>From Mastering Cassandra:
Forcing read repairs at consistency – ALL The type of repair isn't really part of the Apache Cassandra repair paradigm at all. When it was discovered that a read repair will trigger 100% of the time when a query is run at ALL consistency, this method of repair started to gain popularity in the community. In some cases, this method of forcing data consistency provided better results than normal, scheduled repairs. Let's assume, for a second, that an application team is having a hard time logging into a node in a new data center. You try to cqlsh out to these nodes, and notice that you are also experiencing intermittent failures, leading you to suspect that the system_auth tables might be missing a replica or two. On one node you do manage to connect successfully using cqlsh. One quick way to fix consistency on the system_auth tables is to set consistency to ALL, and run an unbound SELECT on every table, tickling each record: use system_auth ; consistency ALL; consistency level set to ALL. SELECT COUNT(*) FROM resource_role_permissons_index ; SELECT COUNT(*) FROM role_permissions ; SELECT COUNT(*) FROM role_members ; SELECT COUNT(*) FROM roles; This problem is often seen when logging in with the default cassandra user. Within cqlsh, there is code that forces the default cassandra user to connect by querying system_auth at QUORUM consistency. This can be problematic in larger clusters, and is another reason why you should never use the default cassandra user. -----Original Message----- From: Jon Haddad [mailto:j...@jonhaddad.com] Sent: Thursday, April 04, 2019 9:21 AM To: user@cassandra.apache.org Subject: Re: Assassinate fails Ken, Alain is right about the system tables. What you're describing only works on non-local tables. Changing the CL doesn't help with keyspaces that use LocalStrategy. Here's the definition of the system keyspace: CREATE KEYSPACE system WITH replication = {'class': 'LocalStrategy'} AND durable_writes = true; Jon On Thu, Apr 4, 2019 at 9:03 AM Kenneth Brotman <kenbrot...@yahoo.com.invalid> wrote: > > The trick below I got from the book Mastering Cassandra. You have to set the > consistency to ALL for it to work. I thought you guys knew that one. > > > > From: Alain RODRIGUEZ [mailto:arodr...@gmail.com] > Sent: Thursday, April 04, 2019 8:46 AM > To: user cassandra.apache.org > Subject: Re: Assassinate fails > > > > Hi Alex, > > > > About previous advices: > > > > You might have inconsistent data in your system tables. Try setting the > consistency level to ALL, then do read query of system tables to force repair. > > > > System tables use the 'LocalStrategy', thus I don't think any repair would > happen for the system.* tables. Regardless the consistency you use. It should > not harm, but I really think it won't help. > > --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org For additional commands, e-mail: user-h...@cassandra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org For additional commands, e-mail: user-h...@cassandra.apache.org
