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diff --git a/bdb/docs/ref/am/stability.html b/bdb/docs/ref/am/stability.html deleted file mode 100644 index b5f6d23864d..00000000000 --- a/bdb/docs/ref/am/stability.html +++ /dev/null @@ -1,49 +0,0 @@ -<!--$Id: stability.so,v 10.20 2000/12/13 16:48:13 bostic Exp $--> -<!--Copyright 1997, 1998, 1999, 2000 by Sleepycat Software, Inc.--> -<!--All rights reserved.--> -<html> -<head> -<title>Berkeley DB Reference Guide: Cursor Stability</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> <a name="3"><!--meow--></a> -<table><tr valign=top> -<td><h3><dl><dt>Berkeley DB Reference Guide:<dd>Transaction Subsystem</dl></h3></td> -<td width="1%"><a href="../../ref/am/curclose.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/am/partial.html"><img src="../../images/next.gif" alt="Next"></a> -</td></tr></table> -<p> -<h1 align=center>Cursor Stability</h1> -<p>In the absence of locking, no guarantees are made about the stability of -cursors in different processes or threads. However, the Btree, Queue -and Recno access methods guarantee that cursor operations, interspersed -with other cursor or non-cursor operations in the same thread of control -will always return keys in order and will return each non-deleted key/data -pair exactly once. Because the Hash access method uses a dynamic hashing -algorithm, it cannot guarantee any form of stability in the presence of -inserts and deletes unless locking is performed. -<p>If locking was specified when the Berkeley DB file was opened, but transactions -are not in effect, the access methods provide repeatable reads with -respect to the cursor. That is, a <a href="../../api_c/dbc_get.html#DB_CURRENT">DB_CURRENT</a> call on the cursor -is guaranteed to return the same record as was returned on the last call -to the cursor. -<p>With the exception of the Queue access method, in the presence of -transactions, all access method calls between a call to <a href="../../api_c/txn_begin.html">txn_begin</a> -and a call to <a href="../../api_c/txn_abort.html">txn_abort</a> or <a href="../../api_c/txn_commit.html">txn_commit</a> provide degree 3 -consistency (serializable transactions). -<p>The Queue access method permits phantom records to appear between calls. -That is, deleted records are not locked, therefore another transaction may -replace a deleted record between two calls to retrieve it. The record would -not appear in the first call but would be seen by the second call. -<p>For all access methods, a cursor scan of the database performed within -the context of a transaction is guaranteed to return each key/data pair -once and only once, except in the following case. If, while performing -a cursor scan using the Hash access method, the transaction performing -the scan inserts a new pair into the database, it is possible that duplicate -key/data pairs will be returned. -<table><tr><td><br></td><td width="1%"><a href="../../ref/am/curclose.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/am/partial.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> |