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diff --git a/bdb/docs/ref/transapp/checkpoint.html b/bdb/docs/ref/transapp/checkpoint.html deleted file mode 100644 index b9bd81a3ed6..00000000000 --- a/bdb/docs/ref/transapp/checkpoint.html +++ /dev/null @@ -1,127 +0,0 @@ -<!--$Id: checkpoint.so,v 10.13 2000/08/16 17:50:40 margo Exp $--> -<!--Copyright 1997, 1998, 1999, 2000 by Sleepycat Software, Inc.--> -<!--All rights reserved.--> -<html> -<head> -<title>Berkeley DB Reference Guide: Checkpoints</title> -<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> -<meta name="keywords" content="embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++"> -</head> -<body bgcolor=white> - <a name="2"><!--meow--></a> -<table><tr valign=top> -<td><h3><dl><dt>Berkeley DB Reference Guide:<dd>Transaction Protected Applications</dl></h3></td> -<td width="1%"><a href="../../ref/transapp/deadlock.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../../ref/toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../../ref/transapp/archival.html"><img src="../../images/next.gif" alt="Next"></a> -</td></tr></table> -<p> -<h1 align=center>Checkpoints</h1> -<p>The second component of the infrastructure is performing checkpoints of -the log files. As transactions commit, change records are written into -the log files, but the actual changes to the database are not -necessarily written to disk. When a checkpoint is performed, the -changes to the database that are part of committed transactions are -written into the backing database file. -<p>Performing checkpoints is necessary for two reasons. First, you can -only remove the Berkeley DB log files from your system after a checkpoint. -Second, the frequency of your checkpoints is inversely proportional to -the amount of time it takes to run database recovery after a system or -application failure. -<p>Once the database pages are written, log files can be archived and removed -from the system because they will never be needed for anything other than -catastrophic failure. In addition, recovery after system or application -failure only has to redo or undo changes since the last checkpoint, since -changes before the checkpoint have all been flushed to the filesystem. -<p>Berkeley DB provides a separate utility, <a href="../../utility/db_checkpoint.html">db_checkpoint</a>, which can be -used to perform checkpoints. Alternatively, applications can write -their own checkpoint utility using the underlying <a href="../../api_c/txn_checkpoint.html">txn_checkpoint</a> -function. The following code fragment checkpoints the database -environment every 60 seconds: -<p><blockquote><pre>int -main(int argc, char *argv) -{ - extern char *optarg; - extern int optind; - DB *db_cats, *db_color, *db_fruit; - DB_ENV *dbenv; - pthread_t ptid; - int ch; -<p> - while ((ch = getopt(argc, argv, "")) != EOF) - switch (ch) { - case '?': - default: - usage(); - } - argc -= optind; - argv += optind; -<p> - env_dir_create(); - env_open(&dbenv); -<p> -<b> /* Start a checkpoint thread. */ - if ((errno = pthread_create( - &ptid, NULL, checkpoint_thread, (void *)dbenv)) != 0) { - fprintf(stderr, - "txnapp: failed spawning checkpoint thread: %s\n", - strerror(errno)); - exit (1); - }</b> -<p> - /* Open database: Key is fruit class; Data is specific type. */ - db_open(dbenv, &db_fruit, "fruit", 0); -<p> - /* Open database: Key is a color; Data is an integer. */ - db_open(dbenv, &db_color, "color", 0); -<p> - /* - * Open database: - * Key is a name; Data is: company name, address, cat breeds. - */ - db_open(dbenv, &db_cats, "cats", 1); -<p> - add_fruit(dbenv, db_fruit, "apple", "yellow delicious"); -<p> - add_color(dbenv, db_color, "blue", 0); - add_color(dbenv, db_color, "blue", 3); -<p> - add_cat(dbenv, db_cats, - "Amy Adams", - "Sleepycat Software", - "394 E. Riding Dr., Carlisle, MA 01741, USA", - "abyssinian", - "bengal", - "chartreaux", - NULL); -<p> - return (0); -} -<p> -<b>void * -checkpoint_thread(void *arg) -{ - DB_ENV *dbenv; - int ret; -<p> - dbenv = arg; - dbenv->errx(dbenv, "Checkpoint thread: %lu", (u_long)pthread_self()); -<p> - /* Checkpoint once a minute. */ - for (;; sleep(60)) - switch (ret = txn_checkpoint(dbenv, 0, 0, 0)) { - case 0: - case DB_INCOMPLETE: - break; - default: - dbenv->err(dbenv, ret, "checkpoint thread"); - exit (1); - } -<p> - /* NOTREACHED */ -}</b></pre></blockquote> -<p>As checkpoints can be quite expensive, choosing how often to perform a -checkpoint is a common tuning parameter for Berkeley DB applications. -<table><tr><td><br></td><td width="1%"><a href="../../ref/transapp/deadlock.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../../ref/toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../../ref/transapp/archival.html"><img src="../../images/next.gif" alt="Next"></a> -</td></tr></table> -<p><font size=1><a href="http://www.sleepycat.com">Copyright Sleepycat Software</a></font> -</body> -</html> |