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Posted to commits@drill.apache.org by br...@apache.org on 2018/12/04 00:44:40 UTC
[drill-site] branch asf-site updated: update doc cross join support
This is an automated email from the ASF dual-hosted git repository.
bridgetb pushed a commit to branch asf-site
in repository https://gitbox.apache.org/repos/asf/drill-site.git
The following commit(s) were added to refs/heads/asf-site by this push:
new 90557fa update doc cross join support
90557fa is described below
commit 90557fa53494d405996039851c76936f61d86d53
Author: Bridget Bevens <bb...@maprtech.com>
AuthorDate: Mon Dec 3 16:44:22 2018 -0800
update doc cross join support
---
docs/from-clause/index.html | 20 ++++++++++++++++++--
docs/select/index.html | 6 +++---
feed.xml | 4 ++--
3 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/docs/from-clause/index.html b/docs/from-clause/index.html
index bed142b..54377d0 100644
--- a/docs/from-clause/index.html
+++ b/docs/from-clause/index.html
@@ -1274,7 +1274,7 @@
</div>
- Aug 3, 2018
+ Dec 4, 2018
<link href="/css/docpage.css" rel="stylesheet" type="text/css">
@@ -1384,7 +1384,23 @@ Return matching rows only, based on the join condition or list of joining column
Return all of the rows that the equivalent inner join would return plus non-matching rows from the "left" table, "right" table, or both tables. The left table is the first-listed table, and the right table is the second-listed table. The non-matching rows contain NULL values to fill the gaps in the output columns. </p>
<p>LATERAL<br>
-A lateral join is essentially a foreach loop in SQL. A lateral join is represented by the keyword LATERAL with an inner subquery in the FROM clause. See <a href="/docs/lateral-join/">Lateral Join</a>.</p>
+A lateral join is essentially a foreach loop in SQL. A lateral join is represented by the keyword LATERAL with an inner subquery in the FROM clause. See <a href="/docs/lateral-join/">Lateral Join</a>. </p>
+
+<p>CROSS JOIN<br>
+Starting in Drill 1.15, Drill supports cross joins. A cross join returns the cartesian product of two tables. Cross joins are disabled by default because they can produce extremely large result sets that cause out of memory errors. </p>
+
+<p>To enable cross joins, disable the <code>planner.enable_nljoin_for_scalar_only</code> option, as shown: </p>
+<div class="highlight"><pre><code class="language-text" data-lang="text">set `planner.enable_nljoin_for_scalar_only` = false;
++-------+-------------------------------------------------+
+| ok | summary |
++-------+-------------------------------------------------+
+| true | planner.enable_nljoin_for_scalar_only updated. |
++-------+-------------------------------------------------+
+</code></pre></div>
+<p>Before you enable the cross join functionality, verify that Drill has enough memory to process the query. Also note the following limitation related to the use of aggregate functions with cross joins.</p>
+
+<p><strong>Limitation</strong><br>
+If the input row count for an aggregate function is larger than the value set for the <code>planner.slice_target</code> option, Drill cannot plan the query. As a workaround, set the <code>planner.enable_multiphase_agg</code> option to false. This limitation will be resolved with <a href="https://issues.apache.org/jira/browse/DRILL-6839">DRILL-6839</a>.</p>
<h2 id="usage-notes">Usage Notes</h2>
diff --git a/docs/select/index.html b/docs/select/index.html
index 801d906..676649d 100644
--- a/docs/select/index.html
+++ b/docs/select/index.html
@@ -1274,7 +1274,7 @@
</div>
- Mar 14, 2017
+ Dec 4, 2018
<link href="/css/docpage.css" rel="stylesheet" type="text/css">
@@ -1330,6 +1330,7 @@ clause.</p>
<ul>
<li>Inner joins</li>
<li>Left, full, and right outer joins</li>
+<li>Cross joins (as of Drill 1.15)</li>
</ul>
<p>The following types of join syntax are supported:</p>
@@ -1350,8 +1351,7 @@ clause.</p>
</tr>
</tbody></table>
-<p>Cross-joins are not yet supported. You must specify a join condition when more
-than one table is listed in the FROM clause.</p>
+<p>You must specify a join condition when more than one table is listed in the FROM clause.</p>
<p>Non-equijoins are supported if the join also contains an equality condition on
the same two tables as part of a conjunction:</p>
diff --git a/feed.xml b/feed.xml
index c34af99..b2d36ea 100644
--- a/feed.xml
+++ b/feed.xml
@@ -6,8 +6,8 @@
</description>
<link>/</link>
<atom:link href="/feed.xml" rel="self" type="application/rss+xml"/>
- <pubDate>Mon, 26 Nov 2018 09:08:54 -0800</pubDate>
- <lastBuildDate>Mon, 26 Nov 2018 09:08:54 -0800</lastBuildDate>
+ <pubDate>Mon, 03 Dec 2018 16:42:02 -0800</pubDate>
+ <lastBuildDate>Mon, 03 Dec 2018 16:42:02 -0800</lastBuildDate>
<generator>Jekyll v2.5.2</generator>
<item>