Summary
gremlin server not getting started with orientDB
description
I am trying to connected gremlin server with orient db but not getting success. while i am trying to start the server it shows Graph [graph] was successfully configured via [conf/orientdb-empty.properties]. after that it gives some groovy.lang.GroovyRuntimeException: error.Below pictures will give you more clarity
https://groups.google.com/forum/#!topic/gremlin-users/YOmjLbl9ObY
followed this post
I'm not sure if those OrientDB "WARNING" messages regarding memory are significant or not. You may want to deal with those separately as OrientDB and Gremlin Server both need JVM memory allocation and you might not want OrientDB taking the full heap.
The error you asked about however is the issue with groovy exception. It looks like you have a simple jar conflict on your path. That can happen sometimes especially if you use a version of a TinkerPop-enabled graph whose TinkerPop version does not match version of Gremlin Server.
My guess is that OrientDB is bringing in an older version of groovy, the 2.4.7 and Gremlin Server already has 2.4.11. You can resolve that pretty easily by examining the ext/orientdb directory in Gremlin Server (assuming that's where the OrientDB plugin installed itself - it should be obvious when you look in the ext directory itself). Remove the groovy 2.4.7 jars from both the ext/orientdb/liband ext/orientdb/plugin directories. Do the same for other conflicts that you come across and things should work. If not, I think you'll have to ask a new more specific question about that particular issue.
Related
We are looking for a embedded graph database that can run withing application scope. I have tried a proof of concept with OrientDB and blazegraph by integrating jar files within application. I'm not sure which one to pick for my application.
Can anybody explain me which is better among these two?
(disclaimer: I was part of the OrientDB team)
The first thing I evaluate is the licence model.
OrientDB is released under ASL while Blazegraph is released under GPLv2.
Can you deal with GPLv2?
Moreover, the blazegraph github repo is not updated since the end of 2016.
OrientDB, AFAIK, is going to release the 3.0 version and 2.2.x should be very stable, it's at 2.2.30 right now.
After that, you can start to evaluate the features
- APIs
- query languages: SQL, gremlin, RDF
- db features: kind on indexes, backup, restore
- addons: console, web interfaces
- client support (java, js, phyton etc.)
Even if you want to go embedded, maybe in the future you will need to deploy your db in standalone way, so I will evaluate compatibility and support of other client languages.
Production system : HDP-2.5.0.0 using Ambari 2.4.0.1
Aplenty demands coming in for executing a range of code(Java MR etc., Scala, Spark, R) atop the HDP but from a desktop Windows machine IDE.
For Spark and R, we have R-Studio set-up.
The challenge lies with Java, Scala and so on, also, people use a range of IDEs from Eclipse to IntelliJ Idea.
I am aware that the Eclipse Hadoop plugin is NOT actively maintained and also has aplenty bugs when working with latest versions of Hadoop, IntelliJ Idea I couldn't find reliable inputs from the official website.
I believe the Hive and HBase client API is a reliable way to connect from Eclipse etc. but I am skeptical about executing MR or other custom Java/Scala code.
I referred several threads like this and this, however, I still have the question that is any IDE like Eclipse/Intellij Idea having an official support for Hadoop ? Even the Spring Data for Hadoop seems to lost traction, it anyways didn't work as expected 2 years ago ;)
As a realistic alternative, which tool/plugin/library should be used to test the MR and other Java/Scala code 'locally' i.e on the desktop machine using a standalone version of the cluster ?
Note : I do not wish to work against/in the sandbox, its about connecting to the prod. cluster directly.
I don't think that there is a genereal solution which would work for all Hadoop services equally. Each solution has it's own development, testing and deployment scenarios as they are different standalone products. For MR case you can use MRUnit to simulate your work locally from IDE. Another option is LocalJobRunner. They both allow you to check your MR logic directly from IDE. For Storm you can use backtype.storm.Testing library to simalate topology's workflow. But they all are used from IDE without direct cluster communications like in case wuth Spark and RStudio integration.
As for the MR recommendation your job should ideally pass the following lifecycle - writing the job and testing it locally, using MRUnit, then you should run it on some development cluster with some test data (see MiniCluster as an option) and then running in on real cluster with some custom counters which would help you to locate your malformed data and to properly maintaine the job.
I am looking for someone that can explain me in simple terms with written instructions how to create a JDBC in PostgreSQL (I am losing my mind with this). I found other answers in this page and others but I couldn't follow them.
I am no programmer, so I didn't undertand any of the instructions of how to do it in webpages and forums -the method mentioned was configuring the classpath environment variable in the command prompt but I got stuck in the command prompt, I think I have to configure the Java console or something.
I am learning some data mining and I wish to connect to some databases in order to practice. I suppose that for someone knowledgeable in this area this should be an easy job.
I prefer to install a driver in postgresql and not using a bridge.
Thanks a lot!
The phrase “how to create a JDBC” makes no sense.
You need to learn some basics first. Be clear on what JDBC is (a standard for connecting or mediating between a database and a Java app), what a JDBC driver is (a particular implementation of JDBC for a specific database.
There are four types of JDBC drivers, the Type 4 (pure Java) being most common in my experience.
For any particular database, you may find there are zero, one or more drivers implemented and available. Some are free-of-cost and open-source, some are not. For example, in Postgres there are two open source drivers, the classic one and a newer rewrite-from-scratch one, as well as some commercial products.
A JDBC driver is only useful when trying to connect a Java app to your database. That may be your own app you are writing, or a finished app you obtained such as a database-administration tool.
You must have a Java implementation installed on your computer, such as one from Oracle or from the OpenJDK project, or from another vendor such as Azul (Zing & Zulu).
You need to learn about the Java Classpath, the list of all the folders where the JVM will be looking for Java classes and JAR files. Read the Oracle Tutorial. The easiest way to go is to drop your JDBC driver JAR into an already existing folder on the Classpath, so you do not need to twiddle with setting the Classpath. For example, on a Mac you could drop your driver into /Library/Java/Extensions.
The JDBC driver sits between the database engine and the Java app. You do not install the JDBC driver into the database engine, such as your Questions mentioned, “install a driver in postgresql”.
[Postgres] ↔ [JDBC driver] ↔ [JVM] ↔ [Java app]
I just installed Membase's version of Memcached (because it seems to be the only / best option to run memcached on windows) and I'm finding a strange problem.
I'm trying to make a little debug tool for myself (only for dev, not for production), and i'm trying to get the contents of memcached. However, all these commands fail:
stats maps
stats cachedump
stats slabs
stats items
stats sizes
I'm running these both from PHP and from telnet.
The only stats options that seem to work are plain "stats", and "stats reset". All the others just say "ERROR"
I'm running memcached version 1.4.4_304_g7d5a132 (according to "stats") or 1.6.4_1_ga5cbcfd (according to "version"). Not sure which one it is.
I've found references to these commands all over the Internet, and I haven't found any information about being deprecated.
Am I doing something wrong?
Are these commands removed from Membase?
Any recommendation on another version of memcached that I can simply install and will run on Windows (the simpler it is to install, the better)
Thank you!
Daniel
Hey Daniel, the Membase server version of memcached is the easiest/best version for Windows available. I'm happy to help you get the information you want...it might also be good to post something on our forums so all can see: http://techzone.couchbase.com/forums/
The main problem here is that we have currently implemented a proxy to allow easier cluster management. I can get more into the details there, but the proxy will aggregate statistics across the cluster and these particular commands don't make sense to aggregate.
If you download the latest Membase version (1.7, pre-release: http://techzone.couchbase.com/products/membase/1-7-beta) you will get the following stats script that will allow you to run all of these commands:
C:\Program Files\Membase\Server\bin\mbstats :11210 raw [maps|items|slabs|sizes] [bucket_name]
I would recommend against using cachedump as it can have performance problems and isn't officially supported by the memcached server (even though it "works" in some small scales).
Perry Krug
Sr. Solutions Architect, Couchbase, Inc.
I can't see any of my schemas when I try to use Eclipse data source explorer. It's not a problem with JDBC connection because I can connect and execute SQL statements. It's just that the tables don't appear. How do I make them to appear?
Very likely you cannot. Access has a very limited ODBC support (as I suppose you are using the JDBC-ODBC bridge driver). You don't have many options. You could purchase a JDBC driver with more functionality (expensive), and if your Access is 97 or 2000, the QuantumDB Eclipse plugin has a trick to get metadata information from these versions, by exploring the system tables. Perhaps you can find other plugins that manage that for more recent versions, but otherwise, you are stuck.