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BigchainDB – A scalable blockchain database (github.com/bigchaindb)
56 points by jashmenn on Nov 2, 2017 | hide | past | favorite | 66 comments

Why use Python rather than a statically-typed language? This thing looks like it will become a resource gobbling beast that runs very slowly

Hi, it's Trent here, CTO at BigchainDB.

Summary: Python isn't the bottleneck yet, and if it becomes one, C will become the last 1%.

I've been working on production apps in Python since 2002, including ones doing large-scale compute running 1000+ machines at once. How: 99% python, 1% C. But the trick is, you only build in the C once you've worked out all the kinks and optimized the big-picture stuff elsewhere. Python is great for not only connecting things, but rapidly iterating on algorithms and building maintainable code.

The AI / ML community has discovered this too: Python is now the most popular language in that community. Despite the heavy compute. How: most of the popular libraries have efficient C (etc) implementations under the hood.

This is exactly the philosophy we've been following at BigchainDB, with success. Python to connect things, iterate quickly in improving algorithms, and ship maintainable code. We haven't got far enough to resort to building our own C libraries yet, though many 3rd party libraries we use are implemented in C.

[EDIT] Based on the comments below, I'll now mention here too: BigchainDB wraps MongoDB, which is written in C++. And, Python 3.5+ (which BDB uses) has gradual typing, which brings many benefits of static typing to Python.

Is there a successful database written in python? I probably need to dig through your code a bit more to understand how your utilizing it.

The actual database is not written in python.

Good point - BigchainDB wraps MongoDB, which is in C++. I updated my comment above to help future readers.

Trent, dean here. met you at ICCAD few years ago (2014?) and we had dinner with Bill Swartz at an Asian place. We discussed bitcoin and I remember it was $600 back then. Funny that it's now 6k$ and I didn't know you're gonna be in this space. Just wanna shout out that bigchaindb looks legit/cool and good luck in the future!!

Oh cool! Thanks for the ping, Dean. I hope you're well. Yeah blockchain space is a bit crazier than EDA, but some of us are engineers bringing our discipline and experience to this new field:)

I encourage you to give BigchainDB a whirl, it's easy: https://www.bigchaindb.com/getstarted/

Will definitely kick the tires on this one. And people should take notice that you guys didn't raise funds through an ICO. If anything, that right there is a big sign that Bigchain db is a cut above the rest in terms of riding the block chain hype train.gl

+1 :)

Another hi from the past! I'm going to have to check this out, since, well, it's you and there's been some discussion about "blockchain applications that aren't just trading currency" at work. Cheers! Glad to see you're still working on crazy interesting shit!

Hey Tony, great to hear from you! Yes please do check this out, we think it's interesting too:) Also interesting is BigchainDB's sister project www.oceanprotocol.com. Cheers!

If this db is blockchain-like, does that mean that every node must carry a full copy of the db?

To me, "blockchain-like" is about getting the benefits of decentralized, immutability (tamper-resistance), and assets.

How one goes about getting those characteristics is wide open. Most blockchain systems do have a full copy of the database at each server node, i.e. fully replicated. Also, they are "peer to peer" which means there is no distinction between clients and servers. (They do have SPV wallets though which is kinda similar.)

BigchainDB's focus has always been about scale. We're partly there but not fully: we are currently fully replicated but are targeting sharding to address that [1]. Where we do get scale already is properly distinguishing between between clients and servers. Servers are "super peers", decentralized among themselves. They do the heavy lifting, i.e storage. Apps don't need to run a server node; instead they simply are clients to the network, and of course can query >1 node.

[1] https://blog.bigchaindb.com/bigchaindb-developer-update-2d32...

That still doesn't encompass the advantages of a statically-typed language...

I totally acknowledge that there are pros and cons for both dynamically and statically typed languages. (We could start a 10 page discussion here. But I've been there before, perhaps you have too, how about we save our energy? ;)

For the latest and greatest 10 pages about that; just search for the the Hickey 10 year Clojure (rant-ish in places) talk and the Haskell community responding to it.

OK! :)

Well done for gracefully and thoroughly responding to the usual HN barrage of technical critiques.

Thank you:) Even if there's hype and critique, we can always rise above and maintain our integrity as we build things that matter.

Python has optional typing support in the standard library since version 3.5. Granted, not type _checking_, but that is offloaded to external tools like mypy[0].

I feel that gradual typing offers the best of both worlds: rapid prototyping, but also the strictness of types where you need it.

0: http://mypy-lang.org/

Good point! I think the Python folks made a great design choice there. I updated my comment above to help future readers.

I'm unclear how this is any different from a centralized mongodb as a service platform. It seems that it doesn't offer any proof of work related security or consensus building other than a centralized "trust our cluster" policy [1].

[1] https://docs.bigchaindb.com/en/latest/bft.html

Hi, it's Trent here, I'm CTO at BigchainDB.

BigchainDB targets giving the following benefits beyond traditional database as a service:

1. decentralized - no single entity controls it, which means tolerant to malicious / Byzantine faults. Benefit: groups that don't necessarily trust each other can share infrastructure.

2. immutable - which practically speaking means more tamper resistant, e.g. it's append only. Benefit: well-defined provenance for history of assets, data, etc.

3. assets - you can create and issue assets, where you own them if you have the private key. How: each tx is signed. Benefit: moving around assets on a substrate that no single entity owns or controls. Lower friction in exchanges. And the digital signatures gives cryptographic proof that about who did what.

These are the targets. We're not fully there yet. Most notably, we still need to address some Byzantine faults as our docs ([1] above) mention. This will come in an upcoming release. We are also working on improved scalability while maintaining the security guarantees [2].

Re consensus: BigchainDB has a two-layer consensus, as follows.

* The lower layer directly uses MongoDB's consensus (which it builds on) to agree on whether a transaction should be stored.

* The higher level has federation-style voting on whether a transaction is valid or not.

Our documentation describes this further.

BigchainDB is explicitly not trying to do Bitcoin-style proof of work. PoW solves for an additional problem: (theoretical) anonymity of servers. That additional goal compromises scale. And, in practice you know who's running the servers anyway (ie big Chinese Bitcoin miners), which is why I say "theoretical". BTW I am a fan of Bitcoin, it just has different goals than BigchainDB.

[2] https://blog.bigchaindb.com/bigchaindb-developer-update-2d32...

How is this different from Mysql with sharding+encryption?

Neither sharding nor encryption give "decentralized", "immutable", or "assets". E.g. how many sysadmins can MySQL have? (And the answer is 1. Hence, not decentralized.)

Not sure whether BigchainDB implements consensus/PoW, but my attempt at building a blockchain-based database sure does. [1] Scaling a solution like that however is very difficult, and I can imagine BigchainDB aiming for applications where consensus/PoW is less needed.

[1] https://github.com/pixelspark/catena

I'm sure you know this but I will clarify for readers: PoW is only one consensus algorithm. Consensus algorithms go back decades. They're powering all the distributed DBs, file systems, etc that power the web. Some are fault tolerant (eg Paxos), some add in Byzantine tolerance (eg PBFT), some add in Sybil tolerance (eg PoW).

> Not sure whether BigchainDB implements consensus/PoW

It has a 2-layer consensus algorithm. (See a comment above, or BigchainDB docs.) It does not use PoW because PoW is inefficient; BigchainDB doesn't target applications needing Sybil tolerance.

I should also mention that we've been working on supporting a BFT option. It should be out in the next release or two. https://github.com/bigchaindb/bigchaindb/blob/master/docs/ro...

I find it very amusing that "scalable blockchain database" is the core selling point here. I must be experiencing buzzword fatigue I think. Why would I want to Chuck my boring MySQL installation for this?

Hi, it's Trent here, CTO of BigchainDB.

FYI we started working on the precursor to this in 2013 (ascribe). Bitcoin hadn't even hit the mainstream then, let alone blockchain. We didn't build it to mash together buzzwords. We built it because we saw a clear need for it. We had been building on Bitcoin, and (a) didn't scale to meet our needs and (b) was super-hard to use because it didn't act like a database. So we built BigchainDB to address issues (a) and (b).

Obviously, good old "boring" MySQL is incredibly useful for tons of problems. If you're already solving a problem with MySQL, then BigchainDB is not a fit. Don't use it, stick with the thing that's working.

Where it is useful is applications that want at least one of the following benefits:

1. decentralized, so that >1 orgs can share resources

2. immutable / tamper resistance, for provenance of ownership of art, spare parts, food, etc

3. assets, so you can exchange digital goods more readily.

More details here: https://blog.bigchaindb.com/three-blockchain-benefits-ae3a2a...

My Cassanda db can be "decentralized" too by your definition because I can have it distributed between multiple corporations, where multiple people have read/write access. This is extremely common practice.

I'm not defining "decentralized" as simply "distributed between multiple corporations, where multiple people have read/write access".

To be "decentralized", it's key that there are >1 sysadmins (ie runners of server nodes); and bad behavior from some sysadmins does not take the whole system down.

We experimented with a bit with decentralizing Cassandra. From what we saw, it is possible to decentralized it in the way I define it. We also tested other DBs. We chose RethinkDB because we liked their approach to global oplog; and we preferred a document-store interface over a column store interface. Later we added MongoDB support because of customer interest and some technical benefits. (For the record we added this support before Rethink's woes. Glad to see it found a foundation:)

I’m curious about the choice of python here. If your building a scalable high throughput data store, python seems like an odd choice

See the comment "Why use Python rather than..." and my response to it. Cheers,

I never understood how blockchains could scale.

A global list of hashes that is also append only? This just screams to blow up sooner or later.

I know. I think if I read "scalable" and "blockchain" in the same sentence again I'll scream.

Once bitcoin can handle Visa's transaction volume (250M transactions/day) we can talk scale.

EDIT: after reading the comments more, seems the project operates without PoW, which allows it to scale more. I'm curious, then, what differentiates it from something like cockroachdb. It seems to be an append-only, distributed database. How does the bockchain fit in?

Hi, it's Trent here, the CTO of blockchain.

> I know. I think if I read "scalable" and "blockchain" in the same sentence again I'll scream. I acknowledge the hype out there.

FYI we were working on blockchain in 2013; long before the hype. We started encountering massive scale problems in 2014 and working on it in 2015, long before the "scale + blockchain" hype. We started work on this. So we're not doing this because it's some fancy combo of buzzwords, we're doing it because we identified a problem years ago, and have been making steady progress to improve it ever since. It was a surprise to me to see BigchainDB to hit HN front page today, since we've been shipping it since Feb 2016!

> Once bitcoin can handle Visa's transaction volume (250M transactions/day) we can talk scale. We're not trying to improve Bitcoin. We're building our own thing. As we continue to improve the technology, it becomes useful to ever-wider classes of users.

Re CockroachDB: it's a cool technology. The big difference is that it's distributed but not decentralized. That is, the compute resources (in this case mainly storage) are spread across many machines; but the control is in the hands of a single entity / sysadmin. Whereas decentralized means the the control is spread across many sysadmins; and even a few rogue sysadmins won't take down the system.

Oh I don't think it's a hype thing, I just think I don't understand it :D

As I understood blockchains, they are basically linked lists of hashes, yes?

And the decentralization means, that every node hast this list, not just parts of it, so everyone can always check if the list is consistent.

Also, these lists are append only.

The part were every node has a copy AND the list is append only leads me to something that doesn't scale well. It will always get bigger with every action that is appended AND it will always be multiplied by every node in the network.

I'm probably missing something here, but that is my current state of blockchains, haha.

Many people disagree about what blockchain technology is. To me, it' about the characteristics, rather than how they're implemented. I see three characteristics: decentralized, immutable, assets [1].

Under this framing, the "linked list of hashes" is one partial way to achieve immutability. And "every node has this list" is one partial way to get to decentralization is achieved. But that's only part of it. Eg you need to address: what if a node acts badly? And you want a means to create & issue assets.

> every node has a copy AND the list is append only leads me to something that doesn't scale well.

Correct. That's why there is work to scale better, e.g. via sharding by BigchainDB and by others.

[1] https://blog.bigchaindb.com/three-blockchain-benefits-ae3a2a...

Does sharding still let you know the "whole truth"?

"Truth" of course is a red herring. "Claim" is better. And, "digitally signed claim" is better yet.

Then to answer your Q: a good sharding approach should let you see all digitally signed claims (including when those claims were made) with probability --> 1.0. I'm framing this probabilistically because many sharding approaches rely on that definition. (And even non-sharded blockchains like Bitcoin itself.)

Also, I had the impression that a blockchain is a specific type of data structure.

So, what you are describing seems like a way to accomplish behavior of this kind of data structure with a different one so you may get bettee scaling out of it.

As you'll see in my other comments (and articles on it), "blockchain" is better described as a field with a set of related goals for technology artifacts, rather than a specific data structure [1]. I frame it as: it has blockchain characteristics if it's decentralized, immutable, and assets [2].

This is a much healthier framing, because it doesn't constrain the goals to a particular approach (e.g. a particular data structure).

[1] https://blog.bigchaindb.com/blockchain-as-a-field-47c9f45894...

[2] https://blog.bigchaindb.com/three-blockchain-benefits-ae3a2a...

I don't think i'm knowledgable enough to do anything other than refer you to sharding (we don't need to store the whole chain, just like in distributed computing) and the recent paper by Vitalik (Ethereum) and Joseph Poon of Lighting Networks on Plasma, which seems like MapReduce/Hadoop/Spark stuff with a blockchain




> Once bitcoin can handle Visa's transaction volume (250M transactions/day) we can talk scale.

blockchain != bitcoin. solutions such as ripple, iota, and others have tech in place that can scale to those levels and beyond. i don't think any of them are ready to replace visa yet, but the hurdles are not fundamental to blockchain.

Thanks for responding to this query as well. Fully agreed:)

BTW we work closely with the Ripple folks (especially on Interledger Protocol) and the iota folks (they're also in Berlin:)

Some types of data need to be geographically stay in a certain area. For example, European PII data cannot be hosted on servers outside of the EU. That's easy to handle if you're using AWS for example.

How can a company comply to these kinds of laws using a distributed system like BigChainDB? Is there a some kind of geo fencing possibility?

Hi, it's Trent here, CTO of BigchainDB.

That's a great question. It's surprising how few people are aware of the current German data protection laws (where we're based) and the upcoming EU data protection laws aka GDPR.

There are a few ways to address the issue:

1. Don't store any PII on the database, rather only use it to link to data that's stored on-premise in many places. The database has permissioning, and therefore acts as (decentralized) access control logic. Have a TOS with proper legal teeth so that if a database user does store PII on the database, they are liable in the real world.

2. Run an instance of BigchainDB within a region, e.g. within Germany, and comply with the appropriate laws there. Let PII be on the database. But, each node must follow data protection guidelines, similar to how a single centralized entity would, but now do it for each node.

3. Force encryption of all PII, and pray.

(3) is really a non-option. I stated it because many people are saying "just encrypt". But the problem is quantum computing. In 5-15 years quantum computing will be sufficiently easy to access that any encrypted data that's publicly available can be decrypted. You might say "well let's migrate to quantum-tolerant crypto before then" but that doesn't stop a malicious actor from copying encrypted PII now. You might say "let's use quantum tolerant crypto now" but we've seen with most crypto algorithms that it takes years to harden them. Would you trust your PII with untested crypto algorithms? I wouldn't. In short: putting encrypted PII on public nets is a bad idea. Please, please don't do it.

Hi Tent, thanks for your answer. Can you elaborate on #2? Is your suggestion to run a private BigChainDB network of nodes you control?

Also, are suggesting that no sensitive data should ever be stored in a BigChainDB, or I misinterpret #3?

Re (2): this would be a group of people or organizations running nodes together. (If it was just nodes you controlled it misses the point of being decentralized.) You could store sensitive data in this setup, if each person/org had the proper data protection setup. This is not easy, however.

> Also, are suggesting that no sensitive data should ever be stored in a BigChainDB, or I misinterpret #3?

Actually option (2) shows a way to store PII on BigchainDB. But it's not easy. My recommendation is to do (1). And, like my comment before, please please don't do (3) ;)

just a suggestion but it might be worth having in your FAQs some technical questions like "why would I want to use this over a SQL alternative?" and "what kind of applications can I build with this?"

Hi, thanks for the thoughts.

For "why would I want to use this over a SQL alternative" see [2].

For "what kind of applications can I build with this?" see [1][2][3][4].


[1] https://www.bigchaindb.com/usecases/

[2] https://blog.bigchaindb.com/three-blockchain-benefits-ae3a2a...

[3] https://blog.bigchaindb.com/six-blockchain-application-verti...

[4] https://blog.bigchaindb.com/where-does-blockchain-scalabilit...

"Scaleable BlockChain" is redundant, isn't it? Same with "BlockChain Database"?

The abstract also seems to imply that this in fact IS NOT a blockchain?

Hi, it's Trent here, CTO of BigchainDB.

The word "blockchain" is much misunderstood. There is a ton of argument over what it actually is. Just a linked list of hashes? Bitcoin and nothing else? I could go on and on.

To me, that debate is less interesting than building systems that actually work. For this, it's useful to think about compute stacks in the past, from mainframe to desktop, from web to cloud to mobile. In each, there are core building blocks that each have their own way of instantiating the elements of computing (storage, processing, communications). Yes, let's go back to first principles:)

Take cloud, on say AWS. Here are some blocks:

* Storage:blob storage -- S3

* Storage:database -- DynamoDB

* Processing -- EC2

* And so on.

The emerging decentralized stack [1] is no different. There is no single monolithic block called "blockchain" that magically does everything, though much of the rhetoric would have you believe that. Rather, there are emerging building blocks.

* Storage:blob storage -- IPFS + FileCoin (and more)

* Storage:database -- BigchainDB

* Storage:pure-play-token -- Bitcoin (this is specific to decentralized space)

* Processing:business logic (aka "smart contracts) -- Ethereum (and more)

"Blockchain" is best treated as a label for the space of decentralization. Side by side with other fields like "artificial intelligence" or "cloud computing".

I think we can all agree that DynamoDB is not "a cloud". It's just an implementation of the "database" building block for the "cloud computing" field. Similarly, BigchainDB is not "a blockchain". It's just an implementation of the "database" building block for the "blockchain" field.

[1] https://blog.bigchaindb.com/blockchain-infrastructure-landsc...

I would say they are polar opposites. Blockchains are incredibly inefficient since every node has to redo the computations. Adding more nodes does not scale them which is what i consider a core part of scalable systems.

Hi, traditional "blockchains" have full replication which of course doesn't scale as you mention. Replication factor of 5000 is overkill (basically what Bitcoin has). Full replication isn't a prerequisite to building something useful. Instead, replicate less, use the extra nodes to store other shards of data, and make sure you have the right guarantees. That's the path.

correct me if I'm wrong, but I'm pretty sure block chains are not super scalable ATM. bitcoin is blocked at 6 transactions a second and future changes are supposed to improve it to 30? that doesn't seem very scalable to me. I could very well be wrong about the details but the point stands. block chains aren't all that scalable

Decentralized blockchains aren't scaleable.

Centralized blockchains on the other hand are easy to scale.

Being centralized kinda defeats the point of them though.... It's better to just have a database.

(Hi, it's Trent here, CTO of BigchainDB.)

We can do a lot better than the scale of Bitcoin. And we are. Scale is part of the point. And you don't need to centralize to get scale. We did improve upon the Model T, didn't we? Or, I remember programming with 16K memory on my computer. Technology improves. And it is here too. That's what we do at BigchainDB.

Hmm, after skimming the white paper, it seems like what you are doing is you are having your consensus algorithm be that Nodes simply vote on what they believe to be the current blockchain.

How does this solution respond to someone spinning up a thousand nodes, and simply voting for their double spend attack?

In part of the paper it is states that " In a BigchainDB network, the governing organization behind the network controls the member list, so Sybil attacks are not an issue.", which is directly contradictory to your statement that it is decentralized.

A decentralized network has no "governing organization".

> How does this solution respond to someone spinning up a thousand nodes, and simply voting for their double spend attack? This is the classic "Sybil attack". But I bet you knew that:)

If you have a member list (ie list of public keys) of who can be server nodes, then you can control this. Each member (public key) only gets one vote. So even if that person makes 1000 copies, it's only 1 vote total from that member.

> governing organization behind the network controls the member list, so Sybil attacks are not an issue.", which is directly contradictory to your statement that it is decentralized. A decentralized network has no "governing organization".

Great question. However the control of this organization is decentralized too. Here's how. IPDB is the BigchainDB public net, and foundation to help govern. Net: each server node is run by a "caretaker". Foundation: each caretaker has one vote. They vote to control the member list (list of caretakers), as well as IPDB board. So, it's decentralized: no single entity is controlling it.

There are other ways to curate "member lists" to address Sybil attacks. E.g. Bitcoin's PoW is basically "one electron one vote" on average (assuming everyone has a modern ASIC). In search of block rewards, many players work hard to maximize their electron spend (ie big ASIC farms), which of course eats a lot of power. Or BitShares' PoS is a riff on "one token one vote". There are more. We simplified the problem for IPDB: start with a great initial member list of reputable orgs that deeply care about the future of the internet (Internet Archive, Open Media Foundation, COALA, etc); and give them control from there. Some heavy lifting up-front to set this up allows great gains in efficiency.

Hello, just wanted to thank you for answering to every question this post gets. It really helps to get the gist of what BigchainDB is! Will read the primer/white paper for sure!

You're welcome! :)

Also, I encourage you to try out BigchainDB. Within just a few seconds you can send your first transaction to IPDB (BigchainDB public net): https://www.bigchaindb.com/getstarted/


Hi, Trent here, CTO of BigchainDB.

Correct, traditional blockchains like Bitcoin aren't scalable.

The whole point of BigchainDB is to bring scale to (the database part) of the blockchain space, using the learnings from distributed databases which do scale.

More info at www.bigchaindb.com, I encourage you to have a read:)

What if I don’t need a scalable blockchain, but I need a tamper-proof persistent ledger? Are there tools that are lighter-weight that can help me there?

Perhaps you're looking for an append-only logging / messaging system like Apache Kafka? Good to explore what's out there and understand what's possible.

BTW using BigchainDB can feel pretty lightweight: it feels like a DBaaS but you don't have to set up the back end, you just get going. In the following, you'll have a tx on the BigchainDB public net (IPDB) in seconds. And the JS or py code to do it yourself is right there too. https://www.bigchaindb.com/getstarted/

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