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<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-5931] Secondary reads in sharded clusters need stronger consistency</title>
                <link>https://jira.mongodb.org/browse/SERVER-5931</link>
                <project id="10000" key="SERVER">Core Server</project>
                    <description>&lt;p&gt;Secondary reads in MongoDB are only eventually consistent - the state of the system will not reflect the latest changes. When balancing, the state of the cluster is changing implicitly, and so secondary reads are inconsistent. This means that duplicate, stale, or missing data can be observed when balancing operations are active, along with orphaned data from aborted balancer operations.&lt;/p&gt;

&lt;p&gt;Issues with orphaned data affecting results from primary reads are different problems - see &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-3645&quot; title=&quot;Sharded collection counts (on primary) can report too many results&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-3645&quot;&gt;&lt;del&gt;SERVER-3645&lt;/del&gt;&lt;/a&gt; for example.&lt;/p&gt;

&lt;p&gt;Original description:&lt;/p&gt;

&lt;p&gt;Mongo may return too many documents in a sharded system. This may occur when a document is located on more than one shard. We don&apos;t know yet why some documents are located on more than one shard because we never access shards directly. We always access mongoDB through mongos (router). Perhaps these documents result from a failed chunk migration?&lt;/p&gt;

&lt;p&gt;In any case, even if these documents exist on more than one shard, mongo should be clever enough to return only those, which are tracked by the config servers.&lt;/p&gt;

&lt;p&gt;Let me show you a test case (documents are sharded by _id):&lt;/p&gt;

&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;mongos&amp;gt; db.offer.find({shopId:100}).count()&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;0&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;## no doc of shopId:100 exist yet, so let add one through the router:&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;mongos&amp;gt; db.offer.save({&quot;_id&quot; : 100, &quot;shopId&quot; : 100, &quot;version&quot;: 1})&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;mongos&amp;gt; exit&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;bye&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;## let&apos;s add an document on another shard (this time by accessing it directly to beeing able to reproduce)&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&amp;gt; mongo localhost:20017/offerStore&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;MongoDB shell version: 2.0.5&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;connecting to: localhost:20017/offerStore&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;PRIMARY&amp;gt; db.offer.find({shopId:100}).count()&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;0&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;PRIMARY&amp;gt; db.offer.save({&quot;_id&quot; : 100, &quot;shopId&quot; : 100, &quot;version&quot;: 2})&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;PRIMARY&amp;gt; db.offer.find({shopId:100}).count()&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;1&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;PRIMARY&amp;gt; exit&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;bye&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;## let&apos;s check what mongos thinks how many docs of shopId:100 it has:&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;MongoDB shell version: 2.0.5&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;connecting to: localhost:20021/offerStore&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;mongos&amp;gt; db.offer.find({shopId:100}).count()&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;2&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;## this is a bug, because mongos should find only 1 doc since the 2nd doc is a an orphan, not beeing referenced by config servers:&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;mongos&amp;gt; db.printShardingStatus(true)&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;--- Sharding Status --- &lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;  sharding version: { &quot;_id&quot; : 1, &quot;version&quot; : 3 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;  shards:&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{  &quot;_id&quot; : &quot;shard1&quot;,  &quot;host&quot; : &quot;shard1/localhost:20017&quot; }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{  &quot;_id&quot; : &quot;shard2&quot;,  &quot;host&quot; : &quot;shard2/localhost:20018&quot; }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{  &quot;_id&quot; : &quot;shard3&quot;,  &quot;host&quot; : &quot;shard3/localhost:20019&quot; }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;  databases:&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{  &quot;_id&quot; : &quot;admin&quot;,  &quot;partitioned&quot; : false,  &quot;primary&quot; : &quot;config&quot; }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{  &quot;_id&quot; : &quot;offerStore&quot;,  &quot;partitioned&quot; : true,  &quot;primary&quot; : &quot;shard1&quot; }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;		offerStore.offer chunks:&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;				shard3	6&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;				shard1	7&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;				shard2	7&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : { $minKey : 1 } } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(538697491) } on : shard3 { &quot;t&quot; : 4000, &quot;i&quot; : 2 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(538697491) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(538748351) } on : shard3 { &quot;t&quot; : 4000, &quot;i&quot; : 4 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(538748351) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(538827239) } on : shard3 { &quot;t&quot; : 5000, &quot;i&quot; : 4 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(538827239) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(538893516) } on : shard3 { &quot;t&quot; : 6000, &quot;i&quot; : 2 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(538893516) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(591546899) } on : shard3 { &quot;t&quot; : 6000, &quot;i&quot; : 3 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(591546899) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(647519529) } on : shard1 { &quot;t&quot; : 6000, &quot;i&quot; : 1 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(647519529) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(660087036) } on : shard1 { &quot;t&quot; : 3000, &quot;i&quot; : 2 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(660087036) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(675320121) } on : shard1 { &quot;t&quot; : 3000, &quot;i&quot; : 6 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(675320121) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(691204023) } on : shard1 { &quot;t&quot; : 3000, &quot;i&quot; : 7 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(691204023) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(706454221) } on : shard1 { &quot;t&quot; : 3000, &quot;i&quot; : 4 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(706454221) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(751548202) } on : shard1 { &quot;t&quot; : 3000, &quot;i&quot; : 5 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(751548202) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(799095936) } on : shard1 { &quot;t&quot; : 7000, &quot;i&quot; : 0 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(799095936) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(844050111) } on : shard2 { &quot;t&quot; : 7000, &quot;i&quot; : 1 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(844050111) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(896132956) } on : shard2 { &quot;t&quot; : 6000, &quot;i&quot; : 8 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(896132956) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(937716362) } on : shard2 { &quot;t&quot; : 6000, &quot;i&quot; : 10 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(937716362) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(960061623) } on : shard2 { &quot;t&quot; : 6000, &quot;i&quot; : 11 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(960061623) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(995515056) } on : shard2 { &quot;t&quot; : 5000, &quot;i&quot; : 2 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(995515056) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(1021076450) } on : shard2 { &quot;t&quot; : 6000, &quot;i&quot; : 4 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(1021076450) } --&amp;gt;&amp;gt; { &quot;_id&quot; : NumberLong(1035798084) } on : shard2 { &quot;t&quot; : 6000, &quot;i&quot; : 5 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	{ &quot;_id&quot; : NumberLong(1035798084) } --&amp;gt;&amp;gt; { &quot;_id&quot; : { $maxKey : 1 } } on : shard3 { &quot;t&quot; : 5000, &quot;i&quot; : 0 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&amp;nbsp;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;mongos&amp;gt; db.offer.find({shopId:100})&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;{ &quot;_id&quot; : 100, &quot;shopId&quot; : 100, &quot;version&quot; : 1 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;## this is correct (only 1 doc found) BUT see the next one:&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;mongos&amp;gt; rs.slaveOk()&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;mongos&amp;gt; db.offer.find({shopId:100})&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;{ &quot;_id&quot; : 100, &quot;shopId&quot; : 100, &quot;version&quot; : 2 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;{ &quot;_id&quot; : 100, &quot;shopId&quot; : 100, &quot;version&quot; : 1 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;## this is a bug since mongo queries all shards without ever asking whether they return orphan docs or not&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;mongos&amp;gt; db.offer.find({_id:100})&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;{ &quot;_id&quot; : 100, &quot;shopId&quot; : 100, &quot;version&quot; : 1 }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;## When searching by sharding key, mongo get it correct.&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;</description>
                <environment>ubuntu lucid 64 bit</environment>
        <key id="39607">SERVER-5931</key>
            <summary>Secondary reads in sharded clusters need stronger consistency</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="dianna.hohensee@mongodb.com">Dianna Hohensee</assignee>
                                    <reporter username="kay.agahd@idealo.de">Kay Agahd</reporter>
                        <labels>
                            <label>setShardVersion</label>
                    </labels>
                <created>Fri, 25 May 2012 12:59:56 +0000</created>
                <updated>Thu, 6 Apr 2023 18:54:36 +0000</updated>
                            <resolved>Mon, 31 Jul 2017 14:04:23 +0000</resolved>
                                                    <fixVersion>3.5.11</fixVersion>
                                    <component>Querying</component>
                    <component>Replication</component>
                    <component>Sharding</component>
                                        <votes>41</votes>
                                    <watches>63</watches>
                                                                                                                <comments>
                            <comment id="2163005" author="kaloian.manassiev" created="Tue, 26 Feb 2019 15:23:50 +0000"  >&lt;p&gt;Hello &lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=lucasoares&quot; class=&quot;user-hover&quot; rel=&quot;lucasoares&quot;&gt;lucasoares&lt;/a&gt;,&lt;/p&gt;

&lt;p&gt;This feature is already available in the 3.6.0 and later releases. Please take a look at the &lt;a href=&quot;https://docs.mongodb.com/manual/core/distributed-queries/#read-operations-to-sharded-clusters&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;documentation&lt;/a&gt; for more information.&lt;/p&gt;

&lt;p&gt;Best regards,&lt;br/&gt;
-Kal.&lt;/p&gt;</comment>
                            <comment id="2162975" author="lucasoares" created="Tue, 26 Feb 2019 15:09:44 +0000"  >&lt;p&gt;Hello! This will enter on any near 3.6 release?&lt;/p&gt;

&lt;p&gt;Thank you.&lt;/p&gt;</comment>
                            <comment id="1033298" author="spencer" created="Thu, 17 Sep 2015 17:30:21 +0000"  >&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=jblackburn&quot; class=&quot;user-hover&quot; rel=&quot;jblackburn&quot;&gt;jblackburn&lt;/a&gt;, you may also be interested in watching &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-4935&quot; title=&quot;Mark node Recovering when replication lag exceeds a configured threshold&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-4935&quot;&gt;&lt;del&gt;SERVER-4935&lt;/del&gt;&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="1033021" author="schwerin" created="Thu, 17 Sep 2015 14:40:38 +0000"  >&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=jblackburn&quot; class=&quot;user-hover&quot; rel=&quot;jblackburn&quot;&gt;jblackburn&lt;/a&gt;, this ticket describes a different feature request from the one in your comment.  Your request is more akin to &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-4936&quot; title=&quot;Server support for &amp;quot;maxStalenessMS&amp;quot; read preference option&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-4936&quot;&gt;&lt;del&gt;SERVER-4936&lt;/del&gt;&lt;/a&gt;, where you have also commented.&lt;/p&gt;</comment>
                            <comment id="1030224" author="jblackburn" created="Tue, 15 Sep 2015 16:28:57 +0000"  >&lt;p&gt;It&apos;s currently possible for a SECONDARY to be infinitely&lt;img class=&quot;emoticon&quot; src=&quot;https://jira.mongodb.org/images/icons/emoticons/warning.png&quot; height=&quot;16&quot; width=&quot;16&quot; align=&quot;absmiddle&quot; alt=&quot;&quot; border=&quot;0&quot;/&gt; lagged w.r.t. the PRIMARY (in version 3.0.6).  We saw an issue where large packets (&amp;gt;1500bytes were lost by the network).  Heartbeat still work, but replication stopped. However the SECONDARY never stopped servicing queries CS-24224. &lt;/p&gt;

&lt;p&gt;Ideally the SECONDARY should move to RECOVERING if it becomes too stale, or be configured to fail altogether.&lt;/p&gt;

&lt;p&gt;We have a reasonable tolerance for stale secondaries, but not for hours or days...&lt;/p&gt;</comment>
                            <comment id="757501" author="adamaflynn" created="Thu, 6 Nov 2014 03:39:43 +0000"  >&lt;p&gt;Wanted to add a +1 to this ticket and describe how it&apos;s manifested itself in our deployment (see CS-11107 for more details). We have a workaround now, but I want to make the engineering team aware of a use case where this can be really bad.&lt;/p&gt;

&lt;p&gt;First, I understand the complexity of the issues involved in this one and that it can&apos;t be fixed haphazardly. It&apos;s probably too late for 2.8, but I&apos;d love to see this be a priority in 3.0. I also think it&apos;s important to advertise the symptoms of this limitation more widely (internally &amp;amp; externally) so people can avoid painting themselves into corners until this is fixed.&lt;/p&gt;

&lt;p&gt;We use tagged secondary reads pretty aggressively in our app. With a high read/write ratio, tolerance for eventual consistency (in the form of replication lag, anyway), and a high redundancy requirement that makes us carry a lot of secondaries anyway, a secondary read preference makes a lot of sense. We also split between analytics queries and real-time queries. Having analytics &amp;amp; real-time loads on the same node causes problems, so we use tags to route to different secondaries. Great feature for that! But - the high read-write ratio means a long time can pass between a moveChunk finishing and the primary being hit (especially in analytics tools which often do no writes). &lt;/p&gt;

&lt;p&gt;The behaviour here is that documents seem to disappear and all kinds of queries fail. Until Andrew helped us understand the details (hitting a primary of a shard that knows about the migration refreshes metadata), our only operational fix was &lt;tt&gt;flushRouterConfig&lt;/tt&gt; everywhere. So, when we added new shards and had aggressive balancing, every night or two our error rate would spike way up from &quot;missing&quot; documents. Someone would wake up, flush or restart all &lt;tt&gt;mongos&lt;/tt&gt;, error rate goes down, back to sleep. Random data disappearing until you restart &lt;tt&gt;mongos&lt;/tt&gt; is pretty scary.&lt;/p&gt;

&lt;p&gt;We have 17 shards (68 mongod) now and add shards monthly, so we&apos;re constantly doing a lot of balancing, even with well-distributed writes. Adding shards implied accepting a bunch of things would be transiently broken for a week or two. That obviously isn&apos;t scalable.&lt;/p&gt;

&lt;p&gt;We first opened the ticket about this back in March and the support engineer wasn&apos;t able to nail down what was happening (and we couldn&apos;t reproduce reliably to get logs). After we figured out how to reproduce this and got a high &lt;tt&gt;logLevel&lt;/tt&gt; capture, Andrew was able to nail down that it was a case of this ticket.&lt;/p&gt;

&lt;p&gt;To be clear: I think MongoDB support is excellent and we&apos;ve got a reasonable (if messy) workaround from CS-11107. But, my concern here is that such a big caveat in MongoDB&apos;s consistency semantics isn&apos;t mentioned in the docs and 2 support engineers weren&apos;t initially aware of its symptoms. If it was clear in docs or support discussions that this particular behavior existed, I probably would have made different architectural decisions over the last couple years... but having it come up as a &quot;gotcha&quot; during fast growth is a big concern.&lt;/p&gt;</comment>
                            <comment id="705772" author="greg_10gen" created="Wed, 27 Aug 2014 16:43:45 +0000"  >&lt;p&gt;This issue has had a lot of discussion - summarizing here:&lt;/p&gt;

&lt;p&gt;Secondary reads in MongoDB are only eventually consistent - the state of the system will not reflect the latest changes.  When balancing, the state of the cluster is changing implicitly, and so secondary reads are inconsistent.  This means that duplicate, stale, or missing data can be observed when balancing operations are active, along with orphaned data from aborted balancer operations.&lt;/p&gt;

&lt;p&gt;Issues with orphaned data affecting results from primary reads are different problems - see &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-3645&quot; title=&quot;Sharded collection counts (on primary) can report too many results&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-3645&quot;&gt;&lt;del&gt;SERVER-3645&lt;/del&gt;&lt;/a&gt; for example.&lt;/p&gt;

&lt;p&gt;Filtering results to remove duplicate data is only half of the problem - data that has not yet been replicated to certain secondaries on a TO-shard but has been removed on a FROM-shard may be invisible temporarily.  A full fix is nontrivial and requires tracking differing sets of chunk metadata per-node, integrated with replication, and new targeting logic.&lt;/p&gt;

&lt;p&gt;A partial fix may be possible by forcing migrations to become fully replicated using secondary throttling - this would allow filtering to work, if a primary was online, at the cost of slow migrations.  We&apos;re still considering the options here.&lt;/p&gt;</comment>
                            <comment id="675556" author="thomasr" created="Tue, 29 Jul 2014 20:48:40 +0000"  >&lt;p&gt;Hi Nic, &lt;/p&gt;

&lt;p&gt;to clarify your last question: compact rewrites (and thus compacts) the extents of a collection but does not free up disk space. This is because extents from different collections are kept within the same db file. The space is added to the free list and available to newly inserted data, but you won&apos;t see more available space on the OS level after a compact.&lt;/p&gt;

&lt;p&gt;Regards,&lt;br/&gt;
Thomas&lt;/p&gt;</comment>
                            <comment id="674981" author="tubededentifrice" created="Tue, 29 Jul 2014 14:49:25 +0000"  >&lt;p&gt;@Nic &amp;gt; Probably but I&apos;m not sure it frees up disk space (the docs only states it&apos;s similar to repairDatabase but for a collection). I had not enough disk space to repair my big database too, so I &quot;repaired&quot; small databases first to make enough room to repair the big one, but I don&apos;t know if you can do this too. Let me know &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="674959" author="niccottrell" created="Tue, 29 Jul 2014 14:34:01 +0000"  >&lt;p&gt;I don&apos;t seem to have the required available disk space for an entire copy of the whole db, so will running compact on individual collections give me the same index space savings? Maybe I should just rebuild the entire secondary from the primary data...&lt;/p&gt;</comment>
                            <comment id="674951" author="niccottrell" created="Tue, 29 Jul 2014 14:27:37 +0000"  >&lt;p&gt;@Vicent - I did run on the two mongod primaries directly, but didn&apos;t run the repairs yet. Will give it a try. Many thanks!&lt;/p&gt;</comment>
                            <comment id="674894" author="tubededentifrice" created="Tue, 29 Jul 2014 13:56:12 +0000"  >&lt;p&gt;@Nic Cottrell &amp;gt; Did you make sure you ran the script on &lt;b&gt;mongod&lt;/b&gt; and not &lt;b&gt;mongos&lt;/b&gt;?&lt;br/&gt;
I&apos;m using this piece of code that works pretty well: &lt;a href=&quot;http://pastebin.com/VvPpeH8j&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;http://pastebin.com/VvPpeH8j&lt;/a&gt;&lt;br/&gt;
Also, don&apos;t forget to run a &quot;db.getSiblingDB(&quot;MyDB1&quot;).repairDatabase();&quot; on your secondary(ies) once the script is done, then stepDown the primary and repair it too. To my experience it reduces index size A LOT.&lt;/p&gt;</comment>
                            <comment id="674708" author="niccottrell" created="Tue, 29 Jul 2014 09:58:28 +0000"  >&lt;p&gt;@agahd When running the script from the mongodb.org docs page it sat there running for hours. I didn&apos;t see any printouts that chunks were cleaned up, but some of our errors disappeared. It may be however a change in read preferences in some subroutine.&lt;/p&gt;

&lt;p&gt;We have the same problem where we are on the edge of fitting in to RAM. &lt;/p&gt;

&lt;p&gt;I&apos;m a bit wary of running the chunk-checker.js since it&apos;s from 2010 and many versions of Mongo ago. I don&apos;t want to further mess up sharding &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; Can anyone from MongoDB confirm that the script on the cleanupOrphan page has been tested and confirmed to work?&lt;/p&gt;</comment>
                            <comment id="672704" author="kay.agahd@idealo.de" created="Sun, 27 Jul 2014 11:24:50 +0000"  >&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=niccottrell&quot; class=&quot;user-hover&quot; rel=&quot;niccottrell&quot;&gt;niccottrell&lt;/a&gt;, I&apos;ve tried the script snippet at &lt;a href=&quot;http://docs.mongodb.org/manual/reference/command/cleanupOrphaned/&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;http://docs.mongodb.org/manual/reference/command/cleanupOrphaned/&lt;/a&gt; without luck. The script took a long time but the unreferenced chunks remained on the shard - at least, no space was freed up. &lt;br/&gt;
However, after executing the script &lt;a href=&quot;https://github.com/mongodb/mongo-snippets/blob/master/sharding/chunk-checker.js&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/mongo-snippets/blob/master/sharding/chunk-checker.js&lt;/a&gt; multiple GB&apos;s were retrieved. This is very important for us because  our db needs to fit in RAM completely for best performance.&lt;/p&gt;

&lt;p&gt;It seems to me that balancing and cleaning-up moved chunks is even worse in v2.6 than ever before because it may get stuck and even may crash mongod. Maybe these threads are related: &lt;br/&gt;
&lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-14389&quot; class=&quot;external-link&quot; rel=&quot;nofollow&quot;&gt;https://jira.mongodb.org/browse/SERVER-14389&lt;/a&gt;&lt;br/&gt;
&lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-14261&quot; class=&quot;external-link&quot; rel=&quot;nofollow&quot;&gt;https://jira.mongodb.org/browse/SERVER-14261&lt;/a&gt;&lt;br/&gt;
&lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-11299&quot; class=&quot;external-link&quot; rel=&quot;nofollow&quot;&gt;https://jira.mongodb.org/browse/SERVER-11299&lt;/a&gt;&lt;br/&gt;
&lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-14375&quot; class=&quot;external-link&quot; rel=&quot;nofollow&quot;&gt;https://jira.mongodb.org/browse/SERVER-14375&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="667689" author="sflint@sailthru.com" created="Tue, 22 Jul 2014 16:47:49 +0000"  >&lt;p&gt;You can also use explain() to capture the correct count and this is much faster than itcount().   We put this in our client side application to call explain().n&lt;/p&gt;

&lt;p&gt;As you can see it is accurate and it is faster than itcount().&lt;/p&gt;

&lt;p&gt;	&quot;cursor&quot; : &quot;BtreeCursor client_id_1_lists_1_order_1&quot;,&lt;br/&gt;
	&quot;n&quot; : 5487153,&lt;br/&gt;
	&quot;nChunkSkips&quot; : 17072,&lt;br/&gt;
	&quot;nYields&quot; : 11907,&lt;br/&gt;
	&quot;nscanned&quot; : 5672905,&lt;br/&gt;
	&quot;nscannedAllPlans&quot; : 5672905,&lt;br/&gt;
	&quot;nscannedObjects&quot; : 5672905,&lt;br/&gt;
	&quot;nscannedObjectsAllPlans&quot; : 5672905,&lt;br/&gt;
	&quot;millisShardTotal&quot; : 69749,&lt;br/&gt;
	&quot;millisShardAvg&quot; : 9964,&lt;br/&gt;
	&quot;numQueries&quot; : 7,&lt;br/&gt;
	&quot;numShards&quot; : 7,&lt;br/&gt;
	&quot;millis&quot; : 18282&lt;br/&gt;
}&lt;br/&gt;
mongos&amp;gt; db.profile.find(&lt;/p&gt;
{client_id : 3762}
&lt;p&gt;,&lt;/p&gt;
{client_id:1}
&lt;p&gt;).count()&lt;br/&gt;
5503724&lt;br/&gt;
mongos&amp;gt; db.profile.find(&lt;/p&gt;
{client_id : 3762}
&lt;p&gt;,&lt;/p&gt;
{client_id:1}
&lt;p&gt;).itcount()&lt;br/&gt;
5487153&lt;br/&gt;
mongos&amp;gt; db.profile.find(&lt;/p&gt;
{client_id : 3762}
&lt;p&gt;,&lt;/p&gt;
{client_id:1}
&lt;p&gt;).explain().n&lt;br/&gt;
5487153&lt;/p&gt;</comment>
                            <comment id="666687" author="asya" created="Mon, 21 Jul 2014 20:32:57 +0000"  >&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=niccottrell&quot; class=&quot;user-hover&quot; rel=&quot;niccottrell&quot;&gt;niccottrell&lt;/a&gt; I just realized that your test does &lt;b&gt;not&lt;/b&gt; look at documents, but rather it looks at count() which will be wrong whenever there is a migration in progress (or if there are orphans) due to &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-3645&quot; title=&quot;Sharded collection counts (on primary) can report too many results&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-3645&quot;&gt;&lt;del&gt;SERVER-3645&lt;/del&gt;&lt;/a&gt; - to check the actual count of matched documents you can use itcount() which actually iterates over fetched documents rather than taking a shortcut that &quot;count()&quot; does.&lt;/p&gt;</comment>
                            <comment id="666678" author="asya" created="Mon, 21 Jul 2014 20:27:53 +0000"  >&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=niccottrell&quot; class=&quot;user-hover&quot; rel=&quot;niccottrell&quot;&gt;niccottrell&lt;/a&gt; if your queries are going to the primaries, then it can&apos;t be because of this bug as primaries filter out documents that don&apos;t belong to their chunk ranges.   &lt;/p&gt;

&lt;p&gt;It&apos;s possible that you are seeing a different bug.  If you can confirm the queries are being routed to *&lt;b&gt;primaries&lt;/b&gt;* and you&apos;re seeing duplicates, could you open a new SERVER bug?  &lt;/p&gt;

&lt;p&gt;If the queries are being routed to *&lt;b&gt;secondaries&lt;/b&gt;* when you are requesting primary then it could be either Morphia or Java driver bug or mongos bug which we would also like to track, triage and fix.&lt;/p&gt;
</comment>
                            <comment id="665022" author="niccottrell" created="Mon, 21 Jul 2014 09:02:18 +0000"  >&lt;p&gt;Thanks @agahd! I guess with M2.6+ you could borrow this snippet from &lt;a href=&quot;http://docs.mongodb.org/manual/reference/command/cleanupOrphaned/&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;http://docs.mongodb.org/manual/reference/command/cleanupOrphaned/&lt;/a&gt; : &lt;/p&gt;

&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;while ( nextKey = db.runCommand( {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;                      cleanupOrphaned: &quot;test.user&quot;,&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;                      startingFromKey: nextKey&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;                  } ).stoppedAtKey ) {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;   printjson(nextKey);&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;}&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;

&lt;p&gt;to do the actual cleanup steps.&lt;/p&gt;</comment>
                            <comment id="664967" author="niccottrell" created="Mon, 21 Jul 2014 07:11:58 +0000"  >&lt;p&gt;Definitely querying against primary (at least that&apos;s what I&apos;m instructing Morphia/Java driver) and definitely got duplicate objects with the same ObjectId _id field. Ran the cleanupOrphaned loop example from the MongoDoc and now no longer getting these duplicates - no changes to our code, so really looks like a mongos bug remains..&lt;/p&gt;</comment>
                            <comment id="664896" author="asya" created="Mon, 21 Jul 2014 05:43:34 +0000"  >&lt;p&gt;2.6 supports a command cleanupOrphaned so you should be using it, rather than any scripts.&lt;/p&gt;

&lt;p&gt;However, if you are querying against primaries only, this ticket does not apply and if you&apos;re seeing incorrect results, it&apos;s not because of the issue this ticket is tracking.&lt;/p&gt;

&lt;p&gt;You might want to post your case on mongodb-user google group.&lt;/p&gt;</comment>
                            <comment id="664630" author="kay.agahd@idealo.de" created="Sun, 20 Jul 2014 19:19:58 +0000"  >&lt;p&gt;Nic, I&apos;ve used this one, slightly modified:&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/mongo-snippets/blob/master/sharding/chunk-checker.js&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/mongo-snippets/blob/master/sharding/chunk-checker.js&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="664496" author="niccottrell" created="Sun, 20 Jul 2014 12:38:34 +0000"  >&lt;p&gt;Unfortunately this seems to be a problem. We have a sharded setup with both nodes and mongos running 2.6.3. The collection has shard key which doesn&apos;t including the _id field at all, and we do a query with readPref=primary. We&apos;re using the Morphia interface, i.e.&lt;/p&gt;

&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;      final Datastore datastore = getDatastore(aClass);&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;      final Query&amp;lt;K&amp;gt; query = datastore.get(aClass, ids);&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;      query.useReadPreference(ReadPreference.primary()); &lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;      final List&amp;lt;K&amp;gt; results = query.asList();&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;      assert result.size() &amp;lt;= ids.size() :&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;          &quot;More results than unique IDs (&quot; + ids.size() + RARR + result.size() + &quot;): &quot;&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;          + ids + RARR + result + &quot;, with query=&quot; + query;&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;

&lt;p&gt;And this assert regularly fails in our unit tests. Is there a nice script in 2.6 to clean away these orphan documents automatically?&lt;/p&gt;</comment>
                            <comment id="445703" author="kay.agahd@idealo.de" created="Wed, 23 Oct 2013 22:15:54 +0000"  >&lt;p&gt;Thank you Scott for clarifying. Right now, we have removed all orphans from our db so the export works as expected. As soon as we have new orphans and detect duplicates in our exported dataset, we will let you know. Thanks for your patience.&lt;/p&gt;</comment>
                            <comment id="445458" author="scotthernandez" created="Wed, 23 Oct 2013 17:45:51 +0000"  >&lt;p&gt;If you do any query (find not count, see below or linked issues) on the mongos, with or without the shard key, which goes only to the primaries then all non-owned/orphan docs will be removed from the results. MongoDB has a number of tests which verify this. &lt;/p&gt;

&lt;p&gt;Here is part of the explain which show the &quot;nChunkSkips&quot; which are skipped documents not returned since they are not owned by that shard &amp;#8211; results in no orphans docs being returned:&lt;/p&gt;
&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: #008200; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;// output from https://gist.github.com/scotthernandez/becf47ae9d0c33eac6d6&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: #008200; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;// collection &quot;foo.bar&quot; is sharded on {_id:1}, with value from -50...50 split between shards, with a manually inserted doc {_id:10, x: 10} on both shards.&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: #008200; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;// The test then queries for {x:10}, which is not the shard key, and only gets back one document (with one of the shards skipping the orphaned doc).&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;m30001| 2013-10-23T13:06:56.834-0400 [conn3] query foo.bar query: { query: { x: 10.0 }, $explain: &lt;/span&gt;&lt;span style=&quot;color: #006699; font-weight: bold; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;true&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; } ntoreturn:0 ntoskip:0 keyUpdates:0 locks(micros) r:1470 nreturned:1 reslen:332 1ms&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;{&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;clusteredType&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : &lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;ParallelSort&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;, &lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;shards&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;		&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;localhost:30000&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : [ {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;				&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;n&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : 0,&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;				&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;nscannedObjects&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : 51,&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;...&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;				&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;nChunkSkips&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : 1, }],&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;		&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;localhost:30001&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : [ {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;				&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;n&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : 1,&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;				&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;nscannedObjects&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : 50,&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;...&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;				&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;nChunkSkips&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : 0,}]},&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;n&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : 1,&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;nChunkSkips&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : 1,&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;...&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;numQueries&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : 2,&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
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				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;numShards&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : 2,&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
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						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;	&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;millis&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; : 2&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
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				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;}&lt;/span&gt;&lt;/pre&gt;
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&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;

&lt;p&gt;In your example above you are using count() which has similar issues like a secondaries wrt to queries (via find), but on the primary as well. That issue is here: &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-3645&quot; title=&quot;Sharded collection counts (on primary) can report too many results&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-3645&quot;&gt;&lt;del&gt;SERVER-3645&lt;/del&gt;&lt;/a&gt; &amp;#8211; it affects counts with or without a query predicate even on the primaries.&lt;/p&gt;

&lt;p&gt;In your example above if you use itcount() it will run the query and count the returned documents which will filter out orphans.&lt;/p&gt;

&lt;p&gt;I have also run mongoexport/dump to verify that orphans are not returned when the primary is used. If you see otherwise we need to create a new issue and follow up there.&lt;/p&gt;

&lt;p&gt;You may also be interested in the new cleanupOrphans command in the next version (2.6) which be used to remove orphans in cases where a failure leaves them around: &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-8598&quot; title=&quot;Add command to cleanup orphaned data created by failed chunk migrations&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-8598&quot;&gt;&lt;del&gt;SERVER-8598&lt;/del&gt;&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="445384" author="kay.agahd@idealo.de" created="Wed, 23 Oct 2013 16:27:41 +0000"  >&lt;p&gt;Scott, we are aware that running with slaveOk=true might return inconsistent results. However, what we have experienced and what I&apos;ve shown above demonstrates that one may receive inconsistent results such as duplicates even when using slaveOk=false while going through mongos &lt;b&gt;if&lt;/b&gt; the queried field is NOT the shardkey.&lt;/p&gt;

&lt;p&gt;Please review my above steps to reproduce the problem. The reason I was connecting there to a mongod instead to a mongos was to be able to create some orphan documents in order to demonstrate how mongodb behaves when you run a query against a mongodb system having orphan documents. If mongodb would NOT create orphan documents, probably resulted from a broken chunk move, OR if mongodb was able to automatically remove orphan documents asap OR if mongodb would read the sharding status upon a query request to know whether the found documents belong really to the shard which returned them, then we would NOT have this problem at all. &lt;/p&gt;

&lt;p&gt;Just connecting through mongos with slaveOk=false option does NOT solve the problem.&lt;/p&gt;</comment>
                            <comment id="445151" author="scotthernandez" created="Wed, 23 Oct 2013 11:40:31 +0000"  >&lt;p&gt;agahd, you must use the primary (the default behavior for all langauges/drivers but not all tools) connecting through mongos, not directly to the shards or with slaveOk enabled. All direct connections are unaware of sharding state (even on the primary) and considered administrative/maintenance connections which allow full access to data independent of sharding state (and therefore return &quot;duplicates&quot;). This is why it is always required to change your application/tools to only connect to the mongos servers and never directly to the shard for user data operations.&lt;/p&gt;

&lt;p&gt;Did you run mongoexport against mongos with the &quot;--slaveOk false&quot; option? By default it will try to read from the non-primary, if not the option is explicit.&lt;/p&gt;

&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;$ mongoexport --help&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;Export MongoDB data to CSV, TSV or JSON files.&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&amp;nbsp;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;options:&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;  --help                                produce help message&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; ...&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;  -k [ --slaveOk ] arg (=1)             use secondaries for export if &lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;                                        available, default true&lt;/span&gt;&lt;/pre&gt;
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						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
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			&lt;/td&gt;
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			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;
</comment>
                            <comment id="445105" author="kay.agahd@idealo.de" created="Wed, 23 Oct 2013 08:55:03 +0000"  >&lt;p&gt;Scott, your sugested workaround &quot;that you must use the primary for accurate results&quot; is wrong. Even using the primary returns orphaned documents if the query does not contain the shardkey (see my steps to reproduce above please).&lt;/p&gt;

&lt;p&gt;Btw. this happens also when using mongoexport which is a big pain for us because we can&apos;t always use the shardkey to export some datasets, thus we often have to fight against duplicates in the exported data. It would be nice if this bug could be fixed. Thanks!&lt;/p&gt;</comment>
                            <comment id="265283" author="kay.agahd@idealo.de" created="Wed, 13 Feb 2013 17:28:24 +0000"  >&lt;p&gt;@Holger, during migrations, documents must be on both source and destination server. They will/should be deleted only after migration from the source server. If your query hits the servers during migration, it&apos;s normal that it will find both (with slaveOk on). A job which removes orphan documents wouldn&apos;t help in this case.&lt;br/&gt;
However, the router should be clever enough to read the sharding status to know whether the found documents belong really to the shard which returned them. If they belong to another shard, mongos should refuse to add them to the result set.&lt;/p&gt;</comment>
                            <comment id="265069" author="hmorch" created="Wed, 13 Feb 2013 13:39:45 +0000"  >&lt;p&gt;We are facing the same issue. Since we are a read heavy application we are normally reading with secondary preferred and so it happens that users see orphan objects in the response.&lt;br/&gt;
I think is is important that the secondaries implement the same behavior as the primaries and don&apos;t return such orphan objects. But even if this is place the data is still present on the shard. I think it should be possible if one of the hosts recognizes orphan objects to start a job, that removes this objects to free the space again.&lt;/p&gt;</comment>
                            <comment id="264945" author="christian.tonhaeuser@navteq.com" created="Wed, 13 Feb 2013 09:47:51 +0000"  >&lt;p&gt;Do you think this might make it into 2.3.X?&lt;br/&gt;
We&apos;re facing this problem in our production systems and it&apos;s a real hassle.&lt;/p&gt;</comment>
                            <comment id="124779" author="scotthernandez" created="Thu, 31 May 2012 15:36:22 +0000"  >&lt;p&gt;There is no workaround for this until the underlying bug/system is fixed.&lt;/p&gt;

&lt;p&gt;The workaround is that you must use the primary for accurate results.&lt;/p&gt;</comment>
                            <comment id="124666" author="kay.agahd@idealo.de" created="Thu, 31 May 2012 11:22:17 +0000"  >&lt;p&gt;I understand that orphaned documents may exist but they shouldn&apos;t have any impact on query results, even when queried non-primaries (slaveOk). Can you suggest a better workaround than querying primaries (since this would drop mongoDB performance) or will this issue be fixed soon? Thanks!&lt;/p&gt;</comment>
                            <comment id="123818" author="scotthernandez" created="Tue, 29 May 2012 13:26:39 +0000"  >&lt;p&gt;Yes, this is a known problem and I&apos;ve linked the count related issue which is not related to non-primary queries. In addition as you have noted doing non-primary queries can return documents which are not owned by that shard &amp;#8211; orphaned one. These documents can get there from failed migrations, and of course during migrations, for example, so it is expected that it will happen at times.&lt;/p&gt;</comment>
                            <comment id="123055" author="kay.agahd@idealo.de" created="Fri, 25 May 2012 13:01:14 +0000"  >&lt;p&gt;sorry, the formatting is a bit weird&lt;/p&gt;</comment>
                    </comments>
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