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From jbap...@apache.org
Subject [20/51] [partial] incubator-impala git commit: IMPALA-4181 [DOCS] Publish rendered Impala documentation to ASF site
Date Wed, 12 Apr 2017 18:25:24 GMT
http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/75c46918/docs/build/html/topics/impala_num_nodes.html
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+<!DOCTYPE html
+  SYSTEM "about:legacy-compat">
+<html lang="en"><head><meta http-equiv="Content-Type" content="text/html;
charset=UTF-8"><meta charset="UTF-8"><meta name="copyright" content="(C) Copyright
2017"><meta name="DC.rights.owner" content="(C) Copyright 2017"><meta name="DC.Type"
content="concept"><meta name="DC.Relation" scheme="URI" content="../topics/impala_query_options.html"><meta
name="prodname" content="Impala"><meta name="prodname" content="Impala"><meta
name="version" content="Impala 2.8.x"><meta name="version" content="Impala 2.8.x"><meta
name="DC.Format" content="XHTML"><meta name="DC.Identifier" content="num_nodes"><link
rel="stylesheet" type="text/css" href="../commonltr.css"><title>NUM_NODES Query Option</title></head><body
id="num_nodes"><main role="main"><article role="article" aria-labelledby="ariaid-title1">
+
+  <h1 class="title topictitle1" id="ariaid-title1">NUM_NODES Query Option</h1>
+  
+  
+
+  <div class="body conbody">
+
+    <p class="p">
+      
+      Limit the number of nodes that process a query, typically during debugging.
+    </p>
+
+    <p class="p">
+      <strong class="ph b">Type:</strong> numeric
+    </p>
+
+<p class="p">
+      <strong class="ph b">Allowed values:</strong> Only accepts the values 0
+      (meaning all nodes) or 1 (meaning all work is done on the coordinator node).
+</p>
+
+    <p class="p">
+      <strong class="ph b">Default:</strong> 0
+    </p>
+
+     <p class="p">
+        <strong class="ph b">Usage notes:</strong>
+      </p>
+
+     <p class="p">
+       If you are diagnosing a problem that you suspect is due to a timing issue due to
+       distributed query processing, you can set <code class="ph codeph">NUM_NODES=1</code>
to verify
+       if the problem still occurs when all the work is done on a single node.
+     </p>
+
+    <p class="p">
+        You might set the <code class="ph codeph">NUM_NODES</code> option to
1 briefly, during <code class="ph codeph">INSERT</code> or
+        <code class="ph codeph">CREATE TABLE AS SELECT</code> statements. Normally,
those statements produce one or more data
+        files per data node. If the write operation involves small amounts of data, a Parquet
table, and/or a
+        partitioned table, the default behavior could produce many small files when intuitively
you might expect
+        only a single output file. <code class="ph codeph">SET NUM_NODES=1</code>
turns off the <span class="q">"distributed"</span> aspect of the
+        write operation, making it more likely to produce only one or a few data files.
+      </p>
+
+    <div class="note warning note_warning"><span class="note__title warningtitle">Warning:</span>

+    <p class="p">
+      Because this option results in increased resource utilization on a single host,
+      it could cause problems due to contention with other Impala statements or
+      high resource usage. Symptoms could include queries running slowly, exceeding the memory
limit,
+      or appearing to hang. Use it only in a single-user development/test environment;
+      <strong class="ph b">do not</strong> use it in a production environment
or in a cluster with a high-concurrency
+      or high-volume or performance-critical workload.
+    </p>
+    </div>
+
+
+  </div>
+<nav role="navigation" class="related-links"><div class="familylinks"><div
class="parentlink"><strong>Parent topic:</strong> <a class="link" href="../topics/impala_query_options.html">Query
Options for the SET Statement</a></div></div></nav></article></main></body></html>
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http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/75c46918/docs/build/html/topics/impala_num_scanner_threads.html
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+<!DOCTYPE html
+  SYSTEM "about:legacy-compat">
+<html lang="en"><head><meta http-equiv="Content-Type" content="text/html;
charset=UTF-8"><meta charset="UTF-8"><meta name="copyright" content="(C) Copyright
2017"><meta name="DC.rights.owner" content="(C) Copyright 2017"><meta name="DC.Type"
content="concept"><meta name="DC.Relation" scheme="URI" content="../topics/impala_query_options.html"><meta
name="prodname" content="Impala"><meta name="prodname" content="Impala"><meta
name="version" content="Impala 2.8.x"><meta name="version" content="Impala 2.8.x"><meta
name="DC.Format" content="XHTML"><meta name="DC.Identifier" content="num_scanner_threads"><link
rel="stylesheet" type="text/css" href="../commonltr.css"><title>NUM_SCANNER_THREADS
Query Option</title></head><body id="num_scanner_threads"><main role="main"><article
role="article" aria-labelledby="ariaid-title1">
+
+  <h1 class="title topictitle1" id="ariaid-title1">NUM_SCANNER_THREADS Query Option</h1>
+  
+  
+
+  <div class="body conbody">
+
+    <p class="p">
+      
+      Maximum number of scanner threads (on each node) used for each query. By default, Impala
uses as many cores
+      as are available (one thread per core). You might lower this value if queries are using
excessive resources
+      on a busy cluster. Impala imposes a maximum value automatically, so a high value has
no practical effect.
+    </p>
+
+    <p class="p">
+      <strong class="ph b">Type:</strong> numeric
+    </p>
+
+    <p class="p">
+      <strong class="ph b">Default:</strong> 0
+    </p>
+
+  </div>
+<nav role="navigation" class="related-links"><div class="familylinks"><div
class="parentlink"><strong>Parent topic:</strong> <a class="link" href="../topics/impala_query_options.html">Query
Options for the SET Statement</a></div></div></nav></article></main></body></html>
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http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/75c46918/docs/build/html/topics/impala_odbc.html
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diff --git a/docs/build/html/topics/impala_odbc.html b/docs/build/html/topics/impala_odbc.html
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+<!DOCTYPE html
+  SYSTEM "about:legacy-compat">
+<html lang="en"><head><meta http-equiv="Content-Type" content="text/html;
charset=UTF-8"><meta charset="UTF-8"><meta name="copyright" content="(C) Copyright
2017"><meta name="DC.rights.owner" content="(C) Copyright 2017"><meta name="DC.Type"
content="concept"><meta name="DC.Relation" scheme="URI" content="../topics/impala_config.html"><meta
name="prodname" content="Impala"><meta name="prodname" content="Impala"><meta
name="version" content="Impala 2.8.x"><meta name="version" content="Impala 2.8.x"><meta
name="DC.Format" content="XHTML"><meta name="DC.Identifier" content="impala_odbc"><link
rel="stylesheet" type="text/css" href="../commonltr.css"><title>Configuring Impala
to Work with ODBC</title></head><body id="impala_odbc"><main role="main"><article
role="article" aria-labelledby="impala_odbc__odbc">
+
+  <h1 class="title topictitle1" id="impala_odbc__odbc">Configuring Impala to Work with
ODBC</h1>
+  
+
+  <div class="body conbody">
+
+    <p class="p">
+      
+      Third-party products, especially business intelligence and reporting tools, can access
Impala
+      using the ODBC protocol. For the best experience, ensure any third-party product you
intend to use is supported.
+      Verifying support includes checking that the versions of Impala, ODBC, the operating
system, the
+      Apache Hadoop distribution, and the third-party product have all been approved by the
appropriate suppliers
+      for use together. To configure your systems to use ODBC, download and install a connector,
typically from
+      the supplier of the third-party product or the Hadoop distribution.
+      You may need to sign in and accept license agreements before accessing the pages required
for downloading
+      ODBC connectors.
+    </p>
+
+  </div>
+
+<nav role="navigation" class="related-links"><div class="familylinks"><div
class="parentlink"><strong>Parent topic:</strong> <a class="link" href="../topics/impala_config.html">Managing
Impala</a></div></div></nav></article></main></body></html>
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http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/75c46918/docs/build/html/topics/impala_offset.html
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diff --git a/docs/build/html/topics/impala_offset.html b/docs/build/html/topics/impala_offset.html
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+<!DOCTYPE html
+  SYSTEM "about:legacy-compat">
+<html lang="en"><head><meta http-equiv="Content-Type" content="text/html;
charset=UTF-8"><meta charset="UTF-8"><meta name="copyright" content="(C) Copyright
2017"><meta name="DC.rights.owner" content="(C) Copyright 2017"><meta name="DC.Type"
content="concept"><meta name="DC.Relation" scheme="URI" content="../topics/impala_select.html"><meta
name="prodname" content="Impala"><meta name="prodname" content="Impala"><meta
name="version" content="Impala 2.8.x"><meta name="version" content="Impala 2.8.x"><meta
name="DC.Format" content="XHTML"><meta name="DC.Identifier" content="offset"><link
rel="stylesheet" type="text/css" href="../commonltr.css"><title>OFFSET Clause</title></head><body
id="offset"><main role="main"><article role="article" aria-labelledby="ariaid-title1">
+
+  <h1 class="title topictitle1" id="ariaid-title1">OFFSET Clause</h1>
+  
+
+  <div class="body conbody">
+
+    <p class="p">
+      The <code class="ph codeph">OFFSET</code> clause in a <code class="ph
codeph">SELECT</code> query causes the result set to start some
+      number of rows after the logical first item. The result set is numbered starting from
zero, so <code class="ph codeph">OFFSET
+      0</code> produces the same result as leaving out the <code class="ph codeph">OFFSET</code>
clause. Always use this clause
+      in combination with <code class="ph codeph">ORDER BY</code> (so that it
is clear which item should be first, second, and so
+      on) and <code class="ph codeph">LIMIT</code> (so that the result set covers
a bounded range, such as items 0-9, 100-199,
+      and so on).
+    </p>
+
+    <p class="p">
+        In Impala 1.2.1 and higher, you can combine a <code class="ph codeph">LIMIT</code>
clause with an <code class="ph codeph">OFFSET</code>
+        clause to produce a small result set that is different from a top-N query, for example,
to return items 11
+        through 20. This technique can be used to simulate <span class="q">"paged"</span>
results. Because Impala queries typically
+        involve substantial amounts of I/O, use this technique only for compatibility in
cases where you cannot
+        rewrite the application logic. For best performance and scalability, wherever practical,
query as many
+        items as you expect to need, cache them on the application side, and display small
groups of results to
+        users using application logic.
+      </p>
+
+    <p class="p">
+        <strong class="ph b">Examples:</strong>
+      </p>
+
+    <p class="p">
+      The following example shows how you could run a <span class="q">"paging"</span>
query originally written for a traditional
+      database application. Because typical Impala queries process megabytes or gigabytes
of data and read large
+      data files from disk each time, it is inefficient to run a separate query to retrieve
each small group of
+      items. Use this technique only for compatibility while porting older applications,
then rewrite the
+      application code to use a single query with a large result set, and display pages of
results from the cached
+      result set.
+    </p>
+
+<pre class="pre codeblock"><code>[localhost:21000] &gt; create table numbers
(x int);
+[localhost:21000] &gt; insert into numbers select x from very_long_sequence;
+Inserted 1000000 rows in 1.34s
+[localhost:21000] &gt; select x from numbers order by x limit 5 offset 0;
++----+
+| x  |
++----+
+| 1  |
+| 2  |
+| 3  |
+| 4  |
+| 5  |
++----+
+[localhost:21000] &gt; select x from numbers order by x limit 5 offset 5;
++----+
+| x  |
++----+
+| 6  |
+| 7  |
+| 8  |
+| 9  |
+| 10 |
++----+
+</code></pre>
+  </div>
+<nav role="navigation" class="related-links"><div class="familylinks"><div
class="parentlink"><strong>Parent topic:</strong> <a class="link" href="../topics/impala_select.html">SELECT
Statement</a></div></div></nav></article></main></body></html>
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