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From Parth Chandra <pchan...@mapr.com>
Subject Re: Additional information on JSON_SUB_SCAN operator and access to query profiles not from the Web UI
Date Thu, 19 Jan 2017 22:48:38 GMT
JSON_SUB_SAN is the Json reader. It uses Jackson to do actual parsing, and converts the data
into Drill's internal value vector format. TEXT_SUB_SCAN is the corresponding operator for

If the Drill system has access to the /log/profile directory then you can, in fact, use Drill
to query the json in the query profile. You might want to setup an nfs location for the query
profiles,so that the directory is visible to all drillbits.  The simply create a new workspace
pointing to the directory. You will be able to read the profiles like any other Json file.

From: Nikos R. Katsipoulakis <nick.katsip@gmail.com>
Sent: Wednesday, January 11, 2017 7:37:30 AM
To: user@drill.apache.org
Subject: Additional information on JSON_SUB_SCAN operator and access to query profiles not
from the Web UI

Hello all,

I am a new user of Apache Drill and I am in the process of better
understanding its internals. To that end, I have two questions, for which I
was unable to find more information online.

First, when I execute an EXPLAIN command for a query that gets its data
from JSON files, I see a physical operator named JSON_SUB_SCAN. What does
that operator exactly do? Is it only used for parsing (extracting) fields
from JSON data? Or does it perform additional processing? As far as I know,
Drill uses Jackson Streaming API for extracting JSON data. Is that still
true? Finally, what is the equivalent operator for CSV files?

Second, I need to access query profiles from a server that is behind a
firewall. Therefore, accessing the URL of that machine on port 8047 is a
headache (since I have to submit a ticket to IT Support). My question is
whether I can access the Query Profiles in any other way? Like from the
sqlline or through log/profile files created while executing queries.

Thank you and Kind Regards,

Nikos R. Katsipoulakis,
Department of Computer Science
University of Pittsburgh

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