Hi, what does allow_readonly means?

@ucasfl recently we enabled some table functions for readonly mode, previously all of them were disabled for security reasons.
deltaLake and hudi have network access so it's better if we disable them.
I tagged you just for informative reasons as the author of the original PR.

@ucasfl recently we enabled some table functions for readonly mode, previously all of them were disabled for security reasons. deltaLake and hudi have network access so it's better if we disable them. I tagged you just for informative reasons as the author of the original PR.

Why cluster is allow_readonly but remote is not?

It is determined by the possibility of making requests to arbitrary hostnames.

If users can make a request to an arbitrary hostname, they can get the info from the internal network or manipulate internal APIs (say - put some data into Memcached, which is available only in the corporate network). This is named "SSRF attack".

Or a user can use an open ClickHouse server to amplify DoS attacks.