technical/scalar.html - pub/scm/git/git-htmldocs - Git at Google

 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
     "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
 <head>
 <meta http-equiv="Content-Type" content="application/xhtml+xml; charset=UTF-8" />
 <meta name="generator" content="AsciiDoc 10.2.0" />
 <title>Scalar</title>
 <style type="text/css">
 /* Shared CSS for AsciiDoc xhtml11 and html5 backends */

 /* Default font. */
 body {
   font-family: Georgia,serif;
 }

 /* Title font. */
 h1, h2, h3, h4, h5, h6,
 div.title, caption.title,
 thead, p.table.header,
 #toctitle,
 #author, #revnumber, #revdate, #revremark,
 #footer {
   font-family: Arial,Helvetica,sans-serif;
 }

 body {
   margin: 1em 5% 1em 5%;
 }

 a {
   color: blue;
   text-decoration: underline;
 }
 a:visited {
   color: fuchsia;
 }

 em {
   font-style: italic;
   color: navy;
 }

 strong {
   font-weight: bold;
   color: #083194;
 }

 h1, h2, h3, h4, h5, h6 {
   color: #527bbd;
   margin-top: 1.2em;
   margin-bottom: 0.5em;
   line-height: 1.3;
 }

 h1, h2, h3 {
   border-bottom: 2px solid silver;
 }
 h2 {
   padding-top: 0.5em;
 }
 h3 {
   float: left;
 }
 h3 + * {
   clear: left;
 }
 h5 {
   font-size: 1.0em;
 }

 div.sectionbody {
   margin-left: 0;
 }

 hr {
   border: 1px solid silver;
 }

 p {
   margin-top: 0.5em;
   margin-bottom: 0.5em;
 }

 ul, ol, li > p {
   margin-top: 0;
 }
 ul > li     { color: #aaa; }
 ul > li > * { color: black; }

 .monospaced, code, pre {
   font-family: "Courier New", Courier, monospace;
   font-size: inherit;
   color: navy;
   padding: 0;
   margin: 0;
 }
 pre {
   white-space: pre-wrap;
 }

 #author {
   color: #527bbd;
   font-weight: bold;
   font-size: 1.1em;
 }
 #email {
 }
 #revnumber, #revdate, #revremark {
 }

 #footer {
   font-size: small;
   border-top: 2px solid silver;
   padding-top: 0.5em;
   margin-top: 4.0em;
 }
 #footer-text {
   float: left;
   padding-bottom: 0.5em;
 }
 #footer-badges {
   float: right;
   padding-bottom: 0.5em;
 }

 #preamble {
   margin-top: 1.5em;
   margin-bottom: 1.5em;
 }
 div.imageblock, div.exampleblock, div.verseblock,
 div.quoteblock, div.literalblock, div.listingblock, div.sidebarblock,
 div.admonitionblock {
   margin-top: 1.0em;
   margin-bottom: 1.5em;
 }
 div.admonitionblock {
   margin-top: 2.0em;
   margin-bottom: 2.0em;
   margin-right: 10%;
   color: #606060;
 }

 div.content { /* Block element content. */
   padding: 0;
 }

 /* Block element titles. */
 div.title, caption.title {
   color: #527bbd;
   font-weight: bold;
   text-align: left;
   margin-top: 1.0em;
   margin-bottom: 0.5em;
 }
 div.title + * {
   margin-top: 0;
 }

 td div.title:first-child {
   margin-top: 0.0em;
 }
 div.content div.title:first-child {
   margin-top: 0.0em;
 }
 div.content + div.title {
   margin-top: 0.0em;
 }

 div.sidebarblock > div.content {
   background: #ffffee;
   border: 1px solid #dddddd;
   border-left: 4px solid #f0f0f0;
   padding: 0.5em;
 }

 div.listingblock > div.content {
   border: 1px solid #dddddd;
   border-left: 5px solid #f0f0f0;
   background: #f8f8f8;
   padding: 0.5em;
 }

 div.quoteblock, div.verseblock {
   padding-left: 1.0em;
   margin-left: 1.0em;
   margin-right: 10%;
   border-left: 5px solid #f0f0f0;
   color: #888;
 }

 div.quoteblock > div.attribution {
   padding-top: 0.5em;
   text-align: right;
 }

 div.verseblock > pre.content {
   font-family: inherit;
   font-size: inherit;
 }
 div.verseblock > div.attribution {
   padding-top: 0.75em;
   text-align: left;
 }
 /* DEPRECATED: Pre version 8.2.7 verse style literal block. */
 div.verseblock + div.attribution {
   text-align: left;
 }

 div.admonitionblock .icon {
   vertical-align: top;
   font-size: 1.1em;
   font-weight: bold;
   text-decoration: underline;
   color: #527bbd;
   padding-right: 0.5em;
 }
 div.admonitionblock td.content {
   padding-left: 0.5em;
   border-left: 3px solid #dddddd;
 }

 div.exampleblock > div.content {
   border-left: 3px solid #dddddd;
   padding-left: 0.5em;
 }

 div.imageblock div.content { padding-left: 0; }
 span.image img { border-style: none; vertical-align: text-bottom; }
 a.image:visited { color: white; }

 dl {
   margin-top: 0.8em;
   margin-bottom: 0.8em;
 }
 dt {
   margin-top: 0.5em;
   margin-bottom: 0;
   font-style: normal;
   color: navy;
 }
 dd > *:first-child {
   margin-top: 0.1em;
 }

 ul, ol {
     list-style-position: outside;
 }
 ol.arabic {
   list-style-type: decimal;
 }
 ol.loweralpha {
   list-style-type: lower-alpha;
 }
 ol.upperalpha {
   list-style-type: upper-alpha;
 }
 ol.lowerroman {
   list-style-type: lower-roman;
 }
 ol.upperroman {
   list-style-type: upper-roman;
 }

 div.compact ul, div.compact ol,
 div.compact p, div.compact p,
 div.compact div, div.compact div {
   margin-top: 0.1em;
   margin-bottom: 0.1em;
 }

 tfoot {
   font-weight: bold;
 }
 td > div.verse {
   white-space: pre;
 }

 div.hdlist {
   margin-top: 0.8em;
   margin-bottom: 0.8em;
 }
 div.hdlist tr {
   padding-bottom: 15px;
 }
 dt.hdlist1.strong, td.hdlist1.strong {
   font-weight: bold;
 }
 td.hdlist1 {
   vertical-align: top;
   font-style: normal;
   padding-right: 0.8em;
   color: navy;
 }
 td.hdlist2 {
   vertical-align: top;
 }
 div.hdlist.compact tr {
   margin: 0;
   padding-bottom: 0;
 }

 .comment {
   background: yellow;
 }

 .footnote, .footnoteref {
   font-size: 0.8em;
 }

 span.footnote, span.footnoteref {
   vertical-align: super;
 }

 #footnotes {
   margin: 20px 0 20px 0;
   padding: 7px 0 0 0;
 }

 #footnotes div.footnote {
   margin: 0 0 5px 0;
 }

 #footnotes hr {
   border: none;
   border-top: 1px solid silver;
   height: 1px;
   text-align: left;
   margin-left: 0;
   width: 20%;
   min-width: 100px;
 }

 div.colist td {
   padding-right: 0.5em;
   padding-bottom: 0.3em;
   vertical-align: top;
 }
 div.colist td img {
   margin-top: 0.3em;
 }

 @media print {
   #footer-badges { display: none; }
 }

 #toc {
   margin-bottom: 2.5em;
 }

 #toctitle {
   color: #527bbd;
   font-size: 1.1em;
   font-weight: bold;
   margin-top: 1.0em;
   margin-bottom: 0.1em;
 }

 div.toclevel0, div.toclevel1, div.toclevel2, div.toclevel3, div.toclevel4 {
   margin-top: 0;
   margin-bottom: 0;
 }
 div.toclevel2 {
   margin-left: 2em;
   font-size: 0.9em;
 }
 div.toclevel3 {
   margin-left: 4em;
   font-size: 0.9em;
 }
 div.toclevel4 {
   margin-left: 6em;
   font-size: 0.9em;
 }

 span.aqua { color: aqua; }
 span.black { color: black; }
 span.blue { color: blue; }
 span.fuchsia { color: fuchsia; }
 span.gray { color: gray; }
 span.green { color: green; }
 span.lime { color: lime; }
 span.maroon { color: maroon; }
 span.navy { color: navy; }
 span.olive { color: olive; }
 span.purple { color: purple; }
 span.red { color: red; }
 span.silver { color: silver; }
 span.teal { color: teal; }
 span.white { color: white; }
 span.yellow { color: yellow; }

 span.aqua-background { background: aqua; }
 span.black-background { background: black; }
 span.blue-background { background: blue; }
 span.fuchsia-background { background: fuchsia; }
 span.gray-background { background: gray; }
 span.green-background { background: green; }
 span.lime-background { background: lime; }
 span.maroon-background { background: maroon; }
 span.navy-background { background: navy; }
 span.olive-background { background: olive; }
 span.purple-background { background: purple; }
 span.red-background { background: red; }
 span.silver-background { background: silver; }
 span.teal-background { background: teal; }
 span.white-background { background: white; }
 span.yellow-background { background: yellow; }

 span.big { font-size: 2em; }
 span.small { font-size: 0.6em; }

 span.underline { text-decoration: underline; }
 span.overline { text-decoration: overline; }
 span.line-through { text-decoration: line-through; }

 div.unbreakable { page-break-inside: avoid; }


 /*
  * xhtml11 specific
  *
  * */

 div.tableblock {
   margin-top: 1.0em;
   margin-bottom: 1.5em;
 }
 div.tableblock > table {
   border: 3px solid #527bbd;
 }
 thead, p.table.header {
   font-weight: bold;
   color: #527bbd;
 }
 p.table {
   margin-top: 0;
 }
 /* Because the table frame attribute is overridden by CSS in most browsers. */
 div.tableblock > table[frame="void"] {
   border-style: none;
 }
 div.tableblock > table[frame="hsides"] {
   border-left-style: none;
   border-right-style: none;
 }
 div.tableblock > table[frame="vsides"] {
   border-top-style: none;
   border-bottom-style: none;
 }


 /*
  * html5 specific
  *
  * */

 table.tableblock {
   margin-top: 1.0em;
   margin-bottom: 1.5em;
 }
 thead, p.tableblock.header {
   font-weight: bold;
   color: #527bbd;
 }
 p.tableblock {
   margin-top: 0;
 }
 table.tableblock {
   border-width: 3px;
   border-spacing: 0px;
   border-style: solid;
   border-color: #527bbd;
   border-collapse: collapse;
 }
 th.tableblock, td.tableblock {
   border-width: 1px;
   padding: 4px;
   border-style: solid;
   border-color: #527bbd;
 }

 table.tableblock.frame-topbot {
   border-left-style: hidden;
   border-right-style: hidden;
 }
 table.tableblock.frame-sides {
   border-top-style: hidden;
   border-bottom-style: hidden;
 }
 table.tableblock.frame-none {
   border-style: hidden;
 }

 th.tableblock.halign-left, td.tableblock.halign-left {
   text-align: left;
 }
 th.tableblock.halign-center, td.tableblock.halign-center {
   text-align: center;
 }
 th.tableblock.halign-right, td.tableblock.halign-right {
   text-align: right;
 }

 th.tableblock.valign-top, td.tableblock.valign-top {
   vertical-align: top;
 }
 th.tableblock.valign-middle, td.tableblock.valign-middle {
   vertical-align: middle;
 }
 th.tableblock.valign-bottom, td.tableblock.valign-bottom {
   vertical-align: bottom;
 }


 /*
  * manpage specific
  *
  * */

 body.manpage h1 {
   padding-top: 0.5em;
   padding-bottom: 0.5em;
   border-top: 2px solid silver;
   border-bottom: 2px solid silver;
 }
 body.manpage h2 {
   border-style: none;
 }
 body.manpage div.sectionbody {
   margin-left: 3em;
 }

 @media print {
   body.manpage div#toc { display: none; }
 }


 </style>
 <script type="text/javascript">
 /*<![CDATA[*/
 var asciidoc = {  // Namespace.

 /////////////////////////////////////////////////////////////////////
 // Table Of Contents generator
 /////////////////////////////////////////////////////////////////////

 /* Author: Mihai Bazon, September 2002
  * http://students.infoiasi.ro/~mishoo
  *
  * Table Of Content generator
  * Version: 0.4
  *
  * Feel free to use this script under the terms of the GNU General Public
  * License, as long as you do not remove or alter this notice.
  */

  /* modified by Troy D. Hanson, September 2006. License: GPL */
  /* modified by Stuart Rackham, 2006, 2009. License: GPL */

 // toclevels = 1..4.
 toc: function (toclevels) {

   function getText(el) {
     var text = "";
     for (var i = el.firstChild; i != null; i = i.nextSibling) {
       if (i.nodeType == 3 /* Node.TEXT_NODE */) // IE doesn't speak constants.
         text += i.data;
       else if (i.firstChild != null)
         text += getText(i);
     }
     return text;
   }

   function TocEntry(el, text, toclevel) {
     this.element = el;
     this.text = text;
     this.toclevel = toclevel;
   }

   function tocEntries(el, toclevels) {
     var result = new Array;
     var re = new RegExp('[hH]([1-'+(toclevels+1)+'])');
     // Function that scans the DOM tree for header elements (the DOM2
     // nodeIterator API would be a better technique but not supported by all
     // browsers).
     var iterate = function (el) {
       for (var i = el.firstChild; i != null; i = i.nextSibling) {
         if (i.nodeType == 1 /* Node.ELEMENT_NODE */) {
           var mo = re.exec(i.tagName);
           if (mo && (i.getAttribute("class") || i.getAttribute("className")) != "float") {
             result[result.length] = new TocEntry(i, getText(i), mo[1]-1);
           }
           iterate(i);
         }
       }
     }
     iterate(el);
     return result;
   }

   var toc = document.getElementById("toc");
   if (!toc) {
     return;
   }

   // Delete existing TOC entries in case we're reloading the TOC.
   var tocEntriesToRemove = [];
   var i;
   for (i = 0; i < toc.childNodes.length; i++) {
     var entry = toc.childNodes[i];
     if (entry.nodeName.toLowerCase() == 'div'
      && entry.getAttribute("class")
      && entry.getAttribute("class").match(/^toclevel/))
       tocEntriesToRemove.push(entry);
   }
   for (i = 0; i < tocEntriesToRemove.length; i++) {
     toc.removeChild(tocEntriesToRemove[i]);
   }

   // Rebuild TOC entries.
   var entries = tocEntries(document.getElementById("content"), toclevels);
   for (var i = 0; i < entries.length; ++i) {
     var entry = entries[i];
     if (entry.element.id == "")
       entry.element.id = "_toc_" + i;
     var a = document.createElement("a");
     a.href = "#" + entry.element.id;
     a.appendChild(document.createTextNode(entry.text));
     var div = document.createElement("div");
     div.appendChild(a);
     div.className = "toclevel" + entry.toclevel;
     toc.appendChild(div);
   }
   if (entries.length == 0)
     toc.parentNode.removeChild(toc);
 },


 /////////////////////////////////////////////////////////////////////
 // Footnotes generator
 /////////////////////////////////////////////////////////////////////

 /* Based on footnote generation code from:
  * http://www.brandspankingnew.net/archive/2005/07/format_footnote.html
  */

 footnotes: function () {
   // Delete existing footnote entries in case we're reloading the footnodes.
   var i;
   var noteholder = document.getElementById("footnotes");
   if (!noteholder) {
     return;
   }
   var entriesToRemove = [];
   for (i = 0; i < noteholder.childNodes.length; i++) {
     var entry = noteholder.childNodes[i];
     if (entry.nodeName.toLowerCase() == 'div' && entry.getAttribute("class") == "footnote")
       entriesToRemove.push(entry);
   }
   for (i = 0; i < entriesToRemove.length; i++) {
     noteholder.removeChild(entriesToRemove[i]);
   }

   // Rebuild footnote entries.
   var cont = document.getElementById("content");
   var spans = cont.getElementsByTagName("span");
   var refs = {};
   var n = 0;
   for (i=0; i<spans.length; i++) {
     if (spans[i].className == "footnote") {
       n++;
       var note = spans[i].getAttribute("data-note");
       if (!note) {
         // Use [\s\S] in place of . so multi-line matches work.
         // Because JavaScript has no s (dotall) regex flag.
         note = spans[i].innerHTML.match(/\s*\[([\s\S]*)]\s*/)[1];
         spans[i].innerHTML =
           "[<a id='_footnoteref_" + n + "' href='#_footnote_" + n +
           "' title='View footnote' class='footnote'>" + n + "</a>]";
         spans[i].setAttribute("data-note", note);
       }
       noteholder.innerHTML +=
         "<div class='footnote' id='_footnote_" + n + "'>" +
         "<a href='#_footnoteref_" + n + "' title='Return to text'>" +
         n + "</a>. " + note + "</div>";
       var id =spans[i].getAttribute("id");
       if (id != null) refs["#"+id] = n;
     }
   }
   if (n == 0)
     noteholder.parentNode.removeChild(noteholder);
   else {
     // Process footnoterefs.
     for (i=0; i<spans.length; i++) {
       if (spans[i].className == "footnoteref") {
         var href = spans[i].getElementsByTagName("a")[0].getAttribute("href");
         href = href.match(/#.*/)[0];  // Because IE return full URL.
         n = refs[href];
         spans[i].innerHTML =
           "[<a href='#_footnote_" + n +
           "' title='View footnote' class='footnote'>" + n + "</a>]";
       }
     }
   }
 },

 install: function(toclevels) {
   var timerId;

   function reinstall() {
     asciidoc.footnotes();
     if (toclevels) {
       asciidoc.toc(toclevels);
     }
   }

   function reinstallAndRemoveTimer() {
     clearInterval(timerId);
     reinstall();
   }

   timerId = setInterval(reinstall, 500);
   if (document.addEventListener)
     document.addEventListener("DOMContentLoaded", reinstallAndRemoveTimer, false);
   else
     window.onload = reinstallAndRemoveTimer;
 }

 }
 asciidoc.install();
 /*]]>*/
 </script>
 </head>
 <body class="article">
 <div id="header">
 <h1>Scalar</h1>
 <span id="revdate">2024-04-25</span>
 </div>
 <div id="content">
 <div id="preamble">
 <div class="sectionbody">
 <div class="paragraph"><p>Scalar is a repository management tool that optimizes Git for use in large
 repositories. It accomplishes this by helping users to take advantage of
 advanced performance features in Git. Unlike most other Git built-in commands,
 Scalar is not executed as a subcommand of <em>git</em>; rather, it is built as a
 separate executable containing its own series of subcommands.</p></div>
 </div>
 </div>
 <div class="sect1">
 <h2 id="_background">Background</h2>
 <div class="sectionbody">
 <div class="paragraph"><p>Scalar was originally designed as an add-on to Git and implemented as a .NET
 Core application. It was created based on the learnings from the VFS for Git
 project (another application aimed at improving the experience of working with
 large repositories). As part of its initial implementation, Scalar relied on
 custom features in the Microsoft fork of Git that have since been integrated
 into core Git:</p></div>
 <div class="ulist"><ul>
 <li>
 <p>
 partial clone,
 </p>
 </li>
 <li>
 <p>
 commit graphs,
 </p>
 </li>
 <li>
 <p>
 multi-pack index,
 </p>
 </li>
 <li>
 <p>
 sparse checkout (cone mode),
 </p>
 </li>
 <li>
 <p>
 scheduled background maintenance,
 </p>
 </li>
 <li>
 <p>
 etc
 </p>
 </li>
 </ul></div>
 <div class="paragraph"><p>With the requisite Git functionality in place and a desire to bring the benefits
 of Scalar to the larger Git community, the Scalar application itself was ported
 from C# to C and integrated upstream.</p></div>
 </div>
 </div>
 <div class="sect1">
 <h2 id="_features">Features</h2>
 <div class="sectionbody">
 <div class="paragraph"><p>Scalar is comprised of two major pieces of functionality: automatically
 configuring built-in Git performance features and managing repository
 enlistments.</p></div>
 <div class="paragraph"><p>The Git performance features configured by Scalar (see "Background" for
 examples) confer substantial performance benefits to large repositories, but are
 either too experimental to enable for all of Git yet, or only benefit large
 repositories. As new features are introduced, Scalar should be updated
 accordingly to incorporate them. This will prevent the tool from becoming stale
 while also providing a path for more easily bringing features to the appropriate
 users.</p></div>
 <div class="paragraph"><p>Enlistments are how Scalar knows which repositories on a user&#8217;s system should
 utilize Scalar-configured features. This allows it to update performance
 settings when new ones are added to the tool, as well as centrally manage
 repository maintenance. The enlistment structure - a root directory with a
 <code>src/</code> subdirectory containing the cloned repository itself - is designed to
 encourage users to route build outputs outside of the repository to avoid the
 performance-limiting overhead of ignoring those files in Git.</p></div>
 </div>
 </div>
 <div class="sect1">
 <h2 id="_design">Design</h2>
 <div class="sectionbody">
 <div class="paragraph"><p>Scalar is implemented in C and interacts with Git via a mix of child process
 invocations of Git and direct usage of <code>libgit.a</code>. Internally, it is structured
 much like other built-ins with subcommands (e.g., <code>git stash</code>), containing a
 <code>cmd_&lt;subcommand&gt;()</code> function for each subcommand, routed through a <code>cmd_main()</code>
 function. Most options are unique to each subcommand, with <code>scalar</code> respecting
 some "global" <code>git</code> options (e.g., <code>-c</code> and <code>-C</code>).</p></div>
 <div class="paragraph"><p>Because <code>scalar</code> is not invoked as a Git subcommand (like <code>git scalar</code>), it is
 built and installed as its own executable in the <code>bin/</code> directory, alongside
 <code>git</code>, <code>git-gui</code>, etc.</p></div>
 </div>
 </div>
 </div>
 <div id="footnotes"><hr /></div>
 <div id="footer">
 <div id="footer-text">
 Last updated
  2022-09-19 15:03:44 PDT
 </div>
 </div>
 </body>
 </html>
	<?xml version="1.0" encoding="UTF-8"?>
	<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
	"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
	<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
	<head>
	<meta http-equiv="Content-Type" content="application/xhtml+xml; charset=UTF-8" />
	<meta name="generator" content="AsciiDoc 10.2.0" />
	<title>Scalar</title>
	<style type="text/css">
	/* Shared CSS for AsciiDoc xhtml11 and html5 backends */

	/* Default font. */
	body {
	font-family: Georgia,serif;
	}

	/* Title font. */
	h1, h2, h3, h4, h5, h6,
	div.title, caption.title,
	thead, p.table.header,
	#toctitle,
	#author, #revnumber, #revdate, #revremark,
	#footer {
	font-family: Arial,Helvetica,sans-serif;
	}

	body {
	margin: 1em 5% 1em 5%;
	}

	a {
	color: blue;
	text-decoration: underline;
	}
	a:visited {
	color: fuchsia;
	}

	em {
	font-style: italic;
	color: navy;
	}

	strong {
	font-weight: bold;
	color: #083194;
	}

	h1, h2, h3, h4, h5, h6 {
	color: #527bbd;
	margin-top: 1.2em;
	margin-bottom: 0.5em;
	line-height: 1.3;
	}

	h1, h2, h3 {
	border-bottom: 2px solid silver;
	}
	h2 {
	padding-top: 0.5em;
	}
	h3 {
	float: left;
	}
	h3 + * {
	clear: left;
	}
	h5 {
	font-size: 1.0em;
	}

	div.sectionbody {
	margin-left: 0;
	}

	hr {
	border: 1px solid silver;
	}

	p {
	margin-top: 0.5em;
	margin-bottom: 0.5em;
	}

	ul, ol, li > p {
	margin-top: 0;
	}
	ul > li { color: #aaa; }
	ul > li > * { color: black; }

	.monospaced, code, pre {
	font-family: "Courier New", Courier, monospace;
	font-size: inherit;
	color: navy;
	padding: 0;
	margin: 0;
	}
	pre {
	white-space: pre-wrap;
	}

	#author {
	color: #527bbd;
	font-weight: bold;
	font-size: 1.1em;
	}
	#email {
	}
	#revnumber, #revdate, #revremark {
	}

	#footer {
	font-size: small;
	border-top: 2px solid silver;
	padding-top: 0.5em;
	margin-top: 4.0em;
	}
	#footer-text {
	float: left;
	padding-bottom: 0.5em;
	}
	#footer-badges {
	float: right;
	padding-bottom: 0.5em;
	}

	#preamble {
	margin-top: 1.5em;
	margin-bottom: 1.5em;
	}
	div.imageblock, div.exampleblock, div.verseblock,
	div.quoteblock, div.literalblock, div.listingblock, div.sidebarblock,
	div.admonitionblock {
	margin-top: 1.0em;
	margin-bottom: 1.5em;
	}
	div.admonitionblock {
	margin-top: 2.0em;
	margin-bottom: 2.0em;
	margin-right: 10%;
	color: #606060;
	}

	div.content { /* Block element content. */
	padding: 0;
	}

	/* Block element titles. */
	div.title, caption.title {
	color: #527bbd;
	font-weight: bold;
	text-align: left;
	margin-top: 1.0em;
	margin-bottom: 0.5em;
	}
	div.title + * {
	margin-top: 0;
	}

	td div.title:first-child {
	margin-top: 0.0em;
	}
	div.content div.title:first-child {
	margin-top: 0.0em;
	}
	div.content + div.title {
	margin-top: 0.0em;
	}

	div.sidebarblock > div.content {
	background: #ffffee;
	border: 1px solid #dddddd;
	border-left: 4px solid #f0f0f0;
	padding: 0.5em;
	}

	div.listingblock > div.content {
	border: 1px solid #dddddd;
	border-left: 5px solid #f0f0f0;
	background: #f8f8f8;
	padding: 0.5em;
	}

	div.quoteblock, div.verseblock {
	padding-left: 1.0em;
	margin-left: 1.0em;
	margin-right: 10%;
	border-left: 5px solid #f0f0f0;
	color: #888;
	}

	div.quoteblock > div.attribution {
	padding-top: 0.5em;
	text-align: right;
	}

	div.verseblock > pre.content {
	font-family: inherit;
	font-size: inherit;
	}
	div.verseblock > div.attribution {
	padding-top: 0.75em;
	text-align: left;
	}
	/* DEPRECATED: Pre version 8.2.7 verse style literal block. */
	div.verseblock + div.attribution {
	text-align: left;
	}

	div.admonitionblock .icon {
	vertical-align: top;
	font-size: 1.1em;
	font-weight: bold;
	text-decoration: underline;
	color: #527bbd;
	padding-right: 0.5em;
	}
	div.admonitionblock td.content {
	padding-left: 0.5em;
	border-left: 3px solid #dddddd;
	}

	div.exampleblock > div.content {
	border-left: 3px solid #dddddd;
	padding-left: 0.5em;
	}

	div.imageblock div.content { padding-left: 0; }
	span.image img { border-style: none; vertical-align: text-bottom; }
	a.image:visited { color: white; }

	dl {
	margin-top: 0.8em;
	margin-bottom: 0.8em;
	}
	dt {
	margin-top: 0.5em;
	margin-bottom: 0;
	font-style: normal;
	color: navy;
	}
	dd > *:first-child {
	margin-top: 0.1em;
	}

	ul, ol {
	list-style-position: outside;
	}
	ol.arabic {
	list-style-type: decimal;
	}
	ol.loweralpha {
	list-style-type: lower-alpha;
	}
	ol.upperalpha {
	list-style-type: upper-alpha;
	}
	ol.lowerroman {
	list-style-type: lower-roman;
	}
	ol.upperroman {
	list-style-type: upper-roman;
	}

	div.compact ul, div.compact ol,
	div.compact p, div.compact p,
	div.compact div, div.compact div {
	margin-top: 0.1em;
	margin-bottom: 0.1em;
	}

	tfoot {
	font-weight: bold;
	}
	td > div.verse {
	white-space: pre;
	}

	div.hdlist {
	margin-top: 0.8em;
	margin-bottom: 0.8em;
	}
	div.hdlist tr {
	padding-bottom: 15px;
	}
	dt.hdlist1.strong, td.hdlist1.strong {
	font-weight: bold;
	}
	td.hdlist1 {
	vertical-align: top;
	font-style: normal;
	padding-right: 0.8em;
	color: navy;
	}
	td.hdlist2 {
	vertical-align: top;
	}
	div.hdlist.compact tr {
	margin: 0;
	padding-bottom: 0;
	}

	.comment {
	background: yellow;
	}

	.footnote, .footnoteref {
	font-size: 0.8em;
	}

	span.footnote, span.footnoteref {
	vertical-align: super;
	}

	#footnotes {
	margin: 20px 0 20px 0;
	padding: 7px 0 0 0;
	}

	#footnotes div.footnote {
	margin: 0 0 5px 0;
	}

	#footnotes hr {
	border: none;
	border-top: 1px solid silver;
	height: 1px;
	text-align: left;
	margin-left: 0;
	width: 20%;
	min-width: 100px;
	}

	div.colist td {
	padding-right: 0.5em;
	padding-bottom: 0.3em;
	vertical-align: top;
	}
	div.colist td img {
	margin-top: 0.3em;
	}

	@media print {
	#footer-badges { display: none; }
	}

	#toc {
	margin-bottom: 2.5em;
	}

	#toctitle {
	color: #527bbd;
	font-size: 1.1em;
	font-weight: bold;
	margin-top: 1.0em;
	margin-bottom: 0.1em;
	}

	div.toclevel0, div.toclevel1, div.toclevel2, div.toclevel3, div.toclevel4 {
	margin-top: 0;
	margin-bottom: 0;
	}
	div.toclevel2 {
	margin-left: 2em;
	font-size: 0.9em;
	}
	div.toclevel3 {
	margin-left: 4em;
	font-size: 0.9em;
	}
	div.toclevel4 {
	margin-left: 6em;
	font-size: 0.9em;
	}

	span.aqua { color: aqua; }
	span.black { color: black; }
	span.blue { color: blue; }
	span.fuchsia { color: fuchsia; }
	span.gray { color: gray; }
	span.green { color: green; }
	span.lime { color: lime; }
	span.maroon { color: maroon; }
	span.navy { color: navy; }
	span.olive { color: olive; }
	span.purple { color: purple; }
	span.red { color: red; }
	span.silver { color: silver; }
	span.teal { color: teal; }
	span.white { color: white; }
	span.yellow { color: yellow; }

	span.aqua-background { background: aqua; }
	span.black-background { background: black; }
	span.blue-background { background: blue; }
	span.fuchsia-background { background: fuchsia; }
	span.gray-background { background: gray; }
	span.green-background { background: green; }
	span.lime-background { background: lime; }
	span.maroon-background { background: maroon; }
	span.navy-background { background: navy; }
	span.olive-background { background: olive; }
	span.purple-background { background: purple; }
	span.red-background { background: red; }
	span.silver-background { background: silver; }
	span.teal-background { background: teal; }
	span.white-background { background: white; }
	span.yellow-background { background: yellow; }

	span.big { font-size: 2em; }
	span.small { font-size: 0.6em; }

	span.underline { text-decoration: underline; }
	span.overline { text-decoration: overline; }
	span.line-through { text-decoration: line-through; }

	div.unbreakable { page-break-inside: avoid; }


	/*
	* xhtml11 specific
	*
	* */

	div.tableblock {
	margin-top: 1.0em;
	margin-bottom: 1.5em;
	}
	div.tableblock > table {
	border: 3px solid #527bbd;
	}
	thead, p.table.header {
	font-weight: bold;
	color: #527bbd;
	}
	p.table {
	margin-top: 0;
	}
	/* Because the table frame attribute is overridden by CSS in most browsers. */
	div.tableblock > table[frame="void"] {
	border-style: none;
	}
	div.tableblock > table[frame="hsides"] {
	border-left-style: none;
	border-right-style: none;
	}
	div.tableblock > table[frame="vsides"] {
	border-top-style: none;
	border-bottom-style: none;
	}


	/*
	* html5 specific
	*
	* */

	table.tableblock {
	margin-top: 1.0em;
	margin-bottom: 1.5em;
	}
	thead, p.tableblock.header {
	font-weight: bold;
	color: #527bbd;
	}
	p.tableblock {
	margin-top: 0;
	}
	table.tableblock {
	border-width: 3px;
	border-spacing: 0px;
	border-style: solid;
	border-color: #527bbd;
	border-collapse: collapse;
	}
	th.tableblock, td.tableblock {
	border-width: 1px;
	padding: 4px;
	border-style: solid;
	border-color: #527bbd;
	}

	table.tableblock.frame-topbot {
	border-left-style: hidden;
	border-right-style: hidden;
	}
	table.tableblock.frame-sides {
	border-top-style: hidden;
	border-bottom-style: hidden;
	}
	table.tableblock.frame-none {
	border-style: hidden;
	}

	th.tableblock.halign-left, td.tableblock.halign-left {
	text-align: left;
	}
	th.tableblock.halign-center, td.tableblock.halign-center {
	text-align: center;
	}
	th.tableblock.halign-right, td.tableblock.halign-right {
	text-align: right;
	}

	th.tableblock.valign-top, td.tableblock.valign-top {
	vertical-align: top;
	}
	th.tableblock.valign-middle, td.tableblock.valign-middle {
	vertical-align: middle;
	}
	th.tableblock.valign-bottom, td.tableblock.valign-bottom {
	vertical-align: bottom;
	}


	/*
	* manpage specific
	*
	* */

	body.manpage h1 {
	padding-top: 0.5em;
	padding-bottom: 0.5em;
	border-top: 2px solid silver;
	border-bottom: 2px solid silver;
	}
	body.manpage h2 {
	border-style: none;
	}
	body.manpage div.sectionbody {
	margin-left: 3em;
	}

	@media print {
	body.manpage div#toc { display: none; }
	}


	</style>
	<script type="text/javascript">
	/<![CDATA[/
	var asciidoc = { // Namespace.

	/////////////////////////////////////////////////////////////////////
	// Table Of Contents generator
	/////////////////////////////////////////////////////////////////////

	/* Author: Mihai Bazon, September 2002
	* http://students.infoiasi.ro/~mishoo
	*
	* Table Of Content generator
	* Version: 0.4
	*
	* Feel free to use this script under the terms of the GNU General Public
	* License, as long as you do not remove or alter this notice.
	*/

	/* modified by Troy D. Hanson, September 2006. License: GPL */
	/* modified by Stuart Rackham, 2006, 2009. License: GPL */

	// toclevels = 1..4.
	toc: function (toclevels) {

	function getText(el) {
	var text = "";
	for (var i = el.firstChild; i != null; i = i.nextSibling) {
	if (i.nodeType == 3 /* Node.TEXT_NODE */) // IE doesn't speak constants.
	text += i.data;
	else if (i.firstChild != null)
	text += getText(i);
	}
	return text;
	}

	function TocEntry(el, text, toclevel) {
	this.element = el;
	this.text = text;
	this.toclevel = toclevel;
	}

	function tocEntries(el, toclevels) {
	var result = new Array;
	var re = new RegExp('[hH]([1-'+(toclevels+1)+'])');
	// Function that scans the DOM tree for header elements (the DOM2
	// nodeIterator API would be a better technique but not supported by all
	// browsers).
	var iterate = function (el) {
	for (var i = el.firstChild; i != null; i = i.nextSibling) {
	if (i.nodeType == 1 /* Node.ELEMENT_NODE */) {
	var mo = re.exec(i.tagName);
	if (mo && (i.getAttribute("class") \|\| i.getAttribute("className")) != "float") {
	result[result.length] = new TocEntry(i, getText(i), mo[1]-1);
	}
	iterate(i);
	}
	}
	}
	iterate(el);
	return result;
	}

	var toc = document.getElementById("toc");
	if (!toc) {
	return;
	}

	// Delete existing TOC entries in case we're reloading the TOC.
	var tocEntriesToRemove = [];
	var i;
	for (i = 0; i < toc.childNodes.length; i++) {
	var entry = toc.childNodes[i];
	if (entry.nodeName.toLowerCase() == 'div'
	&& entry.getAttribute("class")
	&& entry.getAttribute("class").match(/^toclevel/))
	tocEntriesToRemove.push(entry);
	}
	for (i = 0; i < tocEntriesToRemove.length; i++) {
	toc.removeChild(tocEntriesToRemove[i]);
	}

	// Rebuild TOC entries.
	var entries = tocEntries(document.getElementById("content"), toclevels);
	for (var i = 0; i < entries.length; ++i) {
	var entry = entries[i];
	if (entry.element.id == "")
	entry.element.id = "_toc_" + i;
	var a = document.createElement("a");
	a.href = "#" + entry.element.id;
	a.appendChild(document.createTextNode(entry.text));
	var div = document.createElement("div");
	div.appendChild(a);
	div.className = "toclevel" + entry.toclevel;
	toc.appendChild(div);
	}
	if (entries.length == 0)
	toc.parentNode.removeChild(toc);
	},


	/////////////////////////////////////////////////////////////////////
	// Footnotes generator
	/////////////////////////////////////////////////////////////////////

	/* Based on footnote generation code from:
	* http://www.brandspankingnew.net/archive/2005/07/format_footnote.html
	*/

	footnotes: function () {
	// Delete existing footnote entries in case we're reloading the footnodes.
	var i;
	var noteholder = document.getElementById("footnotes");
	if (!noteholder) {
	return;
	}
	var entriesToRemove = [];
	for (i = 0; i < noteholder.childNodes.length; i++) {
	var entry = noteholder.childNodes[i];
	if (entry.nodeName.toLowerCase() == 'div' && entry.getAttribute("class") == "footnote")
	entriesToRemove.push(entry);
	}
	for (i = 0; i < entriesToRemove.length; i++) {
	noteholder.removeChild(entriesToRemove[i]);
	}

	// Rebuild footnote entries.
	var cont = document.getElementById("content");
	var spans = cont.getElementsByTagName("span");
	var refs = {};
	var n = 0;
	for (i=0; i<spans.length; i++) {
	if (spans[i].className == "footnote") {
	n++;
	var note = spans[i].getAttribute("data-note");
	if (!note) {
	// Use [\s\S] in place of . so multi-line matches work.
	// Because JavaScript has no s (dotall) regex flag.
	note = spans[i].innerHTML.match(/\s\[([\s\S])]\s*/)[1];
	spans[i].innerHTML =
	"[<a id='_footnoteref_" + n + "' href='#_footnote_" + n +
	"' title='View footnote' class='footnote'>" + n + "</a>]";
	spans[i].setAttribute("data-note", note);
	}
	noteholder.innerHTML +=
	"<div class='footnote' id='_footnote_" + n + "'>" +
	"<a href='#_footnoteref_" + n + "' title='Return to text'>" +
	n + "</a>. " + note + "</div>";
	var id =spans[i].getAttribute("id");
	if (id != null) refs["#"+id] = n;
	}
	}
	if (n == 0)
	noteholder.parentNode.removeChild(noteholder);
	else {
	// Process footnoterefs.
	for (i=0; i<spans.length; i++) {
	if (spans[i].className == "footnoteref") {
	var href = spans[i].getElementsByTagName("a")[0].getAttribute("href");
	href = href.match(/#.*/)[0]; // Because IE return full URL.
	n = refs[href];
	spans[i].innerHTML =
	"[<a href='#_footnote_" + n +
	"' title='View footnote' class='footnote'>" + n + "</a>]";
	}
	}
	}
	},

	install: function(toclevels) {
	var timerId;

	function reinstall() {
	asciidoc.footnotes();
	if (toclevels) {
	asciidoc.toc(toclevels);
	}
	}

	function reinstallAndRemoveTimer() {
	clearInterval(timerId);
	reinstall();
	}

	timerId = setInterval(reinstall, 500);
	if (document.addEventListener)
	document.addEventListener("DOMContentLoaded", reinstallAndRemoveTimer, false);
	else
	window.onload = reinstallAndRemoveTimer;
	}

	}
	asciidoc.install();
	/]]>/
	</script>
	</head>
	<body class="article">
	<div id="header">
	<h1>Scalar</h1>
	<span id="revdate">2024-04-25</span>
	</div>
	<div id="content">
	<div id="preamble">
	<div class="sectionbody">
	<div class="paragraph"><p>Scalar is a repository management tool that optimizes Git for use in large
	repositories. It accomplishes this by helping users to take advantage of
	advanced performance features in Git. Unlike most other Git built-in commands,
	Scalar is not executed as a subcommand of <em>git</em>; rather, it is built as a
	separate executable containing its own series of subcommands.</p></div>
	</div>
	</div>
	<div class="sect1">
	<h2 id="_background">Background</h2>
	<div class="sectionbody">
	<div class="paragraph"><p>Scalar was originally designed as an add-on to Git and implemented as a .NET
	Core application. It was created based on the learnings from the VFS for Git
	project (another application aimed at improving the experience of working with
	large repositories). As part of its initial implementation, Scalar relied on
	custom features in the Microsoft fork of Git that have since been integrated
	into core Git:</p></div>
	<div class="ulist"><ul>
	<li>
	<p>
	partial clone,
	</p>
	</li>
	<li>
	<p>
	commit graphs,
	</p>
	</li>
	<li>
	<p>
	multi-pack index,
	</p>
	</li>
	<li>
	<p>
	sparse checkout (cone mode),
	</p>
	</li>
	<li>
	<p>
	scheduled background maintenance,
	</p>
	</li>
	<li>
	<p>
	etc
	</p>
	</li>
	</ul></div>
	<div class="paragraph"><p>With the requisite Git functionality in place and a desire to bring the benefits
	of Scalar to the larger Git community, the Scalar application itself was ported
	from C# to C and integrated upstream.</p></div>
	</div>
	</div>
	<div class="sect1">
	<h2 id="_features">Features</h2>
	<div class="sectionbody">
	<div class="paragraph"><p>Scalar is comprised of two major pieces of functionality: automatically
	configuring built-in Git performance features and managing repository
	enlistments.</p></div>
	<div class="paragraph"><p>The Git performance features configured by Scalar (see "Background" for
	examples) confer substantial performance benefits to large repositories, but are
	either too experimental to enable for all of Git yet, or only benefit large
	repositories. As new features are introduced, Scalar should be updated
	accordingly to incorporate them. This will prevent the tool from becoming stale
	while also providing a path for more easily bringing features to the appropriate
	users.</p></div>
	<div class="paragraph"><p>Enlistments are how Scalar knows which repositories on a user’s system should
	utilize Scalar-configured features. This allows it to update performance
	settings when new ones are added to the tool, as well as centrally manage
	repository maintenance. The enlistment structure - a root directory with a
	<code>src/</code> subdirectory containing the cloned repository itself - is designed to
	encourage users to route build outputs outside of the repository to avoid the
	performance-limiting overhead of ignoring those files in Git.</p></div>
	</div>
	</div>
	<div class="sect1">
	<h2 id="_design">Design</h2>
	<div class="sectionbody">
	<div class="paragraph"><p>Scalar is implemented in C and interacts with Git via a mix of child process
	invocations of Git and direct usage of <code>libgit.a</code>. Internally, it is structured
	much like other built-ins with subcommands (e.g., <code>git stash</code>), containing a
	<code>cmd_<subcommand>()</code> function for each subcommand, routed through a <code>cmd_main()</code>
	function. Most options are unique to each subcommand, with <code>scalar</code> respecting
	some "global" <code>git</code> options (e.g., <code>-c</code> and <code>-C</code>).</p></div>
	<div class="paragraph"><p>Because <code>scalar</code> is not invoked as a Git subcommand (like <code>git scalar</code>), it is
	built and installed as its own executable in the <code>bin/</code> directory, alongside
	<code>git</code>, <code>git-gui</code>, etc.</p></div>
	</div>
	</div>
	</div>
	<div id="footnotes"><hr /></div>
	<div id="footer">
	<div id="footer-text">
	Last updated
	2022-09-19 15:03:44 PDT
	</div>
	</div>
	</body>
	</html>