<!-- 
RSS generated by JIRA (9.7.1#970001-sha1:2222b88b221c4928ef0de3161136cc90c8356a66) at Thu Feb 08 08:06:38 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-12975] Investigate changes in SERVER-42022: Attempt to remove initial sync missing document fetching</title>
                <link>https://jira.mongodb.org/browse/DOCS-12975</link>
                <project id="10380" key="DOCS">Documentation</project>
                    <description>&lt;h2&gt;&lt;a name=&quot;Description&quot;&gt;&lt;/a&gt;Description&lt;/h2&gt;

    &lt;div class=&quot;panel&quot; style=&quot;background-color: #c2d2c2;border-width: 1px;&quot;&gt;&lt;div class=&quot;panelHeader&quot; style=&quot;border-bottom-width: 1px;background-color: #239eb0;&quot;&gt;&lt;b&gt;Downstream Change Summary&lt;/b&gt;&lt;/div&gt;&lt;div class=&quot;panelContent&quot; style=&quot;background-color: #c2d2c2;&quot;&gt;
&lt;p&gt;    During initial sync, a replica clones all collections, while at the same time buffer its sync source&apos;s new oplog entries. Once cloning completes, the replica sets its &quot;minValid&quot; timestamp to the latest oplog entry, and replays the oplog up to minValid. At this point the replica has constructed a consistent snapshot of the data, and it can transition to a secondary.&lt;/p&gt;

&lt;p&gt;In MMAPv1 days, it was possible to miss a document while cloning a collection, even if the document existed during the whole time we were cloning, because the document was moved during the clone. Therefore, during recovery or initial sync, when a replica would apply an update operation that referred to a missing document (either from a regular update or the &quot;applyOps&quot; command) it would attempt to fetch the document from the sync source, in case the document had been missed during cloning. If the document was found, the replica would advance its minValid timestamp to the sync source&apos;s current opTime, setting back its progress toward achieving a consistent snapshot.&lt;/p&gt;

&lt;p&gt;In MongoDB 4.3 we no longer support MMAPv1, and we don&apos;t even support syncing from a server that uses MMAPv1. Post-MMAPv1 we can&apos;t miss documents during collection clone, so it is no longer necessary to fetch missing documents, nor to advance minValid. If an update refers to a missing document, then there must be a later oplog entry that deletes the document, so the replica can skip the update operation.&lt;/p&gt;

&lt;p&gt;We don&apos;t have much documentation of this process, so not much has to change. replSetGetStatus.initialSyncStatus.fetchedMissingDocs field is removed, see two references in replSetGetStatus.txt and one in getLog.txt. There may be other places that need updating that I have no found, however!&lt;/p&gt;
&lt;/div&gt;&lt;/div&gt;

&lt;h2&gt;&lt;a name=&quot;DescriptionofLinkedTicket&quot;&gt;&lt;/a&gt;Description of Linked Ticket&lt;/h2&gt;
&lt;p&gt;    We currently think this was only necessary for mmapv1 when updates could cause a collection scan to miss a document. If we could remove this step, it could significantly speed up initial sync in certain workloads and simplify initial sync.&lt;/p&gt;

&lt;p&gt;This would require the storage engine API to prohibit updates from causing collection scans to miss a document.&lt;/p&gt;


&lt;h2&gt;&lt;a name=&quot;Scopeofchanges&quot;&gt;&lt;/a&gt;Scope of changes&lt;/h2&gt;

&lt;h2&gt;&lt;a name=&quot;ImpacttoOtherDocs&quot;&gt;&lt;/a&gt;Impact to Other Docs&lt;/h2&gt;

&lt;h2&gt;&lt;a name=&quot;MVP%28WorkandDate%29&quot;&gt;&lt;/a&gt;MVP (Work and Date)&lt;/h2&gt;

&lt;h2&gt;&lt;a name=&quot;Resources%28ScopeorDesignDocs%2CInvision%2Cetc.%29&quot;&gt;&lt;/a&gt;Resources (Scope or Design Docs, Invision, etc.)&lt;/h2&gt;
</description>
                <environment></environment>
        <key id="902802">DOCS-12975</key>
            <summary>Investigate changes in SERVER-42022: Attempt to remove initial sync missing document fetching</summary>
                <type id="3" iconUrl="https://jira.mongodb.org/secure/viewavatar?size=xsmall&amp;avatarId=14718&amp;avatarType=issuetype">Task</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="13201">Fixed</resolution>
                                        <assignee username="kay.kim@mongodb.com">Kay Kim</assignee>
                                    <reporter username="backlog-server-pm">Backlog - Core Eng Program Management Team</reporter>
                        <labels>
                    </labels>
                <created>Wed, 21 Aug 2019 16:15:55 +0000</created>
                <updated>Mon, 13 Nov 2023 18:17:04 +0000</updated>
                            <resolved>Tue, 17 Mar 2020 01:56:53 +0000</resolved>
                                                    <fixVersion>4.3.1</fixVersion>
                    <fixVersion>Server_Docs_20231030</fixVersion>
                    <fixVersion>Server_Docs_20231106</fixVersion>
                    <fixVersion>Server_Docs_20231105</fixVersion>
                    <fixVersion>Server_Docs_20231113</fixVersion>
                                    <component>manual</component>
                    <component>Server</component>
                        <due></due>
                            <votes>0</votes>
                                    <watches>2</watches>
                                                                                                                <comments>
                            <comment id="2982526" author="xgen-internal-githook" created="Mon, 16 Mar 2020 23:39:24 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{&apos;username&apos;: &apos;kay-kim&apos;, &apos;name&apos;: &apos;Kay Kim&apos;, &apos;email&apos;: &apos;kay.kim@10gen.com&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-12975&quot; title=&quot;Investigate changes in SERVER-42022: Attempt to remove initial sync missing document fetching&quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-12975&quot;&gt;&lt;del&gt;DOCS-12975&lt;/del&gt;&lt;/a&gt;: 4.4 remove mmapv1 fetchedMissingDocs metrics&lt;br/&gt;
Branch: master&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/docs/commit/549da48db7be4b80cc63623eb5a7a0c4d7d54e11&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/docs/commit/549da48db7be4b80cc63623eb5a7a0c4d7d54e11&lt;/a&gt;&lt;/p&gt;</comment>
                    </comments>
                <issuelinks>
                            <issuelinktype id="10320">
                    <name>Documented</name>
                                            <outwardlinks description="documents">
                                        <issuelink>
            <issuekey id="829115">SERVER-42022</issuekey>
        </issuelink>
                            </outwardlinks>
                                                        </issuelinktype>
                            <issuelinktype id="10010">
                    <name>Duplicate</name>
                                                                <inwardlinks description="is duplicated by">
                                                        </inwardlinks>
                                    </issuelinktype>
                    </issuelinks>
                <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_10055" key="com.atlassian.jira.ext.charting:firstresponsedate">
                        <customfieldname>Date of 1st Reply</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>Mon, 16 Mar 2020 18:12:59 +0000</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_10052" key="com.atlassian.jira.toolkit:dayslastcommented">
                        <customfieldname>Days since reply</customfieldname>
                        <customfieldvalues>
                                        3 years, 47 weeks, 2 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_10857" key="com.pyxis.greenhopper.jira:gh-epic-link">
                        <customfieldname>Epic Link</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>DOCS-12787</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>emet.ozar@mongodb.com</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_11151" key="com.atlassian.jira.toolkit:LastCommentDate">
                        <customfieldname>Last public comment date</customfieldname>
                        <customfieldvalues>
                            3 years, 47 weeks, 2 days ago
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                            <customfield id="customfield_10051" key="com.atlassian.jira.toolkit:participants">
                        <customfieldname>Participants</customfieldname>
                        <customfieldvalues>
                                        <customfieldvalue>backlog-server-pm</customfieldvalue>
            <customfieldvalue>xgen-internal-githook</customfieldvalue>
            <customfieldvalue>kay.kim@mongodb.com</customfieldvalue>
    
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                        <customfield id="customfield_14254" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>Product Rank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>1|hvm5gv:</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                <customfield id="customfield_12550" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>Rank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>2|hvayb3:</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_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|hvlrq7:</customfieldvalue>

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