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From "Paul Rogers (JIRA)" <j...@apache.org>
Subject [jira] [Created] (DRILL-5006) Drill web UI hangs if execute a query with a large result set
Date Fri, 04 Nov 2016 18:32:58 GMT
Paul Rogers created DRILL-5006:

             Summary: Drill web UI hangs if execute a query with a large result set
                 Key: DRILL-5006
                 URL: https://issues.apache.org/jira/browse/DRILL-5006
             Project: Apache Drill
          Issue Type: Bug
    Affects Versions: 1.8.0
            Reporter: Paul Rogers
            Priority: Minor

Using a pipe-separated file 388 MB in size, do a SELECT * on the file (also added an ORDER
BY). This produces a huge result set. Do this query in the web UI. A number of things happen:

* Using top, we see that Drill grinds on the query for a while, as expected.
* Top shows Drill to stop consuming CPU. The web UI does nothing during this time. This time
lasts several minutes.
* Drill eventually shows the first 30 rows of the query.
* The browser "spins" forever waiting for the server to finish sending data.
* The Safari browser enters the "spinning beachball" state on that page because of memory
use, waiting for data, etc.

Fetching of data seems to never complete, even after many minutes.

It is known that the web UI is limited. But, it should not be possible to overwhelm it with
an errant query. Possible solutions:

1. Spill large results to disk, then page them in the display. Discard them after the web
session ends, after some amount of time, etc. (This is that long-term, but hard solution.)
2. Read the first 30 (or whatever results) and display them. Read and discard all other results
to keep the browser (or web server or whatever is hanging) from becoming overloaded.

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