Hi Craig, I'm not 100 % sure about some corner cases, but I'm sure that LWT should be used with the following consistency levels usually.
LWT write: serial_consistency_level: SERIAL consistency_level: QUORUM LWT read: consistency_level: SERIAL (It's a bit weird and mis-leading as a design that you can set SERIAL to consistency_level in read where as you can't for write.) BTW, I doubt the python doc is correct in especially the following part. "But if the regular consistency_level of that write is ANY, then only a read with a consistency_level of SERIAL is guaranteed to see it (even a read with consistency ALL is not guaranteed to be enough)." It is really true? It doesn't really make sense to me because SERIAL read mostly returns by seeing quorum of replications, and write with ANY returns by writing mostly one replication, so they don't overlap in that case. It would be great if anyone can clarify this. Thanks, Hiro On Thu, May 23, 2019 at 3:53 PM Craig Pastro <siyo...@gmail.com> wrote: > > Hello! > > I am trying to understand the consistency level (not serial consistency) > required for LWTs. Basically what I am trying to understand is that if a > consistency level of ONE is enough for a LWT write operation if I do my read > with a consistency level of SERIAL? > > It would seem so based on what is written for the datastax python driver: > > http://datastax.github.io/python-driver/api/cassandra/query.html#cassandra.query.Statement.serial_consistency_level > > However, that is the only place that I can find this information so I am a > little hesitant to believe it 100%. > > By the way, I did find basically the same question > (https://www.mail-archive.com/user@cassandra.apache.org/msg45453.html) but I > am unsure if the answer there really answers my question. > > Thank you in advance for any help! > > Best regards, > Craig > > --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org For additional commands, e-mail: user-h...@cassandra.apache.org
