Functional stateless tests (address) failed query: 01455_shard_leaf_max_rows_bytes_to_read.sql.
But I run this test case on my server, it's OK. And I don't change any code related to it.
Any advice?

@hexiaoting we recently checked and a lot of users rely on our system tables, for example there are tools that are not longer supported by maintainers that rely on some system.tables structure. As additional change we need to keep old columns as virtual storage columns. Check for example system.dictionaries. That way there will be no backward incompatible changes.

@kitaisreal
So for system tables, I should keep old columns like attributes.names and attributes.values as virtual columns, And also add a corresponding new Column attributes Map(String, String), right?

@hexiaoting yes, it will be best solution for us, because if we merge it as is, there will be issues that some tool that cannot be updated is commited to our system tables column names.

@hexiaoting yes, it will be best solution for us, because if we merge it as is, there will be issues that some tool that cannot be updated is commited to our system tables column names.

OK, I will rewrite the implementation.

@kitaisreal I have check system.dictionaries and found it has an interface called getVirtuals to set virtual columns.
But system tables like query_log, it is not implemented by basing IStorage, It is using std::make_shared<ASTCreateQuery>() to create, so it has no interface to set virtual columns.

Another way, If I using alias like:
attributes Map(String, String)
attribute.names alias mapKeys(attributes)
attribute.types alias mapValues(attributes)
I think It is redundant and not necessary.

So, any advice?

@kitaisreal I need your help. Can you give me some advices when you are free, Thank you.

@hexiaoting sorry for the delay, I need to investigate this. Maybe it will require some additional refactoring, but we cannot change logs tables in backward incompatible way, please check #23435.