Re: [DISCUSS] CASSANDRA-12126: LWTs correcteness and performance

2020-11-23 Thread Paulo Motta
Isn't the plan to change LWT implementation (and performance expectation) in a patch version? This is a breaking change by itself, I'm just proposing to make the trade-off choice explicit in the yaml to prevent unexpected performance degradation during upgrade (for users who are not aware of the ch

Re: [DISCUSS] CASSANDRA-12126: LWTs correcteness and performance

2020-11-23 Thread Benedict Elliott Smith
What do you mean by minor upgrade? We can't break patch upgrades for any of 3.x, as this could also cause surprise outages. On 23/11/2020, 23:51, "Paulo Motta" wrote: I was thinking about the YAML requirement during the 3.X minor upgrade to make the decision explicit (need to update y

Re: [DISCUSS] CASSANDRA-12126: LWTs correcteness and performance

2020-11-23 Thread Paulo Motta
I was thinking about the YAML requirement during the 3.X minor upgrade to make the decision explicit (need to update yaml) rather than implicit (by upgrading you agree with the change), since the latter can go unnoticed by those who don't pay attention to NEWS.txt Em seg., 23 de nov. de 2020 às 2

Re: [DISCUSS] CASSANDRA-12126: LWTs correcteness and performance

2020-11-23 Thread Benedict Elliott Smith
What's the value of the yaml? The user is likely to have upgraded to latest 3.x as part of the upgrade process to 4.0, so they'll already have had a decision made for them. If correctness didn't break anything, there doesn't any longer seem much point in offering a choice? On 23/11/2020, 22:45

Re: [DISCUSS] CASSANDRA-12126: LWTs correcteness and performance

2020-11-23 Thread Brandon Williams
+1 to both as well. On Mon, Nov 23, 2020, 4:42 PM Blake Eggleston wrote: > +1 to correctness, and I like the yaml idea > > > On Nov 23, 2020, at 4:20 AM, Paulo Motta > wrote: > > > > +1 to defaulting for correctness. > > > > In addition to that, how about making it a mandatory cassandra.yaml >

Re: [DISCUSS] CASSANDRA-12126: LWTs correcteness and performance

2020-11-23 Thread Blake Eggleston
+1 to correctness, and I like the yaml idea > On Nov 23, 2020, at 4:20 AM, Paulo Motta wrote: > > +1 to defaulting for correctness. > > In addition to that, how about making it a mandatory cassandra.yaml > property defaulting to correctness? This would make upgrades with an old > cassandra.yam

Re: [DISCUSS] CASSANDRA-12126: LWTs correcteness and performance

2020-11-23 Thread Paulo Motta
+1 to defaulting for correctness. In addition to that, how about making it a mandatory cassandra.yaml property defaulting to correctness? This would make upgrades with an old cassandra.yaml fail unless an option is explicitly specified, making operators aware of the issue and forcing them to make

Re: [DISCUSS] CASSANDRA-12126: LWTs correcteness and performance

2020-11-23 Thread Benjamin Lerer
Thank you very much to everybody that provided feedback. It helped a lot to limit our options. Unfortunately, it seems that some poor soul (me, really!!!) will have to make the final call between #3 and #4. If I reformulate the question to: Do we default to *correctness *or to *performance*? I w