<!-- 
RSS generated by JIRA (9.7.1#970001-sha1:2222b88b221c4928ef0de3161136cc90c8356a66) at Thu Feb 08 07:45:11 UTC 2024

It is possible to restrict the fields that are returned in this document by specifying the 'field' parameter in your request.
For example, to request only the issue key and summary append 'field=key&field=summary' to the URL of your request.
-->
<rss version="0.92" >
<channel>
    <title>MongoDB Jira</title>
    <link>https://jira.mongodb.org</link>
    <description>This file is an XML representation of an issue</description>
    <language>en-us</language>    <build-info>
        <version>9.7.1</version>
        <build-number>970001</build-number>
        <build-date>13-04-2023</build-date>
    </build-info>


<item>
            <title>[DOCS-3187] Difference between nscanned and nscannedObjects is unclear</title>
                <link>https://jira.mongodb.org/browse/DOCS-3187</link>
                <project id="10380" key="DOCS">Documentation</project>
                    <description>&lt;p&gt;On this page &lt;a href=&quot;http://docs.mongodb.org/manual/reference/method/cursor.explain/#explain-output-fields-core&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;http://docs.mongodb.org/manual/reference/method/cursor.explain/#explain-output-fields-core&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;The explanation of the difference between nscanned and nscannedObjects in the explain plan is unclear. &lt;/p&gt;

&lt;p&gt;Need to define the specific differences between the two outputs and give a clear example of a query that will produce different outputs.&lt;/p&gt;

&lt;p&gt;e.g.&lt;/p&gt;

&lt;p&gt;explain.nscannedObjects&lt;br/&gt;
Specifies the total number of documents scanned during the query. The nscannedObjects may be lower than nscanned, such as if the index covers a query. See indexOnly. Additionally, the nscannedObjects may be lower than nscanned in the case of multikey index on an array field with duplicate documents.&lt;/p&gt;

&lt;p&gt;explain.nscanned&lt;br/&gt;
Specifies the total number of documents or index entries scanned during the database operation. You want n and nscanned to be close in value as possible. The nscanned value may be higher than the nscannedObjects value, such as if the index covers a query. See indexOnly.&lt;/p&gt;</description>
                <environment>All</environment>
        <key id="131452">DOCS-3187</key>
            <summary>Difference between nscanned and nscannedObjects is unclear</summary>
                <type id="4" iconUrl="https://jira.mongodb.org/secure/viewavatar?size=xsmall&amp;avatarId=14710&amp;avatarType=issuetype">Improvement</type>
                                            <priority id="3" iconUrl="https://jira.mongodb.org/images/icons/priorities/major.svg">Major - P3</priority>
                        <status id="6" iconUrl="https://jira.mongodb.org/images/icons/statuses/closed.png" description="The issue is considered finished, the resolution is correct. Issues which are closed can be reopened.">Closed</status>
                    <statusCategory id="3" key="done" colorName="success"/>
                                    <resolution id="9">Done</resolution>
                                        <assignee username="tim.slavin">Tim Slavin</assignee>
                                    <reporter username="joe.drumgoole@mongodb.com">Joe Drumgoole</reporter>
                        <labels>
                    </labels>
                <created>Wed, 16 Apr 2014 09:36:11 +0000</created>
                <updated>Mon, 16 Mar 2015 23:55:53 +0000</updated>
                            <resolved>Tue, 1 Jul 2014 16:29:00 +0000</resolved>
                                    <version>mongodb-2.6</version>
                                    <fixVersion>v1.3.7</fixVersion>
                                    <component>manual</component>
                        <due></due>
                            <votes>0</votes>
                                    <watches>2</watches>
                                                                                                                <comments>
                            <comment id="728613" author="xgen-internal-githook" created="Fri, 26 Sep 2014 22:21:27 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{u&apos;username&apos;: u&apos;kay-kim&apos;, u&apos;name&apos;: u&apos;kay&apos;, u&apos;email&apos;: u&apos;kay.kim@10gen.com&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-3187&quot; title=&quot;Difference between nscanned and nscannedObjects is unclear&quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-3187&quot;&gt;&lt;del&gt;DOCS-3187&lt;/del&gt;&lt;/a&gt; additional tweaks&lt;br/&gt;
Branch: master&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/docs/commit/b100d5959a9600df49974c710687febcb200de10&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/docs/commit/b100d5959a9600df49974c710687febcb200de10&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="728612" author="xgen-internal-githook" created="Fri, 26 Sep 2014 22:21:26 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{u&apos;username&apos;: u&apos;TimSlavinMongoDB&apos;, u&apos;name&apos;: u&apos;Tim Slavin (MongoDB)&apos;, u&apos;email&apos;: u&apos;tim.slavin@10gen.com&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-3187&quot; title=&quot;Difference between nscanned and nscannedObjects is unclear&quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-3187&quot;&gt;&lt;del&gt;DOCS-3187&lt;/del&gt;&lt;/a&gt;: provided examples of n, nscanned, nscannedObjects usage&lt;/p&gt;

&lt;p&gt;Signed-off-by: kay &amp;lt;kay.kim@10gen.com&amp;gt;&lt;br/&gt;
Branch: master&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/docs/commit/c9373ae128c4840eee6cfacec5e2eb0ba8f708b0&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/docs/commit/c9373ae128c4840eee6cfacec5e2eb0ba8f708b0&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="551420" author="joe.drumgoole@10gen.com" created="Wed, 16 Apr 2014 10:44:18 +0000"  >&lt;p&gt;This blog has a better explanation:&lt;/p&gt;

&lt;p&gt;&lt;a href=&quot;http://emptysqua.re/blog/optimizing-mongodb-compound-indexes/&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;http://emptysqua.re/blog/optimizing-mongodb-compound-indexes/&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;&quot;For indexed queries, nscanned is the number of index keys in the range that Mongo scanned, and nscannedObjects is the number of documents it looked at to get to the final result. nscannedObjects includes at least all the documents returned, even if Mongo could tell just by looking at the index that the document was definitely a match. Thus, you can see that nscanned &amp;gt;= nscannedObjects &amp;gt;= n always. For simple queries you want the three numbers to be equal. It means you&apos;ve created the ideal index and Mongo is using it.&quot;&lt;/p&gt;</comment>
                    </comments>
                    <attachments>
                    </attachments>
                <subtasks>
                    </subtasks>
                <customfields>
                                                <customfield id="customfield_10050" key="com.atlassian.jira.toolkit:comments">
                        <customfieldname># Replies</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>3.0</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                    <customfield id="customfield_10855" key="com.atlassian.jira.plugin.system.customfieldtypes:float">
                        <customfieldname>Actual Time</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>8.0</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        <customfield id="customfield_10055" key="com.atlassian.jira.ext.charting:firstresponsedate">
                        <customfieldname>Date of 1st Reply</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>Fri, 26 Sep 2014 22:21:26 +0000</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_10052" key="com.atlassian.jira.toolkit:dayslastcommented">
                        <customfieldname>Days since reply</customfieldname>
                        <customfieldvalues>
                                        9 years, 20 weeks, 5 days ago
    
                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_18254" key="com.onresolve.jira.groovy.groovyrunner:scripted-field">
                        <customfieldname>Dependencies</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue><![CDATA[]]></customfieldvalue>


                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_15850" key="com.atlassian.jira.plugins.jira-development-integration-plugin:devsummary">
                        <customfieldname>Development</customfieldname>
                        <customfieldvalues>
                            
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    <customfield id="customfield_10057" key="com.atlassian.jira.toolkit:lastusercommented">
                        <customfieldname>Last comment by Customer</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>true</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_10056" key="com.atlassian.jira.toolkit:lastupdaterorcommenter">
                        <customfieldname>Last commenter</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>jess.mokrzecki@mongodb.com</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_11151" key="com.atlassian.jira.toolkit:LastCommentDate">
                        <customfieldname>Last public comment date</customfieldname>
                        <customfieldvalues>
                            9 years, 20 weeks, 5 days ago
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                            <customfield id="customfield_10051" key="com.atlassian.jira.toolkit:participants">
                        <customfieldname>Participants</customfieldname>
                        <customfieldvalues>
                                        <customfieldvalue>xgen-internal-githook</customfieldvalue>
            <customfieldvalue>joe.drumgoole@mongodb.com</customfieldvalue>
            <customfieldvalue>tim.slavin</customfieldvalue>
    
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                        <customfield id="customfield_14254" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>Product Rank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>1|hrr4nj:</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                <customfield id="customfield_12550" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>Rank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>2|hry20f:</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_10558" key="com.pyxis.greenhopper.jira:gh-global-rank">
                        <customfieldname>Rank (Obsolete)</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>112824</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    <customfield id="customfield_10053" key="com.atlassian.jira.ext.charting:timeinstatus">
                        <customfieldname>Time In Status</customfieldname>
                        <customfieldvalues>
                            
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            <customfield id="customfield_14350" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>serverRank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>1|hryr1j:</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                </customfields>
    </item>
</channel>
</rss>