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openGauss-server/contrib/dblink/dblink.cpp

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/*
* dblink.c
*
* Functions returning results from a remote database
*
* Joe Conway <mail@joeconway.com>
* And contributors:
* Darko Prenosil <Darko.Prenosil@finteh.hr>
* Shridhar Daithankar <shridhar_daithankar@persistent.co.in>
*
* contrib/dblink/dblink.c
* Copyright (c) 2001-2012, PostgreSQL Global Development Group
* ALL RIGHTS RESERVED;
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without a written agreement
* is hereby granted, provided that the above copyright notice and this
* paragraph and the following two paragraphs appear in all copies.
*
* IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
* LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
* DOCUMENTATION, EVEN IF THE AUTHOR OR DISTRIBUTORS HAVE BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* THE AUTHOR AND DISTRIBUTORS SPECIFICALLY DISCLAIMS ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAS NO OBLIGATIONS TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
*/
#include "postgres.h"
#include "knl/knl_variable.h"
#include <limits.h>
#include "libpq-fe.h"
#include "funcapi.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/pg_type.h"
#include "catalog/heap.h"
#include "executor/spi.h"
#include "foreign/foreign.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "parser/scansup.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/rel_gs.h"
#include "access/heapam.h"
#include "dblink.h"
PG_MODULE_MAGIC;
typedef struct remoteConn {
PGconn* conn; /* Hold the remote connection */
int openCursorCount; /* The number of open cursors */
bool newXactForCursor; /* Opened a transaction for a cursor */
} remoteConn;
typedef struct storeInfo {
FunctionCallInfo fcinfo;
Tuplestorestate* tuplestore;
AttInMetadata* attinmeta;
MemoryContext tmpcontext;
char** cstrs;
/* temp storage for results to avoid leaks on exception */
PGresult* last_res;
PGresult* cur_res;
} storeInfo;
/*
* Internal declarations
*/
static Datum dblink_record_internal(FunctionCallInfo fcinfo, bool is_async);
static void prepTuplestoreResult(FunctionCallInfo fcinfo);
static void materializeResult(FunctionCallInfo fcinfo, PGconn* conn, PGresult* res);
static void materializeQueryResult(
FunctionCallInfo fcinfo, PGconn* conn, const char* conname, const char* sql, bool fail);
static PGresult* storeQueryResult(storeInfo* sinfo, PGconn* conn, const char* sql);
static void storeRow(storeInfo* sinfo, PGresult* res, bool first);
static remoteConn* getConnectionByName(const char* name);
static HTAB* createConnHash(void);
static void createNewConnection(const char* name, remoteConn* rconn);
static void deleteConnection(const char* name);
static char** get_pkey_attnames(Relation rel, int16* indnkeyatts);
static char** get_text_array_contents(ArrayType* array, int* numitems);
static char* get_sql_insert(Relation rel, int* pkattnums, int pknumatts, char** src_pkattvals, char** tgt_pkattvals);
static char* get_sql_delete(Relation rel, int* pkattnums, int pknumatts, char** tgt_pkattvals);
static char* get_sql_update(Relation rel, int* pkattnums, int pknumatts, char** src_pkattvals, char** tgt_pkattvals);
static char* quote_ident_cstr(char* rawstr);
static int get_attnum_pk_pos(int* pkattnums, int pknumatts, int key);
static HeapTuple get_tuple_of_interest(Relation rel, int* pkattnums, int pknumatts, char** src_pkattvals);
static Relation get_rel_from_relname(text* relname_text, LOCKMODE lockmode, AclMode aclmode);
static char* generate_relation_name(Relation rel);
static void dblink_connstr_check(const char* connstr);
static void dblink_security_check(PGconn* conn, remoteConn* rconn);
static void dblink_res_error(const char* conname, PGresult* res, const char* dblink_context_msg, bool fail);
static char* get_connect_string(const char* servername);
static char* escape_param_str(const char* from);
static void validate_pkattnums(
Relation rel, int2vector* pkattnums_arg, int32 pknumatts_arg, int** pkattnums, int* pknumatts);
static int applyRemoteGucs(PGconn* conn);
static void restoreLocalGucs(int nestlevel);
/* Global */
static remoteConn* pconn = NULL;
static HTAB* remoteConnHash = NULL;
/*
* Following is list that holds multiple remote connections.
* Calling convention of each dblink function changes to accept
* connection name as the first parameter. The connection list is
* much like ecpg e.g. a mapping between a name and a PGconn object.
*/
typedef struct remoteConnHashEnt {
char name[NAMEDATALEN];
remoteConn* rconn;
} remoteConnHashEnt;
/* initial number of connection hashes */
#define NUMCONN 16
/* general utility */
#define xpfree(var_) \
do { \
if (var_ != NULL) { \
pfree(var_); \
var_ = NULL; \
} \
} while (0)
#define xpstrdup(var_c, var_) \
do { \
if (var_ != NULL) \
var_c = pstrdup(var_); \
else \
var_c = NULL; \
} while (0)
#define DBLINK_RES_INTERNALERROR(p2) \
do { \
msg = pstrdup(PQerrorMessage(conn)); \
if (res) \
PQclear(res); \
elog(ERROR, "%s: %s", p2, msg); \
} while (0)
#define DBLINK_CONN_NOT_AVAIL \
do { \
if (conname) \
ereport(ERROR, \
(errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST), errmsg("connection \"%s\" not available", conname))); \
else \
ereport(ERROR, (errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST), errmsg("connection not available"))); \
} while (0)
#define DBLINK_GET_CONN \
do { \
char* conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(0)); \
rconn = getConnectionByName(conname_or_str); \
if (rconn) { \
conn = rconn->conn; \
conname = conname_or_str; \
} else { \
connstr = get_connect_string(conname_or_str); \
if (connstr == NULL) { \
connstr = conname_or_str; \
} \
dblink_connstr_check(connstr); \
conn = PQconnectdb(connstr); \
if (PQstatus(conn) == CONNECTION_BAD) { \
msg = pstrdup(PQerrorMessage(conn)); \
PQfinish(conn); \
ereport(ERROR, \
(errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION), \
errmsg("could not establish connection"), \
errdetail_internal("%s", msg))); \
} \
dblink_security_check(conn, rconn); \
PQsetClientEncoding(conn, GetDatabaseEncodingName()); \
freeconn = true; \
} \
} while (0)
#define DBLINK_GET_NAMED_CONN \
do { \
conname = text_to_cstring(PG_GETARG_TEXT_PP(0)); \
rconn = getConnectionByName(conname); \
if (rconn) \
conn = rconn->conn; \
else \
DBLINK_CONN_NOT_AVAIL; \
} while (0)
#define DBLINK_INIT \
do { \
if (!pconn) { \
pconn = (remoteConn*)MemoryContextAlloc( \
THREAD_GET_MEM_CXT_GROUP(MEMORY_CONTEXT_COMMUNICATION), sizeof(remoteConn)); \
pconn->conn = NULL; \
pconn->openCursorCount = 0; \
pconn->newXactForCursor = FALSE; \
} \
} while (0)
/*
* Create a persistent connection to another database
*/
PG_FUNCTION_INFO_V1(dblink_connect);
Datum dblink_connect(PG_FUNCTION_ARGS)
{
char* conname_or_str = NULL;
char* connstr = NULL;
char* connname = NULL;
char* msg = NULL;
PGconn* conn = NULL;
remoteConn* rconn = NULL;
DBLINK_INIT;
if (PG_NARGS() == 2) {
conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(1));
connname = text_to_cstring(PG_GETARG_TEXT_PP(0));
} else if (PG_NARGS() == 1)
conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(0));
if (connname)
rconn = (remoteConn*)MemoryContextAlloc(
THREAD_GET_MEM_CXT_GROUP(MEMORY_CONTEXT_COMMUNICATION), sizeof(remoteConn));
/* first check for valid foreign data server */
connstr = get_connect_string(conname_or_str);
if (connstr == NULL)
connstr = conname_or_str;
/* check password in connection string if not superuser */
dblink_connstr_check(connstr);
conn = PQconnectdb(connstr);
if (PQstatus(conn) == CONNECTION_BAD) {
msg = pstrdup(PQerrorMessage(conn));
PQfinish(conn);
if (rconn)
pfree(rconn);
ereport(ERROR,
(errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
errmsg("could not establish connection"),
errdetail_internal("%s", msg)));
}
/* check password actually used if not superuser */
dblink_security_check(conn, rconn);
/* attempt to set client encoding to match server encoding */
PQsetClientEncoding(conn, GetDatabaseEncodingName());
if (connname) {
rconn->conn = conn;
createNewConnection(connname, rconn);
} else
pconn->conn = conn;
PG_RETURN_TEXT_P(cstring_to_text("OK"));
}
/*
* Clear a persistent connection to another database
*/
PG_FUNCTION_INFO_V1(dblink_disconnect);
Datum dblink_disconnect(PG_FUNCTION_ARGS)
{
char* conname = NULL;
remoteConn* rconn = NULL;
PGconn* conn = NULL;
DBLINK_INIT;
if (PG_NARGS() == 1) {
conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
rconn = getConnectionByName(conname);
if (rconn)
conn = rconn->conn;
} else
conn = pconn->conn;
if (!conn)
DBLINK_CONN_NOT_AVAIL;
PQfinish(conn);
if (rconn) {
deleteConnection(conname);
pfree(rconn);
} else
pconn->conn = NULL;
PG_RETURN_TEXT_P(cstring_to_text("OK"));
}
/*
* opens a cursor using a persistent connection
*/
PG_FUNCTION_INFO_V1(dblink_open);
Datum dblink_open(PG_FUNCTION_ARGS)
{
char* msg = NULL;
PGresult* res = NULL;
PGconn* conn = NULL;
char* curname = NULL;
char* sql = NULL;
char* conname = NULL;
StringInfoData buf;
remoteConn* rconn = NULL;
bool fail = true; /* default to backward compatible behavior */
DBLINK_INIT;
initStringInfo(&buf);
if (PG_NARGS() == 2) {
/* text,text */
curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
rconn = pconn;
} else if (PG_NARGS() == 3) {
/* might be text,text,text or text,text,bool */
if (get_fn_expr_argtype(fcinfo->flinfo, 2) == BOOLOID) {
curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
fail = PG_GETARG_BOOL(2);
rconn = pconn;
} else {
conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
sql = text_to_cstring(PG_GETARG_TEXT_PP(2));
rconn = getConnectionByName(conname);
}
} else if (PG_NARGS() == 4) {
/* text,text,text,bool */
conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
sql = text_to_cstring(PG_GETARG_TEXT_PP(2));
fail = PG_GETARG_BOOL(3);
rconn = getConnectionByName(conname);
}
if (!rconn || !rconn->conn)
DBLINK_CONN_NOT_AVAIL;
else
conn = rconn->conn;
/* If we are not in a transaction, start one */
if (PQtransactionStatus(conn) == PQTRANS_IDLE) {
res = PQexec(conn, "START TRANSACTION");
if (PQresultStatus(res) != PGRES_COMMAND_OK)
DBLINK_RES_INTERNALERROR("begin error");
PQclear(res);
rconn->newXactForCursor = TRUE;
/*
* Since transaction state was IDLE, we force cursor count to
* initially be 0. This is needed as a previous ABORT might have wiped
* out our transaction without maintaining the cursor count for us.
*/
rconn->openCursorCount = 0;
}
/* if we started a transaction, increment cursor count */
if (rconn->newXactForCursor)
(rconn->openCursorCount)++;
appendStringInfo(&buf, "DECLARE %s CURSOR FOR %s", curname, sql);
res = PQexec(conn, buf.data);
if (!res || PQresultStatus(res) != PGRES_COMMAND_OK) {
dblink_res_error(conname, res, "could not open cursor", fail);
PG_RETURN_TEXT_P(cstring_to_text("ERROR"));
}
PQclear(res);
PG_RETURN_TEXT_P(cstring_to_text("OK"));
}
/*
* closes a cursor
*/
PG_FUNCTION_INFO_V1(dblink_close);
Datum dblink_close(PG_FUNCTION_ARGS)
{
PGconn* conn = NULL;
PGresult* res = NULL;
char* curname = NULL;
char* conname = NULL;
StringInfoData buf;
char* msg = NULL;
remoteConn* rconn = NULL;
bool fail = true; /* default to backward compatible behavior */
DBLINK_INIT;
initStringInfo(&buf);
if (PG_NARGS() == 1) {
/* text */
curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
rconn = pconn;
} else if (PG_NARGS() == 2) {
/* might be text,text or text,bool */
if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID) {
curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
fail = PG_GETARG_BOOL(1);
rconn = pconn;
} else {
conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
rconn = getConnectionByName(conname);
}
}
if (PG_NARGS() == 3) {
/* text,text,bool */
conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
fail = PG_GETARG_BOOL(2);
rconn = getConnectionByName(conname);
}
if (!rconn || !rconn->conn)
DBLINK_CONN_NOT_AVAIL;
else
conn = rconn->conn;
appendStringInfo(&buf, "CLOSE %s", curname);
/* close the cursor */
res = PQexec(conn, buf.data);
if (!res || PQresultStatus(res) != PGRES_COMMAND_OK) {
dblink_res_error(conname, res, "could not close cursor", fail);
PG_RETURN_TEXT_P(cstring_to_text("ERROR"));
}
PQclear(res);
/* if we started a transaction, decrement cursor count */
if (rconn->newXactForCursor) {
(rconn->openCursorCount)--;
/* if count is zero, commit the transaction */
if (rconn->openCursorCount == 0) {
rconn->newXactForCursor = FALSE;
res = PQexec(conn, "COMMIT");
if (PQresultStatus(res) != PGRES_COMMAND_OK)
DBLINK_RES_INTERNALERROR("commit error");
PQclear(res);
}
}
PG_RETURN_TEXT_P(cstring_to_text("OK"));
}
/*
* Fetch results from an open cursor
*/
PG_FUNCTION_INFO_V1(dblink_fetch);
Datum dblink_fetch(PG_FUNCTION_ARGS)
{
PGresult* res = NULL;
char* conname = NULL;
remoteConn* rconn = NULL;
PGconn* conn = NULL;
StringInfoData buf;
char* curname = NULL;
int howmany = 0;
bool fail = true; /* default to backward compatible */
prepTuplestoreResult(fcinfo);
DBLINK_INIT;
if (PG_NARGS() == 4) {
/* text,text,int,bool */
conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
howmany = PG_GETARG_INT32(2);
fail = PG_GETARG_BOOL(3);
rconn = getConnectionByName(conname);
if (rconn)
conn = rconn->conn;
} else if (PG_NARGS() == 3) {
/* text,text,int or text,int,bool */
if (get_fn_expr_argtype(fcinfo->flinfo, 2) == BOOLOID) {
curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
howmany = PG_GETARG_INT32(1);
fail = PG_GETARG_BOOL(2);
conn = pconn->conn;
} else {
conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
howmany = PG_GETARG_INT32(2);
rconn = getConnectionByName(conname);
if (rconn)
conn = rconn->conn;
}
} else if (PG_NARGS() == 2) {
/* text,int */
curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
howmany = PG_GETARG_INT32(1);
conn = pconn->conn;
}
if (!conn)
DBLINK_CONN_NOT_AVAIL;
initStringInfo(&buf);
appendStringInfo(&buf, "FETCH %d FROM %s", howmany, curname);
/*
* Try to execute the query. Note that since libpq uses malloc, the
* PGresult will be long-lived even though we are still in a short-lived
* memory context.
*/
res = PQexec(conn, buf.data);
if (!res || (PQresultStatus(res) != PGRES_COMMAND_OK && PQresultStatus(res) != PGRES_TUPLES_OK)) {
dblink_res_error(conname, res, "could not fetch from cursor", fail);
return (Datum)0;
} else if (PQresultStatus(res) == PGRES_COMMAND_OK) {
/* cursor does not exist - closed already or bad name */
PQclear(res);
ereport(ERROR, (errcode(ERRCODE_INVALID_CURSOR_NAME), errmsg("cursor \"%s\" does not exist", curname)));
}
materializeResult(fcinfo, conn, res);
return (Datum)0;
}
/*
* Note: this is the new preferred version of dblink
*/
PG_FUNCTION_INFO_V1(dblink_record);
Datum dblink_record(PG_FUNCTION_ARGS)
{
return dblink_record_internal(fcinfo, false);
}
PG_FUNCTION_INFO_V1(dblink_send_query);
Datum dblink_send_query(PG_FUNCTION_ARGS)
{
char* conname = NULL;
PGconn* conn = NULL;
char* sql = NULL;
remoteConn* rconn = NULL;
int retval;
if (PG_NARGS() == 2) {
DBLINK_GET_NAMED_CONN;
sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
} else
/* shouldn't happen */
elog(ERROR, "wrong number of arguments");
/* async query send */
retval = PQsendQuery(conn, sql);
if (retval != 1)
elog(NOTICE, "could not send query: %s", PQerrorMessage(conn));
PG_RETURN_INT32(retval);
}
PG_FUNCTION_INFO_V1(dblink_get_result);
Datum dblink_get_result(PG_FUNCTION_ARGS)
{
return dblink_record_internal(fcinfo, true);
}
static Datum dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
{
PGconn* volatile conn = NULL;
volatile bool freeconn = false;
prepTuplestoreResult(fcinfo);
DBLINK_INIT;
PG_TRY();
{
char* msg = NULL;
char* connstr = NULL;
char* sql = NULL;
char* conname = NULL;
remoteConn* rconn = NULL;
bool fail = true; /* default to backward compatible */
bool is_three = !is_async && PG_NARGS() == 3;
bool is_two = !is_async && PG_NARGS() == 2;
bool is_one = !is_async && PG_NARGS() == 1;
if (is_three) {
/* text,text,bool */
DBLINK_GET_CONN;
sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
fail = PG_GETARG_BOOL(2);
} else if (is_two) {
/* text,text or text,bool */
if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID) {
conn = pconn->conn;
sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
fail = PG_GETARG_BOOL(1);
} else {
DBLINK_GET_CONN;
sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
}
} else if (is_one) {
/* text */
conn = pconn->conn;
sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
} else if (!is_async) {
/* shouldn't happen */
elog(ERROR, "wrong number of arguments");
} /* is_async */
/* get async result */
else if (PG_NARGS() == 2) {
/* text,bool */
DBLINK_GET_NAMED_CONN;
fail = PG_GETARG_BOOL(1);
} else if (PG_NARGS() == 1) {
/* text */
DBLINK_GET_NAMED_CONN;
} else {
/* shouldn't happen */
elog(ERROR, "wrong number of arguments");
}
if (!conn)
DBLINK_CONN_NOT_AVAIL;
if (!is_async) {
/* synchronous query, use efficient tuple collection method */
materializeQueryResult(fcinfo, conn, conname, sql, fail);
} else {
/* async result retrieval, do it the old way */
PGresult* res = PQgetResult(conn);
/* NULL means we're all done with the async results */
if (res) {
if (PQresultStatus(res) != PGRES_COMMAND_OK && PQresultStatus(res) != PGRES_TUPLES_OK) {
dblink_res_error(conname, res, "could not execute query", fail);
/* if fail isn't set, we'll return an empty query result */
} else {
materializeResult(fcinfo, conn, res);
}
}
}
}
PG_CATCH();
{
/* if needed, close the connection to the database */
if (freeconn)
PQfinish(conn);
PG_RE_THROW();
}
PG_END_TRY();
/* if needed, close the connection to the database */
if (freeconn)
PQfinish(conn);
return (Datum)0;
}
/*
* Verify function caller can handle a tuplestore result, and set up for that.
*
* Note: if the caller returns without actually creating a tuplestore, the
* executor will treat the function result as an empty set.
*/
static void prepTuplestoreResult(FunctionCallInfo fcinfo)
{
ReturnSetInfo* rsinfo = (ReturnSetInfo*)fcinfo->resultinfo;
/* check to see if query supports us returning a tuplestore */
if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
if (!(rsinfo->allowedModes & SFRM_Materialize))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("materialize mode required, but it is not allowed in this context")));
/* let the executor know we're sending back a tuplestore */
rsinfo->returnMode = SFRM_Materialize;
/* caller must fill these to return a non-empty result */
rsinfo->setResult = NULL;
rsinfo->setDesc = NULL;
}
/*
* Copy the contents of the PGresult into a tuplestore to be returned
* as the result of the current function.
* The PGresult will be released in this function.
*/
static void materializeResult(FunctionCallInfo fcinfo, PGconn* conn, PGresult* res)
{
ReturnSetInfo* rsinfo = (ReturnSetInfo*)fcinfo->resultinfo;
/* prepTuplestoreResult must have been called previously */
Assert(rsinfo->returnMode == SFRM_Materialize);
PG_TRY();
{
TupleDesc tupdesc;
bool is_sql_cmd = false;
int ntuples;
int nfields;
if (PQresultStatus(res) == PGRES_COMMAND_OK) {
is_sql_cmd = true;
/*
* need a tuple descriptor representing one TEXT column to return
* the command status string as our result tuple
*/
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc, (AttrNumber)1, "status", TEXTOID, -1, 0);
ntuples = 1;
nfields = 1;
} else {
Assert(PQresultStatus(res) == PGRES_TUPLES_OK);
is_sql_cmd = false;
/* get a tuple descriptor for our result type */
switch (get_call_result_type(fcinfo, NULL, &tupdesc)) {
case TYPEFUNC_COMPOSITE:
/* success */
break;
case TYPEFUNC_RECORD:
/* failed to determine actual type of RECORD */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning record called in context "
"that cannot accept type record")));
break;
default:
/* result type isn't composite */
elog(ERROR, "return type must be a row type");
break;
}
/* make sure we have a persistent copy of the tupdesc */
tupdesc = CreateTupleDescCopy(tupdesc);
ntuples = PQntuples(res);
nfields = PQnfields(res);
}
/*
* check result and tuple descriptor have the same number of columns
*/
if (nfields != tupdesc->natts)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("remote query result rowtype does not match "
"the specified FROM clause rowtype")));
if (ntuples > 0) {
AttInMetadata* attinmeta = NULL;
int nestlevel = -1;
Tuplestorestate* tupstore = NULL;
MemoryContext oldcontext;
int row;
char** values;
attinmeta = TupleDescGetAttInMetadata(tupdesc);
/* Set GUCs to ensure we read GUC-sensitive data types correctly */
if (!is_sql_cmd)
nestlevel = applyRemoteGucs(conn);
oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
tupstore = tuplestore_begin_heap(true, false, u_sess->attr.attr_memory.work_mem);
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
values = (char**)palloc(nfields * sizeof(char*));
/* put all tuples into the tuplestore */
for (row = 0; row < ntuples; row++) {
HeapTuple tuple;
if (!is_sql_cmd) {
int i;
for (i = 0; i < nfields; i++) {
if (PQgetisnull(res, row, i))
values[i] = NULL;
else
values[i] = PQgetvalue(res, row, i);
}
} else {
values[0] = PQcmdStatus(res);
}
/* build the tuple and put it into the tuplestore. */
tuple = BuildTupleFromCStrings(attinmeta, values);
tuplestore_puttuple(tupstore, tuple);
}
/* clean up GUC settings, if we changed any */
restoreLocalGucs(nestlevel);
/* clean up and return the tuplestore */
tuplestore_donestoring(tupstore);
}
PQclear(res);
}
PG_CATCH();
{
/* be sure to release the libpq result */
PQclear(res);
PG_RE_THROW();
}
PG_END_TRY();
}
/*
* Execute the given SQL command and store its results into a tuplestore
* to be returned as the result of the current function.
*
* This is equivalent to PQexec followed by materializeResult, but we make
* use of libpq's single-row mode to avoid accumulating the whole result
* inside libpq before it gets transferred to the tuplestore.
*/
static void materializeQueryResult(
FunctionCallInfo fcinfo, PGconn* conn, const char* conname, const char* sql, bool fail)
{
ReturnSetInfo* rsinfo = (ReturnSetInfo*)fcinfo->resultinfo;
PGresult* volatile res = NULL;
storeInfo sinfo;
/* prepTuplestoreResult must have been called previously */
Assert(rsinfo->returnMode == SFRM_Materialize);
/* initialize storeInfo to empty */
(void)memset_s(&sinfo, sizeof(sinfo), 0, sizeof(sinfo));
sinfo.fcinfo = fcinfo;
PG_TRY();
{
/* execute query, collecting any tuples into the tuplestore */
res = storeQueryResult(&sinfo, conn, sql);
if (!res || (PQresultStatus(res) != PGRES_COMMAND_OK && PQresultStatus(res) != PGRES_TUPLES_OK)) {
/*
* dblink_res_error will clear the passed PGresult, so we need
* this ugly dance to avoid doing so twice during error exit
*/
PGresult* res1 = res;
res = NULL;
dblink_res_error(conname, res1, "could not execute query", fail);
/* if fail isn't set, we'll return an empty query result */
} else if (PQresultStatus(res) == PGRES_COMMAND_OK) {
/*
* storeRow didn't get called, so we need to convert the command
* status string to a tuple manually
*/
TupleDesc tupdesc;
AttInMetadata* attinmeta = NULL;
Tuplestorestate* tupstore = NULL;
HeapTuple tuple;
char* values[1];
MemoryContext oldcontext;
/*
* need a tuple descriptor representing one TEXT column to return
* the command status string as our result tuple
*/
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc, (AttrNumber)1, "status", TEXTOID, -1, 0);
attinmeta = TupleDescGetAttInMetadata(tupdesc);
oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
tupstore = tuplestore_begin_heap(true, false, u_sess->attr.attr_memory.work_mem);
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
values[0] = PQcmdStatus(res);
/* build the tuple and put it into the tuplestore. */
tuple = BuildTupleFromCStrings(attinmeta, values);
tuplestore_puttuple(tupstore, tuple);
PQclear(res);
res = NULL;
} else {
Assert(PQresultStatus(res) == PGRES_TUPLES_OK);
/* storeRow should have created a tuplestore */
Assert(rsinfo->setResult != NULL);
PQclear(res);
res = NULL;
}
PQclear(sinfo.last_res);
sinfo.last_res = NULL;
PQclear(sinfo.cur_res);
sinfo.cur_res = NULL;
}
PG_CATCH();
{
/* be sure to release any libpq result we collected */
PQclear(res);
PQclear(sinfo.last_res);
PQclear(sinfo.cur_res);
/* and clear out any pending data in libpq */
while ((res = PQgetResult(conn)) != NULL)
PQclear(res);
PG_RE_THROW();
}
PG_END_TRY();
}
/*
* Execute query, and send any result rows to sinfo->tuplestore.
*/
static PGresult* storeQueryResult(storeInfo* sinfo, PGconn* conn, const char* sql)
{
bool first = true;
int nestlevel = -1;
PGresult* res = NULL;
if (!PQsendQuery(conn, sql))
elog(ERROR, "could not send query: %s", PQerrorMessage(conn));
if (!PQsetSingleRowMode(conn)) /* shouldn't fail */
elog(ERROR, "failed to set single-row mode for dblink query");
for (;;) {
CHECK_FOR_INTERRUPTS();
sinfo->cur_res = PQgetResult(conn);
if (!sinfo->cur_res)
break;
if (PQresultStatus(sinfo->cur_res) == PGRES_SINGLE_TUPLE) {
/* got one row from possibly-bigger resultset */
/*
* Set GUCs to ensure we read GUC-sensitive data types correctly.
* We shouldn't do this until we have a row in hand, to ensure
* libpq has seen any earlier ParameterStatus protocol messages.
*/
if (first && nestlevel < 0)
nestlevel = applyRemoteGucs(conn);
storeRow(sinfo, sinfo->cur_res, first);
PQclear(sinfo->cur_res);
sinfo->cur_res = NULL;
first = false;
} else {
/* if empty resultset, fill tuplestore header */
if (first && PQresultStatus(sinfo->cur_res) == PGRES_TUPLES_OK)
storeRow(sinfo, sinfo->cur_res, first);
/* store completed result at last_res */
PQclear(sinfo->last_res);
sinfo->last_res = sinfo->cur_res;
sinfo->cur_res = NULL;
first = true;
}
}
/* clean up GUC settings, if we changed any */
restoreLocalGucs(nestlevel);
/* return last_res */
res = sinfo->last_res;
sinfo->last_res = NULL;
return res;
}
/*
* Send single row to sinfo->tuplestore.
*
* If "first" is true, create the tuplestore using PGresult's metadata
* (in this case the PGresult might contain either zero or one row).
*/
static void storeRow(storeInfo* sinfo, PGresult* res, bool first)
{
int nfields = PQnfields(res);
HeapTuple tuple;
int i;
MemoryContext oldcontext;
if (first) {
/* Prepare for new result set */
ReturnSetInfo* rsinfo = (ReturnSetInfo*)sinfo->fcinfo->resultinfo;
TupleDesc tupdesc;
/*
* It's possible to get more than one result set if the query string
* contained multiple SQL commands. In that case, we follow PQexec's
* traditional behavior of throwing away all but the last result.
*/
if (sinfo->tuplestore)
tuplestore_end(sinfo->tuplestore);
sinfo->tuplestore = NULL;
/* get a tuple descriptor for our result type */
switch (get_call_result_type(sinfo->fcinfo, NULL, &tupdesc)) {
case TYPEFUNC_COMPOSITE:
/* success */
break;
case TYPEFUNC_RECORD:
/* failed to determine actual type of RECORD */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning record called in context "
"that cannot accept type record")));
break;
default:
/* result type isn't composite */
elog(ERROR, "return type must be a row type");
break;
}
/* make sure we have a persistent copy of the tupdesc */
tupdesc = CreateTupleDescCopy(tupdesc);
/* check result and tuple descriptor have the same number of columns */
if (nfields != tupdesc->natts)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("remote query result rowtype does not match "
"the specified FROM clause rowtype")));
/* Prepare attinmeta for later data conversions */
sinfo->attinmeta = TupleDescGetAttInMetadata(tupdesc);
/* Create a new, empty tuplestore */
oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
sinfo->tuplestore = tuplestore_begin_heap(true, false, u_sess->attr.attr_memory.work_mem);
rsinfo->setResult = sinfo->tuplestore;
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
/* Done if empty resultset */
if (PQntuples(res) == 0)
return;
/*
* Set up sufficiently-wide string pointers array; this won't change
* in size so it's easy to preallocate.
*/
if (sinfo->cstrs)
pfree(sinfo->cstrs);
sinfo->cstrs = (char**)palloc(nfields * sizeof(char*));
/* Create short-lived memory context for data conversions */
if (!sinfo->tmpcontext)
sinfo->tmpcontext = AllocSetContextCreate(CurrentMemoryContext,
"dblink temporary context",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
}
/* Should have a single-row result if we get here */
Assert(PQntuples(res) == 1);
/*
* Do the following work in a temp context that we reset after each tuple.
* This cleans up not only the data we have direct access to, but any
* cruft the I/O functions might leak.
*/
oldcontext = MemoryContextSwitchTo(sinfo->tmpcontext);
/*
* Fill cstrs with null-terminated strings of column values.
*/
for (i = 0; i < nfields; i++) {
if (PQgetisnull(res, 0, i))
sinfo->cstrs[i] = NULL;
else
sinfo->cstrs[i] = PQgetvalue(res, 0, i);
}
/* Convert row to a tuple, and add it to the tuplestore */
tuple = BuildTupleFromCStrings(sinfo->attinmeta, sinfo->cstrs);
tuplestore_puttuple(sinfo->tuplestore, tuple);
/* Clean up */
MemoryContextSwitchTo(oldcontext);
MemoryContextReset(sinfo->tmpcontext);
}
/*
* List all open dblink connections by name.
* Returns an array of all connection names.
* Takes no params
*/
PG_FUNCTION_INFO_V1(dblink_get_connections);
Datum dblink_get_connections(PG_FUNCTION_ARGS)
{
HASH_SEQ_STATUS status;
remoteConnHashEnt* hentry = NULL;
ArrayBuildState* astate = NULL;
if (remoteConnHash) {
hash_seq_init(&status, remoteConnHash);
while ((hentry = (remoteConnHashEnt*)hash_seq_search(&status)) != NULL) {
/* stash away current value */
astate = accumArrayResult(astate, CStringGetTextDatum(hentry->name), false, TEXTOID, CurrentMemoryContext);
}
}
if (astate)
PG_RETURN_ARRAYTYPE_P(makeArrayResult(astate, CurrentMemoryContext));
else
PG_RETURN_NULL();
}
/*
* Checks if a given remote connection is busy
*
* Returns 1 if the connection is busy, 0 otherwise
* Params:
* text connection_name - name of the connection to check
*
*/
PG_FUNCTION_INFO_V1(dblink_is_busy);
Datum dblink_is_busy(PG_FUNCTION_ARGS)
{
char* conname = NULL;
PGconn* conn = NULL;
remoteConn* rconn = NULL;
DBLINK_INIT;
DBLINK_GET_NAMED_CONN;
PQconsumeInput(conn);
PG_RETURN_INT32(PQisBusy(conn));
}
/*
* Cancels a running request on a connection
*
* Returns text:
* "OK" if the cancel request has been sent correctly,
* an error message otherwise
*
* Params:
* text connection_name - name of the connection to check
*
*/
PG_FUNCTION_INFO_V1(dblink_cancel_query);
Datum dblink_cancel_query(PG_FUNCTION_ARGS)
{
int res = 0;
char* conname = NULL;
PGconn* conn = NULL;
remoteConn* rconn = NULL;
PGcancel* cancel = NULL;
char errbuf[256];
DBLINK_INIT;
DBLINK_GET_NAMED_CONN;
cancel = PQgetCancel(conn);
res = PQcancel(cancel, errbuf, 256);
PQfreeCancel(cancel);
if (res == 1)
PG_RETURN_TEXT_P(cstring_to_text("OK"));
else
PG_RETURN_TEXT_P(cstring_to_text(errbuf));
}
/*
* Get error message from a connection
*
* Returns text:
* "OK" if no error, an error message otherwise
*
* Params:
* text connection_name - name of the connection to check
*
*/
PG_FUNCTION_INFO_V1(dblink_error_message);
Datum dblink_error_message(PG_FUNCTION_ARGS)
{
char* msg = NULL;
char* conname = NULL;
PGconn* conn = NULL;
remoteConn* rconn = NULL;
DBLINK_INIT;
DBLINK_GET_NAMED_CONN;
msg = PQerrorMessage(conn);
if (msg == NULL || msg[0] == '\0')
PG_RETURN_TEXT_P(cstring_to_text("OK"));
else
PG_RETURN_TEXT_P(cstring_to_text(msg));
}
/*
* Execute an SQL non-SELECT command
*/
PG_FUNCTION_INFO_V1(dblink_exec);
Datum dblink_exec(PG_FUNCTION_ARGS)
{
text* volatile sql_cmd_status = NULL;
PGconn* volatile conn = NULL;
volatile bool freeconn = false;
DBLINK_INIT;
PG_TRY();
{
char* msg = NULL;
PGresult* res = NULL;
char* connstr = NULL;
char* sql = NULL;
char* conname = NULL;
remoteConn* rconn = NULL;
bool fail = true; /* default to backward compatible behavior */
if (PG_NARGS() == 3) {
/* must be text,text,bool */
DBLINK_GET_CONN;
sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
fail = PG_GETARG_BOOL(2);
} else if (PG_NARGS() == 2) {
/* might be text,text or text,bool */
if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID) {
conn = pconn->conn;
sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
fail = PG_GETARG_BOOL(1);
} else {
DBLINK_GET_CONN;
sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
}
} else if (PG_NARGS() == 1) {
/* must be single text argument */
conn = pconn->conn;
sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
} else
/* shouldn't happen */
elog(ERROR, "wrong number of arguments");
if (!conn)
DBLINK_CONN_NOT_AVAIL;
res = PQexec(conn, sql);
if (!res || (PQresultStatus(res) != PGRES_COMMAND_OK && PQresultStatus(res) != PGRES_TUPLES_OK)) {
dblink_res_error(conname, res, "could not execute command", fail);
/*
* and save a copy of the command status string to return as our
* result tuple
*/
sql_cmd_status = cstring_to_text("ERROR");
} else if (PQresultStatus(res) == PGRES_COMMAND_OK) {
/*
* and save a copy of the command status string to return as our
* result tuple
*/
sql_cmd_status = cstring_to_text(PQcmdStatus(res));
PQclear(res);
} else {
PQclear(res);
ereport(ERROR,
(errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
errmsg("statement returning results not allowed")));
}
}
PG_CATCH();
{
/* if needed, close the connection to the database */
if (freeconn)
PQfinish(conn);
PG_RE_THROW();
}
PG_END_TRY();
/* if needed, close the connection to the database */
if (freeconn)
PQfinish(conn);
PG_RETURN_TEXT_P(sql_cmd_status);
}
/*
* dblink_get_pkey
*
* Return list of primary key fields for the supplied relation,
* or NULL if none exists.
*/
PG_FUNCTION_INFO_V1(dblink_get_pkey);
Datum dblink_get_pkey(PG_FUNCTION_ARGS)
{
int16 indnkeyatts;
char** results;
FuncCallContext* funcctx = NULL;
int32 call_cntr;
int32 max_calls;
AttInMetadata* attinmeta = NULL;
MemoryContext oldcontext;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL()) {
Relation rel;
TupleDesc tupdesc;
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/*
* switch to memory context appropriate for multiple function calls
*/
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* open target relation */
rel = get_rel_from_relname(PG_GETARG_TEXT_P(0), AccessShareLock, ACL_SELECT);
/* get the array of attnums */
results = get_pkey_attnames(rel, &indnkeyatts);
relation_close(rel, AccessShareLock);
/*
* need a tuple descriptor representing one INT and one TEXT column
*/
tupdesc = CreateTemplateTupleDesc(2, false);
TupleDescInitEntry(tupdesc, (AttrNumber)1, "position", INT4OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber)2, "colname", TEXTOID, -1, 0);
/*
* Generate attribute metadata needed later to produce tuples from raw
* C strings
*/
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
if ((results != NULL) && (indnkeyatts > 0)) {
funcctx->max_calls = indnkeyatts;
/* got results, keep track of them */
funcctx->user_fctx = results;
} else {
/* fast track when no results */
MemoryContextSwitchTo(oldcontext);
SRF_RETURN_DONE(funcctx);
}
MemoryContextSwitchTo(oldcontext);
}
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
/*
* initialize per-call variables
*/
call_cntr = funcctx->call_cntr;
max_calls = funcctx->max_calls;
results = (char**)funcctx->user_fctx;
attinmeta = funcctx->attinmeta;
if (call_cntr < max_calls) /* do when there is more left to send */
{
char** values;
HeapTuple tuple;
Datum result;
const int valLen = 12;
values = (char**)palloc(2 * sizeof(char*));
values[0] = (char*)palloc(valLen); /* sign, 10 digits, '\0' */
int rc = sprintf_s(values[0], valLen, "%d", call_cntr + 1);
securec_check_ss(rc, "\0", "\0");
values[1] = results[call_cntr];
/* build the tuple */
tuple = BuildTupleFromCStrings(attinmeta, values);
/* make the tuple into a datum */
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
} else {
/* do when there is no more left */
SRF_RETURN_DONE(funcctx);
}
}
/*
* dblink_build_sql_insert
*
* Used to generate an SQL insert statement
* based on an existing tuple in a local relation.
* This is useful for selectively replicating data
* to another server via dblink.
*
* API:
* <relname> - name of local table of interest
* <pkattnums> - an int2vector of attnums which will be used
* to identify the local tuple of interest
* <pknumatts> - number of attnums in pkattnums
* <src_pkattvals_arry> - text array of key values which will be used
* to identify the local tuple of interest
* <tgt_pkattvals_arry> - text array of key values which will be used
* to build the string for execution remotely. These are substituted
* for their counterparts in src_pkattvals_arry
*/
PG_FUNCTION_INFO_V1(dblink_build_sql_insert);
Datum dblink_build_sql_insert(PG_FUNCTION_ARGS)
{
text* relname_text = PG_GETARG_TEXT_P(0);
int2vector* pkattnums_arg = (int2vector*)PG_GETARG_POINTER(1);
int32 pknumatts_arg = PG_GETARG_INT32(2);
ArrayType* src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
ArrayType* tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(4);
Relation rel;
int* pkattnums = NULL;
int pknumatts;
char** src_pkattvals;
char** tgt_pkattvals;
int src_nitems;
int tgt_nitems;
char* sql = NULL;
/*
* Open target relation.
*/
rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
/*
* Process pkattnums argument.
*/
validate_pkattnums(rel, pkattnums_arg, pknumatts_arg, &pkattnums, &pknumatts);
/*
* Source array is made up of key values that will be used to locate the
* tuple of interest from the local system.
*/
src_pkattvals = get_text_array_contents(src_pkattvals_arry, &src_nitems);
/*
* There should be one source array key value for each key attnum
*/
if (src_nitems != pknumatts)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("source key array length must match number of key "
"attributes")));
/*
* Target array is made up of key values that will be used to build the
* SQL string for use on the remote system.
*/
tgt_pkattvals = get_text_array_contents(tgt_pkattvals_arry, &tgt_nitems);
/*
* There should be one target array key value for each key attnum
*/
if (tgt_nitems != pknumatts)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("target key array length must match number of key "
"attributes")));
/*
* Prep work is finally done. Go get the SQL string.
*/
sql = get_sql_insert(rel, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
/*
* Now we can close the relation.
*/
relation_close(rel, AccessShareLock);
/*
* And send it
*/
PG_RETURN_TEXT_P(cstring_to_text(sql));
}
/*
* dblink_build_sql_delete
*
* Used to generate an SQL delete statement.
* This is useful for selectively replicating a
* delete to another server via dblink.
*
* API:
* <relname> - name of remote table of interest
* <pkattnums> - an int2vector of attnums which will be used
* to identify the remote tuple of interest
* <pknumatts> - number of attnums in pkattnums
* <tgt_pkattvals_arry> - text array of key values which will be used
* to build the string for execution remotely.
*/
PG_FUNCTION_INFO_V1(dblink_build_sql_delete);
Datum dblink_build_sql_delete(PG_FUNCTION_ARGS)
{
text* relname_text = PG_GETARG_TEXT_P(0);
int2vector* pkattnums_arg = (int2vector*)PG_GETARG_POINTER(1);
int32 pknumatts_arg = PG_GETARG_INT32(2);
ArrayType* tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
Relation rel;
int* pkattnums = NULL;
int pknumatts;
char** tgt_pkattvals;
int tgt_nitems;
char* sql = NULL;
/*
* Open target relation.
*/
rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
/*
* Process pkattnums argument.
*/
validate_pkattnums(rel, pkattnums_arg, pknumatts_arg, &pkattnums, &pknumatts);
/*
* Target array is made up of key values that will be used to build the
* SQL string for use on the remote system.
*/
tgt_pkattvals = get_text_array_contents(tgt_pkattvals_arry, &tgt_nitems);
/*
* There should be one target array key value for each key attnum
*/
if (tgt_nitems != pknumatts)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("target key array length must match number of key "
"attributes")));
/*
* Prep work is finally done. Go get the SQL string.
*/
sql = get_sql_delete(rel, pkattnums, pknumatts, tgt_pkattvals);
/*
* Now we can close the relation.
*/
relation_close(rel, AccessShareLock);
/*
* And send it
*/
PG_RETURN_TEXT_P(cstring_to_text(sql));
}
/*
* dblink_build_sql_update
*
* Used to generate an SQL update statement
* based on an existing tuple in a local relation.
* This is useful for selectively replicating data
* to another server via dblink.
*
* API:
* <relname> - name of local table of interest
* <pkattnums> - an int2vector of attnums which will be used
* to identify the local tuple of interest
* <pknumatts> - number of attnums in pkattnums
* <src_pkattvals_arry> - text array of key values which will be used
* to identify the local tuple of interest
* <tgt_pkattvals_arry> - text array of key values which will be used
* to build the string for execution remotely. These are substituted
* for their counterparts in src_pkattvals_arry
*/
PG_FUNCTION_INFO_V1(dblink_build_sql_update);
Datum dblink_build_sql_update(PG_FUNCTION_ARGS)
{
text* relname_text = PG_GETARG_TEXT_P(0);
int2vector* pkattnums_arg = (int2vector*)PG_GETARG_POINTER(1);
int32 pknumatts_arg = PG_GETARG_INT32(2);
ArrayType* src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
ArrayType* tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(4);
Relation rel;
int* pkattnums = NULL;
int pknumatts;
char** src_pkattvals;
char** tgt_pkattvals;
int src_nitems;
int tgt_nitems;
char* sql = NULL;
/*
* Open target relation.
*/
rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
/*
* Process pkattnums argument.
*/
validate_pkattnums(rel, pkattnums_arg, pknumatts_arg, &pkattnums, &pknumatts);
/*
* Source array is made up of key values that will be used to locate the
* tuple of interest from the local system.
*/
src_pkattvals = get_text_array_contents(src_pkattvals_arry, &src_nitems);
/*
* There should be one source array key value for each key attnum
*/
if (src_nitems != pknumatts)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("source key array length must match number of key "
"attributes")));
/*
* Target array is made up of key values that will be used to build the
* SQL string for use on the remote system.
*/
tgt_pkattvals = get_text_array_contents(tgt_pkattvals_arry, &tgt_nitems);
/*
* There should be one target array key value for each key attnum
*/
if (tgt_nitems != pknumatts)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("target key array length must match number of key "
"attributes")));
/*
* Prep work is finally done. Go get the SQL string.
*/
sql = get_sql_update(rel, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
/*
* Now we can close the relation.
*/
relation_close(rel, AccessShareLock);
/*
* And send it
*/
PG_RETURN_TEXT_P(cstring_to_text(sql));
}
/*
* dblink_current_query
* return the current query string
* to allow its use in (among other things)
* rewrite rules
*/
PG_FUNCTION_INFO_V1(dblink_current_query);
Datum dblink_current_query(PG_FUNCTION_ARGS)
{
/* This is now just an alias for the built-in function current_query() */
PG_RETURN_DATUM(current_query(fcinfo));
}
/*
* Retrieve async notifications for a connection.
*
* Returns a setof record of notifications, or an empty set if none received.
* Can optionally take a named connection as parameter, but uses the unnamed
* connection per default.
*
*/
#define DBLINK_NOTIFY_COLS 3
PG_FUNCTION_INFO_V1(dblink_get_notify);
Datum dblink_get_notify(PG_FUNCTION_ARGS)
{
char* conname = NULL;
PGconn* conn = NULL;
remoteConn* rconn = NULL;
PGnotify* notify = NULL;
ReturnSetInfo* rsinfo = (ReturnSetInfo*)fcinfo->resultinfo;
TupleDesc tupdesc;
Tuplestorestate* tupstore = NULL;
MemoryContext per_query_ctx;
MemoryContext oldcontext;
prepTuplestoreResult(fcinfo);
DBLINK_INIT;
if (PG_NARGS() == 1)
DBLINK_GET_NAMED_CONN;
else
conn = pconn->conn;
/* create the tuplestore in per-query memory */
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
tupdesc = CreateTemplateTupleDesc(DBLINK_NOTIFY_COLS, false);
TupleDescInitEntry(tupdesc, (AttrNumber)1, "notify_name", TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber)2, "be_pid", INT4OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber)3, "extra", TEXTOID, -1, 0);
tupstore = tuplestore_begin_heap(true, false, u_sess->attr.attr_memory.work_mem);
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
PQconsumeInput(conn);
while ((notify = PQnotifies(conn)) != NULL) {
Datum values[DBLINK_NOTIFY_COLS] = {0};
bool nulls[DBLINK_NOTIFY_COLS] = {false};
if (notify->relname != NULL)
values[0] = CStringGetTextDatum(notify->relname);
else
nulls[0] = true;
values[1] = Int32GetDatum(notify->be_pid);
if (notify->extra != NULL)
values[2] = CStringGetTextDatum(notify->extra);
else
nulls[2] = true;
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
PQfreemem(notify);
PQconsumeInput(conn);
}
/* clean up and return the tuplestore */
tuplestore_donestoring(tupstore);
return (Datum)0;
}
/*************************************************************
* internal functions
*/
/*
* get_pkey_attnames
*
* Get the primary key attnames for the given relation.
* Return NULL, and set indnkeyatts = 0, if no primary key exists.
*/
static char** get_pkey_attnames(Relation rel, int16* indnkeyatts)
{
Relation indexRelation;
ScanKeyData skey;
SysScanDesc scan;
HeapTuple indexTuple;
int i;
char** result = NULL;
TupleDesc tupdesc;
/* initialize indnkeyatts to 0 in case no primary key exists */
*indnkeyatts = 0;
tupdesc = rel->rd_att;
/* Prepare to scan pg_index for entries having indrelid = this rel. */
indexRelation = heap_open(IndexRelationId, AccessShareLock);
ScanKeyInit(&skey, Anum_pg_index_indrelid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(rel)));
scan = systable_beginscan(indexRelation, IndexIndrelidIndexId, true, SnapshotNow, 1, &skey);
while (HeapTupleIsValid(indexTuple = systable_getnext(scan))) {
Form_pg_index index = (Form_pg_index)GETSTRUCT(indexTuple);
/* we're only interested if it is the primary key */
if (index->indisprimary) {
*indnkeyatts = GetIndexKeyAttsByTuple(NULL, indexTuple);
if (*indnkeyatts > 0) {
result = (char**)palloc(*indnkeyatts * sizeof(char*));
for (i = 0; i < *indnkeyatts; i++) {
result[i] = SPI_fname(tupdesc, index->indkey.values[i]);
}
}
break;
}
}
systable_endscan(scan);
heap_close(indexRelation, AccessShareLock);
return result;
}
/*
* Deconstruct a text[] into C-strings (note any NULL elements will be
* returned as NULL pointers)
*/
static char** get_text_array_contents(ArrayType* array, int* numitems)
{
int ndim = ARR_NDIM(array);
int* dims = ARR_DIMS(array);
int nitems;
int16 typlen;
bool typbyval = false;
char typalign;
char** values;
char* ptr = NULL;
bits8* bitmap = NULL;
int bitmask;
int i;
Assert(ARR_ELEMTYPE(array) == TEXTOID);
*numitems = nitems = ArrayGetNItems(ndim, dims);
get_typlenbyvalalign(ARR_ELEMTYPE(array), &typlen, &typbyval, &typalign);
values = (char**)palloc(nitems * sizeof(char*));
ptr = ARR_DATA_PTR(array);
bitmap = ARR_NULLBITMAP(array);
bitmask = 1;
for (i = 0; i < nitems; i++) {
if (bitmap && (*bitmap & bitmask) == 0) {
values[i] = NULL;
} else {
values[i] = TextDatumGetCString(PointerGetDatum(ptr));
ptr = att_addlength_pointer(ptr, typlen, ptr);
ptr = (char*)att_align_nominal(ptr, typalign);
}
/* advance bitmap pointer if any */
if (bitmap) {
bitmask <<= 1;
if (bitmask == 0x100) {
bitmap++;
bitmask = 1;
}
}
}
return values;
}
static char* get_sql_insert(Relation rel, int* pkattnums, int pknumatts, char** src_pkattvals, char** tgt_pkattvals)
{
char* relname = NULL;
HeapTuple tuple;
TupleDesc tupdesc;
int natts;
StringInfoData buf;
char* val = NULL;
int key;
int i;
bool needComma = false;
initStringInfo(&buf);
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(rel);
tupdesc = rel->rd_att;
natts = tupdesc->natts;
tuple = get_tuple_of_interest(rel, pkattnums, pknumatts, src_pkattvals);
if (!tuple)
ereport(ERROR, (errcode(ERRCODE_CARDINALITY_VIOLATION), errmsg("source row not found")));
appendStringInfo(&buf, "INSERT INTO %s(", relname);
needComma = false;
for (i = 0; i < natts; i++) {
if (tupdesc->attrs[i]->attisdropped)
continue;
if (needComma)
appendStringInfo(&buf, ",");
appendStringInfoString(&buf, quote_ident_cstr(NameStr(tupdesc->attrs[i]->attname)));
needComma = true;
}
appendStringInfo(&buf, ") VALUES(");
/*
* Note: i is physical column number (counting from 0).
*/
needComma = false;
for (i = 0; i < natts; i++) {
if (tupdesc->attrs[i]->attisdropped)
continue;
if (needComma)
appendStringInfo(&buf, ",");
key = get_attnum_pk_pos(pkattnums, pknumatts, i);
if (key >= 0)
val = tgt_pkattvals[key] ? pstrdup(tgt_pkattvals[key]) : NULL;
else
val = SPI_getvalue(tuple, tupdesc, i + 1);
if (val != NULL) {
appendStringInfoString(&buf, quote_literal_cstr(val));
pfree(val);
} else
appendStringInfo(&buf, "NULL");
needComma = true;
}
appendStringInfo(&buf, ")");
return (buf.data);
}
static char* get_sql_delete(Relation rel, int* pkattnums, int pknumatts, char** tgt_pkattvals)
{
char* relname = NULL;
TupleDesc tupdesc;
StringInfoData buf;
int i;
initStringInfo(&buf);
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(rel);
tupdesc = rel->rd_att;
appendStringInfo(&buf, "DELETE FROM %s WHERE ", relname);
for (i = 0; i < pknumatts; i++) {
int pkattnum = pkattnums[i];
if (i > 0)
appendStringInfo(&buf, " AND ");
appendStringInfoString(&buf, quote_ident_cstr(NameStr(tupdesc->attrs[pkattnum]->attname)));
if (tgt_pkattvals[i] != NULL)
appendStringInfo(&buf, " = %s", quote_literal_cstr(tgt_pkattvals[i]));
else
appendStringInfo(&buf, " IS NULL");
}
return (buf.data);
}
static char* get_sql_update(Relation rel, int* pkattnums, int pknumatts, char** src_pkattvals, char** tgt_pkattvals)
{
char* relname = NULL;
HeapTuple tuple;
TupleDesc tupdesc;
int natts;
StringInfoData buf;
char* val = NULL;
int key;
int i;
bool needComma = false;
initStringInfo(&buf);
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(rel);
tupdesc = rel->rd_att;
natts = tupdesc->natts;
tuple = get_tuple_of_interest(rel, pkattnums, pknumatts, src_pkattvals);
if (!tuple)
ereport(ERROR, (errcode(ERRCODE_CARDINALITY_VIOLATION), errmsg("source row not found")));
appendStringInfo(&buf, "UPDATE %s SET ", relname);
/*
* Note: i is physical column number (counting from 0).
*/
needComma = false;
for (i = 0; i < natts; i++) {
if (tupdesc->attrs[i]->attisdropped)
continue;
if (needComma)
appendStringInfo(&buf, ", ");
appendStringInfo(&buf, "%s = ", quote_ident_cstr(NameStr(tupdesc->attrs[i]->attname)));
key = get_attnum_pk_pos(pkattnums, pknumatts, i);
if (key >= 0)
val = tgt_pkattvals[key] ? pstrdup(tgt_pkattvals[key]) : NULL;
else
val = SPI_getvalue(tuple, tupdesc, i + 1);
if (val != NULL) {
appendStringInfoString(&buf, quote_literal_cstr(val));
pfree(val);
} else
appendStringInfoString(&buf, "NULL");
needComma = true;
}
appendStringInfo(&buf, " WHERE ");
for (i = 0; i < pknumatts; i++) {
int pkattnum = pkattnums[i];
if (i > 0)
appendStringInfo(&buf, " AND ");
appendStringInfo(&buf, "%s", quote_ident_cstr(NameStr(tupdesc->attrs[pkattnum]->attname)));
val = tgt_pkattvals[i];
if (val != NULL)
appendStringInfo(&buf, " = %s", quote_literal_cstr(val));
else
appendStringInfo(&buf, " IS NULL");
}
return (buf.data);
}
/*
* Return a properly quoted identifier.
* Uses quote_ident in quote.c
*/
static char* quote_ident_cstr(char* rawstr)
{
text* rawstr_text = NULL;
text* result_text = NULL;
char* result = NULL;
rawstr_text = cstring_to_text(rawstr);
result_text = DatumGetTextP(DirectFunctionCall1(quote_ident, PointerGetDatum(rawstr_text)));
result = text_to_cstring(result_text);
return result;
}
static int get_attnum_pk_pos(int* pkattnums, int pknumatts, int key)
{
int i;
/*
* Not likely a long list anyway, so just scan for the value
*/
for (i = 0; i < pknumatts; i++)
if (key == pkattnums[i])
return i;
return -1;
}
static HeapTuple get_tuple_of_interest(Relation rel, int* pkattnums, int pknumatts, char** src_pkattvals)
{
char* relname = NULL;
TupleDesc tupdesc;
int natts;
StringInfoData buf;
int ret;
HeapTuple tuple;
int i;
/*
* Connect to SPI manager
*/
if ((ret = SPI_connect()) < 0)
/* internal error */
elog(ERROR, "SPI connect failure - returned %d", ret);
initStringInfo(&buf);
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(rel);
tupdesc = rel->rd_att;
natts = tupdesc->natts;
/*
* Build sql statement to look up tuple of interest, ie, the one matching
* src_pkattvals. We used to use "SELECT *" here, but it's simpler to
* generate a result tuple that matches the table's physical structure,
* with NULLs for any dropped columns. Otherwise we have to deal with two
* different tupdescs and everything's very confusing.
*/
appendStringInfoString(&buf, "SELECT ");
for (i = 0; i < natts; i++) {
if (i > 0)
appendStringInfoString(&buf, ", ");
if (tupdesc->attrs[i]->attisdropped)
appendStringInfoString(&buf, "NULL");
else
appendStringInfoString(&buf, quote_ident_cstr(NameStr(tupdesc->attrs[i]->attname)));
}
appendStringInfo(&buf, " FROM %s WHERE ", relname);
for (i = 0; i < pknumatts; i++) {
int pkattnum = pkattnums[i];
if (i > 0)
appendStringInfo(&buf, " AND ");
appendStringInfoString(&buf, quote_ident_cstr(NameStr(tupdesc->attrs[pkattnum]->attname)));
if (src_pkattvals[i] != NULL)
appendStringInfo(&buf, " = %s", quote_literal_cstr(src_pkattvals[i]));
else
appendStringInfo(&buf, " IS NULL");
}
/*
* Retrieve the desired tuple
*/
ret = SPI_exec(buf.data, 0);
pfree(buf.data);
/*
* Only allow one qualifying tuple
*/
if ((ret == SPI_OK_SELECT) && (SPI_processed > 1))
ereport(
ERROR, (errcode(ERRCODE_CARDINALITY_VIOLATION), errmsg("source criteria matched more than one record")));
else if (ret == SPI_OK_SELECT && SPI_processed == 1) {
SPITupleTable* tuptable = SPI_tuptable;
tuple = SPI_copytuple(tuptable->vals[0]);
SPI_finish();
return tuple;
} else {
/*
* no qualifying tuples
*/
SPI_finish();
return NULL;
}
/*
* never reached, but keep compiler quiet
*/
return NULL;
}
/*
* Open the relation named by relname_text, acquire specified type of lock,
* verify we have specified permissions.
* Caller must close rel when done with it.
*/
static Relation get_rel_from_relname(text* relname_text, LOCKMODE lockmode, AclMode aclmode)
{
RangeVar* relvar = NULL;
Relation rel;
AclResult aclresult;
relvar = makeRangeVarFromNameList(textToQualifiedNameList(relname_text));
rel = heap_openrv(relvar, lockmode);
aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(), aclmode);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_CLASS, RelationGetRelationName(rel));
return rel;
}
/*
* generate_relation_name - copied from ruleutils.c
* Compute the name to display for a relation
*
* The result includes all necessary quoting and schema-prefixing.
*/
static char* generate_relation_name(Relation rel)
{
char* nspname = NULL;
char* result = NULL;
/* Qualify the name if not visible in search path */
if (RelationIsVisible(RelationGetRelid(rel)))
nspname = NULL;
else
nspname = get_namespace_name(rel->rd_rel->relnamespace);
result = quote_qualified_identifier(nspname, RelationGetRelationName(rel));
return result;
}
static remoteConn* getConnectionByName(const char* name)
{
remoteConnHashEnt* hentry = NULL;
char* key = NULL;
if (!remoteConnHash)
remoteConnHash = createConnHash();
key = pstrdup(name);
truncate_identifier(key, strlen(key), false);
hentry = (remoteConnHashEnt*)hash_search(remoteConnHash, key, HASH_FIND, NULL);
if (hentry)
return (hentry->rconn);
return (NULL);
}
static HTAB* createConnHash(void)
{
HASHCTL ctl;
ctl.keysize = NAMEDATALEN;
ctl.entrysize = sizeof(remoteConnHashEnt);
return hash_create("Remote Con hash", NUMCONN, &ctl, HASH_ELEM);
}
static void createNewConnection(const char* name, remoteConn* rconn)
{
remoteConnHashEnt* hentry = NULL;
bool found = false;
char* key = NULL;
if (!remoteConnHash)
remoteConnHash = createConnHash();
key = pstrdup(name);
truncate_identifier(key, strlen(key), true);
hentry = (remoteConnHashEnt*)hash_search(remoteConnHash, key, HASH_ENTER, &found);
if (found) {
PQfinish(rconn->conn);
pfree(rconn);
ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("duplicate connection name")));
}
hentry->rconn = rconn;
strlcpy(hentry->name, name, sizeof(hentry->name));
}
static void deleteConnection(const char* name)
{
remoteConnHashEnt* hentry = NULL;
bool found = false;
char* key = NULL;
if (!remoteConnHash)
remoteConnHash = createConnHash();
key = pstrdup(name);
truncate_identifier(key, strlen(key), false);
hentry = (remoteConnHashEnt*)hash_search(remoteConnHash, key, HASH_REMOVE, &found);
if (!hentry)
ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("undefined connection name")));
}
static void dblink_security_check(PGconn* conn, remoteConn* rconn)
{
if (!superuser()) {
if (!PQconnectionUsedPassword(conn)) {
PQfinish(conn);
if (rconn)
pfree(rconn);
ereport(ERROR,
(errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
errmsg("password is required"),
errdetail("Non-system-admin cannot connect if the server does not request a password."),
errhint("Target server's authentication method must be changed.")));
}
}
}
/*
* For non-superusers, insist that the connstr specify a password. This
* prevents a password from being picked up from .pgpass, a service file,
* the environment, etc. We don't want the postgres user's passwords
* to be accessible to non-superusers.
*/
static void dblink_connstr_check(const char* connstr)
{
if (!superuser()) {
PQconninfoOption* options = NULL;
PQconninfoOption* option = NULL;
bool connstr_gives_password = false;
options = PQconninfoParse(connstr, NULL);
if (options) {
for (option = options; option->keyword != NULL; option++) {
if (strcmp(option->keyword, "password") == 0) {
if (option->val != NULL && option->val[0] != '\0') {
connstr_gives_password = true;
break;
}
}
}
PQconninfoFree(options);
}
if (!connstr_gives_password)
ereport(ERROR,
(errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
errmsg("password is required"),
errdetail("Non-system-admin must provide a password in the connection string.")));
}
}
static void dblink_res_error(const char* conname, PGresult* res, const char* dblink_context_msg, bool fail)
{
int level;
char* pg_diag_sqlstate = PQresultErrorField(res, PG_DIAG_SQLSTATE);
char* pg_diag_message_primary = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY);
char* pg_diag_message_detail = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL);
char* pg_diag_message_hint = PQresultErrorField(res, PG_DIAG_MESSAGE_HINT);
char* pg_diag_context = PQresultErrorField(res, PG_DIAG_CONTEXT);
int sqlstate;
char* message_primary = NULL;
char* message_detail = NULL;
char* message_hint = NULL;
char* message_context = NULL;
const char* dblink_context_conname = "unnamed";
if (fail)
level = ERROR;
else
level = NOTICE;
if (pg_diag_sqlstate)
sqlstate = MAKE_SQLSTATE(
pg_diag_sqlstate[0], pg_diag_sqlstate[1], pg_diag_sqlstate[2], pg_diag_sqlstate[3], pg_diag_sqlstate[4]);
else
sqlstate = ERRCODE_CONNECTION_FAILURE;
xpstrdup(message_primary, pg_diag_message_primary);
xpstrdup(message_detail, pg_diag_message_detail);
xpstrdup(message_hint, pg_diag_message_hint);
xpstrdup(message_context, pg_diag_context);
if (res)
PQclear(res);
if (conname)
dblink_context_conname = conname;
ereport(level,
(errcode(sqlstate),
message_primary ? errmsg_internal("%s", message_primary) : errmsg("unknown error"),
message_detail ? errdetail_internal("%s", message_detail) : 0,
message_hint ? errhint("%s", message_hint) : 0,
message_context ? errcontext("%s", message_context) : 0,
errcontext(
"Error occurred on dblink connection named \"%s\": %s.", dblink_context_conname, dblink_context_msg)));
}
/*
* Obtain connection string for a foreign server
*/
static char* get_connect_string(const char* servername)
{
ForeignServer* foreign_server = NULL;
UserMapping* user_mapping = NULL;
ListCell* cell = NULL;
StringInfo buf = makeStringInfo();
ForeignDataWrapper* fdw = NULL;
AclResult aclresult;
char* srvname = NULL;
/* first gather the server connstr options */
srvname = pstrdup(servername);
truncate_identifier(srvname, strlen(srvname), false);
foreign_server = GetForeignServerByName(srvname, true);
if (foreign_server) {
Oid serverid = foreign_server->serverid;
Oid fdwid = foreign_server->fdwid;
Oid userid = GetUserId();
user_mapping = GetUserMapping(userid, serverid);
fdw = GetForeignDataWrapper(fdwid);
/* Check permissions, user must have usage on the server. */
aclresult = pg_foreign_server_aclcheck(serverid, userid, ACL_USAGE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_FOREIGN_SERVER, foreign_server->servername);
foreach (cell, fdw->options) {
DefElem* def = (DefElem*)lfirst(cell);
appendStringInfo(buf, "%s='%s' ", def->defname, escape_param_str(strVal(def->arg)));
}
foreach (cell, foreign_server->options) {
DefElem* def = (DefElem*)lfirst(cell);
appendStringInfo(buf, "%s='%s' ", def->defname, escape_param_str(strVal(def->arg)));
}
foreach (cell, user_mapping->options) {
DefElem* def = (DefElem*)lfirst(cell);
appendStringInfo(buf, "%s='%s' ", def->defname, escape_param_str(strVal(def->arg)));
}
return buf->data;
} else
return NULL;
}
/*
* Escaping libpq connect parameter strings.
*
* Replaces "'" with "\'" and "\" with "\\".
*/
static char* escape_param_str(const char* str)
{
const char* cp = NULL;
StringInfo buf = makeStringInfo();
for (cp = str; *cp; cp++) {
if (*cp == '\\' || *cp == '\'')
appendStringInfoChar(buf, '\\');
appendStringInfoChar(buf, *cp);
}
return buf->data;
}
/*
* Validate the PK-attnums argument for dblink_build_sql_insert() and related
* functions, and translate to the internal representation.
*
* The user supplies an int2vector of 1-based logical attnums, plus a count
* argument (the need for the separate count argument is historical, but we
* still check it). We check that each attnum corresponds to a valid,
* non-dropped attribute of the rel. We do *not* prevent attnums from being
* listed twice, though the actual use-case for such things is dubious.
* Note that before Postgres 9.0, the user's attnums were interpreted as
* physical not logical column numbers; this was changed for future-proofing.
*
* The internal representation is a palloc'd int array of 0-based physical
* attnums.
*/
static void validate_pkattnums(
Relation rel, int2vector* pkattnums_arg, int32 pknumatts_arg, int** pkattnums, int* pknumatts)
{
TupleDesc tupdesc = rel->rd_att;
int natts = tupdesc->natts;
int i;
/* Don't take more array elements than there are */
pknumatts_arg = Min(pknumatts_arg, pkattnums_arg->dim1);
/* Must have at least one pk attnum selected */
if (pknumatts_arg <= 0)
ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("number of key attributes must be > 0")));
/* Allocate output array */
*pkattnums = (int*)palloc(pknumatts_arg * sizeof(int));
*pknumatts = pknumatts_arg;
/* Validate attnums and convert to internal form */
for (i = 0; i < pknumatts_arg; i++) {
int pkattnum = pkattnums_arg->values[i];
int lnum;
int j;
/* Can throw error immediately if out of range */
if (pkattnum <= 0 || pkattnum > natts)
ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("invalid attribute number %d", pkattnum)));
/* Identify which physical column has this logical number */
lnum = 0;
for (j = 0; j < natts; j++) {
/* dropped columns don't count */
if (tupdesc->attrs[j]->attisdropped)
continue;
if (++lnum == pkattnum)
break;
}
if (j < natts)
(*pkattnums)[i] = j;
else
ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("invalid attribute number %d", pkattnum)));
}
}
/*
* Copy the remote session's values of GUCs that affect datatype I/O
* and apply them locally in a new GUC nesting level. Returns the new
* nestlevel (which is needed by restoreLocalGucs to undo the settings),
* or -1 if no new nestlevel was needed.
*
* We use the equivalent of a function SET option to allow the settings to
* persist only until the caller calls restoreLocalGucs. If an error is
* thrown in between, guc.c will take care of undoing the settings.
*/
static int applyRemoteGucs(PGconn* conn)
{
static const char* const GUCsAffectingIO[] = {"DateStyle", "IntervalStyle"};
int nestlevel = -1;
int i;
for (i = 0; i < lengthof(GUCsAffectingIO); i++) {
const char* gucName = GUCsAffectingIO[i];
const char* remoteVal = PQparameterStatus(conn, gucName);
const char* localVal = NULL;
/*
* If the remote server is pre-8.4, it won't have u_sess->attr.attr_common.IntervalStyle, but
* that's okay because its output format won't be ambiguous. So just
* skip the GUC if we don't get a value for it. (We might eventually
* need more complicated logic with remote-version checks here.)
*/
if (remoteVal == NULL)
continue;
/*
* Avoid GUC-setting overhead if the remote and local GUCs already
* have the same value.
*/
localVal = GetConfigOption(gucName, false, false);
Assert(localVal != NULL);
if (strcmp(remoteVal, localVal) == 0)
continue;
/* Create new GUC nest level if we didn't already */
if (nestlevel < 0)
nestlevel = NewGUCNestLevel();
/* Apply the option (this will throw error on failure) */
(void)set_config_option(gucName, remoteVal, PGC_USERSET, PGC_S_SESSION, GUC_ACTION_SAVE, true, 0);
}
return nestlevel;
}
/*
* Restore local GUCs after they have been overlaid with remote settings.
*/
static void restoreLocalGucs(int nestlevel)
{
/* Do nothing if no new nestlevel was created */
if (nestlevel > 0)
AtEOXact_GUC(true, nestlevel);
}
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