1<!--Copyright 1999-2009 Oracle. All rights reserved.--> 2<HTML> 3<HEAD> 4 <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> 5 <META NAME="GENERATOR" CONTENT="Mozilla/4.08 [en] (X11; I; FreeBSD 3.3-RELEASE i386) [Netscape]"> 6</HEAD> 7<BODY> 8 9<H2> 10<A NAME="Logging Commands"></A>Logging Commands</H2> 11Logging commands work from the environment handle to control the use of 12the log files. Log files are opened when the environment is opened 13and closed when the environment is closed. In all of the commands 14in the logging subsystem that take or return a log sequence number, it 15is of the form: 16<BR><B>{<I>fileid offset</I>}</B> 17<BR>where the <B><I>fileid</I></B> is an identifier of the log file, as 18returned from the <A HREF="#> <env> log_get">log_get</A> call. 19<P><B>> <env> log_archive [-arch_abs] [-arch_data] [-arch_log]</B> 20<P>This command returns a list of log files that are no longer in 21use. It is a direct call to the <A HREF="../../docs/api_c/log_archive.html">log_archive</A> 22function. The arguments are: 23<UL> 24<LI> 25<B>-arch_abs </B>selects DB_ARCH_ABS to return all pathnames as absolute 26pathnames</LI> 27 28<LI> 29<B>-arch_data </B>selects DB_ARCH_DATA to return a list of database files</LI> 30 31<LI> 32<B>-arch_log </B>selects DB_ARCH_LOG to return a list of log files</LI> 33</UL> 34 35<HR WIDTH="100%"> 36<BR><B>> <env> log_compare <I>lsn1 lsn2</I></B> 37<P>This command compares two log sequence numbers, given as <B><I>lsn1</I></B> 38and <B><I>lsn2</I></B>. It is a direct call to the <A HREF="../../docs/api_c/log_compare.html">log_compare</A> 39function. It will return a -1, 0, 1 to indicate if <B><I>lsn1</I></B> 40is less than, equal to or greater than <B><I>lsn2</I></B> respectively. 41<BR> 42<HR WIDTH="100%"> 43<BR><B>> <env> log_file <I>lsn</I></B> 44<P>This command returns the file name associated with the given <B><I>lsn</I></B>. 45It is a direct call to the <A HREF="../../docs/api_c/log_file.html">log_file</A> 46function. 47<BR> 48<HR WIDTH="100%"> 49<BR><B>> <env> log_flush [<I>lsn</I>]</B> 50<P>This command flushes the log up to the specified <B><I>lsn</I></B> 51or flushes all records if none is given It is a direct call to the 52<A HREF="../../docs/api_c/log_flush.html">log_flush</A> 53function. It returns either a 0 (for success), a DB error message 54or it throws a Tcl error with a system message. 55<BR> 56<HR WIDTH="100%"> 57<BR><A NAME="<env> log_get"></A><B>> <env> log_get<I> </I>[-checkpoint] 58[-current] [-first] [-last] [-next] [-prev] [-set <I>lsn</I>]</B> 59<P>This command retrieves a record from the log according to the <B><I>lsn</I></B> 60given and returns it and the data. It is a direct call to the <A HREF="../../docs/api_c/log_get.html">log_get</A> 61function. It is a way of implementing a manner of log iteration similar 62to <A HREF="../../docs/api_tcl/db_cursor.html">cursors</A>. 63The information we return is similar to database information. We 64return a list where the first item is the LSN (which is a list itself) 65and the second item is the data. So it looks like, fully expanded, 66<B>{{<I>fileid</I> 67<I>offset</I>} 68<I>data</I>}.</B> 69In the case where DB_NOTFOUND is returned, we return an empty list <B>{}</B>. 70All other errors return a Tcl error. The arguments are: 71<UL> 72<LI> 73<B>-checkpoint </B>selects the DB_CHECKPOINT flag to return the LSN/data 74pair of the last record written through <A HREF="#> <env> log_put">log_put</A> 75with DB_CHECKPOINT specified</LI> 76 77<LI> 78<B>-current</B> selects the DB_CURRENT flag to return the current record</LI> 79 80<LI> 81<B>-first</B> selects the DB_FIRST flag to return the first record in the 82log.</LI> 83 84<LI> 85<B>-last </B>selects the DB_LAST flag to return the last record in the 86log.</LI> 87 88<LI> 89<B>-next</B> selects the DB_NEXT flag to return the next record in the 90log.</LI> 91 92<LI> 93<B>-prev </B>selects the DB_PREV flag to return the previous record 94in the log.</LI> 95 96<LI> 97<B>-set</B> selects the DB_SET flag to return the record specified by the 98given <B><I>lsn</I></B></LI> 99</UL> 100 101<HR WIDTH="100%"> 102<BR><A NAME="> <env> log_put"></A><B>> <env> log_put<I> </I>[-checkpoint] 103[-flush] <I>record</I></B> 104<P>This command stores a <B><I>record</I></B> into the log and returns 105the LSN of the log record. It is a direct call to the <A HREF="../../docs/api_c/log_put.html">log_put</A> 106function. It returns either an LSN or it throws a Tcl error with 107a system message. <B> </B>The arguments are: 108<UL> 109<LI> 110<B>-checkpoint </B>selects the DB_CHECKPOINT flag</LI> 111 112<LI> 113<B>-flush </B>selects the DB_FLUSH flag to flush the log to disk.</LI> 114</UL> 115 116<HR WIDTH="100%"> 117<BR><B>> <env> log_stat</B> 118<P>This command returns the statistics associated with the logging 119subsystem. It is a direct call to the <A HREF="../../docs/api_c/log_stat.html">log_stat</A> 120function. It returns a list of name/value pairs of the DB_LOG_STAT 121structure. 122</BODY> 123</HTML> 124