Server never responds when the queries are sent from client libraries

[suzaku]

Summary

Description for this bug.

How to reproduce

Use client libraries of Go/Python to connect Databend as clickhouse or mysql.

We can use pymysql as an example here, but I have observed similar situation when using the Go standard library.

import pymysql
conn = pymysql.Connection(host='localhost', user='root', port=3307)
c = conn.cursor()
c.execute("SELECT avg(number) FROM numbers(1000000);")

Error message and/or stacktrace

[2021-11-28T06:45:49Z INFO  databend_query::servers::mysql::mysql_handler] MySQL connection coming: Ok(172.17.0.1:64158)
[2021-11-28T06:46:04Z DEBUG databend_query::servers::mysql::mysql_interactive_worker] SELECT avg(number) FROM numbers(1000000);

The logs show that Databend has received the query, but it just stops there and seems to be waiting for some kind of event to happen.

If I use the Go standard library which retries every minute I'll observe the following logs:

[2021-11-28T06:34:55Z DEBUG common_clickhouse_srv] Handle New session
[2021-11-28T06:34:55Z DEBUG databend_query::servers::clickhouse::interactive_worker_base] SELECT VERSION()

[2021-11-28T06:35:55Z INFO  databend_query::servers::clickhouse::clickhouse_handler] ClickHouse connection coming: Ok(172.17.0.1:55228)
[2021-11-28T06:35:55Z DEBUG common_clickhouse_srv] Handle New session
[2021-11-28T06:35:55Z DEBUG databend_query::servers::clickhouse::interactive_worker_base] SELECT VERSION()



[2021-11-28T06:36:55Z INFO  databend_query::servers::clickhouse::clickhouse_handler] ClickHouse connection coming: Ok(172.17.0.1:55232)
[2021-11-28T06:36:55Z DEBUG common_clickhouse_srv] Handle New session
[2021-11-28T06:36:55Z DEBUG databend_query::servers::clickhouse::interactive_worker_base] SELECT VERSION()

[ZhiHanZ]

Hi @suzaku , not sure about your databend version for testing third party clients.
I have tested it manually on my local machine， and pymysql snippet works
Init a single node cluster

make cluster
# check on cluster healthiness
make cluster_view

Run python3 client query

Client library integration test is very important, which has not been finished yet and there are several issues related to it.
#1766
#1773

feel free to take those part if you are interested :)

[suzaku]

The Databend server I connected was started with docker run --init --rm -p 9001:9001 -p 9191:9191 -p 3307:3307 datafuselabs/databend.

[suzaku]

I would love to help, but it takes too long to compile a Rust project on my laptop and it starts to feel like a waste of time 🤣

[sundy-li]

It's true that the first time to build a large rust project takes a long time. But it'll be faster for increment building.
On my MacBook pro-2021, it needs 1-2 minutes to make debug from zero caches.

Thanks for the report, I'll try to reproduce it from your steps.

[sundy-li]

docker run --init --rm -p 9001:9001 -p 9191:9191 -p 3307:3307 datafuselabs/databend

logs:

[2021-11-28T13:12:46Z INFO  databend_query] DatabendQuery v-0.1.0-9533dd1-simd(1.57.0-nightly-2021-10-26T01:51:09.305927968+00:00)

Seems the docker image is out of date, is this because we forgot to change the branch from master to main in databend-docker.yml? @ZhiHanZ

[ZhiHanZ]

please update the docker repo, which should be updated

docker run --init --rm -p 9001:9001 -p 9191:9191 -p 3307:3307 datafuselabs/databend

logs:

[2021-11-28T13:12:46Z INFO  databend_query] DatabendQuery v-0.1.0-9533dd1-simd(1.57.0-nightly-2021-10-26T01:51:09.305927968+00:00)

Seems the docker image is out of date, is this because we forgot to change the branch from master to main in databend-docker.yml? @ZhiHanZ

please update latest docker repo, which should get updated

[suzaku]

Thanks. I'll try later. I guess in most cases, I don't really have to do extra setup to integrate Databend, right? I can just use it like a clickhouse server.

[ZhiHanZ]

Thanks. I'll try later. I guess in most cases, I don't really have to do extra setup to integrate Databend, right? I can just use it like a clickhouse server.

we maintain mysql and clickhouse protocol by default, feel free to open any issues on compatibility part.

[suzaku]

Good to know that, thanks.