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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

#161

Post by daenney »

ex3ndr wrote: post #142
tedd4u wrote: post #33

The team here at Quizlet did a lot of performance testing on Spanner with one of our MySQL workloads to see if it's an option for us. Here are the test results: https://quizlet.com/blog/quizlet-cloud-spanner

> So a query that accesses 10 rows in disparate parts of the primary key space will take longer than one where the keys reside on the same splits. This is expected with a distributed system. No, why? Query can be executed in parallel. BTW, isn't 20k/sec is a very very small performance for 30 node installation. Cassandra can handle 50k+ (both writes and read) on a single node. When in most queries you are trying to c…

I don't think that comparison holds. It's easy to push 50k+ on a single node, you're basically only resource bound on that machine. Pushing 20k+ on something that's globally consistent spread out over so many instances is a different exercise entirely. It also depends on the level of consistency you're asking from Cassandra. You'd probably need to set this to EACH_QUORUM or ALL to mimic the behaviour Spanner gives you.

And yes Cassandra will scale linearly-ish as long as you're in the same datacenter. Try running a geo-distributed 30-node Cassandra ring and it's a whole different story at that level of consistency and availability.

Re: Introducing Cloud Spanner, a Global Database Service

#162

Post by advisedwang »

BinaryIdiot wrote: post #147

Oh this looks really compelling! Though I'm guessing this is targeted to companies? I'd love to use this for some personal projects but the pricing seems really high. Am I reading it right that a single node being used at least a tiny bit every hour is about $670 a month? Maybe I'm misunderstanding how the pricing works here. Any clarification would be highly welcomed :)

It's targeted to large datasets more than companies. There isn't really any advantage of a single node Cloud Spanner instance over Cloud SQL. Cloud Spanner becomes worthwhile when you have more data/throughput than a single node system can support, at which point the pricing is competitive with other options.

Re: Introducing Cloud Spanner, a Global Database Service

#163

Post by takeda »

koolba wrote: post #5

> Today, we’re excited to announce the public beta for Cloud Spanner, a globally distributed relational database service that lets customers have their cake and eat it too: ACID transactions and SQL semantics, without giving up horizontal scaling and high availability. This is a bold claim. What do they know about the CAP theorem that I don't? Separately, (emphasis mine): > If you have a MySQL or PostgreSQL system th…

> From the rest of the article it seems like the wire protocol for accessing it is MySQL. I wonder if they mean to add a PostgreSQL compatibility layer at some point.

I doubt it, the spanner is not even offering full MySQL capabilities, so it's unlikely to to support any advanced PG SQL.

Re: Introducing Cloud Spanner, a Global Database Service

#164

Post by sudhirj »

zzzcpan wrote: post #143
sudhirj wrote: post #140

Earlier quoted context omitted.

From the technical blog post > Does this mean that Spanner is a CA system as defined by CAP? The short answer is “no” technically, but “yes” in effect and its users can and do assume CA. The purist answer is “no” because partitions can happen and in fact have happened at Google, and during some partitions, Spanner chooses C and forfeits A. It is technically a CP system. However, no system provides 100% availability,…

Except that A in CAP has nothing to do with overall system's availability over time and using it as such is just confusing.

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.

Re: Introducing Cloud Spanner, a Global Database Service

#165

Post by darkerside »

theDoug wrote: post #59
darkerside wrote: post #4

> Unlike most wide-area networks, and especially the public internet, Google controls the entire network and thus can ensure redundancy of hardware and paths, and can also control upgrades and operations in general I know this is a single system, but I'll still say it. This seems like another step in a scary trend for our internet.

I am an employee, and have my biases, but I’ll always prefer a customer's data stay on our backbone and not be passed through the public internet. Our customers also prefer it, and it's not something other Cloud providers can fully cover.

That probably came off as more offensive than I intended. I just feel a more decentralized internet is a stronger one. Not assuming any nefarious intent.

Re: Introducing Cloud Spanner, a Global Database Service

#166

Post by dietrichepp »

hueving wrote: post #138
jedberg wrote: post #110

This release shows the different philosophies of Google vs Amazon in an interesting way. Google prefers building advanced systems that let you do things "the old way" but making them horizontally scalable. Amazon prefers to acknowledge that network partitions exist and try to get you to do things "the new way" that deals with that failure case in the software instead of trying to hide it. I'm not saying either system…

>and release products that let you do things "the old way" while hiding the details in an abstraction. However, by 'abstracting' this away, you're not being forced to think about failure domains. If there is ever a massive country-wide connectivity break to the wider Internet (feasible for lots of people inside censored countries), you'll be pretty pissed when you can't use the DB services for your servers in the Goo…

Cloud Spanner is currently a regional service, not a global service. So you would only lose availability for failures within the region.

Re: Introducing Cloud Spanner, a Global Database Service

#167

Post by tamalsaha001 »

One thing to note is Spanner's transactions are different compared to what you get with a traditional RDBMS. See https://cloud.google.com/spanner/docs/transactions#ro_transa...

An example is the rows you get back from a query like "select * from T where x=a" can't be part of a RW transaction. I believe because they don't have the time-stamp associated with them. So, you have to re-read those rows via primary key inside a RW transaction to update them. This can be a surprise if you are coming from a traditional RDBMS background. If you are think about porting your app from MySQL/PostgreSQL to Spanner, it will be more than just updating query syntax.

Disclaimer: I used F1 (built on top of Spanner, https://research.google.com/pubs/pub41344.html) few years ago.

Re: Introducing Cloud Spanner, a Global Database Service

#168

Post by jhugg »

xapata wrote: post #74
jhugg wrote: post #60

Earlier quoted context omitted.

I would expect more from Brewer. "CA except when there are partitions" is CP. It's not "effectively CA".

No, he's saying it's effectively CAP because the A downtime is so small. It's one thing to do that for a key-value store. Entirely another to support joins on a globally distributed database. This ain't just one availability zone. Spanner is amazing. It took them a few years to make it a service, but when they announced its use internally a few years ago, it seemed like the nail in the coffin for in-house database ho…

I understand what he's saying. It's marketing.

There's nothing wrong with saying it's CP, but since we control everything there's extremely rare P. Then he can show availability numbers (which he kinda does).

Saying it's "effectively CA" defeats the point of the CAP theorem, which says you have to make tradeoffs. See: https://codahale.com/you-cant-sacrifice-partition-tolerance/

Re: Introducing Cloud Spanner, a Global Database Service

#169

Post by sandGorgon »

craigkerstiens wrote: post #155
kornish wrote: post #129

Earlier quoted context omitted.

> It will be interesting if Amazon and Microsoft choose to compete with Google on this service. If we get to the point where you have databases, compute, storage, and connectivity services from those three at equal scale, well that would be a lot of choice for the developers! There are also plenty of choices evolving for developers who aren't looking for hosted solutions (which can sometimes be a showstopper for ente…

Craig from Citus here. Thanks for the kind words. We've seen a lot of people scale-out transactional workloads with Citus as well. In particular, we've seen a lot of multi-tenant apps that need to keep scaling beyond a single node when they're running into memory or compute issues. If you are looking for something that is more Postgres flavored (meaning we're just an extension to it so you get all the good stuff of P…

It would be very interesting to have your product at the 200-300$ pricepoint. Currently, the lowest tier starts at almost 2000$ per month for the high availability version.

I'm not trying to compare on a per-mb level, but it would be nice for smaller scale workloads.

Re: Introducing Cloud Spanner, a Global Database Service

#170

Post by knz42 »

aamederen wrote: post #132
tedd4u wrote: post #33

The team here at Quizlet did a lot of performance testing on Spanner with one of our MySQL workloads to see if it's an option for us. Here are the test results: https://quizlet.com/blog/quizlet-cloud-spanner

I'm reading the test results and had a question. >> Cloud Spanner doesn't, however, support data manipulation language (DML) statements. DML includes SQL queries like INSERT and UPDATE. Instead, Spanner's interface definition includes RPCs for mutating rows given their primary key[21]. Does this mean I need to rewrite my application? My application uses an ORM and it typically converts my logic to SQL statements and…

yes.
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