Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Introducing Cloud Spanner, a Global Database Service

cloudplatform.googleblog.com

Post reply on HN
Print view View original

91–100 of 456 posts

Re: Introducing Cloud Spanner, a Global Database Service

#91

Post by noahl »

andy_ppp wrote: post #12

> clients can do globally consistent reads across the entire database without locking How is this possible across data centres? Does it send data everywhere at once? Seems too good to be true of course but if it works and scales it might be worthwhile just not having to worry about your database scaling? Still I don't believe it ;-) EDIT: further info... > Spanner mitigates this by having each member be a Paxos group…

Another point is that since all records are globally timestamped, you can do a read that is consistent at a timestamp in the past (i.e. read data as the database was 1 second ago, or something like that).

If data from other places has synchronized to your zone, you may be able to do this globally-consistent read while only touching your local datacenter (because TrueTime guarantees that no other records anywhere in the system will be created at the time you are querying).

Note: I work at Google, but I don't know more about Spanner than the Spanner paper.

Re: Introducing Cloud Spanner, a Global Database Service

#92

Post by snikch »

ChuckMcM wrote: post #89

Congratulations to the Spanner team for becoming part of the Google public cloud! And for those wondering, this is why Oracle wants billions of dollars from Google for "Java Copyright Infringement" because the only growth market for Oracle right now is their hosted database service, and whoops Google has a better one now. It will be interesting if Amazon and Microsoft choose to compete with Google on this service. If…

Amazon's Aurora databases seem to be solving the same problem, and are MySQL or Postgres compatible to boot.

Re: Introducing Cloud Spanner, a Global Database Service

#93

Post by jrowley »

mikeyouse wrote: post #81
jrowley wrote: post #72

Earlier quoted context omitted.

Check out this post mentioned in the original post: https://cloudplatform.googleblog.com/2017/02/inside-Cloud-Sp... Of note: They say Spanner is "both consistent and highly available despite operating over a wide area". So not 100% availability but they've got it to "more than five 9s of availability (less than one failure in 1066)."

I didn't pick up on it until just a moment ago, but when you say "They say", it's actually Eric Brewer saying that -- who's most known for coming up with the CAP theorem. I think they've got a pretty good understanding of it!

ha whoops good catch! I knew the post was written by Brewer, but slipped up with the they... yeah I think we have it on pretty good authority that they system doesn't so how violate CAP yet addresses it's challenges.

Re: Introducing Cloud Spanner, a Global Database Service

#94

Post by [deleted] »

snikch wrote: post #92
ChuckMcM wrote: post #89

Congratulations to the Spanner team for becoming part of the Google public cloud! And for those wondering, this is why Oracle wants billions of dollars from Google for "Java Copyright Infringement" because the only growth market for Oracle right now is their hosted database service, and whoops Google has a better one now. It will be interesting if Amazon and Microsoft choose to compete with Google on this service. If…

Amazon's Aurora databases seem to be solving the same problem, and are MySQL or Postgres compatible to boot.

[deleted]

Re: Introducing Cloud Spanner, a Global Database Service

#95

Post by manacit »

snikch wrote: post #92
ChuckMcM wrote: post #89

Congratulations to the Spanner team for becoming part of the Google public cloud! And for those wondering, this is why Oracle wants billions of dollars from Google for "Java Copyright Infringement" because the only growth market for Oracle right now is their hosted database service, and whoops Google has a better one now. It will be interesting if Amazon and Microsoft choose to compete with Google on this service. If…

Amazon's Aurora databases seem to be solving the same problem, and are MySQL or Postgres compatible to boot.

Aurora is a 'better MySQL mousetrap', IMO.

This is a globally-available, nearly-CAP-beating datastore that powers one of the biggest websites on the internet.

It's not quite apples and oranges, but this is definitely a different problem they are solving.

Re: Introducing Cloud Spanner, a Global Database Service

#96

Post by Scaevolus »

agwa wrote: post #6
jallriddle wrote: post #3

Is this similar to AWS Aurora or is this something else completely different?

Aurora is not globally distributed. Spanner is, and is based on Google research which takes advantage of atomic clocks installed in each server: https://research.google.com/archive/spanner-osdi2012.pdf Edit: not every server has an atomic clock; see replies by Google employees

There are only atomic clocks in some master servers: "TrueTime is implemented by a set of time master machines per datacenter and a timeslave daemon per machine. The majority of masters have GPS receivers with dedicated antennas; these masters are separated physically to reduce the effects of antenna failures, radio interference, and spoofing. The remaining masters (which we refer to as Armageddon masters) are equipped with atomic clocks. An atomic clock is not that expensive: the cost of an Armageddon master is of the same order as that of a GPS master."

The timeslave daemons running on each machine keep them synchronized with the master time servers, and maintain tight bounds on their inaccuracy.

(Disclaimer: I work at Google)

Re: Introducing Cloud Spanner, a Global Database Service

#97

Post by elvinyung »

While everyone is puzzling over how Spanner seems to be claiming to be CA, I would like to take this opportunity to bring up PACELC[1].

The idea is that the A-or-C choice in CAP only applies during network partitions, so it's not sufficient to describe a distributed system as either CP or AP. When the network is fine, the choice is between low latency and consistency.

In the case of Spanner, it chooses consistency over availability during network partitions, and consistency over low latency in the absence of partitions.

1: http://cs-www.cs.yale.edu/homes/dna/papers/abadi-pacelc.pdf

Re: Introducing Cloud Spanner, a Global Database Service

#98

Post by robryk »

rdtsc wrote: post #90
halflings wrote: post #77

Earlier quoted context omitted.

They answer your question just two lines under the one you are quoting: > For distributed systems over a “wide area,” it's generally viewed that partitions are inevitable, although not necessarily common. If you believe that partitions are inevitable, any distributed system must be prepared to forfeit either consistency (AP) or availability (CP), which is not a choice anyone wants to make. In fact, the original point…

> If you believe that partitions are inevitable, any distributed system How does that answer it? Are they implying that partitions will not happen if you don't believe in them?

A CA system is not a system that doesn't have partitions, it's a system that works under the condition that there are no partitions (ie. it is a non-partition-resistant system).

Re: Introducing Cloud Spanner, a Global Database Service

#99

Post by kennethmac2000 »

Looks cool, but the pricing seems a bit non-cloud-native (or at least non-GCP-native).

"You are charged each hour for the maximum number of nodes that exist during that hour."

We've been educated by Google to consider per-minute, per-instance/node billing normal - and presumably all the arguments about why this is the right, pro-customer way to price GCE apply equally to Cloud Spanner.

Re: Introducing Cloud Spanner, a Global Database Service

#100

Post by xapata »

elvinyung wrote: post #85
xapata wrote: post #79

Amazon likes to respond to Google with it's own price drops and product launches. It's telling that their announcements are orthogonal instead of direct competition with Spanner. When Google announced Spanner back in 2012, I'm sure Amazon and Microsoft started teams to reproduce their own versions. Spanner is not just software. The private network reduces partitions. GPS and atomic clocks for every machine help synch…

Amazon already has Aurora: https://aws.amazon.com/rds/aurora/details/ You're right that there's literally nothing else out there that has tight synchronization using atomic clocks, though.

And because of that, Aurora's multi-zone replicas are read-only.

I just noticed Google says the cross-region feature is coming later in 2017. Amazon might be planning to announce a similar change for Aurora in the coming months.

Post reply on HN