Add xid Column to system.zookeeper_connection

Why it matters

This feature provides users with the ability to see the transaction ID (xid) associated with each ZooKeeper connection. It helps in monitoring and debugging distributed coordination by exposing more detailed state information about ZooKeeper sessions within ClickHouse.

How to use it

Query the system.zookeeper_connection system table as usual. The new xid column will be included automatically and can be selected to retrieve the transaction ID for each connection, for example:

SELECT xid, * FROM system.zookeeper_connection