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Introducing Cloud Spanner, a Global Database Service

cloudplatform.googleblog.com

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Re: Introducing Cloud Spanner, a Global Database Service

#411

Post by throwawaydbfif »

detaro wrote: post #396
throwawaydbfif wrote: post #369

Earlier quoted context omitted.

Spanner is unique in a lot of ways, but it still trades off consistency for speed. The most unique thing about spanner is the use of globally synchronized clock timestamps to guarantee "comes before" consistency without the need to actually synchronize everything. There is nothing stopping startups and open source developers from building the same thing in a few years. The missing ingredient is highly stable GPS and…

> This is a new piece of hardware Only "new" in the sense that it is currently not commonly offered, the devices themselves have been available for ages. (If you are a large enough customer you apparently can get at least some colo-facilities to provide you with the roof-access and cabling needed for the antennas). If cloud providers make precise time available I don't see much potential for locking you in with their…

I'm saying I doubt they will ever offer it precisely because it will conflict with their paid offerings. The fact that it takes its hardware is a great excuse to not give your customers the option.

I know GPS time sources have been available forever but a fault tolent database needs a backup. The US GPS is incredibly reliable but there have been multiple issues with both Glonass and Galilio.

It sounds like Google has an additional time source making this possible, probably a highly miniaturized atomic clock, possibly on a single chip. There's no way they're running on GPS alone

Re: Introducing Cloud Spanner, a Global Database Service

#412

Post by the_cap_theorem »

parasubvert wrote: post #340
takeda wrote: post #159

Earlier quoted context omitted.

So essentially a marketing buzz. "It's always available because we spent a lot of money to make it available" CAP is about how the system deals with partitions not whether it has partitions or not.

The person who wrote this "marketing buzz" is Eric Brewer, who was the originator of the CAP theorem in the first place. I think he knows what it was about :)

See my other comment in this thread on how they still used misleading language in their marketing, regardless of who the author is.

Don't fall for these PR tricks. Hiring thought leaders/influencers is one that should be easy to spot. Best to judge claims on their own merit and not by the person that speaks them....

Re: Introducing Cloud Spanner, a Global Database Service

#413

Post by the_cap_theorem »

thesandlord wrote: post #182
sudhirj wrote: post #164

Earlier quoted context omitted.

But it makes sense in this case. The system guarantees CP. But as customer it looks like you're getting CA as well, because A is so high. If you drink the kool-aid, you get C & A & P. The kool-aid isn't too bad, though if they can measurably guarantee A > 99.999999%, I'm happy to round off to 100% and call it CAP.

The availability is "only" 99.999%, which IMO is still really high! (I work for Google Cloud)

Where does it say that? Does google cloud spanner guarantee three nines uptime?

On the spanner page it says:

>> This feature is not covered by any SLA

;) ;)

Re: Introducing Cloud Spanner, a Global Database Service

#414

Post by the_cap_theorem »

jpmattia wrote: post #191
suprgeek wrote: post #87

Really a CP system but with the Availability being five 9s or better (less than one failure in 10^6) How: 1)Hardware - Gobs and Gobs of Hardware and SRE experience "Spanner is not running over the public Internet — in fact, every Spanner packet flows only over Google-controlled routers and links (excluding any edge links to remote clients). Furthermore, each data center typically has at least three independent fibers…

> with the Availability being five 9s or better (less than one failure in 10^6) Anyone know how exactly this is defined for them? (Time? Queries? Results?)

Well, this is what the spanner website says if you read the fine print:

>> This feature is not covered by any SLA

So I would guess that you don't get _any_ guarantess. Not five nines and not even one nine.

Re: Introducing Cloud Spanner, a Global Database Service

#416

Post by pvg »

throwawaydbfif wrote: post #408
pvg wrote: post #387

Earlier quoted context omitted.

Did you ever read about how Netflix tried to run their own hardware but can't because they have so much data in AWS that it would basically bankrupt them to extract it? Where did you read this? You can have Amazon send you a truck full of hard drives. I doubt it costs more than Netflix can afford.

Nevermind, I misremembered the story I read about them. They moved the main site to AWS with the huge omission of their movie streaming system. Their own Open Connect servers are far cheaper to use for this becuase of massive AWS outbound data costs. Also, the truck is for data in, not data out. Getting data out of AWS is far more expensive than putting it in. That's the lock in.

The 'huge omission' is by design.

Also, the truck is for data in, not data out. Getting data out of AWS is far more expensive than putting it in. That's the lock in.

This is also not true. The bulk transfer service is bi-directional.

Re: Introducing Cloud Spanner, a Global Database Service

#417

Post by findateamfirst »

jasonwatkinspdx wrote: post #264
krenoten wrote: post #218

Earlier quoted context omitted.

MTBF of 2PC-strapped-to-quorum is no different from MTBF of a 2PC-strapped-to-spof replicas. MTTR is bounded by reelection latency, rather than replica recovery, although you still may eat a write amplification cost for rereplication. write amplification is 3-5x of non-quorum-backed 2PC system, depending on replication ensemble size. google further multiplies write amplification with geo-redundancy, so bump that WA b…

You're making some assumptions. For example if you use epaxos for the quorums there is no unavailability due to a leader failure and re-election. Even then, re-election is likely going to be a lot faster than any sort of fault tolerant 2PC coordinator recovery protocol. You're exaggerating the write amplification. The above offering is single region. Google says they do 5 way geo in their various papers/etc, and ther…

I've worked on a storage system that used 9. 15 doesn't seem impossible to me.

Re: Introducing Cloud Spanner, a Global Database Service

#418

Post by bdarnell »

behrangsa wrote: post #404
bdarnell wrote: post #189

Earlier quoted context omitted.

(Cockroach Labs CTO here) Google launching Spanner is generally a positive thing for our industry and our product. It's more proof that what we're aiming for is possible and that there's demand for it. We expect that in five years, all tech companies will be deploying technology like ours. One of the big differences is that Spanner only uses SQL for read-only operations, with a custom API for writes. We use standard…

Would Cockroach 1.0 comply with SQL:2011?

(CockroachDB CTO here) We haven't implemented everything in the standard yet (Nor will we by 1.0 - there's a lot of stuff there!), but we are aiming to ultimately be compliant with the SQL standard. For example, when we introduced "time travel queries" (https://www.cockroachlabs.com/blog/time-travel-queries-selec...) we adopted the SQL-standard syntax "AS OF SYSTEM TIME" (as opposed to the non-standard out-of-band parameter used in Cloud Spanner)

Re: Introducing Cloud Spanner, a Global Database Service

#419

Post by detaro »

throwawaydbfif wrote: post #411
detaro wrote: post #396

Earlier quoted context omitted.

> This is a new piece of hardware Only "new" in the sense that it is currently not commonly offered, the devices themselves have been available for ages. (If you are a large enough customer you apparently can get at least some colo-facilities to provide you with the roof-access and cabling needed for the antennas). If cloud providers make precise time available I don't see much potential for locking you in with their…

I'm saying I doubt they will ever offer it precisely because it will conflict with their paid offerings. The fact that it takes its hardware is a great excuse to not give your customers the option. I know GPS time sources have been available forever but a fault tolent database needs a backup. The US GPS is incredibly reliable but there have been multiple issues with both Glonass and Galilio. It sounds like Google has…

Yes, they clearly say that they use atomic clocks in addition, but that's commercially available as well. Atomic clock for frequency stability short- to mid-term, GPS to keep it synced to global time. E.g. in many cases, mobile-phone base stations contain just such a setup, and the data-center versions should fit in a few HE.

Re: Introducing Cloud Spanner, a Global Database Service

#420

Post by parasubvert »

the_cap_theorem wrote: post #412
parasubvert wrote: post #340

Earlier quoted context omitted.

The person who wrote this "marketing buzz" is Eric Brewer, who was the originator of the CAP theorem in the first place. I think he knows what it was about :)

See my other comment in this thread on how they still used misleading language in their marketing, regardless of who the author is. Don't fall for these PR tricks. Hiring thought leaders/influencers is one that should be easy to spot. Best to judge claims on their own merit and not by the person that speaks them....

What am I supposed to think about someone who creates a throwaway account called "the_cap_theorem"? You look like a competitor that's freaking out and throwing FUD.

I don't think Eric's words were misleading. People will judge Cloud Spanner on its own merit, but given the reputation Eric has both academically and professionally, I think Cloud Spanner is deserving of attention, and is not a "PR trick".

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