mapR | Combining the power of Hadoop and R
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kandi X-RAY | mapR Summary
Combining the power of Hadoop and R
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QUESTION
I'm trying to create a table in Hadoop but with the current_timestamp() as default value for a column:
...ANSWER
Answered 2022-Mar-15 at 17:55DEFAULT
constraint in Hive DDL was implemented in version 3.0, see JIRA HIVE-18726.
Ashutosh Chauhan added a comment - 22/May/18 23:16
This jira is resolved and released with Hive 3.0 If you find an issue with it, please create a new jira.
But even in that version, you can only define the constraints on MANAGED tables, and MANAGED tables do not support Parquet format.
For EXTERNAL tables (that can work with Parquet files), only RELY
constraint is supported, according to Hive manual.
QUESTION
In my application config i have defined the following properties:
...ANSWER
Answered 2022-Feb-16 at 13:12Acording to this answer: https://stackoverflow.com/a/51236918/16651073 tomcat falls back to default logging if it can resolve the location
Can you try to save the properties without the spaces.
Like this:
logging.file.name=application.logs
QUESTION
I have a Go application running in a Kubernetes cluster which needs to read files from a large MapR cluster. The two clusters are separate and the Kubernetes cluster does not permit us to use the CSI driver. All I can do is run userspace apps in Docker containers inside Kubernetes pods and I am given maprticket
s to connect to the MapR cluster.
I'm able to use the com.mapr.hadoop
maprfs
jar to write a Java app which is able to connect and read files using a maprticket
, but we need to integrate this into a Go app, which, ideally, shouldn't require a Java sidecar process.
ANSWER
Answered 2022-Jan-27 at 21:16This is a good question because it highlights the way that some environments impose limits that violate the assumptions external software may hold.
And just for reference, MapR was acquired by HPE so a MapR cluster is now an HPE Ezmeral Data Fabric cluster. I am still training myself to say that.
Anyway, the accepted method for a generic program in language X to communicate with the Ezmeral Data Fabric (the filesystem formerly known as MapR FS) is to mount the file system and just talk to it using file APIs like open/read/write and such. This applies to Go, Python, C, Julia or whatever. Inside Kubernetes, the normal way to do this mount is to use a CSI driver that has some kind of operator working in the background. That operator isn't particularly magical ... it just does what is needful. In the case of data fabric, the operator mounts the data fabric using NFS or FUSE and then bind mounts[1] part of that into the pod's awareness.
But this question is cool because it precludes all of that. If you can't install an operator, then this other stuff is just a dead letter.
There are three alternative approaches that may work.
NFS mounts were included in Kubernetes as a native capability before the CSI plugin approach was standardized. It might still be possible to use that on a very vanilla Kubernetes cluster and that could give access to the data cluster.
It is possible to integrate a container into your pod that does the necessary FUSE mount in an unprivileged way. This will be kind of painful because you would have to tease apart the FUSE driver from the data fabric install and get it to work. That would let you see the data fabric inside the pod. Even then, there is no guarantee Kubernetes or the OS will allow this to work.
There is an unpublished Go file system client that users the low level data fabric API directly. We don't yet release that separately. For more information on that, folks should ping me directly (my contact info is everywhere ... email to ted.dunning hpe.com or gmail.com works)
The data fabric allows you to access data via S3. With the 7.0 release of Ezmeral Data Fabric, this capability is heavily revamped to give massive performance especially since you can scale up the number of gateways essentially without limit (I have heard numbers like 3-5GB/s per stateless connection to a gateway, but YMMV). This will require the least futzing and should give plenty of performance. You can even access files as if they were S3 objects.
QUESTION
I have Hadoop/HBase/Pig all running successfully under windows 10. But when I go to install Hive 3.1.2 using this guide I get an error initializing Hive under Cygwin:
...ANSWER
Answered 2021-Dec-31 at 16:15To get rid of the first error I'd found (and posted about in the OP), I had to go to the $HIVE_HOME/lib
directory and remove this old guava library file: guava-19.0.jar
I had to make sure that the guava library I'd copied from the Hadoop library was there: guava-27.0-jre.jar
On the next attempt I got a different error:
QUESTION
I have a scala spark project that fails because of some dependency hell. Here is my build.sbt:
...ANSWER
Answered 2021-Dec-19 at 18:12I had to do the inevitable and add this to my build.sbt:
QUESTION
Loaded data of spark data frame in hive table. Before loading df.show(10) shows date column in proper format and data, but while querying hive table date column shows null.
...ANSWER
Answered 2021-Dec-17 at 07:47Can you try changing the DDL to use serde rather than TxtInputFormat.
QUESTION
I've created hive external table.
...ANSWER
Answered 2021-Nov-16 at 13:17If nothing else helps, as a workaround you can drop/create table and recover partitions. The table is EXTERNAL and drop will not affect the data.
(1) Drop table
QUESTION
I'm trying to export a HDFS to MYSQL database. I found various different solution but none of them worked, I even tried to remove the WINDOWS-1251 chars from the file.
As a small summary - I'm using virtualbox with Hortonworks image for this operations.
My HIVE in the default database:
...ANSWER
Answered 2021-Sep-13 at 11:36Solution to your first problem -
--hcatalog-database mydb --hcatalog-table airquality
and remove --export dir
parameter.
Sqoop export cannot replace data. Pls issue a sqoop eval statement before loading main table to truncate it.
QUESTION
I am pretty new to MapR and I have a task about creating a MapR volume. I used this command
...ANSWER
Answered 2021-Sep-13 at 09:51When you say;
I created this path '/MyCluster/apps/application_logs/node1' using mkdir
I assume that you have created it in local file system. The path
parameter needs to be created in MapR
file system.
To do that, you can either create the dir by interacting with MapR
file system directly as follows;
QUESTION
I have a working Java Map Reduce Program with 2 jobs. The output of the first reduce is written on a file and read by the second mapper.
I would like to change the first reducer output to be a SequenceFile.
How can i do this?
This is the main of my program
...ANSWER
Answered 2021-Aug-10 at 10:01context.write(Text, Text)
and job.setOutputValueClass(IntWritable.class);
disagree with one another. Make them consistent and it should work.
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Install mapR
From command line, run in the terminal: <pre><code>export HADOOP_HOME="path/to/home" export HADOOP_CMD="${HADOOP_HOME}/bin/hadoop" </code></pre>
From RStudio, append to your ~/.Renviron file the following two lines (basically no export!): <pre><code>HADOOP_HOME="path/to/home" HADOOP_CMD="${HADOOP_HOME}/bin/hadoop" </code></pre>
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