **kwargs)
  File "/usr/src/app/app/tasks.py", line 70, in __call__
    return super().__call__(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/celery/app/trace.py", line 632, in __protected_call__
    return self.run(*args, **kwargs)
  File "/usr/src/app/app/tasks.py", line 142, in accumulate_block_recursive
    raise HarvesterCouldNotAddBlock(block_hash) from exc
app.processors.converters.HarvesterCouldNotAddBlock: 0xbf62f20192a6d35c59a846d10831ee06275fdcccb179b279832405a804fa5500

If we check the flower console, not every app.tasks.accumulate_block_recursive task fail.

It looks like related to type_registry. We found types for Kusama, Polkadot, and a substrate-node-template. However we are based on substrate/bin/node, not that similar to any of the above types. We didn't find a docs to generate the type definition.

So far we have tried:

• Sync to kusama: works
• Sync to our blockchain with kusama config: shows above error
• Sync to our blockchain with node-template config: shows above error

[h4x3rotab]

Turned out it's due to a field too short. A change to the table schema is needed. After a quick change, the job is still broken though.

[arjanz]

We just pushed on update and probably fix the issues your experiencing, after an update described in https://github.com/polkascan/polkascan-os/blob/master/README.md you can also try the following:

1. Check status of processed blocks at http://127.0.0.1:8080/node-template/harvester/admin If for some reason the harvester gets stuck you can try to give it a 'nudge' by pressing the 'Process' button.

2. Check http://127.0.0.1:8080/node-template/runtime-type if all types are supported. If not, add the custom types to: harvester/app/type_registry/substrate-node-template.json

[arjanz]

I updated the README with some basic troubleshooting: https://github.com/polkascan/polkascan-os#add-custom-types-for-substrate-node-template

[jasl]

Hi I've figured out the root cause.

the root casue is default = sa.Column(sa.String(255)) overflow in our chain (276 length, but varchar max is 255).

Will you accept PR to change this field to TEXT? our chain base on Flaming fir which is an another reference implementation in substrate repo