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    <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-19095] $lookup</title>
                <link>https://jira.mongodb.org/browse/SERVER-19095</link>
                <project id="10000" key="SERVER">Core Server</project>
                    <description>&lt;h1&gt;&lt;a name=&quot;Summary&quot;&gt;&lt;/a&gt;Summary&lt;/h1&gt;
&lt;p&gt;Add a $lookUp operator to the aggregation pipeline to pull data from one collection into a pipeline executed on a different collection.&lt;/p&gt;

&lt;h2&gt;&lt;a name=&quot;Goals&quot;&gt;&lt;/a&gt;Goals&lt;/h2&gt;
&lt;ul class=&quot;alternate&quot; type=&quot;square&quot;&gt;
	&lt;li&gt;Aggregation stage to do left outer join&lt;/li&gt;
	&lt;li&gt;Works across any shard/collection boundary
	&lt;ul class=&quot;alternate&quot; type=&quot;square&quot;&gt;
		&lt;li&gt;left-hand side sharded, right-hand side unsharded&lt;/li&gt;
	&lt;/ul&gt;
	&lt;/li&gt;
&lt;/ul&gt;


&lt;h2&gt;&lt;a name=&quot;NonGoals&quot;&gt;&lt;/a&gt;Non-Goals&lt;/h2&gt;
&lt;ul class=&quot;alternate&quot; type=&quot;square&quot;&gt;
	&lt;li&gt;Enforced collocation of &#8220;related&#8221; chunks.&lt;/li&gt;
	&lt;li&gt;More parallelization for agg&lt;/li&gt;
	&lt;li&gt;Small collections that co-exist on all shards (aka, &#8220;enum&#8221; collections)&lt;/li&gt;
&lt;/ul&gt;


&lt;h2&gt;&lt;a name=&quot;Examples&quot;&gt;&lt;/a&gt;Examples&lt;/h2&gt;
&lt;p&gt;Forthcoming&lt;/p&gt;</description>
                <environment></environment>
        <key id="212584">SERVER-19095</key>
            <summary>$lookup</summary>
                <type id="2" iconUrl="https://jira.mongodb.org/secure/viewavatar?size=xsmall&amp;avatarId=14711&amp;avatarType=issuetype">New Feature</type>
                                            <priority id="3" iconUrl="https://jira.mongodb.org/images/icons/priorities/major.svg">Major - P3</priority>
                        <status id="6" iconUrl="https://jira.mongodb.org/images/icons/statuses/closed.png" description="The issue is considered finished, the resolution is correct. Issues which are closed can be reopened.">Closed</status>
                    <statusCategory id="3" key="done" colorName="success"/>
                                    <resolution id="9">Done</resolution>
                                        <assignee username="charlie.swanson@mongodb.com">Charlie Swanson</assignee>
                                    <reporter username="ian@mongodb.com">Ian Whalen</reporter>
                        <labels>
                    </labels>
                <created>Tue, 23 Jun 2015 21:48:54 +0000</created>
                <updated>Tue, 28 Jun 2016 14:52:28 +0000</updated>
                            <resolved>Thu, 1 Oct 2015 19:37:31 +0000</resolved>
                                                    <fixVersion>3.2.0-rc2</fixVersion>
                                    <component>Aggregation Framework</component>
                                        <votes>9</votes>
                                    <watches>40</watches>
                                                                                                                <comments>
                            <comment id="1308690" author="ramon.fernandez" created="Tue, 28 Jun 2016 14:52:28 +0000"  >&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=mgoetzke&quot; class=&quot;user-hover&quot; rel=&quot;mgoetzke&quot;&gt;mgoetzke&lt;/a&gt;, please take a look at the &lt;tt&gt;$graphLookup&lt;/tt&gt; operator in &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-23725&quot; title=&quot;Implement $graphLookup.&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-23725&quot;&gt;&lt;del&gt;SERVER-23725&lt;/del&gt;&lt;/a&gt; to see if it meets your needs.&lt;/p&gt;

&lt;p&gt;Thanks,&lt;br/&gt;
Ram&#243;n.&lt;/p&gt;</comment>
                            <comment id="1308681" author="mgoetzke" created="Tue, 28 Jun 2016 14:45:49 +0000"  >&lt;p&gt;good start .. is there a plan to make this join recursively .. a-&amp;gt;b-&amp;gt;c-&amp;gt;d ... ?&lt;/p&gt;</comment>
                            <comment id="1079426" author="ramon.fernandez" created="Wed, 4 Nov 2015 16:45:38 +0000"  >&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=StealthyDev&quot; class=&quot;user-hover&quot; rel=&quot;StealthyDev&quot;&gt;StealthyDev&lt;/a&gt;, MongoDB 3.2.0-rc2 release candidate &lt;a href=&quot;https://www.mongodb.org/downloads/#development&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;has been released and its available for download&lt;/a&gt;. Thanks for your patience.&lt;/p&gt;</comment>
                            <comment id="1078196" author="ramon.fernandez" created="Tue, 3 Nov 2015 16:21:48 +0000"  >&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=StealthyDev&quot; class=&quot;user-hover&quot; rel=&quot;StealthyDev&quot;&gt;StealthyDev&lt;/a&gt;, we&apos;re working on 3.2.0-rc2 right now, it should be available in the coming days. An announcement will be posted in the &lt;a href=&quot;https://groups.google.com/forum/#!forum/mongodb-announce&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;mongodb-announce&lt;/a&gt;, &lt;a href=&quot;https://groups.google.com/forum/#!forum/mongodb-dev&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;mongodb-dev&lt;/a&gt; and &lt;a href=&quot;https://groups.google.com/forum/#!forum/mongodb-user&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;mongodb-user&lt;/a&gt; groups, as well as the &lt;a href=&quot;http://blog.mongodb.org/&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;MongoDB blog&lt;/a&gt; when 3.2.0-rc2 is available for download.&lt;/p&gt;</comment>
                            <comment id="1078052" author="jsingleton" created="Tue, 3 Nov 2015 14:57:41 +0000"  >&lt;p&gt;@StealthyDev - You can try the latest nightly build from the main downloads page. &lt;a href=&quot;https://www.mongodb.org/downloads#development&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://www.mongodb.org/downloads#development&lt;/a&gt;  Not sure if it&apos;s made the build yet but its the latest you can get other than building from source.&lt;/p&gt;</comment>
                            <comment id="1078033" author="stealthydev" created="Tue, 3 Nov 2015 14:41:28 +0000"  >&lt;p&gt;Sorry I was not sure where to ask this question.&lt;br/&gt;
Just wondering when is the release date for 3.2.0-rc2? Is there a daily build i can download to try this $lookup feature?&lt;/p&gt;

&lt;p&gt;&lt;span class=&quot;error&quot;&gt;&amp;#91;edit&amp;#93;&lt;/span&gt; Another question: is this feature not available in the free version of MongoDB?&lt;/p&gt;

&lt;p&gt;Thank you&lt;/p&gt;</comment>
                            <comment id="1075393" author="xgen-internal-githook" created="Fri, 30 Oct 2015 16:19:53 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{u&apos;username&apos;: u&apos;cswanson310&apos;, u&apos;name&apos;: u&apos;Charlie Swanson&apos;, u&apos;email&apos;: u&apos;cswanson310@gmail.com&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-19095&quot; title=&quot;$lookup&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-19095&quot;&gt;&lt;del&gt;SERVER-19095&lt;/del&gt;&lt;/a&gt; Move $lookup to community edition&lt;br/&gt;
Branch: master&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/mongo/commit/2cc2d7da2be074f5a7d75c4c435a72b0303f7eaf&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/mongo/commit/2cc2d7da2be074f5a7d75c4c435a72b0303f7eaf&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="1075392" author="xgen-internal-githook" created="Fri, 30 Oct 2015 16:19:43 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{u&apos;username&apos;: u&apos;cswanson310&apos;, u&apos;name&apos;: u&apos;Charlie Swanson&apos;, u&apos;email&apos;: u&apos;cswanson310@gmail.com&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-19095&quot; title=&quot;$lookup&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-19095&quot;&gt;&lt;del&gt;SERVER-19095&lt;/del&gt;&lt;/a&gt; Move $lookup to community edition&lt;br/&gt;
Branch: master&lt;br/&gt;
&lt;a href=&quot;https://github.com/10gen/mongo-enterprise-modules/commit/9c7bd6e5fbb5422503063e72419755fd59dc7e38&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/10gen/mongo-enterprise-modules/commit/9c7bd6e5fbb5422503063e72419755fd59dc7e38&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="1074708" author="jdegoes" created="Thu, 29 Oct 2015 21:32:43 +0000"  >&lt;p&gt;Hurray! Thanks to all the folks at MongoDB who made this happen, and to all the users whose voices were ultimately heard! &lt;img class=&quot;emoticon&quot; src=&quot;https://jira.mongodb.org/images/icons/emoticons/smile.png&quot; height=&quot;16&quot; width=&quot;16&quot; align=&quot;absmiddle&quot; alt=&quot;&quot; border=&quot;0&quot;/&gt;&lt;/p&gt;</comment>
                            <comment id="1074687" author="ron.avnur@10gen.com" created="Thu, 29 Oct 2015 21:14:17 +0000"  >&lt;p&gt;All,&lt;/p&gt;

&lt;p&gt;We are making a change that is detailed in &lt;a href=&quot;https://www.mongodb.com/blog/post/revisiting-usdlookup&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://www.mongodb.com/blog/post/revisiting-usdlookup&lt;/a&gt; and you can expect a 3.2 release candidate community build that includes $lookup in to be released soon.&lt;/p&gt;

&lt;p&gt;Ron&lt;/p&gt;</comment>
                            <comment id="1068753" author="jsingleton" created="Fri, 23 Oct 2015 07:19:46 +0000"  >&lt;p&gt;Making the API different between editions at this level is very bad, everyone has already stated the reasons so I won&apos;t reiterate.  &lt;/p&gt;

&lt;p&gt;But I also understand their side of needing profit making features.  &lt;/p&gt;

&lt;p&gt;Maybe it&apos;s time they started having different editions for all levels like SQL Server editions of Express, Standard, Developer and Enterprise.  Which of course Express and Enterprise already exist and I do mean a paid Developer edition.&lt;/p&gt;</comment>
                            <comment id="1068640" author="jdegoes" created="Fri, 23 Oct 2015 01:19:00 +0000"  >&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=bugslayer&quot; class=&quot;user-hover&quot; rel=&quot;bugslayer&quot;&gt;bugslayer&lt;/a&gt; I actually agree with you. I don&apos;t think this is the right or best place to draw the line between CE and EE, for all the reasons listed above (and more). To prevent lock-in, to allow developers without EE to actually write applications using $lookup (locally and in test environments, etc.), to encourage open source projects to support $lookup, to compete with Couchbase, to draw a clear and consistent line between CE and EE features, and so on &#8212; all these and more are good reasons for putting $lookup in the community edition.&lt;/p&gt;

&lt;p&gt;That said, the decision is really beyond our &quot;pay grade&quot;, so to speak. So my above comments are more like, &quot;OK, given that the issue appears to be decided, now what do we do?&quot; I feel like, while it&apos;s a bit disappointing, it&apos;s not &lt;b&gt;yet&lt;/b&gt; the end of the world. &lt;img class=&quot;emoticon&quot; src=&quot;https://jira.mongodb.org/images/icons/emoticons/smile.png&quot; height=&quot;16&quot; width=&quot;16&quot; align=&quot;absmiddle&quot; alt=&quot;&quot; border=&quot;0&quot;/&gt;&lt;/p&gt;</comment>
                            <comment id="1068623" author="bugslayer" created="Fri, 23 Oct 2015 00:53:58 +0000"  >&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=jdegoes&quot; class=&quot;user-hover&quot; rel=&quot;jdegoes&quot;&gt;jdegoes&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;I noticed this problem when I asked: &quot;Does it make sense to upgrade to EE for this?&quot;. The answer is that no, it doesn&apos;t, for the reasons mentioned.&lt;/p&gt;

&lt;p&gt;I didn&apos;t claim the end of the world, but there is a specific aspect of the way software is developed in the real world that they clearly forgot about with this decision, which makes this not only a disservice to community users, but also to enterprise users. With the current constraints, $lookup has very limited use in application development outside of MongoDB, Inc., even when those applications use Enterprise Edition on their production servers. Highlighting that problem on the thread that is used to discuss the correctness of the design is appropriate and constructive.&lt;/p&gt;

&lt;p&gt;I am plenty familiar with alternatives to having a $lookup, but that seems rather beside the point on a thread about whether the $lookup that has actually been implemented can work for anyone, don&apos;t you think?&lt;/p&gt;</comment>
                            <comment id="1068239" author="jdegoes" created="Thu, 22 Oct 2015 19:24:15 +0000"  >&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=debrando&quot; class=&quot;user-hover&quot; rel=&quot;debrando&quot;&gt;debrando&lt;/a&gt; &lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=bugslayer&quot; class=&quot;user-hover&quot; rel=&quot;bugslayer&quot;&gt;bugslayer&lt;/a&gt; &lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=fgrillini&quot; class=&quot;user-hover&quot; rel=&quot;fgrillini&quot;&gt;fgrillini&lt;/a&gt; &lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=nefiga&quot; class=&quot;user-hover&quot; rel=&quot;nefiga&quot;&gt;nefiga&lt;/a&gt; &lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=sallgeud&quot; class=&quot;user-hover&quot; rel=&quot;sallgeud&quot;&gt;sallgeud&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;Of course, as a developer on the community edition, I prefer &lt;tt&gt;$lookup&lt;/tt&gt; to be in the community edition, but I understand MongoDB has their reasons.&lt;/p&gt;

&lt;p&gt;It&apos;s not the end of the world, however, as some comments above suggest. For point joins and analytic / reporting joins, you &lt;b&gt;do&lt;/b&gt; have great alternatives. Read more about them on this blog post: &lt;a href=&quot;http://slamdata.com/blog/2015/10/21/mongodb-missing-join.html&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;MongoDB and the Case of the Missing JOIN&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="1067658" author="debrando" created="Thu, 22 Oct 2015 08:56:00 +0000"  >&lt;p&gt;I think John Crenshaw totally got the point, but let me add more from my company perspective.&lt;/p&gt;

&lt;p&gt;We supply our software in a flexible way to address specific customers needs, from in-house self installation and maintenance to full-feature SaaS. Some customer is big and can afford a full enterprise installation, but someone else have small budget and we cannot just say &quot;We&apos;re sorry, oure next release needs the EE: you&apos;ll have to pay extra 20k&#8364;/year&quot;. On the other hands, forking our software to support the new feature only if avaible would not be an option. This mean that for at least two years we couldn&apos;t use the $lookup.&lt;/p&gt;

&lt;p&gt;The main objection I must face against a wider adoption of MongoDB in our software is exactly the lack of some form of join in order to address reporting needs, and saying we could have it but only with the most expensive license would be a little funny because we&apos;re evalutaing to move reporting away from OracleDB exactly to cut costs and leaving the painful forked development caused by license-bonded features.&lt;/p&gt;

&lt;p&gt;I understand the needs of monetize your wonderful product, but on my company the choice about $lookup licensing could ground our entire MongoDB adoption roadmap...&lt;/p&gt;


</comment>
                            <comment id="1067510" author="bugslayer" created="Thu, 22 Oct 2015 00:53:42 +0000"  >&lt;p&gt;The decision to limit this to enterprise makes the feature unusable, &lt;b&gt;even for enterprise users&lt;/b&gt;. Stable modern software development requires that developers be able to run and test their code in local isolated environments. This means that developers have all of the necessary tooling running locally, on their own $500 laptop. For web development this typically includes a local web server instance (often Apache or IIS), a web development language of choice (often PHP, Node.js, Ruby, or .Net), and the DB server of choice (which you hope is will be MongoDB). These local environments will never include software that has a $10k licensing cost.&lt;/p&gt;

&lt;p&gt;Because local environments need to be able to run the entire system, and because this language feature has been restricted to enterprise only, your enterprise users have to make a choice: a) violate the isolation of development environments (and accept the endless flood of problems that comes with that), or b) don&apos;t use the new $lookup language feature.&lt;/p&gt;

&lt;p&gt;With only rare exception, the technology leaders in an organization would have to be bone dead stupid to choose option a.&lt;/p&gt;

&lt;p&gt;I seriously hope you will consider how this actually impacts your users, especially in stable well designed development environments, and reconsider the decision to lock this language feature. To encourage enterprise deployments, the developers building those deployments need to be able to do their job, and this decision actually interferes with that goal rather than advancing it.&lt;/p&gt;</comment>
                            <comment id="1066607" author="fgrillini" created="Wed, 21 Oct 2015 08:24:00 +0000"  >&lt;p&gt;I completely agree with Ben Rotz. In my company i have to fight to make some collegues understand that mongodb is more than a file storage system, because they think that a relational dbms has more powerful search capabilities.&lt;br/&gt;
This is a basic feature for a dbms, not an enterprise one.&lt;/p&gt;</comment>
                            <comment id="1057353" author="nefiga" created="Sun, 11 Oct 2015 03:50:58 +0000"  >&lt;p&gt;Please reconsider your decision about having $lookup in the enterprise edition only. The blog post didn&apos;t really offer a &lt;b&gt;good&lt;/b&gt; reason for not having this functionality available in the non-enterprise build. And feature split with functions at this level makes me nervous about what next &quot;most requested&quot; feature is going to get the enterprise-only treatment.&lt;/p&gt;</comment>
                            <comment id="1055474" author="sallgeud" created="Thu, 8 Oct 2015 15:49:29 +0000"  >&lt;p&gt;That&apos;s got to be a joke.. it&apos;s not April 1.  To ask for help from people like our team, and to suggest the reason the questions on functionality were being asked was to help us out, and to then take that feedback and valuable input and exclude those who had input is just wrong. This has bee one of the most requested items out there. The blog seems to be trying desperately to make excuses and avoid the real reasons this was done.&lt;/p&gt;</comment>
                            <comment id="1048152" author="ron.avnur@10gen.com" created="Thu, 1 Oct 2015 00:02:11 +0000"  >&lt;p&gt;Hi Mitar and Neville, &lt;/p&gt;

&lt;p&gt;You&#8217;re correct that the $lookup aggregation stage is available in the enterprise builds. Please see the following blog post for a detailed explanation: &lt;a href=&quot;https://www.mongodb.com/blog/post/thoughts-on-new-feature-lookup&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://www.mongodb.com/blog/post/thoughts-on-new-feature-lookup&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="1044556" author="mitar" created="Mon, 28 Sep 2015 04:35:17 +0000"  >&lt;p&gt;Oh, enterprise version only? I thought that enterprise version does not differ in core features from community version?&lt;/p&gt;</comment>
                            <comment id="1043728" author="asya" created="Fri, 25 Sep 2015 18:11:54 +0000"  >&lt;p&gt;We don&apos;t have explicit/scheduled plans, but it&apos;s a safe assumption that in future releases we will enhance this feature to allow more functionality and to reduce restrictions.&lt;/p&gt;

&lt;p&gt;Those will be tracked in separate tickets though.&lt;/p&gt;

</comment>
                            <comment id="1043667" author="nevi_me" created="Fri, 25 Sep 2015 17:39:20 +0000"  >&lt;p&gt;Are there plans to make $lookup work across databases? I also see that it&apos;s only available on enterprise builds &lt;img class=&quot;emoticon&quot; src=&quot;https://jira.mongodb.org/images/icons/emoticons/sad.png&quot; height=&quot;16&quot; width=&quot;16&quot; align=&quot;absmiddle&quot; alt=&quot;&quot; border=&quot;0&quot;/&gt;&lt;/p&gt;</comment>
                            <comment id="1043648" author="asya" created="Fri, 25 Sep 2015 17:25:27 +0000"  >&lt;p&gt;The $lookup stage is analogous to a left outer join - based on the join condition, the number of documents from &quot;other&quot; collection that are brought into the pipeline may be 0, 1 or many.  Since result is represented as an array, the array will have 0, 1 or multiple elements.&lt;/p&gt;

&lt;p&gt;There are some examples in the 3.1 docs (though note these are not guaranteed to stay the same for final 3.2 release).&lt;br/&gt;
&lt;a href=&quot;http://docs.mongodb.org/manual/release-notes/3.1-dev-series/#left-outer-join&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;http://docs.mongodb.org/manual/release-notes/3.1-dev-series/#left-outer-join&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="1041610" author="mitar" created="Thu, 24 Sep 2015 04:22:49 +0000"  >&lt;p&gt;Please, can you give some feedback on what will be semantics of this? It is being quietly implemented without any open discussion on its design. Can we discuss this? Is there a better place to discuss it?&lt;/p&gt;

&lt;p&gt;For example, how does $lookup behave with missing fields? Can it be treated as outer join?&lt;/p&gt;</comment>
                            <comment id="1001920" author="xgen-internal-githook" created="Tue, 11 Aug 2015 14:56:43 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{u&apos;username&apos;: u&apos;jamesfcohan&apos;, u&apos;name&apos;: u&apos;James Cohan&apos;, u&apos;email&apos;: u&apos;james.cohan@10gen.com&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-19095&quot; title=&quot;$lookup&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-19095&quot;&gt;&lt;del&gt;SERVER-19095&lt;/del&gt;&lt;/a&gt; Adds aggregation stage $lookUp&lt;br/&gt;
Branch: master&lt;br/&gt;
&lt;a href=&quot;https://github.com/10gen/mongo-enterprise-modules/commit/0bb7e669884d0112818b10335361bff9b7f6504c&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/10gen/mongo-enterprise-modules/commit/0bb7e669884d0112818b10335361bff9b7f6504c&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="1001914" author="xgen-internal-githook" created="Tue, 11 Aug 2015 14:55:00 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{u&apos;username&apos;: u&apos;jamesfcohan&apos;, u&apos;name&apos;: u&apos;James Cohan&apos;, u&apos;email&apos;: u&apos;james.cohan@10gen.com&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-19095&quot; title=&quot;$lookup&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-19095&quot;&gt;&lt;del&gt;SERVER-19095&lt;/del&gt;&lt;/a&gt; Changes parsing of stages in authorization checking and adds enterprise pipeline tests to aggregation suite&lt;br/&gt;
Branch: master&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/mongo/commit/ff9624152b6b9d017d65cf5055dc5f3a9907f062&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/mongo/commit/ff9624152b6b9d017d65cf5055dc5f3a9907f062&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="999992" author="mitar" created="Sat, 8 Aug 2015 08:04:08 +0000"  >&lt;p&gt;This is great work. What exactly will be the syntax and semantic of this operation? Is there any design doc?&lt;/p&gt;

&lt;p&gt;Also, if $lookup is left outer join, how will you represent the missing relations? With null? Empty document? Missing field?&lt;/p&gt;</comment>
                            <comment id="999637" author="xgen-internal-githook" created="Fri, 7 Aug 2015 17:58:07 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{u&apos;username&apos;: u&apos;jamesfcohan&apos;, u&apos;name&apos;: u&apos;James Cohan&apos;, u&apos;email&apos;: u&apos;james.cohan@10gen.com&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-19095&quot; title=&quot;$lookup&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-19095&quot;&gt;&lt;del&gt;SERVER-19095&lt;/del&gt;&lt;/a&gt; Fix formatting&lt;br/&gt;
Branch: master&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/mongo/commit/34536a3631de2e6013b1e46d30895ac7086b2aec&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/mongo/commit/34536a3631de2e6013b1e46d30895ac7086b2aec&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="999416" author="xgen-internal-githook" created="Fri, 7 Aug 2015 15:04:40 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{u&apos;username&apos;: u&apos;jamesfcohan&apos;, u&apos;name&apos;: u&apos;James Cohan&apos;, u&apos;email&apos;: u&apos;james.cohan@10gen.com&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-19095&quot; title=&quot;$lookup&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-19095&quot;&gt;&lt;del&gt;SERVER-19095&lt;/del&gt;&lt;/a&gt; Prep for $lookUp, add checks for auth and sharded collection(s)&lt;br/&gt;
Branch: master&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/mongo/commit/9285c02fa61049b2a011a0f9f53ccfbc46a0facb&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/mongo/commit/9285c02fa61049b2a011a0f9f53ccfbc46a0facb&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="971198" author="elranu" created="Tue, 21 Jul 2015 17:13:26 +0000"  >&lt;p&gt;This is the feature that was missing Mongo!!!! MongoDB needs this!!!&lt;/p&gt;

&lt;p&gt;I&apos;m happy that this started to be a priority to MongoDB!&lt;/p&gt;</comment>
                            <comment id="957805" author="nevi_me" created="Fri, 3 Jul 2015 17:26:28 +0000"  >&lt;p&gt;This will be great!&lt;/p&gt;</comment>
                    </comments>
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