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diff --git a/bdb/docs/ref/transapp/read.html b/bdb/docs/ref/transapp/read.html deleted file mode 100644 index 912401e8758..00000000000 --- a/bdb/docs/ref/transapp/read.html +++ /dev/null @@ -1,40 +0,0 @@ -<!--$Id: read.so,v 1.1 2000/07/25 17:56:36 bostic Exp $--> -<!--Copyright 1997, 1998, 1999, 2000 by Sleepycat Software, Inc.--> -<!--All rights reserved.--> -<html> -<head> -<title>Berkeley DB Reference Guide: Repeatable reads</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> -<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/inc.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/cursor.html"><img src="../../images/next.gif" alt="Next"></a> -</td></tr></table> -<p> -<h1 align=center>Repeatable reads</h1> -<p>The fourth reason listed for using transactions was repeatable reads. -Generally, most applications do not need to place reads inside a -transaction for performance reasons. The problem is that a -transactionally protected cursor, reading each key/data pair in a -database, will acquire a read lock on most of the pages in the database -and so will gradually block all write operations on the databases until -the transaction commits or aborts. Note, however, if there are update -transactions present in the application, the reading transactions must -still use locking, and should be prepared to repeat any operation -(possibly closing and reopening a cursor) which fails with a return -value of <a href="../../ref/program/errorret.html#DB_LOCK_DEADLOCK">DB_LOCK_DEADLOCK</a>. -<p>The exceptions to this rule are when the application is doing a -read-modify-write operation and so requires atomicity, and when an -application requires the ability to repeatedly access a data item -knowing that it will not have changed. A repeatable read simply means -that, for the life of the transaction, every time a request is made by -any thread of control to read a data item, it will be unchanged from -its previous value, that is, that the value will not change until the -transaction commits or aborts. -<table><tr><td><br></td><td width="1%"><a href="../../ref/transapp/inc.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/cursor.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> |