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[DOCS] Fixed an inconsistent table ordering recommendations with STRAIGHT_JOIN

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Change-Id: I9ff2245b6d8e3160a10aae64f622813a40121ee8
Reviewed-on: http://gerrit.cloudera.org:8080/10519
Reviewed-by: Tim Armstrong <tarmstrong@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
This commit is contained in:
Alex Rodoni
2018-05-25 13:14:24 -07:00
committed by Impala Public Jenkins
parent e4c52e3155
commit 2f22a6f67f
1 changed files with 4 additions and 5 deletions
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9
docs/topics/impala_perf_joins.xml
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@@ -85,13 +85,13 @@ under the License.
<li>
Join the next smallest table, then the next smallest, and so on.
</li>
</ul>
<li>
<p>
For example, if you had tables <codeph>BIG</codeph>, <codeph>MEDIUM</codeph>, <codeph>SMALL</codeph>, and
<codeph>TINY</codeph>, the logical join order to try would be <codeph>BIG</codeph>, <codeph>TINY</codeph>,
<codeph>SMALL</codeph>, <codeph>MEDIUM</codeph>.
</li>
</ul>
</p>
<p>
The terms <q>largest</q> and <q>smallest</q> refers to the size of the intermediate result set based on the
@@ -153,8 +153,7 @@ under the License.
immediately after the <codeph>SELECT</codeph> and any <codeph>DISTINCT</codeph> or <codeph>ALL</codeph>
keywords. The <codeph>STRAIGHT_JOIN</codeph> keyword turns off
the reordering of join clauses that Impala does internally, and produces a plan that relies on the join
clauses being ordered optimally in the query text. In this case, rewrite the query so that the largest
table is on the left, followed by the next largest, and so on until the smallest table is on the right.
clauses being ordered optimally in the query text.
</p>
<note>