<!-- 
RSS generated by JIRA (9.7.1#970001-sha1:2222b88b221c4928ef0de3161136cc90c8356a66) at Thu Feb 08 05:53:04 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>[SERVER-61687] Extend index multikeyness metadata for positional paths</title>
                <link>https://jira.mongodb.org/browse/SERVER-61687</link>
                <project id="10000" key="SERVER">Core Server</project>
                    <description>&lt;p&gt;The fix for &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-57588&quot; title=&quot;Inconsistent query results when an array position is indexed whose value is an array&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-57588&quot;&gt;&lt;del&gt;SERVER-57588&lt;/del&gt;&lt;/a&gt; is to check if an $elemMatch is on a field which is a positional path component of an indexed path. If that is the case, the index cannot be used for $elemMatch because key boundaries cannot be formed. The problem with that patch is that it is too crude, and may prevent index use even when the parent path doesn&apos;t contain arrays. In this case the positional path is not an array index, it has the meaning of a regular path, and the index can still be used.&lt;/p&gt;

&lt;p&gt;&#160;&lt;/p&gt;

&lt;p&gt;In order to refine that patch, and make multikeyness index metadata more complete, it is necessary to simplify the metadata and collect multikey information even when the index path contains positional components.&lt;/p&gt;</description>
                <environment></environment>
        <key id="1930904">SERVER-61687</key>
            <summary>Extend index multikeyness metadata for positional paths</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="10038" iconUrl="https://jira.mongodb.org/images/icons/subtask.gif" description="">Backlog</status>
                    <statusCategory id="2" key="new" colorName="default"/>
                                    <resolution id="-1">Unresolved</resolution>
                                        <assignee username="backlog-query-optimization">Backlog - Query Optimization</assignee>
                                    <reporter username="timour.katchaounov@mongodb.com">Timour Katchaounov</reporter>
                        <labels>
                            <label>indexv3</label>
                    </labels>
                <created>Mon, 22 Nov 2021 11:54:22 +0000</created>
                <updated>Tue, 6 Dec 2022 00:46:22 +0000</updated>
                                                                                                <votes>0</votes>
                                    <watches>6</watches>
                                                                                                                <comments>
                            <comment id="4223930" author="david.storch" created="Wed, 1 Dec 2021 13:07:50 +0000"  >&lt;p&gt;To provide a bit more detail, this ticket suggests changing the definition of multikeyness metadata for index key patterns with positional components such as {&quot;a.0&quot;: 1}. To provide a concrete example, imagine that you have the index&#160;{&quot;a.0&quot;: 1} and the user inserts the document {a:&#160;[1, 2, 3]}. For all index versions existing today, path &quot;a&quot; will &lt;em&gt;not&lt;/em&gt; be considered multikey&#160;in this scenario. This means that for indexes with positional path components, the query optimizer cannot rely on the multikeyness metadata in order to determine whether &quot;a&quot; is ever an array. The whole purpose of the multikeyness metadata is to be able to detect definitively when an indexed path component never contains an array, since this can permit certain beneficial optimizations (such as tighter index bounds). Therefore, it would be an improvement to track paths containing arrays as multikey even if those arrays are positionally indexed.&lt;/p&gt;

&lt;p&gt;After some discussion, we&apos;ve decided that this change would require a bump of the index version, so we have labeled this ticket &quot;indexv3&quot;. The old definition of multikeyness for positional path components would continue to apply for v:2 and earlier indexes, but the new definition would apply for v:3 indexes. This way, the optimizer could know to interpret the multikeyness metadata differently for v:3 indexes. Also, it means that we could delete any code associated with the old multikeyness definition once v:2 indexes are no longer supported by the system.&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>1.0</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                <customfield id="customfield_12751" key="com.atlassian.jira.plugin.system.customfieldtypes:multiselect">
                        <customfieldname>Assigned Teams</customfieldname>
                        <customfieldvalues>
                                <customfieldvalue key="25126"><![CDATA[Query Optimization]]></customfieldvalue>
    
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    <customfield id="customfield_10055" key="com.atlassian.jira.ext.charting:firstresponsedate">
                        <customfieldname>Date of 1st Reply</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>Wed, 1 Dec 2021 12:56:34 +0000</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_10052" key="com.atlassian.jira.toolkit:dayslastcommented">
                        <customfieldname>Days since reply</customfieldname>
                        <customfieldvalues>
                                        2 years, 10 weeks 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_10857" key="com.pyxis.greenhopper.jira:gh-epic-link">
                        <customfieldname>Epic Link</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>PM-2663</customfieldvalue>
                        </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>alexander.golin@mongodb.com</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_11151" key="com.atlassian.jira.toolkit:LastCommentDate">
                        <customfieldname>Last public comment date</customfieldname>
                        <customfieldvalues>
                            2 years, 10 weeks ago
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                    <customfield id="customfield_10051" key="com.atlassian.jira.toolkit:participants">
                        <customfieldname>Participants</customfieldname>
                        <customfieldvalues>
                                        <customfieldvalue>backlog-query-optimization</customfieldvalue>
            <customfieldvalue>david.storch@mongodb.com</customfieldvalue>
            <customfieldvalue>timour.katchaounov@mongodb.com</customfieldvalue>
    
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                        <customfield id="customfield_14254" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>Product Rank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>1|i0b82f:</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                <customfield id="customfield_12550" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>Rank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>2|hr2be7:</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_10558" key="com.pyxis.greenhopper.jira:gh-global-rank">
                        <customfieldname>Rank (Obsolete)</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>9223372036854775807</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                                            <customfield id="customfield_23361" key="com.onresolve.jira.groovy.groovyrunner:scripted-field">
                        <customfieldname>Requested By</customfieldname>
                        <customfieldvalues>
                                

                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    <customfield id="customfield_22870" key="com.onresolve.jira.groovy.groovyrunner:scripted-field">
                        <customfieldname>Triagers</customfieldname>
                        <customfieldvalues>
                                

                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                    <customfield id="customfield_14350" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>serverRank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>1|i0au7r:</customfieldvalue>

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