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https://issues.apache.org/jira/browse/HIVE-19700?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16491193#comment-16491193
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Naveen Gangam commented on HIVE-19700:
--------------------------------------
[~ychena] Thanks for the comments. I am not sure what you mean by print
everything.
In the output I posted above, there is some rogue characters (see the null at
the begining of the line?)
{code}
$ cat /tmp/b_multi.out
null+-------------+-------------+-------------+-------------+-------------+--------------+--------------+--------------+--+
{code}
That null character is addressed.
I althought that making the prompt "" was a cleaner fix. However, in case of
multiline queries in a script file, beeline prints out a blank line for every
line of the query at the begining and end of the resultset. The code that
causes that behavior is below (prompt="" and mask !=null)
{code}
private void beforeReadLine(final String prompt, final Character mask) {
if (mask != null && maskThread == null) {
final String fullPrompt = "\r" + prompt
+ " "
+ " "
+ " "
+ "\r" + prompt;
{code}
So if the script file had a 20-line query, the beeline output will contain 20
blank lines before the output and 20 blank lines after the output. So that
could break existing usecases. Thanks
> Workaround for JLine issue with UnsupportedTerminal
> ---------------------------------------------------
>
> Key: HIVE-19700
> URL: https://issues.apache.org/jira/browse/HIVE-19700
> Project: Hive
> Issue Type: Bug
> Reporter: Naveen Gangam
> Assignee: Naveen Gangam
> Priority: Major
> Fix For: 2.2.1
>
> Attachments: HIVE-19700.patch
>
>
> From the JLine's ConsoleReader, readLine(prompt, mask) calls the following
> beforeReadLine() method.
> {code}
> try {
> // System.out.println("is terminal supported " +
> terminal.isSupported());
> if (!terminal.isSupported()) {
> beforeReadLine(prompt, mask);
> }
> {code}
> So specifically when using UnsupportedTerminal {{-Djline.terminal}} and
> {{prompt=null}} and {{mask!=null}}, a "null" string gets printed to the
> console before and after the query result. {{UnsupportedTerminal}} is
> required to be used when running beeline as a background process, hangs
> otherwise.
> {code}
> private void beforeReadLine(final String prompt, final Character mask) {
> if (mask != null && maskThread == null) {
> final String fullPrompt = "\r" + prompt
> + " "
> + " "
> + " "
> + "\r" + prompt;
> maskThread = new Thread()
> {
> public void run() {
> while (!interrupted()) {
> try {
> Writer out = getOutput();
> out.write(fullPrompt);
> {code}
> So the {{prompt}} is null and {{mask}} is NOT in atleast 2 scenarios in
> beeline.
> when beeline's silent=true, prompt is null
> *
> https://github.com/apache/hive/blob/master/beeline/src/java/org/apache/hive/beeline/BeeLine.java#L1264
> when running multiline queries
> *
> https://github.com/apache/hive/blob/master/beeline/src/java/org/apache/hive/beeline/Commands.java#L1093
> When executing beeline in script mode (commands in a file), there should not
> be any masking while reading lines from the script file. aka, entire line
> should be a beeline command or part of a multiline hive query.
> So it should be safe to use a null mask instead of
> {{ConsoleReader.NULL_MASK}} when using UnsupportedTerminal as jline terminal.
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