<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <HTML ><HEAD ><TITLE >Environment Variables</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REV="MADE" HREF="mailto:pgsql-docs@postgresql.org"><LINK REL="HOME" TITLE="PostgreSQL 7.4.1 Documentation" HREF="index.html"><LINK REL="UP" TITLE="libpq - C Library" HREF="libpq.html"><LINK REL="PREVIOUS" TITLE="Notice Processing" HREF="libpq-notice-processing.html"><LINK REL="NEXT" TITLE="The Password File" HREF="libpq-pgpass.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="stylesheet.css"><META NAME="creation" CONTENT="2003-12-22T03:48:47"></HEAD ><BODY CLASS="SECT1" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="5" ALIGN="center" VALIGN="bottom" >PostgreSQL 7.4.1 Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="libpq-notice-processing.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="libpq.html" >Fast Backward</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" >Chapter 27. <SPAN CLASS="APPLICATION" >libpq</SPAN > - C Library</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="libpq.html" >Fast Forward</A ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="libpq-pgpass.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="LIBPQ-ENVARS" >27.10. Environment Variables</A ></H1 ><A NAME="AEN21725" ></A ><P >The following environment variables can be used to select default connection parameter values, which will be used by <CODE CLASS="FUNCTION" >PQconnectdb</CODE >, <CODE CLASS="FUNCTION" >PQsetdbLogin</CODE > and <CODE CLASS="FUNCTION" >PQsetdb</CODE > if no value is directly specified by the calling code. These are useful to avoid hard-coding database connection information into simple client applications, for example. <P ></P ></P><UL ><LI ><P ><A NAME="AEN21734" ></A > <TT CLASS="ENVAR" >PGHOST</TT > sets the database server name. If this begins with a slash, it specifies Unix-domain communication rather than TCP/IP communication; the value is the name of the directory in which the socket file is stored (default <TT CLASS="FILENAME" >/tmp</TT >).</P ></LI ><LI ><P ><A NAME="AEN21741" ></A > <TT CLASS="ENVAR" >PGHOSTADDR</TT > specifies the numeric IP address of the database server. This can be set instead of <TT CLASS="ENVAR" >PGHOST</TT > to avoid DNS lookup overhead. See the documentation of these parameters, under <CODE CLASS="FUNCTION" >PQconnectdb</CODE > above, for details on their interaction.</P ></LI ><LI ><P ><A NAME="AEN21749" ></A > <TT CLASS="ENVAR" >PGPORT</TT > sets the TCP port number or Unix-domain socket file extension for communicating with the <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > server.</P ></LI ><LI ><P ><A NAME="AEN21756" ></A > <TT CLASS="ENVAR" >PGDATABASE</TT > sets the <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > database name.</P ></LI ><LI ><P ><A NAME="AEN21763" ></A > <TT CLASS="ENVAR" >PGUSER</TT > sets the user name used to connect to the database.</P ></LI ><LI ><P ><A NAME="AEN21769" ></A > <TT CLASS="ENVAR" >PGPASSWORD</TT > sets the password used if the server demands password authentication. This environment variable is deprecated for security reasons; consider migrating to use the <TT CLASS="FILENAME" >$HOME/.pgpass</TT > file (see <A HREF="libpq-pgpass.html" >Section 27.11</A >).</P ></LI ><LI ><P ><A NAME="AEN21777" ></A > <TT CLASS="ENVAR" >PGSERVICE</TT > sets the service name to be looked up in <TT CLASS="FILENAME" >pg_service.conf</TT >. This offers a shorthand way of setting all the parameters.</P ></LI ><LI ><P ><A NAME="AEN21784" ></A > <TT CLASS="ENVAR" >PGREALM</TT > sets the Kerberos realm to use with <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN >, if it is different from the local realm. If <TT CLASS="ENVAR" >PGREALM</TT > is set, <SPAN CLASS="APPLICATION" >libpq</SPAN > applications will attempt authentication with servers for this realm and use separate ticket files to avoid conflicts with local ticket files. This environment variable is only used if Kerberos authentication is selected by the server.</P ></LI ><LI ><P ><A NAME="AEN21793" ></A > <TT CLASS="ENVAR" >PGOPTIONS</TT > sets additional run-time options for the <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > server.</P ></LI ><LI ><P ><A NAME="AEN21800" ></A > <TT CLASS="ENVAR" >PGSSLMODE</TT > determines whether and with what priority an <ACRONYM CLASS="ACRONYM" >SSL</ACRONYM > connection will be negotiated with the server. There are four modes: <TT CLASS="LITERAL" >disable</TT > will attempt only an unencrypted <ACRONYM CLASS="ACRONYM" >SSL</ACRONYM > connection; <TT CLASS="LITERAL" >allow</TT > will negotiate, trying first a non-<ACRONYM CLASS="ACRONYM" >SSL</ACRONYM > connection, then if that fails, trying an <ACRONYM CLASS="ACRONYM" >SSL</ACRONYM > connection; <TT CLASS="LITERAL" >prefer</TT > (the default) will negotiate, trying first an <ACRONYM CLASS="ACRONYM" >SSL</ACRONYM > connection, then if that fails, trying a regular non-<ACRONYM CLASS="ACRONYM" >SSL</ACRONYM > connection; <TT CLASS="LITERAL" >require</TT > will try only an <ACRONYM CLASS="ACRONYM" >SSL</ACRONYM > connection. If <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > is compiled without SSL support, using option <TT CLASS="LITERAL" >require</TT > will cause an error, and options <TT CLASS="LITERAL" >allow</TT > and <TT CLASS="LITERAL" >prefer</TT > will be tolerated but <SPAN CLASS="APPLICATION" >libpq</SPAN > will be unable to negotiate an <ACRONYM CLASS="ACRONYM" >SSL</ACRONYM > connection.</P ></LI ><LI ><P ><A NAME="AEN21823" ></A > <TT CLASS="ENVAR" >PGREQUIRESSL</TT > sets whether or not the connection must be made over <ACRONYM CLASS="ACRONYM" >SSL</ACRONYM >. If set to <SPAN CLASS="QUOTE" >"1"</SPAN >, <SPAN CLASS="APPLICATION" >libpq</SPAN > will refuse to connect if the server does not accept an <ACRONYM CLASS="ACRONYM" >SSL</ACRONYM > connection (equivalent to <TT CLASS="LITERAL" >sslmode</TT > <TT CLASS="LITERAL" >prefer</TT >). This option is deprecated in favor of the <TT CLASS="LITERAL" >sslmode</TT > setting, and is only available if <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > is compiled with SSL support.</P ></LI ><LI ><P ><A NAME="AEN21837" ></A > <TT CLASS="ENVAR" >PGCONNECT_TIMEOUT</TT > sets the maximum number of seconds that <SPAN CLASS="APPLICATION" >libpq</SPAN > will wait when attempting to connect to the <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > server. If unset or set to zero, <SPAN CLASS="APPLICATION" >libpq</SPAN > will wait indefinitely. It is not recommended to set the timeout to less than 2 seconds.</P ></LI ></UL ><P></P ><P >The following environment variables can be used to specify default behavior for each <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > session. (See also the <TT CLASS="COMMAND" >ALTER USER</TT > and <TT CLASS="COMMAND" >ALTER DATABASE</TT > commands for ways to set default behavior on a per-user or per-database basis.) <P ></P ></P><UL ><LI ><P ><A NAME="AEN21851" ></A > <TT CLASS="ENVAR" >PGDATESTYLE</TT > sets the default style of date/time representation. (Equivalent to <TT CLASS="LITERAL" >SET datestyle TO ...</TT >.)</P ></LI ><LI ><P ><A NAME="AEN21858" ></A > <TT CLASS="ENVAR" >PGTZ</TT > sets the default time zone. (Equivalent to <TT CLASS="LITERAL" >SET timezone TO ...</TT >.)</P ></LI ><LI ><P ><A NAME="AEN21865" ></A > <TT CLASS="ENVAR" >PGCLIENTENCODING</TT > sets the default client character set encoding. (Equivalent to <TT CLASS="LITERAL" >SET client_encoding TO ...</TT >.)</P ></LI ><LI ><P ><A NAME="AEN21872" ></A > <TT CLASS="ENVAR" >PGGEQO</TT > sets the default mode for the genetic query optimizer. (Equivalent to <TT CLASS="LITERAL" >SET geqo TO ...</TT >.)</P ></LI ></UL ><P> Refer to the <ACRONYM CLASS="ACRONYM" >SQL</ACRONYM > command <TT CLASS="COMMAND" >SET</TT > for information on correct values for these environment variables.</P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="libpq-notice-processing.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="libpq-pgpass.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Notice Processing</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="libpq.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >The Password File</TD ></TR ></TABLE ></DIV ></BODY ></HTML >
