<!-- 
RSS generated by JIRA (9.7.1#970001-sha1:2222b88b221c4928ef0de3161136cc90c8356a66) at Thu Feb 08 08:03:49 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-11866] Document Causal Consistency behavior for different read and write concerns</title>
                <link>https://jira.mongodb.org/browse/DOCS-11866</link>
                <project id="10380" key="DOCS">Documentation</project>
                    <description>&lt;p&gt;----------------------------&lt;/p&gt;
&lt;h2&gt;&lt;a name=&quot;OriginalDescription&quot;&gt;&lt;/a&gt;Original Description&lt;/h2&gt;

&lt;p&gt;Causal Consistency behavior varies depending on the read and write concerns as described in &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-35316&quot; title=&quot;Causal Consistency Violation for local read/write concerns in Jepsen Sharded Cluster Test&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-35316&quot;&gt;&lt;del&gt;SERVER-35316&lt;/del&gt;&lt;/a&gt;. The documentation needs an update to provide more details to the user and avoid confusion while using this feature.&lt;br/&gt;
----------------------------&lt;/p&gt;
&lt;h2&gt;&lt;a name=&quot;Description&quot;&gt;&lt;/a&gt;Description&lt;/h2&gt;

&lt;p&gt;Copied from &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-35316&quot; title=&quot;Causal Consistency Violation for local read/write concerns in Jepsen Sharded Cluster Test&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-35316&quot;&gt;&lt;del&gt;SERVER-35316&lt;/del&gt;&lt;/a&gt;:&lt;/p&gt;

&lt;p&gt;When running a test against 2 replica set shards, with rc &#8220;local&#8221; and wc &#8220;w1&#8221; we get reads returning the base value of the document, nil, despite occurring after acknowledged writes in the session. Each single threaded client is writing to one key at a time, using one session, against a single mongos router, and does not have writes to secondaries enabled. The nemesis partitions the network into random halves for 10 seconds, with a 10 second wait in between (This failure has not appeared with partitions disabled.&lt;/p&gt;

&lt;p&gt;The expected pattern of operations in this test is read nil/0, write 1, read 1, write 2, read 2. In the test histories I&#8217;ve attached below, the :position field is the op&#8217;s optime value, read from the session after acknowledgement. It&#8217;s :link field is the previous optime value the client has seen in that key&#8217;s session. &lt;/p&gt;

&lt;p&gt;In the first set of results (rwr-initial-read-1), this occurs in 3 keys over a 40 second test. In each failing key (15 23 16), we see a read of 0 (representing the initial empty document&#8217;s read nil for the checker), and a successful write of 1. Then the read following write 2 returns an empty document.  &lt;/p&gt;

&lt;p&gt;The second result set (rwr-initial-read-2) provided is a longer test over 300 seconds, where we observe this anomaly 6 times. Keys 50, 51, 82, 125, and 143 appear to drop the value on write 2. However, key 116 is missing the value for write 1.  Also of note is that in the history for key 116, (under independent/116) write 2 succeeds and appears in the final read for the key. See op `{:type :ok, :f :read, :value 2, :process 5, :time 205602064887, :position 6559250071353819138, :link 6559250071353819137, :index 1206}`&lt;/p&gt;

&lt;h2&gt;&lt;a name=&quot;Scopeofchanges%28filesthatneedworkandhowmuch%29&quot;&gt;&lt;/a&gt;Scope of changes (files that need work and how much)&lt;/h2&gt;

&lt;h2&gt;&lt;a name=&quot;Impacttootherdocsoutsideofthisproduct&quot;&gt;&lt;/a&gt;Impact to other docs outside of this product&lt;/h2&gt;

&lt;h2&gt;&lt;a name=&quot;MVP%28workanddate%3F%29&quot;&gt;&lt;/a&gt;MVP (work and date?)&lt;/h2&gt;

&lt;h2&gt;&lt;a name=&quot;Resources%28e.g.ScopeDocs%2CInvision%29&quot;&gt;&lt;/a&gt;Resources (e.g. Scope Docs, Invision)&lt;/h2&gt;</description>
                <environment>&lt;a href=&quot;https://docs.mongodb.com/manual/core/read-isolation-consistency-recency/index.html#causal-consistency&quot;&gt;https://docs.mongodb.com/manual/core/read-isolation-consistency-recency/index.html#causal-consistency&lt;/a&gt;</environment>
        <key id="569264">DOCS-11866</key>
            <summary>Document Causal Consistency behavior for different read and write concerns</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="13201">Fixed</resolution>
                                        <assignee username="kay.kim@mongodb.com">Kay Kim</assignee>
                                    <reporter username="misha.tyulenev@mongodb.com">Misha Tyulenev</reporter>
                        <labels>
                            <label>consistency</label>
                    </labels>
                <created>Mon, 9 Jul 2018 14:46:59 +0000</created>
                <updated>Mon, 30 Oct 2023 20:57:35 +0000</updated>
                            <resolved>Wed, 5 Sep 2018 14:49:39 +0000</resolved>
                                                    <fixVersion>Server_Docs_20231030</fixVersion>
                                    <component>Server</component>
                        <due></due>
                            <votes>0</votes>
                                    <watches>4</watches>
                                                                                                                <comments>
                            <comment id="1994106" author="xgen-internal-githook" created="Wed, 5 Sep 2018 17:36:01 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{&apos;name&apos;: &apos;kay&apos;, &apos;email&apos;: &apos;kay.kim@10gen.com&apos;, &apos;username&apos;: &apos;kay-kim&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-11866&quot; title=&quot;Document Causal Consistency behavior for different read and write concerns&quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-11866&quot;&gt;&lt;del&gt;DOCS-11866&lt;/del&gt;&lt;/a&gt;: add redirects&lt;br/&gt;
Branch: master&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/docs/commit/19e15ad8ff4a9b28ec2644beaf116e7a9107fb71&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/docs/commit/19e15ad8ff4a9b28ec2644beaf116e7a9107fb71&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="1994063" author="xgen-internal-githook" created="Wed, 5 Sep 2018 17:10:43 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{&apos;name&apos;: &apos;kay&apos;, &apos;email&apos;: &apos;kay.kim@10gen.com&apos;, &apos;username&apos;: &apos;kay-kim&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-11866&quot; title=&quot;Document Causal Consistency behavior for different read and write concerns&quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-11866&quot;&gt;&lt;del&gt;DOCS-11866&lt;/del&gt;&lt;/a&gt;, &lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-11882&quot; title=&quot;New examples for  causally consistent sessions &quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-11882&quot;&gt;&lt;del&gt;DOCS-11882&lt;/del&gt;&lt;/a&gt;: updates to causally consistent sessions&lt;br/&gt;
Branch: v3.6&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/docs/commit/9f63dd868be3a1c8b4d7668f7f84d8685adcd51b&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/docs/commit/9f63dd868be3a1c8b4d7668f7f84d8685adcd51b&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="1994061" author="xgen-internal-githook" created="Wed, 5 Sep 2018 17:10:31 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{&apos;name&apos;: &apos;kay&apos;, &apos;email&apos;: &apos;kay.kim@10gen.com&apos;, &apos;username&apos;: &apos;kay-kim&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-11866&quot; title=&quot;Document Causal Consistency behavior for different read and write concerns&quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-11866&quot;&gt;&lt;del&gt;DOCS-11866&lt;/del&gt;&lt;/a&gt;, &lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-11882&quot; title=&quot;New examples for  causally consistent sessions &quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-11882&quot;&gt;&lt;del&gt;DOCS-11882&lt;/del&gt;&lt;/a&gt;: updates to causally consistent sessions&lt;br/&gt;
Branch: master&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/docs/commit/6fba10ec6d58ba39b713efbf7ee749b5929af947&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/docs/commit/6fba10ec6d58ba39b713efbf7ee749b5929af947&lt;/a&gt;&lt;/p&gt;</comment>
                    </comments>
                <issuelinks>
                            <issuelinktype id="10011">
                    <name>Depends</name>
                                            <outwardlinks description="depends on">
                                        <issuelink>
            <issuekey id="552253">SERVER-35316</issuekey>
        </issuelink>
                            </outwardlinks>
                                                        </issuelinktype>
                    </issuelinks>
                <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_10055" key="com.atlassian.jira.ext.charting:firstresponsedate">
                        <customfieldname>Date of 1st Reply</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>Wed, 15 Aug 2018 20:12:59 +0000</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_10052" key="com.atlassian.jira.toolkit:dayslastcommented">
                        <customfieldname>Days since reply</customfieldname>
                        <customfieldvalues>
                                        5 years, 23 weeks ago
    
                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_18254" key="com.onresolve.jira.groovy.groovyrunner:scripted-field">
                        <customfieldname>Dependencies</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue><![CDATA[<s><a href='https://jira.mongodb.org/browse/SERVER-35316'>SERVER-35316</a></s>]]></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>emet.ozar@mongodb.com</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_11151" key="com.atlassian.jira.toolkit:LastCommentDate">
                        <customfieldname>Last public comment date</customfieldname>
                        <customfieldvalues>
                            5 years, 23 weeks ago
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                            <customfield id="customfield_10051" key="com.atlassian.jira.toolkit:participants">
                        <customfieldname>Participants</customfieldname>
                        <customfieldvalues>
                                        <customfieldvalue>xgen-internal-githook</customfieldvalue>
            <customfieldvalue>kay.kim@mongodb.com</customfieldvalue>
            <customfieldvalue>misha.tyulenev@mongodb.com</customfieldvalue>
    
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                        <customfield id="customfield_14254" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>Product Rank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>1|hu294n:</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                <customfield id="customfield_12550" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>Rank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>2|httbgn:</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_10557" key="com.pyxis.greenhopper.jira:gh-sprint">
                        <customfieldname>Sprint</customfieldname>
                        <customfieldvalues>
                                <customfieldvalue id="2387">Sharding 2018-07-30</customfieldvalue>
    <customfieldvalue id="2451">Sharding 2018-08-13</customfieldvalue>
    <customfieldvalue id="2452">Sharding 2018-08-27</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                                                                        <customfield id="customfield_10555" key="com.atlassian.jira.plugin.system.customfieldtypes:float">
                        <customfieldname>Story Points</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>1.0</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|hu1vdz:</customfieldvalue>

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