difference between LWT/Paxos queries's timestamp and normal queries' timestamp in cassandra -


when using cassandra, if execute following 2 cql, second 1 not success.

insert job_info (id, create_time) values (5be224c6-8231-11e7-9619-9801b2a97471, 0) if not exists; insert job_info (id, create_time) values (5be224c6-8231-11e7-9619-9801b2a97471, 1);

the keyspace , table this:

create keyspace scheduler replication = {'class': 'simplestrategy', 'replication_factor': '1'}  , durable_writes = true;  create table scheduler.job_info (     id timeuuid primary key,     create_time int ) caching = {'keys':'all', 'rows_per_partition':'none'};

i posted issue on https://issues.apache.org/jira/browse/cassandra-13767, , commant said that:

you're mixing lwt/paxos queries ({{if not exists}}, deals timestamp in own way, "normal" queries, , known lead unpredictable results in term of ordering (what happens here not 2nd insert fails, it's gets assigned timestamp lower 1st query , ignored). long story short, don't mix lwt/paxos queries other queries (at least on same partition) , you'll avoid issue.

my question is, difference between lwt/paxos queries , "normal" queries' timestamp?

the first cql , second cql can executed interval of many seconds, second 1 still not success. , problem caused timestamp?


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