Add support for using SQL/MED compliant FOREIGN DATA WRAPPER, SERVER,
and USER MAPPING as method to supply dblink connect parameters. Per mailing list and PGCon discussions.
This commit is contained in:
Joe Conway
parent
af98bb2ad7
commit
4334695b30
@ -8,7 +8,7 @@
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* Darko Prenosil <Darko.Prenosil@finteh.hr>
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* Shridhar Daithankar <shridhar_daithankar@persistent.co.in>
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*
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* $PostgreSQL: pgsql/contrib/dblink/dblink.c,v 1.78 2009/06/02 03:21:56 joe Exp $
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* $PostgreSQL: pgsql/contrib/dblink/dblink.c,v 1.79 2009/06/06 21:27:56 joe Exp $
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* Copyright (c) 2001-2009, PostgreSQL Global Development Group
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* ALL RIGHTS RESERVED;
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*
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@ -46,6 +46,7 @@
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#include "catalog/pg_type.h"
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#include "executor/executor.h"
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#include "executor/spi.h"
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#include "foreign/foreign.h"
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#include "lib/stringinfo.h"
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#include "miscadmin.h"
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#include "nodes/execnodes.h"
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@ -96,6 +97,8 @@ static char *generate_relation_name(Oid relid);
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static void dblink_connstr_check(const char *connstr);
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static void dblink_security_check(PGconn *conn, remoteConn *rconn);
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static void dblink_res_error(const char *conname, PGresult *res, const char *dblink_context_msg, bool fail);
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static char *get_connect_string(const char *servername);
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static char *escape_param_str(const char *from);
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/* Global */
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static remoteConn *pconn = NULL;
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@ -165,7 +168,11 @@ typedef struct remoteConnHashEnt
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} \
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else \
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{ \
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connstr = conname_or_str; \
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connstr = get_connect_string(conname_or_str); \
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if (connstr == NULL) \
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{ \
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connstr = conname_or_str; \
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} \
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dblink_connstr_check(connstr); \
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conn = PQconnectdb(connstr); \
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if (PQstatus(conn) == CONNECTION_BAD) \
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@ -210,6 +217,7 @@ PG_FUNCTION_INFO_V1(dblink_connect);
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Datum
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dblink_connect(PG_FUNCTION_ARGS)
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{
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char *conname_or_str = NULL;
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char *connstr = NULL;
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char *connname = NULL;
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char *msg;
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@ -220,16 +228,21 @@ dblink_connect(PG_FUNCTION_ARGS)
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if (PG_NARGS() == 2)
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{
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connstr = text_to_cstring(PG_GETARG_TEXT_PP(1));
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conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(1));
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connname = text_to_cstring(PG_GETARG_TEXT_PP(0));
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}
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else if (PG_NARGS() == 1)
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connstr = text_to_cstring(PG_GETARG_TEXT_PP(0));
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conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(0));
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if (connname)
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rconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext,
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sizeof(remoteConn));
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/* first check for valid foreign data server */
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connstr = get_connect_string(conname_or_str);
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if (connstr == NULL)
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connstr = conname_or_str;
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/* check password in connection string if not superuser */
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dblink_connstr_check(connstr);
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conn = PQconnectdb(connstr);
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@ -2353,3 +2366,86 @@ dblink_res_error(const char *conname, PGresult *res, const char *dblink_context_
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errcontext("Error occurred on dblink connection named \"%s\": %s.",
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dblink_context_conname, dblink_context_msg)));
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}
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/*
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* Obtain connection string for a foreign server
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*/
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static char *
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get_connect_string(const char *servername)
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{
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ForeignServer *foreign_server = NULL;
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UserMapping *user_mapping;
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ListCell *cell;
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StringInfo buf = makeStringInfo();
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ForeignDataWrapper *fdw;
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AclResult aclresult;
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/* first gather the server connstr options */
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if (strlen(servername) < NAMEDATALEN)
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foreign_server = GetForeignServerByName(servername, true);
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if (foreign_server)
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{
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Oid serverid = foreign_server->serverid;
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Oid fdwid = foreign_server->fdwid;
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Oid userid = GetUserId();
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user_mapping = GetUserMapping(userid, serverid);
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fdw = GetForeignDataWrapper(fdwid);
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/* Check permissions, user must have usage on the server. */
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aclresult = pg_foreign_server_aclcheck(serverid, userid, ACL_USAGE);
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if (aclresult != ACLCHECK_OK)
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aclcheck_error(aclresult, ACL_KIND_FOREIGN_SERVER, foreign_server->servername);
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foreach (cell, fdw->options)
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{
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DefElem *def = lfirst(cell);
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appendStringInfo(buf, "%s='%s' ", def->defname,
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escape_param_str(strVal(def->arg)));
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}
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foreach (cell, foreign_server->options)
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{
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DefElem *def = lfirst(cell);
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appendStringInfo(buf, "%s='%s' ", def->defname,
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escape_param_str(strVal(def->arg)));
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}
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foreach (cell, user_mapping->options)
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{
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DefElem *def = lfirst(cell);
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appendStringInfo(buf, "%s='%s' ", def->defname,
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escape_param_str(strVal(def->arg)));
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}
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return buf->data;
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}
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else
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return NULL;
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}
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/*
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* Escaping libpq connect parameter strings.
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*
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* Replaces "'" with "\'" and "\" with "\\".
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*/
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static char *
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escape_param_str(const char *str)
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{
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const char *cp;
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StringInfo buf = makeStringInfo();
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for (cp = str; *cp; cp++)
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{
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if (*cp == '\\' || *cp == '\'')
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appendStringInfoChar(buf, '\\');
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appendStringInfoChar(buf, *cp);
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}
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return buf->data;
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}
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@ -784,3 +784,46 @@ SELECT dblink_disconnect('dtest1');
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OK
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(1 row)
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-- test foreign data wrapper functionality
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CREATE USER dblink_regression_test;
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CREATE FOREIGN DATA WRAPPER postgresql;
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CREATE SERVER fdtest FOREIGN DATA WRAPPER postgresql OPTIONS (dbname 'contrib_regression');
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CREATE USER MAPPING FOR public SERVER fdtest;
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GRANT USAGE ON FOREIGN SERVER fdtest TO dblink_regression_test;
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GRANT EXECUTE ON FUNCTION dblink_connect_u(text, text) TO dblink_regression_test;
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\set ORIGINAL_USER :USER
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\c - dblink_regression_test
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-- should fail
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SELECT dblink_connect('myconn', 'fdtest');
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ERROR: password is required
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DETAIL: Non-superusers must provide a password in the connection string.
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-- should succeed
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SELECT dblink_connect_u('myconn', 'fdtest');
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dblink_connect_u
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------------------
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OK
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(1 row)
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SELECT * FROM dblink('myconn','SELECT * FROM foo') AS t(a int, b text, c text[]);
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a | b | c
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----+---+---------------
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0 | a | {a0,b0,c0}
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1 | b | {a1,b1,c1}
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2 | c | {a2,b2,c2}
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3 | d | {a3,b3,c3}
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4 | e | {a4,b4,c4}
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5 | f | {a5,b5,c5}
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6 | g | {a6,b6,c6}
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7 | h | {a7,b7,c7}
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8 | i | {a8,b8,c8}
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9 | j | {a9,b9,c9}
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10 | k | {a10,b10,c10}
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(11 rows)
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\c - :ORIGINAL_USER
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REVOKE USAGE ON FOREIGN SERVER fdtest FROM dblink_regression_test;
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REVOKE EXECUTE ON FUNCTION dblink_connect_u(text, text) FROM dblink_regression_test;
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DROP USER dblink_regression_test;
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DROP USER MAPPING FOR public SERVER fdtest;
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DROP SERVER fdtest;
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DROP FOREIGN DATA WRAPPER postgresql;
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@ -364,3 +364,28 @@ SELECT * from
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SELECT dblink_cancel_query('dtest1');
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SELECT dblink_error_message('dtest1');
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SELECT dblink_disconnect('dtest1');
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-- test foreign data wrapper functionality
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CREATE USER dblink_regression_test;
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CREATE FOREIGN DATA WRAPPER postgresql;
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CREATE SERVER fdtest FOREIGN DATA WRAPPER postgresql OPTIONS (dbname 'contrib_regression');
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CREATE USER MAPPING FOR public SERVER fdtest;
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GRANT USAGE ON FOREIGN SERVER fdtest TO dblink_regression_test;
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GRANT EXECUTE ON FUNCTION dblink_connect_u(text, text) TO dblink_regression_test;
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\set ORIGINAL_USER :USER
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\c - dblink_regression_test
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-- should fail
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SELECT dblink_connect('myconn', 'fdtest');
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-- should succeed
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SELECT dblink_connect_u('myconn', 'fdtest');
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SELECT * FROM dblink('myconn','SELECT * FROM foo') AS t(a int, b text, c text[]);
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\c - :ORIGINAL_USER
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REVOKE USAGE ON FOREIGN SERVER fdtest FROM dblink_regression_test;
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REVOKE EXECUTE ON FUNCTION dblink_connect_u(text, text) FROM dblink_regression_test;
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DROP USER dblink_regression_test;
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DROP USER MAPPING FOR public SERVER fdtest;
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DROP SERVER fdtest;
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DROP FOREIGN DATA WRAPPER postgresql;
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@ -1,4 +1,4 @@
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<!-- $PostgreSQL: pgsql/doc/src/sgml/dblink.sgml,v 1.6 2008/11/12 15:52:44 petere Exp $ -->
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<!-- $PostgreSQL: pgsql/doc/src/sgml/dblink.sgml,v 1.7 2009/06/06 21:27:56 joe Exp $ -->
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<sect1 id="dblink">
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<title>dblink</title>
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@ -42,6 +42,18 @@
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only one unnamed connection is permitted at a time. The connection
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will persist until closed or until the database session is ended.
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</para>
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<para>
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The connection string may also be the name of an existing foreign
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server that utilizes the postgresql_fdw foreign data wrapper library.
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See the example below, as well as the following:
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<simplelist type="inline">
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<member><xref linkend="sql-createforeigndatawrapper" endterm="sql-createforeigndatawrapper-title"></member>
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<member><xref linkend="sql-createserver" endterm="sql-createserver-title"></member>
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<member><xref linkend="sql-createusermapping" endterm="sql-createusermapping-title"></member>
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</simplelist>
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</para>
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</refsect1>
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<refsect1>
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@ -113,6 +125,53 @@
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----------------
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OK
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(1 row)
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-- FOREIGN DATA WRAPPER functionality
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-- Note: local connection must require password authentication for this to work properly
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-- Otherwise, you will receive the following error from dblink_connect():
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-- ----------------------------------------------------------------------
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-- ERROR: password is required
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-- DETAIL: Non-superuser cannot connect if the server does not request a password.
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-- HINT: Target server's authentication method must be changed.
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CREATE USER dblink_regression_test WITH PASSWORD 'secret';
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CREATE FOREIGN DATA WRAPPER postgresql;
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CREATE SERVER fdtest FOREIGN DATA WRAPPER postgresql OPTIONS (hostaddr '127.0.0.1', dbname 'contrib_regression');
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CREATE USER MAPPING FOR dblink_regression_test SERVER fdtest OPTIONS (user 'dblink_regression_test', password 'secret');
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GRANT USAGE ON FOREIGN SERVER fdtest TO dblink_regression_test;
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GRANT SELECT ON TABLE foo TO dblink_regression_test;
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\set ORIGINAL_USER :USER
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\c - dblink_regression_test
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SELECT dblink_connect('myconn', 'fdtest');
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dblink_connect
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----------------
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OK
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(1 row)
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SELECT * FROM dblink('myconn','SELECT * FROM foo') AS t(a int, b text, c text[]);
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a | b | c
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----+---+---------------
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0 | a | {a0,b0,c0}
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1 | b | {a1,b1,c1}
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2 | c | {a2,b2,c2}
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3 | d | {a3,b3,c3}
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4 | e | {a4,b4,c4}
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5 | f | {a5,b5,c5}
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6 | g | {a6,b6,c6}
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7 | h | {a7,b7,c7}
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8 | i | {a8,b8,c8}
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9 | j | {a9,b9,c9}
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10 | k | {a10,b10,c10}
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(11 rows)
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\c - :ORIGINAL_USER
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REVOKE USAGE ON FOREIGN SERVER fdtest FROM dblink_regression_test;
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REVOKE SELECT ON TABLE foo FROM dblink_regression_test;
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DROP USER MAPPING FOR dblink_regression_test SERVER fdtest;
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DROP USER dblink_regression_test;
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DROP SERVER fdtest;
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DROP FOREIGN DATA WRAPPER postgresql;
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</programlisting>
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</refsect1>
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</refentry>
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