From: Tom Lane <tgl@sss.pgh.pa.us>

Attached are diffs (from current cvs sources) to bring libpq.sgml
and libpq.3 up to date.

It appears that at various times in the past, people have made edits to
one or the other of these files but not both.  I propagated some changes
from each into the other, but I don't think I caught every
inconsistency.  It'd be real nice if the man pages could be
automatically generated from the SGML...

doc/src/sgml/libpq.sgml

@@ -36,6 +36,8 @@
 <ListItem>
 <Para>
 <Acronym>PGHOST</Acronym> sets the default server name.
+If it is set to a non-zero-length string, it causes TCP/IP
+communication to be used, rather than the default local Unix domain sockets.
 </Para>
 </ListItem>
 <ListItem>
@@ -45,7 +47,9 @@
 </ListItem>
 <ListItem>
 <Para>
-<Acronym>PGPORT</Acronym>  sets the default port for communicating with the <ProductName>Postgres</ProductName> backend.
+<Acronym>PGPORT</Acronym>  sets the default port or local Unix domain socket
+file extension for communicating with the <ProductName>Postgres</ProductName>
+backend.
 </Para>
 </ListItem>
 <ListItem>
@@ -71,6 +75,63 @@
 </ListItem>
 </ItemizedList>
 </Para>
+
+<Para>
+The following environment variables can be used to specify user-level default
+behavior for every Postgres session:
+
+<ItemizedList>
+<ListItem>
+<Para>
+<Acronym>PGDATESTYLE</Acronym>
+sets the default style of date/time representation.
+</Para>
+</ListItem>
+<ListItem>
+<Para>
+<Acronym>PGTZ</Acronym>
+sets the default time zone.
+</Para>
+</ListItem>
+</ItemizedList>
+</Para>
+
+<Para>
+The following environment variables can be used to specify default internal
+behavior for every Postgres session:
+
+<ItemizedList>
+<ListItem>
+<Para>
+<Acronym>PGGEQO</Acronym>
+sets the default mode for the genetic optimizer.
+</Para>
+</ListItem>
+<ListItem>
+<Para>
+<Acronym>PGRPLANS</Acronym>
+sets the default mode to allow or disable right-sided plans in the optimizer.
+</Para>
+</ListItem>
+<ListItem>
+<Para>
+<Acronym>PGCOSTHEAP</Acronym>
+sets the default cost for heap searches for the optimizer.
+</Para>
+</ListItem>
+<ListItem>
+<Para>
+<Acronym>PGCOSTINDEX</Acronym>
+sets the default cost for indexed searches for the optimizer.
+</Para>
+</ListItem>
+</ItemizedList>
+</Para>
+
+<Para>
+See the set(l)
+man page for information on the arguments for these environment variables.
+
 </Sect1>
 
 <Sect1>
@@ -250,30 +311,6 @@ void PQreset(PGconn *conn)
 </ProgramListing>
 </Para>
 </ListItem>
-
-<ListItem>
-<Para>
-<Function>PQtrace</Function>
-          Enables  tracing  of  messages  passed between the
-          frontend and the backend.  The messages are echoed
-          to the debug_port file stream.
-<ProgramListing>
-void PQtrace(PGconn *conn,
-             FILE* debug_port);
-</ProgramListing>
-</Para>
-</ListItem>
-
-<ListItem>
-<Para>
-<Function>PQuntrace</Function>
-          Disables  tracing  of  messages passed between the
-          frontend and the backend.
-<ProgramListing>
-void PQuntrace(PGconn *conn);
-</ProgramListing>
-</Para>
-</ListItem>
 </ItemizedList>
 </Para>
 </Sect1>
@@ -445,7 +482,7 @@ int PQgetisnull(PGresult *res,
                 int field_num);
 </ProgramListing>
             This function returns  1 if the field contains a NULL, 0 if
-            it contains a known value..
+            it contains a known value.
 </Para>
 </ListItem>
 
@@ -597,8 +634,9 @@ want to block waiting for the response.
 </ListItem>
 <ListItem>
 <Para>
-Since control is buried inside PQexec, there is no way for the frontend
-to decide it would like to try to cancel the ongoing query.
+Since control is buried inside PQexec, it is hard for the frontend
+to decide it would like to try to cancel the ongoing query.  (It can be
+done from a signal handler, but not otherwise.)
 </Para>
 </ListItem>
 <ListItem>
@@ -773,10 +811,13 @@ Note that if the current query is part of a transaction, cancellation
 will abort the whole transaction.
 
 <Para>
-The current implementation of cancel requests uses "out of band" messages.
-This feature is supported only on TCP/IP connections.  If the backend
-communication is being done through a Unix socket, PQrequestCancel will
-always fail.
+PQrequestCancel can safely be invoked from a signal handler.  So, it is
+also possible to use it in conjunction with plain PQexec, if the decision
+to cancel can be made in a signal handler.  For example, psql invokes
+PQrequestCancel from a SIGINT signal handler, thus allowing interactive
+cancellation of queries that it issues through PQexec.  Note that
+PQrequestCancel will have no effect if the connection is not currently open
+or the backend is not currently processing a query.
 
 </Sect1>
 
@@ -819,7 +860,7 @@ typedef struct {
 </ProgramListing>
      PQfn always returns a valid PGresult*.  The  resultStatus  should be checked before the result is used.   The
      caller is responsible for  freeing  the  PGresult  with
-     PQclear when it is not longer needed.
+     PQclear when it is no longer needed.
 </Para>
 </ListItem>
 </ItemizedList>
@@ -966,6 +1007,10 @@ void PQputline(PGconn *conn,
 <ProgramListing>
 int PQendcopy(PGconn *conn);
 </ProgramListing>
+
+<Para>
+As an example:
+
 <ProgramListing>
 PQexec(conn, "create table foo (a int4, b char16, d float8)");
 PQexec(conn, "copy foo from stdin");
@@ -1036,7 +1081,9 @@ void PQuntrace(PGconn *conn)
   (e.g.,  obtaining <Acronym>Kerberos</Acronym> tickets),
      the frontend/backend authentication process is  handled
      by  <Function>PQexec</Function>  without any further intervention.
-  The following routines may be called by <FileName>libpq</FileName> programs to tailor the behavior of the authentication process.
+The authentication method is now
+determined entirely by the DBA (see pga_hba.conf(5)).  The following
+routines no longer have any effect and should not be used.
 </Para>
 
 <Para>
@@ -1157,7 +1204,7 @@ void fe_setauthsvc(char *name,
            PQclear(res);
 
            /* fetch instances from the pg_database, the system catalog of databases*/
-           res = PQexec(conn,"DECLARE myportal CURSOR FOR select * from pg_database");
+           res = PQexec(conn,"DECLARE mycursor CURSOR FOR select * from pg_database");
            if (PQresultStatus(res) != PGRES_COMMAND_OK) {
              fprintf(stderr,"DECLARE CURSOR command failed\n");
              PQclear(res);
@@ -1165,7 +1212,7 @@ void fe_setauthsvc(char *name,
            }
            PQclear(res);
 
-           res = PQexec(conn,"FETCH ALL in myportal");
+           res = PQexec(conn,"FETCH ALL in mycursor");
            if (PQresultStatus(res) != PGRES_TUPLES_OK) {
              fprintf(stderr,"FETCH ALL command didn't return tuples properly\n");
              PQclear(res);
@@ -1189,8 +1236,8 @@ void fe_setauthsvc(char *name,
 
            PQclear(res);
 
-           /* close the portal */
-           res = PQexec(conn, "CLOSE myportal");
+           /* close the cursor */
+           res = PQexec(conn, "CLOSE mycursor");
            PQclear(res);
 
            /* end the transaction */
@@ -1446,7 +1493,7 @@ void fe_setauthsvc(char *name,
 
            PQclear(res);
 
-           /* close the portal */
+           /* close the cursor */
            res = PQexec(conn, "CLOSE mycursor");
            PQclear(res);