The warn is a hint you’ve got tombstones, maybe not a big deal, but a hint at
your data model. It’s not causing this
The log at INFO is Cassandra connection to your app getting severed, Cassandra
is saying the reset is on the other side (app side, maybe firewall or something
in the middle too).
Update: Still getting the NoHostAvailable periodically in client logs.
Also seeing these INFO and WARN messages in
/var/log/cassandra/system.log
INFO [epollEventLoopGroup-2-5] 2018-01-06 01:39:02,412
Message.java:623 - Unexpected exception during request; channel = [id:
0xae99b597, L:/10.1.2.3:
Still getting the NoHostAvailable with more hosts, just occurring less
frequently. Created a JIRA issue on the Python cassandra-driver tracker:
https://datastax-oss.atlassian.net/browse/PYTHON-891
On Mon, Jan 1, 2018 at 8:43 PM, Alan Hamlett wrote:
> Adding more nodes to the cluster fixed the er
Adding more nodes to the cluster fixed the error. Looks like a bug in
python-driver connection pool:
1. The connection pool only has one host
2. A query times out, causing that connection to be removed from the pool
3. Another query executes, but there are no hosts in the pool
On Mon, Jan 1, 2018
Well the python driver you reference is a third party driver, because the
project doesn’t ship official drivers. You may have better luck looking for a
datastax driver support forum, or wait until after the holiday for more people
to be checking email.
--
Jeff Jirsa
> On Jan 1, 2018, at 12:
Still getting the cassandra.cluster.NoHostAvailable error periodically from
uWSGI hosts. Setting up the connection with postfork:
https://github.com/alanhamlett/flask-cqlalchemy/blob/653ed3298af7dd617a972e9f87437f6e53f741b9/flask_cqlalchemy/__init__.py#L56
Lazy connection is False, Retry connectio
Thanks for the reply, I think it's related. However, after using a fork of
Flask-CQLAlchemy with postfork I'm still getting the NoHostAvailable error
once per 4k requests. One strange thing is the error rate doesn't increase
with the number of requests, since some uWSGI clients with ~20k requests
o
uWSGI forks and the driver / cqlalchemy may need to reconnect or otherwise fix
the state after each fork - you could try to prove this is the cause by
checking uWSGI logs or ps for indication that a worker process has exited/been
recycled. If you think it may be related to this, check out @postf
More info: The NoHostAvailable error is happening at random times on each
client host, so it's probably a client error. If the Cassandra cluster was
really offline then all client hosts would report the error at the same
time instead of different random times. The NoHostAvailable error occurs
about
I'm seeing tracebacks in my Python Flask app when creating rows:
Traceback (most recent call last):
File "/opt/app/current/app/api.py", line 1174, in consume_heartbeat
Heartbeat.create(**form_data)
File
"/opt/app/current/venv/lib/python3.4/site-packages/cassandra/cqlengine/models.py",
lin
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