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>FreeTDS</SPAN
> User Guide: A Guide to Installing, Configuring, and Running <SPAN
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>FreeTDS</SPAN
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>Chapter 8. Troubleshooting</TD
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><H1
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><A
NAME="LOGGING"
>Logging</A
></H1
><P
><SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> has quite extensive logging capabilities.  These are often invaluable in setting up new configurations, when it's hard to be sure precisely what configuration information is being used, and what communication is (not) working.   Often such questions can be quickly resolved by turning on logging and examining the logs.</P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="ENVIRONMENT"
>Environment Variables that Control Logging</A
></H2
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><CODE
CLASS="ENVAR"
>TDSDUMP</CODE
></DT
><DD
><P
>Log files can be turned on using the <CODE
CLASS="ENVAR"
>TDSDUMP</CODE
> environment variable.  For instance, setting the location of a dumpfile
<PRE
CLASS="SCREEN"
>	<SAMP
CLASS="PROMPT"
>$ </SAMP
><KBD
CLASS="USERINPUT"
>export TDSDUMP=/tmp/freetds.log</KBD
></PRE
>
	Will generate a log file named <TT
CLASS="FILENAME"
>freetds.log</TT
> in the <TT
CLASS="FILENAME"
>/tmp</TT
> directory.
	<DIV
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><P
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><P
> The filenames <TT
CLASS="FILENAME"
>stdout</TT
> and <TT
CLASS="FILENAME"
>stderr</TT
> are also supported.  They can be handy if you want to intersperse the log output with your application's output, or if your application opens more than one connection.  (The logfile is otherwise normally truncated each time the library connects to the server.)</P
></TD
></TR
></TABLE
></DIV
></P
></DD
><DT
><CODE
CLASS="ENVAR"
>TDSDUMPCONFIG</CODE
></DT
><DD
><P
>Set <CODE
CLASS="ENVAR"
>TDSDUMPCONFIG</CODE
> to a file to
							write information to on how the configuration information is being
							obtained, e.g. from environment variables, a <TT
CLASS="FILENAME"
>freetds.conf</TT
> file, or <TT
CLASS="FILENAME"
>interfaces</TT
> file.  Sometimes it's unclear what source of information <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> is using to connect to a given servername.  This variable can make that bright and clear.</P
></DD
></DL
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><P
>What if you were running <SPAN
CLASS="PRODUCTNAME"
>Apache</SPAN
>/PHP?  <SPAN
CLASS="PRODUCTNAME"
>Apache</SPAN
> has many children.
					Setting the <CODE
CLASS="ENVAR"
>TDSDUMP</CODE
> (and/or <CODE
CLASS="ENVAR"
>TDSDUMPCONFIG</CODE
>) variable to a null string will cause <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> to open a log under every PID.
<PRE
CLASS="SCREEN"
>	<SAMP
CLASS="PROMPT"
>$ </SAMP
><KBD
CLASS="USERINPUT"
>export TDSDUMP=""</KBD
></PRE
>
	The log files will be named <TT
CLASS="FILENAME"
>/tmp/freetds.log.<TT
CLASS="REPLACEABLE"
><I
>9999</I
></TT
></TT
>, where <TT
CLASS="REPLACEABLE"
><I
>9999</I
></TT
> is the pid number of the process generating the log.</P
></TD
></TR
></TABLE
></DIV
><P
>A couple of important notes about using the logs with <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
>.  First,
				the logs tend to grow large, so trim or archive them often.  Secondly,
				<SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> will record certain network packets to the log, this
				<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>includes login packets which can contain clear text or clear text
					equivalent passwords.</I
></SPAN
> So, if this is a concern (most likely
				is) make sure that the files are not world readable, and avoid posting
				them to mailing lists.</P
><P
>Once in a while, someone writes to the mailing list, asking why <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> is so <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>slow</I
></SPAN
>.  It sometimes turns out that logging was left turned on.  Don't you be the next victim!  <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> logs are meant for development and debugging, not as a system monitoring tool.</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="LOGGING.FREETDS.CONF"
><TT
CLASS="FILENAME"
>freetds.conf</TT
> variables that Control Logging</A
></H2
><P
>See <A
HREF="freetdsconf.htm#TAB.FREETDS.CONF.DEBUGFLAGS"
>Valid bitmask values for <TT
CLASS="LITERAL"
>debug flags</TT
> entry in <TT
CLASS="FILENAME"
>freetds.conf</TT
></A
></P
><P
>The logfile is normally truncated each time <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> connects to the server.</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="LOGGING.ODBC"
>Logging in ODBC land</A
></H2
><FONT
COLOR="RED"
>(Tree-huggers need not worry)</FONT
><P
>Many ODBC Driver Managers have their own support for logging. How logging is controlled, however, varies widely by implementation. The ODBC log is often very helpful because it provides a log of all calls made directly by the application.</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
>unixODBC</DT
><DD
><P
>unixODBC supports logging via some entries in <TT
CLASS="FILENAME"
>odbcinst.ini</TT
>. For example:
<PRE
CLASS="SCREEN"
>	[ODBC]
	Trace        = Yes
	TraceFile    = /tmp/sql.log
	ForceTrace   = Yes</PRE
>
	Will generate a log file named <TT
CLASS="FILENAME"
>sql.log</TT
> in the <TT
CLASS="FILENAME"
>/tmp</TT
> directory.</P
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