Thanx Erick
Is there a way to turn on tracing based on certain criteria,
I would like to start tracing when there is some sort of failure, i.e. in this 
case when a READ REPAIR is triggered as I would like to know why we sometimes 
can’t reach one of the nodes
-Tobias

From: Erick Ramirez <erick.rami...@datastax.com>
Reply to: "user@cassandra.apache.org" <user@cassandra.apache.org>
Date: Wednesday, 12 August 2020 at 01:30
To: "user@cassandra.apache.org" <user@cassandra.apache.org>
Subject: Re: Why a READ REPAIR ?

Perhaps this is super obvious but I need a confirmation as you say “…not 
subsequent reads for other data unrelated to the read being repaired…”
But this is subsequent reads to the _same_ partition key
So to be more explicit
READ 1 with Local Quorum : SELECT * FROM products WHERE id = ABC123
READ 2 with Local One : SELECT * FROM products WHERE id = ABC123

Would read (2) be blocked by the READ REPAIR that was done by read (1)
As I understand that the read repair is working not on the whole table but on 
the partition key it had problems with

Not at all. We (the community) are continuing to invest more on improving the 
docs because these things are not obvious or well-understood.

The read request is blocked while the repair of replicas is in progress. To be 
clear, it is the request (singular) that is blocked and not some locking 
mechanism at the partition level (say like LWTs). Other requests (read 2 in 
your case) will continue to work. Cheers!

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