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postgresql/contrib/dblink/dblink.c
Joe Conway 056eb1412c When a cursor is opened using dblink_open, only start a transaction 
if there isn't one already open. Upon dblink_close, only commit
the open transaction if it was started by dblink_open, and only
then when all cursors opened by dblink_open are closed. The transaction
accounting is done individually for all named connections, plus
the persistent unnamed connection.
2005-10-18 02:55:49 +00:00

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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>
*
* Copyright (c) 2001-2005, 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 "libpq-fe.h"
#include "fmgr.h"
#include "funcapi.h"
#include "access/tupdesc.h"
#include "access/heapam.h"
#include "catalog/namespace.h"
#include "catalog/pg_index.h"
#include "catalog/pg_type.h"
#include "executor/executor.h"
#include "executor/spi.h"
#include "lib/stringinfo.h"
#include "nodes/nodes.h"
#include "nodes/execnodes.h"
#include "nodes/pg_list.h"
#include "parser/parse_type.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/array.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "utils/dynahash.h"
#include "utils/hsearch.h"
#include "utils/memutils.h"
#include "dblink.h"
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;
/*
* Internal declarations
*/
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(Oid relid, int16 *numatts);
static char *get_sql_insert(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals);
static char *get_sql_delete(Oid relid, int2vector *pkattnums, int16 pknumatts, char **tgt_pkattvals);
static char *get_sql_update(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals);
static char *quote_literal_cstr(char *rawstr);
static char *quote_ident_cstr(char *rawstr);
static int16 get_attnum_pk_pos(int2vector *pkattnums, int16 pknumatts, int16 key);
static HeapTuple get_tuple_of_interest(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals);
static Oid get_relid_from_relname(text *relname_text);
static char *generate_relation_name(Oid relid);
/* 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 GET_TEXT(cstrp) DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(cstrp)))
#define GET_STR(textp) DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(textp)))
#define xpfree(var_) \
do { \
if (var_ != NULL) \
{ \
pfree(var_); \
var_ = 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_RES_ERROR(p2) \
do { \
msg = pstrdup(PQerrorMessage(conn)); \
if (res) \
PQclear(res); \
ereport(ERROR, \
(errcode(ERRCODE_SYNTAX_ERROR), \
errmsg("%s", p2), \
errdetail("%s", msg))); \
} while (0)
#define DBLINK_RES_ERROR_AS_NOTICE(p2) \
do { \
msg = pstrdup(PQerrorMessage(conn)); \
if (res) \
PQclear(res); \
ereport(NOTICE, \
(errcode(ERRCODE_SYNTAX_ERROR), \
errmsg("%s", p2), \
errdetail("%s", 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 = GET_STR(PG_GETARG_TEXT_P(0)); \
rconn = getConnectionByName(conname_or_str); \
if(rconn) \
{ \
conn = rconn->conn; \
} \
else \
{ \
connstr = conname_or_str; \
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("%s", msg))); \
} \
freeconn = true; \
} \
} while (0)
#define DBLINK_INIT \
do { \
if (!pconn) \
{ \
pconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext, 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 *connstr = NULL;
char *connname = NULL;
char *msg;
MemoryContext oldcontext;
PGconn *conn = NULL;
remoteConn *rconn = NULL;
DBLINK_INIT;
if (PG_NARGS() == 2)
{
connstr = GET_STR(PG_GETARG_TEXT_P(1));
connname = GET_STR(PG_GETARG_TEXT_P(0));
}
else if (PG_NARGS() == 1)
connstr = GET_STR(PG_GETARG_TEXT_P(0));
oldcontext = MemoryContextSwitchTo(TopMemoryContext);
if (connname)
rconn = (remoteConn *) palloc(sizeof(remoteConn));
conn = PQconnectdb(connstr);
MemoryContextSwitchTo(oldcontext);
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("%s", msg)));
}
if (connname)
{
rconn->conn = conn;
createNewConnection(connname, rconn);
}
else
pconn->conn = conn;
PG_RETURN_TEXT_P(GET_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 = GET_STR(PG_GETARG_TEXT_P(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(GET_TEXT("OK"));
}
/*
* opens a cursor using a persistent connection
*/
PG_FUNCTION_INFO_V1(dblink_open);
Datum
dblink_open(PG_FUNCTION_ARGS)
{
char *msg;
PGresult *res = NULL;
PGconn *conn = NULL;
char *curname = NULL;
char *sql = NULL;
char *conname = NULL;
StringInfo str = makeStringInfo();
remoteConn *rconn = NULL;
bool fail = true; /* default to backward compatible behavior */
DBLINK_INIT;
if (PG_NARGS() == 2)
{
/* text,text */
curname = GET_STR(PG_GETARG_TEXT_P(0));
sql = GET_STR(PG_GETARG_TEXT_P(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 = GET_STR(PG_GETARG_TEXT_P(0));
sql = GET_STR(PG_GETARG_TEXT_P(1));
fail = PG_GETARG_BOOL(2);
rconn = pconn;
}
else
{
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
sql = GET_STR(PG_GETARG_TEXT_P(2));
rconn = getConnectionByName(conname);
}
}
else if (PG_NARGS() == 4)
{
/* text,text,text,bool */
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
sql = GET_STR(PG_GETARG_TEXT_P(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, "BEGIN");
if (PQresultStatus(res) != PGRES_COMMAND_OK)
DBLINK_RES_INTERNALERROR("begin error");
PQclear(res);
rconn->newXactForCursor = TRUE;
}
/* if we started a transaction, increment cursor count */
if (rconn->newXactForCursor)
(rconn->openCursorCount)++;
appendStringInfo(str, "DECLARE %s CURSOR FOR %s", curname, sql);
res = PQexec(conn, str->data);
if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
{
if (fail)
DBLINK_RES_ERROR("sql error");
else
{
DBLINK_RES_ERROR_AS_NOTICE("sql error");
PG_RETURN_TEXT_P(GET_TEXT("ERROR"));
}
}
PQclear(res);
PG_RETURN_TEXT_P(GET_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;
StringInfo str = makeStringInfo();
char *msg;
remoteConn *rconn = NULL;
bool fail = true; /* default to backward compatible behavior */
DBLINK_INIT;
if (PG_NARGS() == 1)
{
/* text */
curname = GET_STR(PG_GETARG_TEXT_P(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 = GET_STR(PG_GETARG_TEXT_P(0));
fail = PG_GETARG_BOOL(1);
rconn = pconn;
}
else
{
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
rconn = getConnectionByName(conname);
}
}
if (PG_NARGS() == 3)
{
/* text,text,bool */
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
fail = PG_GETARG_BOOL(2);
rconn = getConnectionByName(conname);
}
if (!rconn || !rconn->conn)
DBLINK_CONN_NOT_AVAIL;
else
conn = rconn->conn;
appendStringInfo(str, "CLOSE %s", curname);
/* close the cursor */
res = PQexec(conn, str->data);
if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
{
if (fail)
DBLINK_RES_ERROR("sql error");
else
{
DBLINK_RES_ERROR_AS_NOTICE("sql error");
PG_RETURN_TEXT_P(GET_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(GET_TEXT("OK"));
}
/*
* Fetch results from an open cursor
*/
PG_FUNCTION_INFO_V1(dblink_fetch);
Datum
dblink_fetch(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
TupleDesc tupdesc = NULL;
int call_cntr;
int max_calls;
AttInMetadata *attinmeta;
char *msg;
PGresult *res = NULL;
MemoryContext oldcontext;
char *conname = NULL;
remoteConn *rconn = NULL;
DBLINK_INIT;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
PGconn *conn = NULL;
StringInfo str = makeStringInfo();
char *curname = NULL;
int howmany = 0;
bool fail = true; /* default to backward compatible */
if (PG_NARGS() == 4)
{
/* text,text,int,bool */
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(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 = GET_STR(PG_GETARG_TEXT_P(0));
howmany = PG_GETARG_INT32(1);
fail = PG_GETARG_BOOL(2);
conn = pconn->conn;
}
else
{
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
howmany = PG_GETARG_INT32(2);
rconn = getConnectionByName(conname);
if (rconn)
conn = rconn->conn;
}
}
else if (PG_NARGS() == 2)
{
/* text,int */
curname = GET_STR(PG_GETARG_TEXT_P(0));
howmany = PG_GETARG_INT32(1);
conn = pconn->conn;
}
if (!conn)
DBLINK_CONN_NOT_AVAIL;
/* 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);
appendStringInfo(str, "FETCH %d FROM %s", howmany, curname);
res = PQexec(conn, str->data);
if (!res ||
(PQresultStatus(res) != PGRES_COMMAND_OK &&
PQresultStatus(res) != PGRES_TUPLES_OK))
{
if (fail)
DBLINK_RES_ERROR("sql error");
else
{
DBLINK_RES_ERROR_AS_NOTICE("sql error");
SRF_RETURN_DONE(funcctx);
}
}
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)));
}
funcctx->max_calls = PQntuples(res);
/* got results, keep track of them */
funcctx->user_fctx = res;
/* fast track when no results */
if (funcctx->max_calls < 1)
{
if (res)
PQclear(res);
SRF_RETURN_DONE(funcctx);
}
/* 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);
/* store needed metadata for subsequent calls */
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
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;
res = (PGresult *) funcctx->user_fctx;
attinmeta = funcctx->attinmeta;
tupdesc = attinmeta->tupdesc;
if (call_cntr < max_calls) /* do when there is more left to send */
{
char **values;
HeapTuple tuple;
Datum result;
int i;
int nfields = PQnfields(res);
values = (char **) palloc(nfields * sizeof(char *));
for (i = 0; i < nfields; i++)
{
if (PQgetisnull(res, call_cntr, i) == 0)
values[i] = PQgetvalue(res, call_cntr, i);
else
values[i] = NULL;
}
/* 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 */
PQclear(res);
SRF_RETURN_DONE(funcctx);
}
}
/*
* Note: this is the new preferred version of dblink
*/
PG_FUNCTION_INFO_V1(dblink_record);
Datum
dblink_record(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
TupleDesc tupdesc = NULL;
int call_cntr;
int max_calls;
AttInMetadata *attinmeta;
char *msg;
PGresult *res = NULL;
bool is_sql_cmd = false;
char *sql_cmd_status = NULL;
MemoryContext oldcontext;
bool freeconn = false;
DBLINK_INIT;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
PGconn *conn = NULL;
char *connstr = NULL;
char *sql = NULL;
char *conname = NULL;
remoteConn *rconn = NULL;
bool fail = true; /* default to backward compatible */
/* 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);
if (PG_NARGS() == 3)
{
/* text,text,bool */
DBLINK_GET_CONN;
sql = GET_STR(PG_GETARG_TEXT_P(1));
fail = PG_GETARG_BOOL(2);
}
else if (PG_NARGS() == 2)
{
/* text,text or text,bool */
if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
{
conn = pconn->conn;
sql = GET_STR(PG_GETARG_TEXT_P(0));
fail = PG_GETARG_BOOL(1);
}
else
{
DBLINK_GET_CONN;
sql = GET_STR(PG_GETARG_TEXT_P(1));
}
}
else if (PG_NARGS() == 1)
{
/* text */
conn = pconn->conn;
sql = GET_STR(PG_GETARG_TEXT_P(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))
{
if (fail)
DBLINK_RES_ERROR("sql error");
else
{
DBLINK_RES_ERROR_AS_NOTICE("sql error");
if (freeconn)
PQfinish(conn);
SRF_RETURN_DONE(funcctx);
}
}
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
is_sql_cmd = true;
/* need a tuple descriptor representing one TEXT column */
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
TEXTOID, -1, 0);
/*
* and save a copy of the command status string to return as our
* result tuple
*/
sql_cmd_status = PQcmdStatus(res);
funcctx->max_calls = 1;
}
else
funcctx->max_calls = PQntuples(res);
/* got results, keep track of them */
funcctx->user_fctx = res;
/* if needed, close the connection to the database and cleanup */
if (freeconn)
PQfinish(conn);
/* fast track when no results */
if (funcctx->max_calls < 1)
{
if (res)
PQclear(res);
SRF_RETURN_DONE(funcctx);
}
if (!is_sql_cmd)
{
/* 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);
}
/* store needed metadata for subsequent calls */
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
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;
res = (PGresult *) funcctx->user_fctx;
attinmeta = funcctx->attinmeta;
tupdesc = attinmeta->tupdesc;
if (call_cntr < max_calls) /* do when there is more left to send */
{
char **values;
HeapTuple tuple;
Datum result;
if (!is_sql_cmd)
{
int i;
int nfields = PQnfields(res);
values = (char **) palloc(nfields * sizeof(char *));
for (i = 0; i < nfields; i++)
{
if (PQgetisnull(res, call_cntr, i) == 0)
values[i] = PQgetvalue(res, call_cntr, i);
else
values[i] = NULL;
}
}
else
{
values = (char **) palloc(1 * sizeof(char *));
values[0] = sql_cmd_status;
}
/* 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 */
PQclear(res);
SRF_RETURN_DONE(funcctx);
}
}
/*
* Execute an SQL non-SELECT command
*/
PG_FUNCTION_INFO_V1(dblink_exec);
Datum
dblink_exec(PG_FUNCTION_ARGS)
{
char *msg;
PGresult *res = NULL;
text *sql_cmd_status = NULL;
TupleDesc tupdesc = NULL;
PGconn *conn = NULL;
char *connstr = NULL;
char *sql = NULL;
char *conname = NULL;
remoteConn *rconn = NULL;
bool freeconn = false;
bool fail = true; /* default to backward compatible behavior */
DBLINK_INIT;
if (PG_NARGS() == 3)
{
/* must be text,text,bool */
DBLINK_GET_CONN;
sql = GET_STR(PG_GETARG_TEXT_P(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 = GET_STR(PG_GETARG_TEXT_P(0));
fail = PG_GETARG_BOOL(1);
}
else
{
DBLINK_GET_CONN;
sql = GET_STR(PG_GETARG_TEXT_P(1));
}
}
else if (PG_NARGS() == 1)
{
/* must be single text argument */
conn = pconn->conn;
sql = GET_STR(PG_GETARG_TEXT_P(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))
{
if (fail)
DBLINK_RES_ERROR("sql error");
else
DBLINK_RES_ERROR_AS_NOTICE("sql error");
/* need a tuple descriptor representing one TEXT column */
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
TEXTOID, -1, 0);
/*
* and save a copy of the command status string to return as our
* result tuple
*/
sql_cmd_status = GET_TEXT("ERROR");
}
else if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
/* need a tuple descriptor representing one TEXT column */
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
TEXTOID, -1, 0);
/*
* and save a copy of the command status string to return as our
* result tuple
*/
sql_cmd_status = GET_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")));
}
/* if needed, close the connection to the database and cleanup */
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 numatts;
Oid relid;
char **results;
FuncCallContext *funcctx;
int32 call_cntr;
int32 max_calls;
AttInMetadata *attinmeta;
MemoryContext oldcontext;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
TupleDesc tupdesc = NULL;
/* 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);
/* convert relname to rel Oid */
relid = get_relid_from_relname(PG_GETARG_TEXT_P(0));
if (!OidIsValid(relid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
GET_STR(PG_GETARG_TEXT_P(0)))));
/*
* 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;
/* get an array of attnums */
results = get_pkey_attnames(relid, &numatts);
if ((results != NULL) && (numatts > 0))
{
funcctx->max_calls = numatts;
/* got results, keep track of them */
funcctx->user_fctx = results;
}
else
/* fast track when no results */
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;
values = (char **) palloc(2 * sizeof(char *));
values[0] = (char *) palloc(12); /* sign, 10 digits, '\0' */
sprintf(values[0], "%d", call_cntr + 1);
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);
}
}
#ifndef SHRT_MAX
#define SHRT_MAX (0x7FFF)
#endif
/*
* 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)
{
Oid relid;
text *relname_text;
int2vector *pkattnums;
int pknumatts_tmp;
int16 pknumatts = 0;
char **src_pkattvals;
char **tgt_pkattvals;
ArrayType *src_pkattvals_arry;
ArrayType *tgt_pkattvals_arry;
int src_ndim;
int *src_dim;
int src_nitems;
int tgt_ndim;
int *tgt_dim;
int tgt_nitems;
int i;
char *ptr;
char *sql;
int16 typlen;
bool typbyval;
char typalign;
relname_text = PG_GETARG_TEXT_P(0);
/*
* Convert relname to rel OID.
*/
relid = get_relid_from_relname(relname_text);
if (!OidIsValid(relid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
GET_STR(relname_text))));
pkattnums = (int2vector *) PG_GETARG_POINTER(1);
pknumatts_tmp = PG_GETARG_INT32(2);
if (pknumatts_tmp <= SHRT_MAX)
pknumatts = pknumatts_tmp;
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("input for number of primary key " \
"attributes too large")));
/*
* There should be at least one key attribute
*/
if (pknumatts == 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("number of key attributes must be > 0")));
src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(4);
/*
* Source array is made up of key values that will be used to locate the
* tuple of interest from the local system.
*/
src_ndim = ARR_NDIM(src_pkattvals_arry);
src_dim = ARR_DIMS(src_pkattvals_arry);
src_nitems = ArrayGetNItems(src_ndim, src_dim);
/*
* 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")));
/*
* get array of pointers to c-strings from the input source array
*/
Assert(ARR_ELEMTYPE(src_pkattvals_arry) == TEXTOID);
get_typlenbyvalalign(ARR_ELEMTYPE(src_pkattvals_arry),
&typlen, &typbyval, &typalign);
src_pkattvals = (char **) palloc(src_nitems * sizeof(char *));
ptr = ARR_DATA_PTR(src_pkattvals_arry);
for (i = 0; i < src_nitems; i++)
{
src_pkattvals[i] = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(ptr)));
ptr = att_addlength(ptr, typlen, PointerGetDatum(ptr));
ptr = (char *) att_align(ptr, typalign);
}
/*
* Target array is made up of key values that will be used to build the
* SQL string for use on the remote system.
*/
tgt_ndim = ARR_NDIM(tgt_pkattvals_arry);
tgt_dim = ARR_DIMS(tgt_pkattvals_arry);
tgt_nitems = ArrayGetNItems(tgt_ndim, tgt_dim);
/*
* 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")));
/*
* get array of pointers to c-strings from the input target array
*/
Assert(ARR_ELEMTYPE(tgt_pkattvals_arry) == TEXTOID);
get_typlenbyvalalign(ARR_ELEMTYPE(tgt_pkattvals_arry),
&typlen, &typbyval, &typalign);
tgt_pkattvals = (char **) palloc(tgt_nitems * sizeof(char *));
ptr = ARR_DATA_PTR(tgt_pkattvals_arry);
for (i = 0; i < tgt_nitems; i++)
{
tgt_pkattvals[i] = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(ptr)));
ptr = att_addlength(ptr, typlen, PointerGetDatum(ptr));
ptr = (char *) att_align(ptr, typalign);
}
/*
* Prep work is finally done. Go get the SQL string.
*/
sql = get_sql_insert(relid, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
/*
* And send it
*/
PG_RETURN_TEXT_P(GET_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)
{
Oid relid;
text *relname_text;
int2vector *pkattnums;
int pknumatts_tmp;
int16 pknumatts = 0;
char **tgt_pkattvals;
ArrayType *tgt_pkattvals_arry;
int tgt_ndim;
int *tgt_dim;
int tgt_nitems;
int i;
char *ptr;
char *sql;
int16 typlen;
bool typbyval;
char typalign;
relname_text = PG_GETARG_TEXT_P(0);
/*
* Convert relname to rel OID.
*/
relid = get_relid_from_relname(relname_text);
if (!OidIsValid(relid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
GET_STR(relname_text))));
pkattnums = (int2vector *) PG_GETARG_POINTER(1);
pknumatts_tmp = PG_GETARG_INT32(2);
if (pknumatts_tmp <= SHRT_MAX)
pknumatts = pknumatts_tmp;
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("input for number of primary key " \
"attributes too large")));
/*
* There should be at least one key attribute
*/
if (pknumatts == 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("number of key attributes must be > 0")));
tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
/*
* Target array is made up of key values that will be used to build the
* SQL string for use on the remote system.
*/
tgt_ndim = ARR_NDIM(tgt_pkattvals_arry);
tgt_dim = ARR_DIMS(tgt_pkattvals_arry);
tgt_nitems = ArrayGetNItems(tgt_ndim, tgt_dim);
/*
* 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")));
/*
* get array of pointers to c-strings from the input target array
*/
Assert(ARR_ELEMTYPE(tgt_pkattvals_arry) == TEXTOID);
get_typlenbyvalalign(ARR_ELEMTYPE(tgt_pkattvals_arry),
&typlen, &typbyval, &typalign);
tgt_pkattvals = (char **) palloc(tgt_nitems * sizeof(char *));
ptr = ARR_DATA_PTR(tgt_pkattvals_arry);
for (i = 0; i < tgt_nitems; i++)
{
tgt_pkattvals[i] = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(ptr)));
ptr = att_addlength(ptr, typlen, PointerGetDatum(ptr));
ptr = (char *) att_align(ptr, typalign);
}
/*
* Prep work is finally done. Go get the SQL string.
*/
sql = get_sql_delete(relid, pkattnums, pknumatts, tgt_pkattvals);
/*
* And send it
*/
PG_RETURN_TEXT_P(GET_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)
{
Oid relid;
text *relname_text;
int2vector *pkattnums;
int pknumatts_tmp;
int16 pknumatts = 0;
char **src_pkattvals;
char **tgt_pkattvals;
ArrayType *src_pkattvals_arry;
ArrayType *tgt_pkattvals_arry;
int src_ndim;
int *src_dim;
int src_nitems;
int tgt_ndim;
int *tgt_dim;
int tgt_nitems;
int i;
char *ptr;
char *sql;
int16 typlen;
bool typbyval;
char typalign;
relname_text = PG_GETARG_TEXT_P(0);
/*
* Convert relname to rel OID.
*/
relid = get_relid_from_relname(relname_text);
if (!OidIsValid(relid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
GET_STR(relname_text))));
pkattnums = (int2vector *) PG_GETARG_POINTER(1);
pknumatts_tmp = PG_GETARG_INT32(2);
if (pknumatts_tmp <= SHRT_MAX)
pknumatts = pknumatts_tmp;
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("input for number of primary key " \
"attributes too large")));
/*
* There should be one source array key values for each key attnum
*/
if (pknumatts == 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("number of key attributes must be > 0")));
src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(4);
/*
* Source array is made up of key values that will be used to locate the
* tuple of interest from the local system.
*/
src_ndim = ARR_NDIM(src_pkattvals_arry);
src_dim = ARR_DIMS(src_pkattvals_arry);
src_nitems = ArrayGetNItems(src_ndim, src_dim);
/*
* 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")));
/*
* get array of pointers to c-strings from the input source array
*/
Assert(ARR_ELEMTYPE(src_pkattvals_arry) == TEXTOID);
get_typlenbyvalalign(ARR_ELEMTYPE(src_pkattvals_arry),
&typlen, &typbyval, &typalign);
src_pkattvals = (char **) palloc(src_nitems * sizeof(char *));
ptr = ARR_DATA_PTR(src_pkattvals_arry);
for (i = 0; i < src_nitems; i++)
{
src_pkattvals[i] = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(ptr)));
ptr = att_addlength(ptr, typlen, PointerGetDatum(ptr));
ptr = (char *) att_align(ptr, typalign);
}
/*
* Target array is made up of key values that will be used to build the
* SQL string for use on the remote system.
*/
tgt_ndim = ARR_NDIM(tgt_pkattvals_arry);
tgt_dim = ARR_DIMS(tgt_pkattvals_arry);
tgt_nitems = ArrayGetNItems(tgt_ndim, tgt_dim);
/*
* 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")));
/*
* get array of pointers to c-strings from the input target array
*/
Assert(ARR_ELEMTYPE(tgt_pkattvals_arry) == TEXTOID);
get_typlenbyvalalign(ARR_ELEMTYPE(tgt_pkattvals_arry),
&typlen, &typbyval, &typalign);
tgt_pkattvals = (char **) palloc(tgt_nitems * sizeof(char *));
ptr = ARR_DATA_PTR(tgt_pkattvals_arry);
for (i = 0; i < tgt_nitems; i++)
{
tgt_pkattvals[i] = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(ptr)));
ptr = att_addlength(ptr, typlen, PointerGetDatum(ptr));
ptr = (char *) att_align(ptr, typalign);
}
/*
* Prep work is finally done. Go get the SQL string.
*/
sql = get_sql_update(relid, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
/*
* And send it
*/
PG_RETURN_TEXT_P(GET_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)
{
PG_RETURN_TEXT_P(GET_TEXT(debug_query_string));
}
/*************************************************************
* internal functions
*/
/*
* get_pkey_attnames
*
* Get the primary key attnames for the given relation.
* Return NULL, and set numatts = 0, if no primary key exists.
*/
static char **
get_pkey_attnames(Oid relid, int16 *numatts)
{
Relation indexRelation;
ScanKeyData entry;
HeapScanDesc scan;
HeapTuple indexTuple;
int i;
char **result = NULL;
Relation rel;
TupleDesc tupdesc;
/* open relation using relid, get tupdesc */
rel = relation_open(relid, AccessShareLock);
tupdesc = rel->rd_att;
/* initialize numatts to 0 in case no primary key exists */
*numatts = 0;
/* use relid to get all related indexes */
indexRelation = heap_open(IndexRelationId, AccessShareLock);
ScanKeyInit(&entry,
Anum_pg_index_indrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relid));
scan = heap_beginscan(indexRelation, SnapshotNow, 1, &entry);
while ((indexTuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
Form_pg_index index = (Form_pg_index) GETSTRUCT(indexTuple);
/* we're only interested if it is the primary key */
if (index->indisprimary == TRUE)
{
*numatts = index->indnatts;
if (*numatts > 0)
{
result = (char **) palloc(*numatts * sizeof(char *));
for (i = 0; i < *numatts; i++)
result[i] = SPI_fname(tupdesc, index->indkey.values[i]);
}
break;
}
}
heap_endscan(scan);
heap_close(indexRelation, AccessShareLock);
relation_close(rel, AccessShareLock);
return result;
}
static char *
get_sql_insert(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals)
{
Relation rel;
char *relname;
HeapTuple tuple;
TupleDesc tupdesc;
int natts;
StringInfo str = makeStringInfo();
char *sql;
char *val;
int16 key;
int i;
bool needComma;
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(relid);
/*
* Open relation using relid
*/
rel = relation_open(relid, AccessShareLock);
tupdesc = rel->rd_att;
natts = tupdesc->natts;
tuple = get_tuple_of_interest(relid, pkattnums, pknumatts, src_pkattvals);
if (!tuple)
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
errmsg("source row not found")));
appendStringInfo(str, "INSERT INTO %s(", relname);
needComma = false;
for (i = 0; i < natts; i++)
{
if (tupdesc->attrs[i]->attisdropped)
continue;
if (needComma)
appendStringInfo(str, ",");
appendStringInfo(str, "%s",
quote_ident_cstr(NameStr(tupdesc->attrs[i]->attname)));
needComma = true;
}
appendStringInfo(str, ") VALUES(");
/*
* remember attvals are 1 based
*/
needComma = false;
for (i = 0; i < natts; i++)
{
if (tupdesc->attrs[i]->attisdropped)
continue;
if (needComma)
appendStringInfo(str, ",");
if (tgt_pkattvals != NULL)
key = get_attnum_pk_pos(pkattnums, pknumatts, i + 1);
else
key = -1;
if (key > -1)
val = pstrdup(tgt_pkattvals[key]);
else
val = SPI_getvalue(tuple, tupdesc, i + 1);
if (val != NULL)
{
appendStringInfo(str, "%s", quote_literal_cstr(val));
pfree(val);
}
else
appendStringInfo(str, "NULL");
needComma = true;
}
appendStringInfo(str, ")");
sql = pstrdup(str->data);
pfree(str->data);
pfree(str);
relation_close(rel, AccessShareLock);
return (sql);
}
static char *
get_sql_delete(Oid relid, int2vector *pkattnums, int16 pknumatts, char **tgt_pkattvals)
{
Relation rel;
char *relname;
TupleDesc tupdesc;
int natts;
StringInfo str = makeStringInfo();
char *sql;
char *val = NULL;
int i;
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(relid);
/*
* Open relation using relid
*/
rel = relation_open(relid, AccessShareLock);
tupdesc = rel->rd_att;
natts = tupdesc->natts;
appendStringInfo(str, "DELETE FROM %s WHERE ", relname);
for (i = 0; i < pknumatts; i++)
{
int16 pkattnum = pkattnums->values[i];
if (i > 0)
appendStringInfo(str, " AND ");
appendStringInfo(str, "%s",
quote_ident_cstr(NameStr(tupdesc->attrs[pkattnum - 1]->attname)));
if (tgt_pkattvals != NULL)
val = pstrdup(tgt_pkattvals[i]);
else
/* internal error */
elog(ERROR, "target key array must not be NULL");
if (val != NULL)
{
appendStringInfo(str, " = %s", quote_literal_cstr(val));
pfree(val);
}
else
appendStringInfo(str, " IS NULL");
}
sql = pstrdup(str->data);
pfree(str->data);
pfree(str);
relation_close(rel, AccessShareLock);
return (sql);
}
static char *
get_sql_update(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals)
{
Relation rel;
char *relname;
HeapTuple tuple;
TupleDesc tupdesc;
int natts;
StringInfo str = makeStringInfo();
char *sql;
char *val;
int16 key;
int i;
bool needComma;
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(relid);
/*
* Open relation using relid
*/
rel = relation_open(relid, AccessShareLock);
tupdesc = rel->rd_att;
natts = tupdesc->natts;
tuple = get_tuple_of_interest(relid, pkattnums, pknumatts, src_pkattvals);
if (!tuple)
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
errmsg("source row not found")));
appendStringInfo(str, "UPDATE %s SET ", relname);
needComma = false;
for (i = 0; i < natts; i++)
{
if (tupdesc->attrs[i]->attisdropped)
continue;
if (needComma)
appendStringInfo(str, ", ");
appendStringInfo(str, "%s = ",
quote_ident_cstr(NameStr(tupdesc->attrs[i]->attname)));
if (tgt_pkattvals != NULL)
key = get_attnum_pk_pos(pkattnums, pknumatts, i + 1);
else
key = -1;
if (key > -1)
val = pstrdup(tgt_pkattvals[key]);
else
val = SPI_getvalue(tuple, tupdesc, i + 1);
if (val != NULL)
{
appendStringInfo(str, "%s", quote_literal_cstr(val));
pfree(val);
}
else
appendStringInfo(str, "NULL");
needComma = true;
}
appendStringInfo(str, " WHERE ");
for (i = 0; i < pknumatts; i++)
{
int16 pkattnum = pkattnums->values[i];
if (i > 0)
appendStringInfo(str, " AND ");
appendStringInfo(str, "%s",
quote_ident_cstr(NameStr(tupdesc->attrs[pkattnum - 1]->attname)));
if (tgt_pkattvals != NULL)
val = pstrdup(tgt_pkattvals[i]);
else
val = SPI_getvalue(tuple, tupdesc, pkattnum);
if (val != NULL)
{
appendStringInfo(str, " = %s", quote_literal_cstr(val));
pfree(val);
}
else
appendStringInfo(str, " IS NULL");
}
sql = pstrdup(str->data);
pfree(str->data);
pfree(str);
relation_close(rel, AccessShareLock);
return (sql);
}
/*
* Return a properly quoted literal value.
* Uses quote_literal in quote.c
*/
static char *
quote_literal_cstr(char *rawstr)
{
text *rawstr_text;
text *result_text;
char *result;
rawstr_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(rawstr)));
result_text = DatumGetTextP(DirectFunctionCall1(quote_literal, PointerGetDatum(rawstr_text)));
result = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(result_text)));
return result;
}
/*
* Return a properly quoted identifier.
* Uses quote_ident in quote.c
*/
static char *
quote_ident_cstr(char *rawstr)
{
text *rawstr_text;
text *result_text;
char *result;
rawstr_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(rawstr)));
result_text = DatumGetTextP(DirectFunctionCall1(quote_ident, PointerGetDatum(rawstr_text)));
result = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(result_text)));
return result;
}
static int16
get_attnum_pk_pos(int2vector *pkattnums, int16 pknumatts, int16 key)
{
int i;
/*
* Not likely a long list anyway, so just scan for the value
*/
for (i = 0; i < pknumatts; i++)
if (key == pkattnums->values[i])
return i;
return -1;
}
static HeapTuple
get_tuple_of_interest(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals)
{
Relation rel;
char *relname;
TupleDesc tupdesc;
StringInfo str = makeStringInfo();
char *sql = NULL;
int ret;
HeapTuple tuple;
int i;
char *val = NULL;
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(relid);
/*
* Open relation using relid
*/
rel = relation_open(relid, AccessShareLock);
tupdesc = CreateTupleDescCopy(rel->rd_att);
relation_close(rel, AccessShareLock);
/*
* Connect to SPI manager
*/
if ((ret = SPI_connect()) < 0)
/* internal error */
elog(ERROR, "SPI connect failure - returned %d", ret);
/*
* Build sql statement to look up tuple of interest Use src_pkattvals as
* the criteria.
*/
appendStringInfo(str, "SELECT * FROM %s WHERE ", relname);
for (i = 0; i < pknumatts; i++)
{
int16 pkattnum = pkattnums->values[i];
if (i > 0)
appendStringInfo(str, " AND ");
appendStringInfo(str, "%s",
quote_ident_cstr(NameStr(tupdesc->attrs[pkattnum - 1]->attname)));
val = pstrdup(src_pkattvals[i]);
if (val != NULL)
{
appendStringInfo(str, " = %s", quote_literal_cstr(val));
pfree(val);
}
else
appendStringInfo(str, " IS NULL");
}
sql = pstrdup(str->data);
pfree(str->data);
pfree(str);
/*
* Retrieve the desired tuple
*/
ret = SPI_exec(sql, 0);
pfree(sql);
/*
* 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;
}
static Oid
get_relid_from_relname(text *relname_text)
{
RangeVar *relvar;
Relation rel;
Oid relid;
relvar = makeRangeVarFromNameList(textToQualifiedNameList(relname_text));
rel = heap_openrv(relvar, AccessShareLock);
relid = RelationGetRelid(rel);
relation_close(rel, AccessShareLock);
return relid;
}
/*
* generate_relation_name - copied from ruleutils.c
* Compute the name to display for a relation specified by OID
*
* The result includes all necessary quoting and schema-prefixing.
*/
static char *
generate_relation_name(Oid relid)
{
HeapTuple tp;
Form_pg_class reltup;
char *nspname;
char *result;
tp = SearchSysCache(RELOID,
ObjectIdGetDatum(relid),
0, 0, 0);
if (!HeapTupleIsValid(tp))
elog(ERROR, "cache lookup failed for relation %u", relid);
reltup = (Form_pg_class) GETSTRUCT(tp);
/* Qualify the name if not visible in search path */
if (RelationIsVisible(relid))
nspname = NULL;
else
nspname = get_namespace_name(reltup->relnamespace);
result = quote_qualified_identifier(nspname, NameStr(reltup->relname));
ReleaseSysCache(tp);
return result;
}
static remoteConn *
getConnectionByName(const char *name)
{
remoteConnHashEnt *hentry;
char key[NAMEDATALEN];
if (!remoteConnHash)
remoteConnHash = createConnHash();
MemSet(key, 0, NAMEDATALEN);
snprintf(key, NAMEDATALEN - 1, "%s", name);
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;
bool found;
char key[NAMEDATALEN];
if (!remoteConnHash)
remoteConnHash = createConnHash();
MemSet(key, 0, NAMEDATALEN);
snprintf(key, NAMEDATALEN - 1, "%s", name);
hentry = (remoteConnHashEnt *) hash_search(remoteConnHash, key,
HASH_ENTER, &found);
if (found)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("duplicate connection name")));
hentry->rconn = rconn;
strncpy(hentry->name, name, NAMEDATALEN - 1);
}
static void
deleteConnection(const char *name)
{
remoteConnHashEnt *hentry;
bool found;
char key[NAMEDATALEN];
if (!remoteConnHash)
remoteConnHash = createConnHash();
MemSet(key, 0, NAMEDATALEN);
snprintf(key, NAMEDATALEN - 1, "%s", name);
hentry = (remoteConnHashEnt *) hash_search(remoteConnHash,
key, HASH_REMOVE, &found);
if (!hentry)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("undefined connection name")));
}
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