Adding upstream version 3.40.1.upstream/3.40.1 upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
author: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-05-05 17:28:19 +0000
committer: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-05-05 17:28:19 +0000
commit: 18657a960e125336f704ea058e25c27bd3900dcb (patch)
tree: 17b438b680ed45a996d7b59951e6aa34023783f2 /www/c3ref/backup_finish.html
parent: Initial commit. (diff)
download: sqlite3-18657a960e125336f704ea058e25c27bd3900dcb.tar.xz
sqlite3-18657a960e125336f704ea058e25c27bd3900dcb.zip
1 files changed, 327 insertions, 0 deletions
diff --git a/www/c3ref/backup_finish.html b/www/c3ref/backup_finish.html
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+<!DOCTYPE html>
+<html><head>
+<meta name="viewport" content="width=device-width, initial-scale=1.0">
+<meta http-equiv="content-type" content="text/html; charset=UTF-8">
+<link href="../sqlite.css" rel="stylesheet">
+<title>Online Backup API.</title>
+<!-- path=../ -->
+</head>
+<body>
+<div class=nosearch>
+<a href="../index.html">
+<img class="logo" src="../images/sqlite370_banner.gif" alt="SQLite" border="0">
+</a>
+<div><!-- IE hack to prevent disappearing logo --></div>
+<div class="tagline desktoponly">
+Small. Fast. Reliable.<br>Choose any three.
+</div>
+<div class="menu mainmenu">
+<ul>
+<li><a href="../index.html">Home</a>
+<li class='mobileonly'><a href="javascript:void(0)" onclick='toggle_div("submenu")'>Menu</a>
+<li class='wideonly'><a href='../about.html'>About</a>
+<li class='desktoponly'><a href="../docs.html">Documentation</a>
+<li class='desktoponly'><a href="../download.html">Download</a>
+<li class='wideonly'><a href='../copyright.html'>License</a>
+<li class='desktoponly'><a href="../support.html">Support</a>
+<li class='desktoponly'><a href="../prosupport.html">Purchase</a>
+<li class='search' id='search_menubutton'>
+<a href="javascript:void(0)" onclick='toggle_search()'>Search</a>
+</ul>
+</div>
+<div class="menu submenu" id="submenu">
+<ul>
+<li><a href='../about.html'>About</a>
+<li><a href='../docs.html'>Documentation</a>
+<li><a href='../download.html'>Download</a>
+<li><a href='../support.html'>Support</a>
+<li><a href='../prosupport.html'>Purchase</a>
+</ul>
+</div>
+<div class="searchmenu" id="searchmenu">
+<form method="GET" action="../search">
+<select name="s" id="searchtype">
+<option value="d">Search Documentation</option>
+<option value="c">Search Changelog</option>
+</select>
+<input type="text" name="q" id="searchbox" value="">
+<input type="submit" value="Go">
+</form>
+</div>
+</div>
+<script>
+function toggle_div(nm) {
+var w = document.getElementById(nm);
+if( w.style.display=="block" ){
+w.style.display = "none";
+}else{
+w.style.display = "block";
+}
+}
+function toggle_search() {
+var w = document.getElementById("searchmenu");
+if( w.style.display=="block" ){
+w.style.display = "none";
+} else {
+w.style.display = "block";
+setTimeout(function(){
+document.getElementById("searchbox").focus()
+}, 30);
+}
+}
+function div_off(nm){document.getElementById(nm).style.display="none";}
+window.onbeforeunload = function(e){div_off("submenu");}
+/* Disable the Search feature if we are not operating from CGI, since */
+/* Search is accomplished using CGI and will not work without it. */
+if( !location.origin || !location.origin.match || !location.origin.match(/http/) ){
+document.getElementById("search_menubutton").style.display = "none";
+}
+/* Used by the Hide/Show button beside syntax diagrams, to toggle the */
+function hideorshow(btn,obj){
+var x = document.getElementById(obj);
+var b = document.getElementById(btn);
+if( x.style.display!='none' ){
+x.style.display = 'none';
+b.innerHTML='show';
+}else{
+x.style.display = '';
+b.innerHTML='hide';
+}
+return false;
+}
+var antiRobot = 0;
+function antiRobotGo(){
+if( antiRobot!=3 ) return;
+antiRobot = 7;
+var j = document.getElementById("mtimelink");
+if(j && j.hasAttribute("data-href")) j.href=j.getAttribute("data-href");
+}
+function antiRobotDefense(){
+document.body.onmousedown=function(){
+antiRobot |= 2;
+antiRobotGo();
+document.body.onmousedown=null;
+}
+document.body.onmousemove=function(){
+antiRobot |= 2;
+antiRobotGo();
+document.body.onmousemove=null;
+}
+setTimeout(function(){
+antiRobot |= 1;
+antiRobotGo();
+}, 100)
+antiRobotGo();
+}
+antiRobotDefense();
+</script>
+<!-- keywords: sqlite3_backup_finish sqlite3_backup_init sqlite3_backup_pagecount sqlite3_backup_remaining sqlite3_backup_step -->
+<div class=nosearch>
+<a href="intro.html"><h2>SQLite C Interface</h2></a>
+<h2>Online Backup API.</h2>
+</div>
+<blockquote><pre>
+sqlite3_backup *sqlite3_backup_init(
+  sqlite3 *pDest,                        /* Destination database handle */
+  const char *zDestName,                 /* Destination database name */
+  sqlite3 *pSource,                      /* Source database handle */
+  const char *zSourceName                /* Source database name */
+);
+int sqlite3_backup_step(sqlite3_backup *p, int nPage);
+int sqlite3_backup_finish(sqlite3_backup *p);
+int sqlite3_backup_remaining(sqlite3_backup *p);
+int sqlite3_backup_pagecount(sqlite3_backup *p);
+</pre></blockquote>
+<p>
+The backup API copies the content of one database into another.
+It is useful either for creating backups of databases or
+for copying in-memory databases to or from persistent files.</p>
+
+<p>See Also: <a href="../backup.html">Using the SQLite Online Backup API</a></p>
+
+<p>SQLite holds a write transaction open on the destination database file
+for the duration of the backup operation.
+The source database is read-locked only while it is being read;
+it is not locked continuously for the entire backup operation.
+Thus, the backup may be performed on a live source database without
+preventing other database connections from
+reading or writing to the source database while the backup is underway.</p>
+
+<p>To perform a backup operation:
+<ol>
+<li><b>sqlite3_backup_init()</b> is called once to initialize the
+backup,
+<li><b>sqlite3_backup_step()</b> is called one or more times to transfer
+the data between the two databases, and finally
+<li><b>sqlite3_backup_finish()</b> is called to release all resources
+associated with the backup operation.
+</ol>
+There should be exactly one call to sqlite3_backup_finish() for each
+successful call to sqlite3_backup_init().</p>
+
+<p><a name="sqlite3backupinit"></a>
+ <b>sqlite3_backup_init()</b></p>
+
+<p>The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
+<a href="../c3ref/sqlite3.html">database connection</a> associated with the destination database
+and the database name, respectively.
+The database name is "main" for the main database, "temp" for the
+temporary database, or the name specified after the AS keyword in
+an <a href="../lang_attach.html">ATTACH</a> statement for an attached database.
+The S and M arguments passed to
+sqlite3_backup_init(D,N,S,M) identify the <a href="../c3ref/sqlite3.html">database connection</a>
+and database name of the source database, respectively.
+The source and destination <a href="../c3ref/sqlite3.html">database connections</a> (parameters S and D)
+must be different or else sqlite3_backup_init(D,N,S,M) will fail with
+an error.</p>
+
+<p>A call to sqlite3_backup_init() will fail, returning NULL, if
+there is already a read or read-write transaction open on the
+destination database.</p>
+
+<p>If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
+returned and an error code and error message are stored in the
+destination <a href="../c3ref/sqlite3.html">database connection</a> D.
+The error code and message for the failed call to sqlite3_backup_init()
+can be retrieved using the <a href="../c3ref/errcode.html">sqlite3_errcode()</a>, <a href="../c3ref/errcode.html">sqlite3_errmsg()</a>, and/or
+<a href="../c3ref/errcode.html">sqlite3_errmsg16()</a> functions.
+A successful call to sqlite3_backup_init() returns a pointer to an
+<a href="../c3ref/backup.html">sqlite3_backup</a> object.
+The <a href="../c3ref/backup.html">sqlite3_backup</a> object may be used with the sqlite3_backup_step() and
+sqlite3_backup_finish() functions to perform the specified backup
+operation.</p>
+
+<p><a name="sqlite3backupstep"></a>
+ <b>sqlite3_backup_step()</b></p>
+
+<p>Function sqlite3_backup_step(B,N) will copy up to N pages between
+the source and destination databases specified by <a href="../c3ref/backup.html">sqlite3_backup</a> object B.
+If N is negative, all remaining source pages are copied.
+If sqlite3_backup_step(B,N) successfully copies N pages and there
+are still more pages to be copied, then the function returns <a href="../rescode.html#ok">SQLITE_OK</a>.
+If sqlite3_backup_step(B,N) successfully finishes copying all pages
+from source to destination, then it returns <a href="../rescode.html#done">SQLITE_DONE</a>.
+If an error occurs while running sqlite3_backup_step(B,N),
+then an <a href="../rescode.html">error code</a> is returned. As well as <a href="../rescode.html#ok">SQLITE_OK</a> and
+<a href="../rescode.html#done">SQLITE_DONE</a>, a call to sqlite3_backup_step() may return <a href="../rescode.html#readonly">SQLITE_READONLY</a>,
+<a href="../rescode.html#nomem">SQLITE_NOMEM</a>, <a href="../rescode.html#busy">SQLITE_BUSY</a>, <a href="../rescode.html#locked">SQLITE_LOCKED</a>, or an
+<a href="../rescode.html#ioerr_access">SQLITE_IOERR_XXX</a> extended error code.</p>
+
+<p>The sqlite3_backup_step() might return <a href="../rescode.html#readonly">SQLITE_READONLY</a> if
+<ol>
+<li> the destination database was opened read-only, or
+<li> the destination database is using write-ahead-log journaling
+and the destination and source page sizes differ, or
+<li> the destination database is an in-memory database and the
+destination and source page sizes differ.
+</ol></p>
+
+<p>If sqlite3_backup_step() cannot obtain a required file-system lock, then
+the <a href="../c3ref/busy_handler.html">busy-handler function</a>
+is invoked (if one is specified). If the
+busy-handler returns non-zero before the lock is available, then
+<a href="../rescode.html#busy">SQLITE_BUSY</a> is returned to the caller. In this case the call to
+sqlite3_backup_step() can be retried later. If the source
+<a href="../c3ref/sqlite3.html">database connection</a>
+is being used to write to the source database when sqlite3_backup_step()
+is called, then <a href="../rescode.html#locked">SQLITE_LOCKED</a> is returned immediately. Again, in this
+case the call to sqlite3_backup_step() can be retried later on. If
+<a href="../rescode.html#ioerr_access">SQLITE_IOERR_XXX</a>, <a href="../rescode.html#nomem">SQLITE_NOMEM</a>, or
+<a href="../rescode.html#readonly">SQLITE_READONLY</a> is returned, then
+there is no point in retrying the call to sqlite3_backup_step(). These
+errors are considered fatal.  The application must accept
+that the backup operation has failed and pass the backup operation handle
+to the sqlite3_backup_finish() to release associated resources.</p>
+
+<p>The first call to sqlite3_backup_step() obtains an exclusive lock
+on the destination file. The exclusive lock is not released until either
+sqlite3_backup_finish() is called or the backup operation is complete
+and sqlite3_backup_step() returns <a href="../rescode.html#done">SQLITE_DONE</a>.  Every call to
+sqlite3_backup_step() obtains a <a href="../lockingv3.html#shared_lock">shared lock</a> on the source database that
+lasts for the duration of the sqlite3_backup_step() call.
+Because the source database is not locked between calls to
+sqlite3_backup_step(), the source database may be modified mid-way
+through the backup process.  If the source database is modified by an
+external process or via a database connection other than the one being
+used by the backup operation, then the backup will be automatically
+restarted by the next call to sqlite3_backup_step(). If the source
+database is modified by the using the same database connection as is used
+by the backup operation, then the backup database is automatically
+updated at the same time.</p>
+
+<p><a name="sqlite3backupfinish"></a>
+ <b>sqlite3_backup_finish()</b></p>
+
+<p>When sqlite3_backup_step() has returned <a href="../rescode.html#done">SQLITE_DONE</a>, or when the
+application wishes to abandon the backup operation, the application
+should destroy the <a href="../c3ref/backup.html">sqlite3_backup</a> by passing it to sqlite3_backup_finish().
+The sqlite3_backup_finish() interfaces releases all
+resources associated with the <a href="../c3ref/backup.html">sqlite3_backup</a> object.
+If sqlite3_backup_step() has not yet returned <a href="../rescode.html#done">SQLITE_DONE</a>, then any
+active write-transaction on the destination database is rolled back.
+The <a href="../c3ref/backup.html">sqlite3_backup</a> object is invalid
+and may not be used following a call to sqlite3_backup_finish().</p>
+
+<p>The value returned by sqlite3_backup_finish is <a href="../rescode.html#ok">SQLITE_OK</a> if no
+sqlite3_backup_step() errors occurred, regardless or whether or not
+sqlite3_backup_step() completed.
+If an out-of-memory condition or IO error occurred during any prior
+sqlite3_backup_step() call on the same <a href="../c3ref/backup.html">sqlite3_backup</a> object, then
+sqlite3_backup_finish() returns the corresponding <a href="../rescode.html">error code</a>.</p>
+
+<p>A return of <a href="../rescode.html#busy">SQLITE_BUSY</a> or <a href="../rescode.html#locked">SQLITE_LOCKED</a> from sqlite3_backup_step()
+is not a permanent error and does not affect the return value of
+sqlite3_backup_finish().</p>
+
+<p><a name="sqlite3backupremaining"></a>
+ <a name="sqlite3backuppagecount"></a>
+
+<b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b></p>
+
+<p>The sqlite3_backup_remaining() routine returns the number of pages still
+to be backed up at the conclusion of the most recent sqlite3_backup_step().
+The sqlite3_backup_pagecount() routine returns the total number of pages
+in the source database at the conclusion of the most recent
+sqlite3_backup_step().
+The values returned by these functions are only updated by
+sqlite3_backup_step(). If the source database is modified in a way that
+changes the size of the source database or the number of pages remaining,
+those changes are not reflected in the output of sqlite3_backup_pagecount()
+and sqlite3_backup_remaining() until after the next
+sqlite3_backup_step().</p>
+
+<p><b>Concurrent Usage of Database Handles</b></p>
+
+<p>The source <a href="../c3ref/sqlite3.html">database connection</a> may be used by the application for other
+purposes while a backup operation is underway or being initialized.
+If SQLite is compiled and configured to support threadsafe database
+connections, then the source database connection may be used concurrently
+from within other threads.</p>
+
+<p>However, the application must guarantee that the destination
+<a href="../c3ref/sqlite3.html">database connection</a> is not passed to any other API (by any thread) after
+sqlite3_backup_init() is called and before the corresponding call to
+sqlite3_backup_finish().  SQLite does not currently check to see
+if the application incorrectly accesses the destination <a href="../c3ref/sqlite3.html">database connection</a>
+and so no error code is reported, but the operations may malfunction
+nevertheless.  Use of the destination database connection while a
+backup is in progress might also cause a mutex deadlock.</p>
+
+<p>If running in <a href="../sharedcache.html">shared cache mode</a>, the application must
+guarantee that the shared cache used by the destination database
+is not accessed while the backup is running. In practice this means
+that the application must guarantee that the disk file being
+backed up to is not accessed by any connection within the process,
+not just the specific connection that was passed to sqlite3_backup_init().</p>
+
+<p>The <a href="../c3ref/backup.html">sqlite3_backup</a> object itself is partially threadsafe. Multiple
+threads may safely make multiple concurrent calls to sqlite3_backup_step().
+However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
+APIs are not strictly speaking threadsafe. If they are invoked at the
+same time as another thread is invoking sqlite3_backup_step() it is
+possible that they return invalid values.
+</p><p>See also lists of
+  <a href="objlist.html">Objects</a>,
+  <a href="constlist.html">Constants</a>, and
+  <a href="funclist.html">Functions</a>.</p>
+
author	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-05-05 17:28:19 +0000
committer	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-05-05 17:28:19 +0000
commit	18657a960e125336f704ea058e25c27bd3900dcb (patch)
tree	17b438b680ed45a996d7b59951e6aa34023783f2 /www/c3ref/backup_finish.html
parent	Initial commit. (diff)
download	sqlite3-18657a960e125336f704ea058e25c27bd3900dcb.tar.xz sqlite3-18657a960e125336f704ea058e25c27bd3900dcb.zip