Thank you for the prompt response. But why is it faster? There is an
implementation of isEmpty for rdd:
def isEmpty(): Boolean = withScope {
partitions.length == 0 || take(1).length == 0
}
Basically, the same take(1). Is it because of limit?
Regards,
Artem Shaitarov
From: jasbir.s...@accenture.com [mailto:jasbir.s...@accenture.com]
Sent: Tuesday, 7 March 2017 5:04 p.m.
To: Artem Shaitarov <ashaita...@nz.imshealth.com>; user@spark.apache.org
Subject: RE: Check if dataframe is empty
Dataframe.take(1) is faster.
From: ashaita...@nz.imshealth.com<mailto:ashaita...@nz.imshealth.com>
[mailto:ashaita...@nz.imshealth.com]
Sent: Tuesday, March 07, 2017 9:22 AM
To: user@spark.apache.org<mailto:user@spark.apache.org>
Subject: Check if dataframe is empty
Hello!
I am pretty sure that I am asking something which has been already asked lots
of times. However, I cannot find the question in the mailing list archive.
The question is - I need to check whether dataframe is empty or not. I receive
a dataframe from 3rd party library and this dataframe can be potentially empty,
but also can be really huge - millions of rows. Thus, I want to avoid of doing
some logic in case the dataframe is empty. How can I efficiently check it?
Right now I am doing it in the following way:
private def isEmpty(df: Option[DataFrame]): Boolean = {
df.isEmpty || (df.isDefined && df.get.limit(1).rdd.isEmpty())
}
But the performance is really slow for big dataframes. I would be grateful for
any suggestions.
Thank you in advance.
Best regards,
Artem
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