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From he...@apache.org
Subject [3/3] incubator-impala git commit: IMPALA-5326: [DOCS] Document REPLACE() function
Date Thu, 01 Jun 2017 17:32:34 GMT
IMPALA-5326: [DOCS] Document REPLACE() function

Included syntax, mention of performance benefit, and examples.
Also added an item in the "new features" list with a link to the
detailed writeup.

Change-Id: Ib576fba03673bd6708a46f45c8388477b25e34da
Reviewed-on: http://gerrit.cloudera.org:8080/6979
Reviewed-by: Greg Rahn <grahn@cloudera.com>
Reviewed-by: Michael Brown <mikeb@cloudera.com>
Tested-by: Impala Public Jenkins


Project: http://git-wip-us.apache.org/repos/asf/incubator-impala/repo
Commit: http://git-wip-us.apache.org/repos/asf/incubator-impala/commit/f2580acb
Tree: http://git-wip-us.apache.org/repos/asf/incubator-impala/tree/f2580acb
Diff: http://git-wip-us.apache.org/repos/asf/incubator-impala/diff/f2580acb

Branch: refs/heads/master
Commit: f2580acba5201628592742b1bda5f49614d1400f
Parents: 64e8538
Author: John Russell <jrussell@cloudera.com>
Authored: Wed May 24 12:23:33 2017 -0700
Committer: Impala Public Jenkins <impala-public-jenkins@gerrit.cloudera.org>
Committed: Thu Jun 1 17:12:27 2017 +0000

----------------------------------------------------------------------
 docs/topics/impala_new_features.xml     | 11 +++++-
 docs/topics/impala_string_functions.xml | 58 ++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 2 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/f2580acb/docs/topics/impala_new_features.xml
----------------------------------------------------------------------
diff --git a/docs/topics/impala_new_features.xml b/docs/topics/impala_new_features.xml
index 76f772d..e6f2afa 100644
--- a/docs/topics/impala_new_features.xml
+++ b/docs/topics/impala_new_features.xml
@@ -60,12 +60,19 @@ under the License.
         <xref keyref="changelog_29">changelog for <keyword keyref="impala29"/></xref>.
       </p>
 
-<!-- Prose explanations of most important new features - TBD.
+      <p>
+        The following are some of the most significant new features in this release:
+      </p>
+
       <ul id="feature_list">
         <li>
+          <p rev="IMPALA-4729">
+            A new function, <codeph>replace()</codeph>, which is faster than
+            <codeph>regexp_replace()</codeph> for simple string substitutions.
+            See <xref keyref="string_functions"/> for details.
+          </p>
         </li>
       </ul>
--->
 
     </conbody>
   </concept>

http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/f2580acb/docs/topics/impala_string_functions.xml
----------------------------------------------------------------------
diff --git a/docs/topics/impala_string_functions.xml b/docs/topics/impala_string_functions.xml
index 11a1673..60b28fc 100644
--- a/docs/topics/impala_string_functions.xml
+++ b/docs/topics/impala_string_functions.xml
@@ -845,6 +845,64 @@ Returned 1 row(s) in 0.12s</codeblock>
 
       </dlentry>
 
+      <dlentry id="replace" rev="2.9.0 IMPALA-4729">
+
+        <dt>
+          <codeph>replace(string initial, string target, string replacement)</codeph>
+        </dt>
+
+        <dd>
+          <indexterm audience="hidden">replace() function</indexterm>
+          <b>Purpose:</b> Returns the initial argument with all occurrences of
the target string
+          replaced by the replacement string.
+          <p>
+            <b>Return type:</b> <codeph>string</codeph>
+          </p>
+          <p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
+          <p>
+            Because this function does not use any regular expression patterns, it is typically
faster
+            than <codeph>regexp_replace()</codeph> for simple string substitutions.
+          </p>
+          <p>
+            If any argument is <codeph>NULL</codeph>, the return value is <codeph>NULL</codeph>.
+          </p>
+          <p>
+            Matching is case-sensitive.
+          </p>
+          <p>
+            If the replacement string contains another instance of the target
+            string, the expansion is only performed once, instead of
+            applying again to the newly constructed string.
+          </p>
+          <p conref="../shared/impala_common.xml#common/example_blurb"/>
+<codeblock>-- Replace one string with another.
+select replace('hello world','world','earth');
++------------------------------------------+
+| replace('hello world', 'world', 'earth') |
++------------------------------------------+
+| hello earth                              |
++------------------------------------------+
+
+-- All occurrences of the target string are replaced.
+select replace('hello world','o','0');
++----------------------------------+
+| replace('hello world', 'o', '0') |
++----------------------------------+
+| hell0 w0rld                      |
++----------------------------------+
+
+-- If no match is found, the original string is returned unchanged.
+select replace('hello world','xyz','abc');
++--------------------------------------+
+| replace('hello world', 'xyz', 'abc') |
++--------------------------------------+
+| hello world                          |
++--------------------------------------+
+</codeblock>
+        </dd>
+
+      </dlentry>
+
       <dlentry id="reverse">
 
         <dt>


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