ClickHouse, Graphite and Practical Limits for IN (list) clauses

[ste...@activitystream.com]

Hi,

Are there any limits on how many items can be used in a IN (list...) ?

We are using the JDBC driver and, since it's backed by HTTP, I wonder if there are any GET/POST limitations that are not handled automatically (For long queries for example)

Best regards,

 -Stefán

[Alex Zatelepin]

Hi, Stefán!

Yes, there is a hard limit on HTTP URL length which is 16KB. As far as I can tell, JDBC driver sends the query text in the POST body, so that should not be a problem.

There are also relevant limits that you can change:

max_query_size (262144 bytes by default) - limit for the single statement length (possibly excluding INSERTed data)

max_ast_depth (1000 by default), max_ast_elements (50000 by default) - limits on query syntax tree complexity.

[ste...@activitystream.com]

Thank you Alex, good to know.