possible custom Session ID with each query about clickhouse HOT 8 CLOSED

You need parallel query with own session? Or you need pass some specific session_id in each query?

from clickhouse.

You need parallel query with own session --- This is not possible by the design of ClickHouse. If it is I would love to know.

you need pass some specific session_id in each query? -- YES! Exactly!

from clickhouse.

added a PR #52 for the same as well. Please let me know if I am doing something fundamentally wrong here.

from clickhouse.

Just checked the test are added by you at line 300, thanks for looking into the issue however this is not what I meant, as we all know in JS most of the variables are referred apart from numbers and some other.. so the issue is that the same ClickHouse connection is used across multiple routes and connections and requests that are served by the http server at node as well! Now due to same session name the queries will get locked!

But I am sure this was taken care and random sessions are created, however this defeats the purpose of creating a temporary table and serving user the data from this temporary table to prevent further querying the main table over which we won't like to put stress on!

Use Case
I have a complex query that consumes a lot of time, and I simply create a session for one of my user and provide a session id such as sess_${userId} now when this user queries I would use this session_id to access the temporary table I built for this specific user in the specific session.

This can enable people using this driver to create destroy and persist session as per the requirement.

(PS: I upgraded from 19.6 to 20.3 as I got to know about fixed session locking issues, but they still persist, concurrent HTTP calls lock session. I am shifting my code base to build actual memory engine tables and then destroying them over the time by analysing system.tables, hope our discussion helps someone else.)

from clickhouse.

Do you mean interface like this:

// init
const clickhouse = new ClickHouse(...);

// route
const userCH = clickhouse.getSession();
const rows = await userCH.quiery...
const rows2 = await userCH.query...
?

from clickhouse.

Possibly yes, that's another way to put it, in short isolating one request and session name. However, if User A sends me a request, I would like to create a session as session_user_a and for User B I would create sess_user_b and ensure they don't lock each other out at any point in time.

from clickhouse.

I published version with your MR

from clickhouse.

Thanks a ton!

from clickhouse.