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CockroachDB beta-20161013

jepsen.io

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Re: CockroachDB beta-20161013

#2
"For instance, on a cluster of five m3.large nodes, an even mixture of processes performing single-row inserts and selects over a few hundred rows pushed ~40 inserts and ~20 reads per second (steady-state)."

Wow, that's...not fast.

Re: CockroachDB beta-20161013

#3
> Should the clock offset between two nodes grow too large, transactions will no longer be consistent and all bets are off.

A concern I have is that there could be datacorruption in this context, no? It sounds like on a per cluster basis, i.e. Same Raft cluster, there is a strict serializability guarantee. But without linearalizability system wide, you could end up with data corruption on multi-keyspace writes.

Re: CockroachDB beta-20161013

#4
Like Spanner, Cockroach’s correctness depends on the strength of its clocks... Unlike Spanner, CockroachDB users are likely deploying on commodity hardware or the cloud, without GPS and atomic clocks for reference.

I'm curious, do any of the cloud providers offer instances with high-precision clocks? Maybe this is something one of the smaller cloud providers might want to offer to differentiate themselves - instances with GSP clocks.

Re: CockroachDB beta-20161013

#7

Like Spanner, Cockroach’s correctness depends on the strength of its clocks... Unlike Spanner, CockroachDB users are likely deploying on commodity hardware or the cloud, without GPS and atomic clocks for reference. I'm curious, do any of the cloud providers offer instances with high-precision clocks? Maybe this is something one of the smaller cloud providers might want to offer to differentiate themselves - instances…

Why can't these datacenters be using a high precision gps source for their NTP source in the building?

Re: CockroachDB beta-20161013

#8

Like Spanner, Cockroach’s correctness depends on the strength of its clocks... Unlike Spanner, CockroachDB users are likely deploying on commodity hardware or the cloud, without GPS and atomic clocks for reference. I'm curious, do any of the cloud providers offer instances with high-precision clocks? Maybe this is something one of the smaller cloud providers might want to offer to differentiate themselves - instances…

The spanner announcement mentioned offering direct access to the TrueTime api sometime in the not too distant future.

Edit: Quote from Brewer's post: "Next steps For a significantly deeper dive into the details, see the white paper also released today. It covers Spanner, consistency and availability in depth (including new data). It also looks at the role played by Google’s TrueTime system, which provides a globally synchronized clock. We intend to release TrueTime for direct use by Cloud customers in the future."

Re: CockroachDB beta-20161013

#9

Like Spanner, Cockroach’s correctness depends on the strength of its clocks... Unlike Spanner, CockroachDB users are likely deploying on commodity hardware or the cloud, without GPS and atomic clocks for reference. I'm curious, do any of the cloud providers offer instances with high-precision clocks? Maybe this is something one of the smaller cloud providers might want to offer to differentiate themselves - instances…

> I'm curious, do any of the cloud providers offer instances with high-precision clocks?

Essentially that's what Google's doing by selling Spanner, but you don't get access to the clocks directly. I'd guess that as they get more experience selling Spanner, and they bring the price of the hardware down, they'll rent those directly too.

Re: CockroachDB beta-20161013

#10
Wow. Probably fundraising and getting out front of googles new consumer spanner service. I just started experimenting w/ cockroachdb and it sounds/seems great. They def are campaigning hard, landing a Jepsen test and a lot of posts/articles last couple.

I am pulling for them over G on principle. I infer they know people at Stripe where the Rethink team & Aphyr are so hopefully they can learn from them and build an awesome product. G has lost a lot of battles on UX, Docs, attitude and just general product. They have won a lot of battles on sheer size & resources. Be nice to have this stick around.

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