My data is in the format of csv file (sam,1,34,there,hello). I want to add an image to each row in the csv file using hadoop. Does any body have any idea about it. I have seen about Hipi which process the image files and adds it also. But I want to add as a column to csv file.
If you have to use CSV file, consider using Base64 encoding over binary image data - it will give you a printable string. But in general I would recommend you to switch to sequence file, there you would be able to store the image directly in a binary format
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I've created an ADF pipeline that converts a delimited file to parquet in our datalake. I've added an additional column and set the value using the following expression #convertfromutc(utcnow(),'GMT Standard Time','o'). The problem I am having is when I look at the parquet file it is coming back in the US format.
eg 11/25/2021 14:25:49
Even if I use #if(pipeline().parameters.LoadDate,json(concat('[{"name": "LoadDate" , "value": "',formatDateTime(convertfromutc(utcnow(),'GMT Standard Time','o')),'"}]')),NULL) to try to force the format on the extra column it still comes back in the parquet in the US format.
Any idea why this would be and how I can get this to output into parquet as a proper timestamp?
Mention the format pattern while using convertFromUtc function as shown below.
#convertFromUtc(utcnow(),’GMT Standard Time’,’yyyy-MM-dd HH:mm:ss’)
Added date1 column in additional columns under source to get the required date format.
Preview of source data in mappings. Here data is previewed as giving format in convertFromUtc function.
Output parquet file:
Data preview of the sink parquet file after copying data from the source.
I'm doing a string search for certain values that I would expect to be in a parquet file. Some are found, others are not found.
Yet when I view the parquet file content from a databricks notebook, I can find a missing value within the data shown.
Approx 70% of the data I search for with the raw parquet file (on windows) is found. But spot checks for some of the remaining data is found via the notebook.
Why is some data present when viewing the raw parquet content and other data isn't? It's also the same data each time which is or isn't found.
Here's a screenshot example. It shows a case where a value from input json IS found in the raw parquet, and a case where a value from input json is not found in raw parquet (but IS found in a csv export of same data from databricks)
I have to process some raw data files in csv with cleansing transformations and load as .parquet file in clenase layer. Raw layer file(csv) and Cleanse layer file should have same name.
But I cannot save the .parquet file with the given name, it is creating directory and underneath .parquet files are saved with random name. Please help how to accomplish this.
This is how parquet files are designed to be, a collection of multiple row groups.
The name of your parquet is the folder the chunks of data will be saved under.
If you want a single file, you will have to use a different file format, and you will likely lose the parallelization capabilities offered by parquet for both read and write.
I would like to know if there is a way to load a large data in csv format, and then save only a part (ex: 50-100 lines) in csv format.
CSV in reality is just text, you can turn your image into text byte but will not be usable as CSV.
If your data is too large and you can't load everything at once, you could read the csv file line by line and get the data that you want.
What kind of file formats can be read using PIG?
How can I store them in different formats? Say we have CSV file and I want to store it as MXL file how this can be done? Whenever we use STORE command it makes directory and it stores file as part-m-00000 how can I change name of the file and overwrite directory?
what kind of file formats can be read using PIG? how can i store them in different formats?
There are a few built-in loading and storing methods, but they are limited:
BinStorage - "binary" storage
PigStorage - loads and stores data that is delimited by something (such as tab or comma)
TextLoader - loads data line by line (i.e., delimited by the newline character)
piggybank is a library of community contributed user-defined functions and it has a number of loading and storing methods, which includes an XML loader, but not a XML storer.
say we have CSV file n i want to store it as MXL file how this can be done?
I assume you mean XML here... Storing in XML is something that is a bit rough in Hadoop because it splits files on a reducer basis, so how do you know where to put the root tag? this likely should be some sort of post-processing to produce wellformed XML.
One thing you can do is to write a UDF that converts your columns into an XML string:
B = FOREACH A GENERATE customudfs.DataToXML(col1, col2, col3);
For example, say col1, col2, col3 are "foo", 37, "lemons", respectively. Your UDF can output the string "<item><name>Foo</name><num>37</num><fruit>lemons</fruit></item>".
whenever we use STORE command it makes directory and it stores file as part-m-00000 how can i change name of the file and overwrite directory?
You can't change the name of the output file to be something other than part-m-00000. That's just how Hadoop works. If you want to change the name of it, you should do something to it after the fact with something like hadoop fs -mv output/part-m-00000 newoutput/myoutputfile. This could be done with a bash script that runs the pig script then executes this command.