196 lines
6.7 KiB
HTML
196 lines
6.7 KiB
HTML
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<!DOCTYPE html>
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<html><head>
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<meta http-equiv="content-type" content="text/html; charset=UTF-8">
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<link href="sqlite.css" rel="stylesheet">
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<title>SQLite Library Footprint</title>
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<!-- path= -->
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</head>
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<body>
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<div class=nosearch>
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<a href="index.html">
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<img class="logo" src="images/sqlite370_banner.gif" alt="SQLite" border="0">
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</a>
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<div><!-- IE hack to prevent disappearing logo --></div>
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<div class="tagline desktoponly">
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Small. Fast. Reliable.<br>Choose any three.
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</div>
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<div class="menu mainmenu">
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<ul>
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<li><a href="index.html">Home</a>
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<li class='mobileonly'><a href="javascript:void(0)" onclick='toggle_div("submenu")'>Menu</a>
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<li class='wideonly'><a href='about.html'>About</a>
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<li class='desktoponly'><a href="docs.html">Documentation</a>
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<li class='desktoponly'><a href="download.html">Download</a>
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<li class='wideonly'><a href='copyright.html'>License</a>
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<li class='desktoponly'><a href="support.html">Support</a>
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<li class='desktoponly'><a href="prosupport.html">Purchase</a>
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<li class='search' id='search_menubutton'>
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<a href="javascript:void(0)" onclick='toggle_search()'>Search</a>
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</ul>
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</div>
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<div class="menu submenu" id="submenu">
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<ul>
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<li><a href='about.html'>About</a>
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<li><a href='docs.html'>Documentation</a>
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<li><a href='download.html'>Download</a>
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<li><a href='support.html'>Support</a>
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<li><a href='prosupport.html'>Purchase</a>
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</ul>
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</div>
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<div class="searchmenu" id="searchmenu">
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<form method="GET" action="search">
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<select name="s" id="searchtype">
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<option value="d">Search Documentation</option>
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<option value="c">Search Changelog</option>
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</select>
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<input type="text" name="q" id="searchbox" value="">
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<input type="submit" value="Go">
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</form>
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</div>
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</div>
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<script>
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function toggle_div(nm) {
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var w = document.getElementById(nm);
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if( w.style.display=="block" ){
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w.style.display = "none";
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}else{
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w.style.display = "block";
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}
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}
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function toggle_search() {
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var w = document.getElementById("searchmenu");
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if( w.style.display=="block" ){
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w.style.display = "none";
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} else {
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w.style.display = "block";
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setTimeout(function(){
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document.getElementById("searchbox").focus()
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}, 30);
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}
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}
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function div_off(nm){document.getElementById(nm).style.display="none";}
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window.onbeforeunload = function(e){div_off("submenu");}
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/* Disable the Search feature if we are not operating from CGI, since */
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/* Search is accomplished using CGI and will not work without it. */
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if( !location.origin || !location.origin.match || !location.origin.match(/http/) ){
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document.getElementById("search_menubutton").style.display = "none";
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}
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/* Used by the Hide/Show button beside syntax diagrams, to toggle the */
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function hideorshow(btn,obj){
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var x = document.getElementById(obj);
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var b = document.getElementById(btn);
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if( x.style.display!='none' ){
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x.style.display = 'none';
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b.innerHTML='show';
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}else{
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x.style.display = '';
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b.innerHTML='hide';
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}
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return false;
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}
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</script>
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</div>
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<h1 align="center">Size Of The SQLite Library</h1>
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<p>
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The code space used by the SQLite library depends on the target
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platform, the compiler, and optimization settings. These variables
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also affect performance.
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</p>
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<p>
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The chart below shows the relative size and performance for SQLite
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as of 2017-10-08 for various compilers and optimization settings
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as tested on Ubuntu 16.04.3 on x86_64. General observations:
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<ol>
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<li><p>
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The Clang/LLVM compiler is not competitive with GCC. Clang-generated
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binaries are consistently larger and slower than GCC-generated binaries.
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<li><p>
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Profile guided optimization (PGO) is not helpful with SQLite. PGO results
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in binaries that are about 1% larger and about 0.33% slower.
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<li><p>
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GCC-7 generates binaries that are smaller and faster than GCC-5, though
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the difference is not that great.
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<li><p>
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Compiling with GCC and -Os results in a binary that is slightly less
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than 500KB in size. (Update 2018-07-07: Due to the addition of new
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features such as <a href="lang_upsert.html">UPSERT</a> and <a href="windowfunctions.html">window functions</a>, the library footprint
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is now slightly larger than 500KB.)
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<li><p>
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The only significant design decision that developers need to make is
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whether to use -Os (optimize for size) or -O6 (optimize for speed).
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The -O6 setting makes binaries that run about 2% or 3% faster, but which
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are also 66% larger. The performance here is measured by counting CPU
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cycles using cachegrind. I-cache misses are not considered in the
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analysis. If I-cache misses are considered, builds with -O6 might not
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be any faster than builds with -Os.
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<li><p>
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Taking into consideration all of the above, the SQLite developers recommend
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compiling SQLite using GCC-7 with the -Os optimization setting.
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</ol>
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<hr>
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<center>
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<img src='images/cc-diff.jpg'>
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</center>
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</hr>
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<h1>Details</h1>
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<ul>
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<li><p>
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Measurements above were conducted using SQLite version
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<a href="https://sqlite.org/src/timeline?c=5594a121bf132a98">5594a121bf132a98</a> from
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2017-10-08.
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<li><p>
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The only SQLite compile-time option used was <a href="compile.html#enable_memsys5">-DSQLITE_ENABLE_MEMSYS5</a>.
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The optional <a href="malloc.html#memsys5">memsys5</a> memory allocator is used for performance testing
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because it gives results that are more repeatable than the library-supplied
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malloc()/free() on Ubuntu.
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<li><p>
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Performance can be improved and the size reduced by
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enabling <a href="compile.html#threadsafe">-DSQLITE_THREADSAFE=0</a>,
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<a href="compile.html#default_memstatus">-DSQLITE_DEFAULT_MEMSTATUS=0</a>,
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<a href="compile.html#default_wal_synchronous">-DSQLITE_DEFAULT_WAL_SYNCHRONOUS=1</a>,
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<a href="compile.html#like_doesnt_match_blobs">-DSQLITE_LIKE_DOESNT_MATCH_BLOBS</a>,
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<a href="limits.html#max_expr_depth">-DSQLITE_MAX_EXPR_DEPTH=0</a>,
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<a href="compile.html#omit_decltype">-DSQLITE_OMIT_DECLTYPE</a>,
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<a href="compile.html#omit_deprecated">-DSQLITE_OMIT_DEPRECATED</a>,
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<a href="compile.html#omit_progress_callback">-DSQLITE_OMIT_PROGRESS_CALLBACK</a>,
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<a href="compile.html#omit_shared_cache">-DSQLITE_OMIT_SHARED_CACHE</a>, and
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<a href="compile.html#use_alloca">-DSQLITE_USE_ALLOCA</a>.
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All these options together result in about a 3.5% performance increase and
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a 3.0% size reduction.
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<li><p>
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Adding optional features like <a href="compile.html#enable_json1">-DSQLITE_ENABLE_JSON1</a>,
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<a href="compile.html#enable_fts5">-DSQLITE_ENABLE_FTS5</a>, or <a href="compile.html#enable_rtree">-DSQLITE_ENABLE_RTREE</a> will increase the
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size of the library, obviously.
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<li><p>
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Performance was measured using the
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<a href="https://sqlite.org/src/file/test/speedtest1.c">speedtest1.c</a> utility program,
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which attempts to mimic a typical workload for SQLite. Options to
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the test runs are:
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<blockquote>
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<tt>--shrink-memory --reprepare --stats --heap 10000000 64 --size 5</tt>
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</blockquote>
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Performance was measured by running speedtest1 using cachegrind and
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observing the "I refs" output.
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</ul>
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