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    <title>MongoDB Jira</title>
    <link>https://jira.mongodb.org</link>
    <description>This file is an XML representation of an issue</description>
    <language>en-us</language>    <build-info>
        <version>9.7.1</version>
        <build-number>970001</build-number>
        <build-date>13-04-2023</build-date>
    </build-info>


<item>
            <title>[SERVER-9540] How to get the previous mongoDB document from a compound index</title>
                <link>https://jira.mongodb.org/browse/SERVER-9540</link>
                <project id="10000" key="SERVER">Core Server</project>
                    <description>&lt;p&gt;I asked this at mongo-usr, mongo-dev and Stack Overflow with no luck. I may be obtuse and am missing something fundamentally simple.&lt;/p&gt;

&lt;p&gt;Given this data with a unique compound index:&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;db.employees.drop()&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;db.employees.insert( { employeenum : 1, check : &quot;A&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;db.employees.insert( { employeenum : 1, check : &quot;B&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;db.employees.insert( { employeenum : 2, check : &quot;A&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;db.employees.insert( { employeenum : 2, check : &quot;B&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;db.employees.insert( { employeenum : 2, check : &quot;C&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;db.employees.insert( { employeenum : 5, check : &quot;E&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;db.employees.insert( { employeenum : 6, check : &quot;A&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;db.employees.ensureIndex( { employeenum: 1, check : 1 }, {unique: true} )&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;If I want the next document in the index after {{&lt;/p&gt;
{ employeenum : 5, check : &quot;E&quot; }
&lt;p&gt;}}. I can do this:&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;   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;db.employees.find({ query: { $or: [ { employeenum: { $gt: 5 } }, { check: { $gt: &quot;E&quot; } } ] }, $min: { employeenum: 5, check: &quot;E&quot; }, $maxScan: 2 })&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;which returns {{&lt;/p&gt;
{ employeenum : 6, check : &quot;A&quot; }
&lt;p&gt;}}.&lt;/p&gt;

&lt;p&gt;But how do I traverse backwards from {{&lt;/p&gt;
{ employeenum : 5, check : &quot;E&quot; }
&lt;p&gt;}}? How do I fetch {{&lt;/p&gt;
{employeenum : 2, check : &quot;C&quot; }
&lt;p&gt;}}? The way I am doing it:&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;   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;{ query: { $or: [ { employeenum: { $lt: 5 } }, { check: { $lt: &quot;E&quot; } } ] }, $hint: { employeenum: -1, check: -1 }, $min: { employeenum: 5, check: &quot;E&quot; }, $maxScan: 2 }&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;requires a reverse index, a very inefficient solution. Is there a better way? B-tree indexes are bi-directional.&lt;/p&gt;

&lt;p&gt;One suggested:&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;   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;db.Emp.find({$or:[{employeenum{$lt:5}}]}).sort({employeenum:-1,check:-1}).limit(1)&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 yes that will gets me 2-C. Now, how to go from 2-C to 2-B? This:&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;   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;db.employees.find({$or:[{employeenum:{$lt:2}},{check:{$lt:&quot;C&quot;}}]}).sort({employ??eenum:-1,check:-1}).limit(1)&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;returns {{&lt;/p&gt;
{&quot;employeenum&quot; : 6, &quot;check&quot; : &quot;A&quot;}
&lt;p&gt;}} I need a general way to traverse the index from a point on the index. I am using the C++ driver but using the shell here for illustration. We are developing a rapid development tool using mongoDB as the underlying database. This is a (presumably) simple use case: A window displays a single document from a collection with a compound index. The user presses a button to display the next document using the compound index. Or another button to display the previous. &lt;/p&gt;

&lt;p&gt;I did try: &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;   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;db.employees.find({ query: { $or: [ { employeenum: { $lt: 5 } }, { check: { $lt: &quot;E&quot; } } ] }, $max: { employeenum: 5, check: &quot;E&quot; }, orderby: { employeenum: -1, check: -1 }, $maxScan: 2,  $explain: false })&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;But that crashed the server every time which raises a concern that a shell users could crash the server with an (apparently) malformed query in a mission critical application such as ours.&lt;/p&gt;</description>
                <environment>Windows 7 64 bit SP1</environment>
        <key id="73977">SERVER-9540</key>
            <summary>How to get the previous mongoDB document from a compound index</summary>
                <type id="6" iconUrl="https://jira.mongodb.org/secure/viewavatar?size=xsmall&amp;avatarId=14720&amp;avatarType=issuetype">Question</type>
                                            <priority id="4" iconUrl="https://jira.mongodb.org/images/icons/priorities/minor.svg">Minor - P4</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="3">Duplicate</resolution>
                                        <assignee username="thomas.rueckstiess@mongodb.com">Thomas Rueckstiess</assignee>
                                    <reporter username="therefore">George Thompson</reporter>
                        <labels>
                            <label>query</label>
                    </labels>
                <created>Thu, 2 May 2013 16:23:53 +0000</created>
                <updated>Thu, 16 May 2013 15:39:32 +0000</updated>
                            <resolved>Mon, 6 May 2013 02:05:37 +0000</resolved>
                                    <version>2.2.0</version>
                                                    <component>Internal Client</component>
                                        <votes>0</votes>
                                    <watches>4</watches>
                                                                                                                <comments>
                            <comment id="329593" author="therefore" created="Mon, 6 May 2013 17:39:58 +0000"  >&lt;p&gt;Created &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-9598&quot; title=&quot;mongoDB server crashes when using min() / max() with descending order sort&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-9598&quot;&gt;&lt;del&gt;SERVER-9598&lt;/del&gt;&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="329586" author="therefore" created="Mon, 6 May 2013 17:27:01 +0000"  >&lt;p&gt;Yes, I built a debug version for use with the C++ driver. No, I don&apos;t believe it is index corruption since I can replicate this with a small set of test data, first dropping the test collection. Possibly it is related to &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-9547&quot; title=&quot;min() / max() with descending order sort not working&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-9547&quot;&gt;&lt;del&gt;SERVER-9547&lt;/del&gt;&lt;/a&gt; which quietly fails to return documents.&lt;/p&gt;

&lt;p&gt;I&apos;ll file a separate ticket with a full stack trace.&lt;/p&gt;

&lt;p&gt;Thanks&lt;/p&gt;</comment>
                            <comment id="329577" author="tad" created="Mon, 6 May 2013 17:14:12 +0000"  >&lt;p&gt;Hi George,&lt;/p&gt;

&lt;p&gt;Can you file a separate ticket for the unhandled exception in Windows?  Steps to reproduce, a full stack trace (assuming that you got one) and enough log lines before the stack trace to provide context would be helpful.&lt;/p&gt;

&lt;p&gt;The unhandled exception you got (0x80000003) is a breakpoint exception, which is odd because we do not have breakpoints in our released (prebuilt) code.  If you built a debug version yourself then this would make sense; we do have breakpoints in the debug build.&lt;/p&gt;

&lt;p&gt;The assertion failure is suggesting index corruption.  If your query is able to produce this assertion in a non-corrupt index, this would be good to know.  If reindexing made the crashes stop, this would tend to confirm the corrupt index theory.&lt;/p&gt;

&lt;p&gt;Tad&lt;/p&gt;</comment>
                            <comment id="329554" author="therefore" created="Mon, 6 May 2013 16:40:53 +0000"  >&lt;p&gt;Hi Thomas,&lt;/p&gt;

&lt;p&gt;That is exactly what I wanted to do. Thank you very much for your help on this issue.&lt;/p&gt;

&lt;p&gt;For single key backward traversal, I was using:&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;   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;db.docs.find({number: {$lt: 4}}).sort({number: -1}).limit(1)&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;On my setup (Windows 7 64 bit SP1 &amp;amp; mongoDB 2.2.0) &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;   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;db.docs.find().max({number: 4}).sort({number: -1})&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;crashes the mongoDB server with:&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;Mon May 06 09:21:32 [conn1]  PAY.docs Assertion failure la &amp;lt;= 0xffffff c:\mongodb\src\mongo\db\btree.h 243&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;   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;Mon May 06 09:21:33 [conn1] *** unhandled exception 0x80000003 at 0x000007FEFDF03172, terminating&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;I have been using the second reverse index workdaround. Disk space isn&apos;t an issue. My main concern is that this will be required for all indexes that require bi-directional traversal, say, an index on name, address, etc. The small impact will accumulate.&lt;/p&gt;

&lt;p&gt;I&apos;ll keep an eye on &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-9547&quot; title=&quot;min() / max() with descending order sort not working&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-9547&quot;&gt;&lt;del&gt;SERVER-9547&lt;/del&gt;&lt;/a&gt; and hope.&lt;/p&gt;

&lt;p&gt;Thanks for the less complex find query for forward traversal.&lt;/p&gt;</comment>
                            <comment id="329063" author="thomasr" created="Mon, 6 May 2013 02:00:49 +0000"  >&lt;p&gt;Hi George,&lt;/p&gt;

&lt;p&gt;Just to confirm that this is what you want to achieve: &lt;/p&gt;

&lt;p&gt;You&apos;d like to traverse documents from a (compound) index forwards and backwards in the order they&apos;re stored in the index, starting from a given document. Is that correct? &lt;/p&gt;

&lt;p&gt;Walking the index forward (in the direction it was specified) works fine, and I believe you don&apos;t even need the complex find query that you used in your examples:&lt;/p&gt;

&lt;p&gt;Assuming you want to start at {&lt;tt&gt;employeenum:2,check:&quot;B&quot;&lt;/tt&gt;}, walking forwards:&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;   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;db.employees.find().min({employeenum : 2, check : &quot;B&quot;})&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;This results in:&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;{ &quot;_id&quot; : ObjectId(&quot;518317d5639296eff07632d7&quot;), &quot;employeenum&quot; : 2, &quot;check&quot; : &quot;B&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; : ObjectId(&quot;518317d5639296eff07632d8&quot;), &quot;employeenum&quot; : 2, &quot;check&quot; : &quot;C&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; : ObjectId(&quot;518317d5639296eff07632d9&quot;), &quot;employeenum&quot; : 5, &quot;check&quot; : &quot;E&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;{ &quot;_id&quot; : ObjectId(&quot;518317d6639296eff07632da&quot;), &quot;employeenum&quot; : 6, &quot;check&quot; : &quot;A&quot; }&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;If you don&apos;t want the first document, you can add &lt;tt&gt;.skip(1)&lt;/tt&gt; to the query.&lt;/p&gt;

&lt;p&gt;Now for the backwards case. One would expect that adding a &lt;tt&gt;.sort({employeenum:-1,check:-1})&lt;/tt&gt; would do the trick, but the desired behavior is currently not implemented yet when using &lt;tt&gt;.min()&lt;/tt&gt; / &lt;tt&gt;.max()&lt;/tt&gt;. I&apos;ve opened a separate server issue where I&apos;ve minimized your example, using a simple index on a single field, but the result is the same. The additional &lt;tt&gt;.sort()&lt;/tt&gt; causes 0 documents to be returned. See &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-9547&quot; title=&quot;min() / max() with descending order sort not working&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-9547&quot;&gt;&lt;del&gt;SERVER-9547&lt;/del&gt;&lt;/a&gt;. &lt;/p&gt;

&lt;p&gt;As a work-around until this feature is implemented, I see two alternatives: &lt;/p&gt;

&lt;ol&gt;
	&lt;li&gt;You can create a second index traversing the documents in the opposite direction. This has only a very small impact on insert speed, but it does double the space requirements for the index. If space isn&apos;t an issue, I would recommend this solution.
&lt;br class=&quot;atl-forced-newline&quot; /&gt;
&lt;br class=&quot;atl-forced-newline&quot; /&gt;&lt;/li&gt;
	&lt;li&gt;Alternatively, you can store the link information explicitly in the document. Basically you&apos;d store a (doubly) linked list, by using a reference field to the primary key of the previous/next document. However, this only makes sense if you are willing to accept an additional round-trip to the database per document. If you implement some sort of paging behavior, as you describe it, where the user presses a button to move forward/backward, this may be an acceptable solution.&lt;/li&gt;
&lt;/ol&gt;


&lt;p&gt;I hope that one of these work-arounds is suitable for your use-case. &lt;/p&gt;

&lt;p&gt;Thank you for submitting this issue. I will link this ticket to &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-9547&quot; title=&quot;min() / max() with descending order sort not working&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-9547&quot;&gt;&lt;del&gt;SERVER-9547&lt;/del&gt;&lt;/a&gt; and then close it, as we have the necessary description of the problem in a more concise format in &lt;a href=&quot;https://jira.mongodb.org/browse/SERVER-9547&quot; title=&quot;min() / max() with descending order sort not working&quot; class=&quot;issue-link&quot; data-issue-key=&quot;SERVER-9547&quot;&gt;&lt;del&gt;SERVER-9547&lt;/del&gt;&lt;/a&gt;. Feel free to comment on the other ticket and upvote it if you like this to be prioritized.&lt;/p&gt;

&lt;p&gt;Regards,&lt;br/&gt;
Thomas&lt;/p&gt;</comment>
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