Category Archives: Problems

Searching for objects using multiple dimensions

Lets take a look at a scenario where you are trying to search for things by their attributes, not their description. They can be users, documents, or any object that could be described by discrete values in multiple dimensions. What does that mean exactly? Well, let me give you an example: searching for a dog. My family includes 2 four legged furry creatures named Tyler and Ronnie. They are my half lab, half golden retrievers. Dogs come in all shapes and sizes, from teacup breeds with adult weights around 5 lbs, to giant Mastiff breeds over 150 lbs. But most people don’t care exactly how much a dog weights, only their general size.


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Neo4j is faster than MySQL in performing recursive query

5mysql

A user on StackOverflow was wondering about the performance between Neo4j and MySQL for performing a recursive query. They started with Neo4j performing the query in 240 seconds. Then an optimized cypher query got them down to 40 seconds. Then I got them down to…
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Our own Multi-Model Database – Part 6

shitty6

Back in Part 2 we ran some JMH tests to see how many empty nodes we could create. Let’s try that test one more time, but adding some properties. Our nodes will have a username, an age and a weight randomly assigned. It’s not a long test, but just enough to give us a ballpark.
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Our own Multi-Model Database – Part 5

shitty5

In part 4 I promised metrics and a shell, so that’s what we’ll tackle today. We are lucky that the Metrics library can be plugged into Jooby without much effort… and double lucky that the Crash library can also be plugged into Jooby without much effort. This is what we are all about here because we’re a bunch of lazy, impatient developers who are ignorant of the limits of our capabilities and who would rather reuse open source code instead of falling victim to the “Not Invented Here” syndrome and do everything from scratch.
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Our own Multi-Model Database – Part 4

shitty4

Please read parts 1, 2 and 3 before continuing or you’ll be lost.

We started adding an HTTP server to our database last time and created just a couple of end points. Today we’ll finish out the rest of the end points. We’ll also be good open source developers by hooking in Continuous Integration , Test Coverage and Continuous Deployment.

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Multi-Threading a Traversal

multi-threads

What would you think if I ran out of time,
Would you stand up and walk out on me?
Lend me your eyes and I’ll write you a post
And I’ll try not to run out of memory.

Oh, I get by with a little help from my threads
Mm, I get high with a little help from my threads
Mm, gonna try with a little help from my threads

Today we are going to take a look at how to take a Neo4j traversal and split it up into lots of smaller traversals. I promise it will be electrifying.
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Our own Multi-Model Database – Part 3

shitty3

If you haven’t read part 1 and part 2 then do that first or you’ll have no clue what I’m doing, and I’d like to be the only one not knowing what I’m doing.

We’ve built the beginnings of this database but so far it’s just a library and for it to be a proper database we need to be able to talk to it. Following the Neo4j footsteps, we will wrap a web server around our database and see how it performs.

There are a ton of Java based frameworks and micro-frameworks out there. Not as bad as the Javascript folks, but that still leaves us with a lot of choices. So as any developer would do I turn to benchmarks done by other people of stuff that doesn’t apply to me, and you won’t believe what I found –scratch that, yes you will, I got benchmarks.
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OUR OWN MULTI-MODEL DATABASE – PART 2

shitty2

If you haven’t read part 1 then do that first or this won’t make sense, well nothing makes sense but this specially won’t.

So before going much further I decided to benchmark our new database and found that our addNode speed is phenomenal, but it was taking forever to create relationships. See some JMH benchmarks below:

Benchmark                                                           Mode  Cnt     Score     Error  Units
ChronicleGraphBenchmark.measureCreateEmptyNodes                    thrpt   10  1548.235 ± 556.615  ops/s
ChronicleGraphBenchmark.measureCreateEmptyNodesAndRelationships    thrpt   10     0.165 ±   0.007  ops/s

Each time I was creating 1000 users, so this test shows us we can create over a million empty nodes in one second. Yeah ChronicleMap is damn fast. But then when I tried to create 100 relationships for each user (100,000 total) it was taking forever (about 6 seconds). So I opened up YourKit and you won’t believe what I found out next (come on that’s some good clickbait).
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Connected

connected

The Stereo MC’s song “Connected” could be about some recently gained insight and the realization that maybe some of the people you held dear are phonies and while the reality of the situation is scary, you cannot allow yourself to turn a blind eye anymore or allow yourself to backslide by disconnecting from the real world.

Or it could be a warning about how we’ve all been blinded by SQL databases for too long and we must instead look to connect our data with Graph Databases. About how those new connections may be scary (like because of fraud detection) but they are necessary to better understand reality.

Either way, we may want to see if two nodes in Neo4j are connected and I’m going to show you how to do that faster.
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News Feeds

Ron Burgundy Gets Hungry

Ron Burgundy (in Anchorman) gets Hungry

The “News Feed” is a core feature of social networks like Twitter, Facebook, or Vine (RIP). Let’s take a look at how we could model and implement this in Neo4j. Our social network needs Users (otherwise it would be kinda empty) that FOLLOW each other (otherwise it would not be very social). Those users need to POST some Messages (otherwise it would be boring). Here is our first attempt at a model (using Arrows):
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