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ArangoDB

arangodb.org

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Re: ArangoDB

#31

Post by klaustopher »

mk3 wrote: post #26

I have tried to run ArangoDB under Node.js had some little successes, but in general their claim that they have drivers for many platforms is far from reality. Also why not to release node.js binary drivers instead of pushing people to use foxx. Also simple browsable docs would be nice instead of chunked documents covering hell knows what. Finding link to their query language was a big hassle :) Also their graph trav…

There is a node js driver and even an integration into JugglingDB. See https://www.arangodb.org/drivers. And in the end, it's all bascially HTTP calls that you are making to query the database.

Re: ArangoDB

#32

Post by poseid »

mk3 wrote: post #26

I have tried to run ArangoDB under Node.js had some little successes, but in general their claim that they have drivers for many platforms is far from reality. Also why not to release node.js binary drivers instead of pushing people to use foxx. Also simple browsable docs would be nice instead of chunked documents covering hell knows what. Finding link to their query language was a big hassle :) Also their graph trav…

I agree somewhat with the documentation part. The getting started is nice, but the gap between reading about concepts and the actual references, how to use them is a bit large at times. Best would be a reference based documentation, e.g. as in http://underscorejs.org/

Re: ArangoDB

#33

Post by Spearchucker »

jsteemann wrote: post #5
shin_lao wrote: post #4

I have a feeling, tell me if you share it. "Wouldn't it be cool to have a multipurpose database which we would be able to query with a language, but not SQL, because SQL sucks, for some reason.". Put it differently, what does ArangoDB, MongoDB, whateverDB bring that relational databases didn't bring 30 years ago?

To name just a few: - being relaxed about schemas: no more long-running ALTER TABLE commands, no more up-front schema definitions that waste time when doing proof-of-concepts etc. - being friendly to variable and hierarchical data: no more entity-attribute-value patterns and necessity to store JSON etc. as BLOBs - integration of scripting languages such as JavaScript, so you can have one language for the full stack i…

I do all of what you mention using SQL Express (I don't use JSON though, because binary serialisation is faster). Abstraction means I save my data as documents/blobs, can still do joins, don't have to alter tables (when de-serialised entities are self-describing), fully indexed entity content.

It means thinking about what and how you're going to do something before you start coding (design up front). It means creating a throw-away proof of concept before you start coding. But it is flexible, extensible, and changes to the schema, as it were, do not impact up-stream dependencies.

Re: ArangoDB

#34

Post by cwmma »

jsteemann wrote: post #11
vicaya wrote: post #7

"Transactions in ArangoDB are atomic, consistent, isolated, and durable (ACID)." "Collections consist of memory-mapped datafiles...". "by default, ArangoDB uses the eventual way of synchronization...synchronizes data to disk in a background thread." So it's not ACID by default and practically not usable with immedaite sync turned on (huge amount of seeks due to use of mmap), just like mongo.

As in many databases, ArangoDB allows some choices regarding durability. Immediate disk synchronisation is turned off by default in ArangoDB. Synchronisation is then performed by a background thread, which is frequently executing syncs. By the way, several other NoSQL databases have immediate synching turned off by default, e.g. CouchDB, MongoDB. In ArangoDB you turn on immediate synchronisation on a per collection l…

IM pretty sure you can yank the power cord from couchdb as soon as you get a (positive) response and the data will be saved.

Unlike mongo, couch has a sophisticated append only btree format for storing data, that is almost impossible to corrupt.

Re: ArangoDB

#35

Post by Xylakant »

cwmma wrote: post #34
jsteemann wrote: post #11

Earlier quoted context omitted.

As in many databases, ArangoDB allows some choices regarding durability. Immediate disk synchronisation is turned off by default in ArangoDB. Synchronisation is then performed by a background thread, which is frequently executing syncs. By the way, several other NoSQL databases have immediate synching turned off by default, e.g. CouchDB, MongoDB. In ArangoDB you turn on immediate synchronisation on a per collection l…

IM pretty sure you can yank the power cord from couchdb as soon as you get a (positive) response and the data will be saved. Unlike mongo, couch has a sophisticated append only btree format for storing data, that is almost impossible to corrupt.

Saved (durable) and hard to corrupt are different properties of a database. For example elasticsearch uses the lucene index format in the background. It's write once per segment. Once a segment is written, data is save and it's (apart from disk corruption) impossible to corrupts, since the file is never opened for writing again. However, segments are not written immediately after a document is received - so when yanking the power cord right after a write to the cluster, you'll loose data - however without any danger of corruption since the last, partially written segment is discarded. Couchdb behaves in a similar fashion: If the last bit of the storage file contains corrupt data, it is discarded. I'm not absolutely certain atm about the default durability settings in couch, so I can't say if the write happens before or after the "ack" from the server. However, since disk controllers cheat and sometimes a "flush" to disk doesn't actually flush, you can get data loss regardless of the promises your database makes.

Re: ArangoDB

#36

Post by nawitus »

Spearchucker wrote: post #33
jsteemann wrote: post #5

Earlier quoted context omitted.

To name just a few: - being relaxed about schemas: no more long-running ALTER TABLE commands, no more up-front schema definitions that waste time when doing proof-of-concepts etc. - being friendly to variable and hierarchical data: no more entity-attribute-value patterns and necessity to store JSON etc. as BLOBs - integration of scripting languages such as JavaScript, so you can have one language for the full stack i…

I do all of what you mention using SQL Express (I don't use JSON though, because binary serialisation is faster). Abstraction means I save my data as documents/blobs, can still do joins, don't have to alter tables (when de-serialised entities are self-describing), fully indexed entity content. It means thinking about what and how you're going to do something before you start coding (design up front). It means creatin…

SQL Express guarantees consistency, but most NoSQL databases guarantee availability. Although many SQL databases can be used to implement the same functionality as a NoSQL database, that doesn't mean it's as easy. And easiness is what matters, because if something is easier, you may spend less time working on it and that saves money.

The term "NoSQL" database is a bit problematic, because the definition only says that the database is not relational, but the average NoSQL database has other differences with the average SQL database: using JSON and JavaScript, and perhaps queries with HTTP and so on.

The point is not "what is possible", but choosing the best tool for the job.

Re: ArangoDB

#37

Post by bjerun »

Xylakant wrote: post #35
cwmma wrote: post #34

Earlier quoted context omitted.

IM pretty sure you can yank the power cord from couchdb as soon as you get a (positive) response and the data will be saved. Unlike mongo, couch has a sophisticated append only btree format for storing data, that is almost impossible to corrupt.

Saved (durable) and hard to corrupt are different properties of a database. For example elasticsearch uses the lucene index format in the background. It's write once per segment. Once a segment is written, data is save and it's (apart from disk corruption) impossible to corrupts, since the file is never opened for writing again. However, segments are not written immediately after a document is received - so when yank…

Durability is indeed hard to archive - as you pointed out disk controller sometimes simply tell you a lie.

With respect to corruption ArangoDB behaves similar: It uses an append-only log file with CRC checksums. So, if the last bit of storage contains corrupt data, it is discarded.

Re: ArangoDB

#38

Post by Spearchucker »

nawitus wrote: post #36
Spearchucker wrote: post #33

Earlier quoted context omitted.

I do all of what you mention using SQL Express (I don't use JSON though, because binary serialisation is faster). Abstraction means I save my data as documents/blobs, can still do joins, don't have to alter tables (when de-serialised entities are self-describing), fully indexed entity content. It means thinking about what and how you're going to do something before you start coding (design up front). It means creatin…

SQL Express guarantees consistency, but most NoSQL databases guarantee availability. Although many SQL databases can be used to implement the same functionality as a NoSQL database, that doesn't mean it's as easy. And easiness is what matters, because if something is easier, you may spend less time working on it and that saves money. The term "NoSQL" database is a bit problematic, because the definition only says tha…

Indeed. Although I'd say most no-SQL databases guarantee partition tolerance (I can guarantee availability using a SQL database).

SQL Express runs as a single instance on a client so you get all three - consistency, availability and partition tolerance[1]. When running something else on more than one node you can choose two of those three. Availability and consistency are usually chosen because of business drivers. If partition tolerance is required (I've yet to encounter a scenario that makes a compelling case for it [2]) then eventual consistency is the price.

There are databases out there that will suite any combination of the three. Unfortunately the equation is somewhat more complex because databases that offer consistency and partition tolerance (for example) don't typically offer JOIN -like functionality.

Everything's a trade-off. Other considerations are tried and tested v. bleeding edge; painful v. painless; ideal v. affordable; and so forth.

[1] http://en.wikipedia.org/wiki/CAP_theorem

[2] I'm not saying there aren't scenarios where it makes sense (Google, for example) - just that I've not encountered one. I do run into many people that want Mongo and, not understanding what they're asking for would be better of with a relational database.

Re: ArangoDB

#39

Post by poseid »

mrinterweb wrote: post #20
shin_lao wrote: post #4

I have a feeling, tell me if you share it. "Wouldn't it be cool to have a multipurpose database which we would be able to query with a language, but not SQL, because SQL sucks, for some reason.". Put it differently, what does ArangoDB, MongoDB, whateverDB bring that relational databases didn't bring 30 years ago?

I'd say that one of the biggest thing that many of these NoSQL data stores brings is auto-sharding and being able to query/map reduce a distributed data source. Relational dbs work pretty well so long as you can vertically scale your data and or don't need to query across databases. Horizontal scaling is the tricky part for relational dbs that NoSQL data stores market as their big selling point.

Indeed, an the AQL looks interesting for the use case where Mongo fails, e.g. http://www.sarahmei.com/blog/2013/11/11/why-you-should-never...

Re: ArangoDB

#40

Post by nutate »

RyanZAG wrote: post #9
mikro2nd wrote: post #6

> There are driver for all major language like Ruby, Python, PHP, JavaScript, and Perl. I chuckled at the absence of the most widely deployed language on the planet. I dare say that there is a driver for Java - didn't look, because after browsing through a reasonable portion of their site, I still couldn't get a simple explanation of what this DB allegedly does and doesn't do.

There is a Java driver and even an object mapper based off jackson - https://www.arangodb.org/drivers This seems to be a mongodb clone with some extra features added on to make it a bit closer to a relational db, I guess. Looks interesting but likely suffers from the same problems MongoDB suffers from (data safety, scaling difficulties, etc) EDIT: Have to say, the idea of a mongodb database with graph operations buil…

I jumped on arango, looking for a small graphdb I could run locally on my machine. They've since moved it to a much wider scope. Turns out I abandoned that project idea (like most... :D), but I think Arango is sufficiently unique to merit more investment.
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