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124 lines
4.9 KiB
HTML
124 lines
4.9 KiB
HTML
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<!--Copyright (c) 1999, 2010 Oracle and/or its affiliates. All rights reserved.-->
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<HTML>
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<HEAD>
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<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
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<META NAME="GENERATOR" CONTENT="Mozilla/4.08 [en] (X11; I; FreeBSD 3.3-RELEASE i386) [Netscape]">
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</HEAD>
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<BODY>
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<H2>
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<A NAME="Logging Commands"></A>Logging Commands</H2>
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Logging commands work from the environment handle to control the use of
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the log files. Log files are opened when the environment is opened
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and closed when the environment is closed. In all of the commands
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in the logging subsystem that take or return a log sequence number, it
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is of the form:
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<BR><B>{<I>fileid offset</I>}</B>
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<BR>where the <B><I>fileid</I></B> is an identifier of the log file, as
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returned from the <A HREF="#> <env> log_get">log_get</A> call.
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<P><B>> <env> log_archive [-arch_abs] [-arch_data] [-arch_log]</B>
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<P>This command returns a list of log files that are no longer in
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use. It is a direct call to the <A HREF="../../docs/api_c/log_archive.html">log_archive</A>
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function. The arguments are:
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<UL>
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<LI>
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<B>-arch_abs </B>selects DB_ARCH_ABS to return all pathnames as absolute
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pathnames</LI>
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<LI>
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<B>-arch_data </B>selects DB_ARCH_DATA to return a list of database files</LI>
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<LI>
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<B>-arch_log </B>selects DB_ARCH_LOG to return a list of log files</LI>
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</UL>
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<HR WIDTH="100%">
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<BR><B>> <env> log_compare <I>lsn1 lsn2</I></B>
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<P>This command compares two log sequence numbers, given as <B><I>lsn1</I></B>
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and <B><I>lsn2</I></B>. It is a direct call to the <A HREF="../../docs/api_c/log_compare.html">log_compare</A>
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function. It will return a -1, 0, 1 to indicate if <B><I>lsn1</I></B>
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is less than, equal to or greater than <B><I>lsn2</I></B> respectively.
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<BR>
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<HR WIDTH="100%">
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<BR><B>> <env> log_file <I>lsn</I></B>
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<P>This command returns the file name associated with the given <B><I>lsn</I></B>.
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It is a direct call to the <A HREF="../../docs/api_c/log_file.html">log_file</A>
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function.
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<BR>
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<HR WIDTH="100%">
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<BR><B>> <env> log_flush [<I>lsn</I>]</B>
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<P>This command flushes the log up to the specified <B><I>lsn</I></B>
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or flushes all records if none is given It is a direct call to the
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<A HREF="../../docs/api_c/log_flush.html">log_flush</A>
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function. It returns either a 0 (for success), a DB error message
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or it throws a Tcl error with a system message.
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<BR>
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<HR WIDTH="100%">
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<BR><A NAME="<env> log_get"></A><B>> <env> log_get<I> </I>[-checkpoint]
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[-current] [-first] [-last] [-next] [-prev] [-set <I>lsn</I>]</B>
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<P>This command retrieves a record from the log according to the <B><I>lsn</I></B>
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given and returns it and the data. It is a direct call to the <A HREF="../../docs/api_c/log_get.html">log_get</A>
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function. It is a way of implementing a manner of log iteration similar
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to <A HREF="../../docs/api_tcl/db_cursor.html">cursors</A>.
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The information we return is similar to database information. We
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return a list where the first item is the LSN (which is a list itself)
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and the second item is the data. So it looks like, fully expanded,
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<B>{{<I>fileid</I>
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<I>offset</I>}
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<I>data</I>}.</B>
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In the case where DB_NOTFOUND is returned, we return an empty list <B>{}</B>.
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All other errors return a Tcl error. The arguments are:
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<UL>
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<LI>
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<B>-checkpoint </B>selects the DB_CHECKPOINT flag to return the LSN/data
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pair of the last record written through <A HREF="#> <env> log_put">log_put</A>
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with DB_CHECKPOINT specified</LI>
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<LI>
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<B>-current</B> selects the DB_CURRENT flag to return the current record</LI>
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<LI>
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<B>-first</B> selects the DB_FIRST flag to return the first record in the
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log.</LI>
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<LI>
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<B>-last </B>selects the DB_LAST flag to return the last record in the
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log.</LI>
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<LI>
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<B>-next</B> selects the DB_NEXT flag to return the next record in the
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log.</LI>
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<LI>
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<B>-prev </B>selects the DB_PREV flag to return the previous record
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in the log.</LI>
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<LI>
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<B>-set</B> selects the DB_SET flag to return the record specified by the
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given <B><I>lsn</I></B></LI>
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</UL>
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<HR WIDTH="100%">
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<BR><A NAME="> <env> log_put"></A><B>> <env> log_put<I> </I>[-checkpoint]
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[-flush] <I>record</I></B>
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<P>This command stores a <B><I>record</I></B> into the log and returns
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the LSN of the log record. It is a direct call to the <A HREF="../../docs/api_c/log_put.html">log_put</A>
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function. It returns either an LSN or it throws a Tcl error with
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a system message. <B> </B>The arguments are:
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<UL>
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<LI>
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<B>-checkpoint </B>selects the DB_CHECKPOINT flag</LI>
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<LI>
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<B>-flush </B>selects the DB_FLUSH flag to flush the log to disk.</LI>
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</UL>
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<HR WIDTH="100%">
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<BR><B>> <env> log_stat</B>
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<P>This command returns the statistics associated with the logging
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subsystem. It is a direct call to the <A HREF="../../docs/api_c/log_stat.html">log_stat</A>
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function. It returns a list of name/value pairs of the DB_LOG_STAT
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structure.
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</BODY>
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</HTML>
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