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postgresql/contrib/dblink/dblink.c
Bruce Momjian 8f337e86cd Please apply attached patch to contrib/dblink. It adds named persistent 
connections to dblink.

Shridhar Daithanka
2003-06-25 01:10:15 +00:00

1909 lines
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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, 2002, 2003 by 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/catname.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/palloc.h"
#include "utils/dynahash.h"
#include "utils/hsearch.h"
#include "utils/memutils.h"
#include "dblink.h"
typedef struct remoteConn
{
PGconn *con; /* Hold the remote connection */
bool remoteTrFlag; /* Indicates whether or not a transaction
* on remote database is in progress*/
} remoteConn;
/*
* Internal declarations
*/
static remoteConn *getConnectionByName(const char *name);
static HTAB *createConnHash(void);
static bool createNewConnection(const char *name,remoteConn *con);
static void deleteConnection(const char *name);
static char **get_pkey_attnames(Oid relid, int16 *numatts);
static char *get_sql_insert(Oid relid, int16 *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals);
static char *get_sql_delete(Oid relid, int16 *pkattnums, int16 pknumatts, char **tgt_pkattvals);
static char *get_sql_update(Oid relid, int16 *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(int16 *pkattnums, int16 pknumatts, int16 key);
static HeapTuple get_tuple_of_interest(Oid relid, int16 *pkattnums, int16 pknumatts, char **src_pkattvals);
static Oid get_relid_from_relname(text *relname_text);
static TupleDesc pgresultGetTupleDesc(PGresult *res);
static char *generate_relation_name(Oid relid);
/* Global */
List *res_id = NIL;
int res_id_index = 0;
PGconn *persistent_conn = 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 *rcon;
} 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_ERROR(p1, p2) \
do { \
msg = pstrdup(PQerrorMessage(conn)); \
if (res) \
PQclear(res); \
elog(ERROR, "%s: %s: %s", p1, p2, msg); \
} while (0)
#define DBLINK_CONN_NOT_AVAIL(p1) \
do { \
if(conname) \
elog(ERROR, "%s: connection %s not available", p1, conname); \
else \
elog(ERROR, "%s: connection not available", p1); \
} while (0)
#define DBLINK_GET_CONN(p1) \
do { \
char *conname_or_str = GET_STR(PG_GETARG_TEXT_P(0)); \
rcon = getConnectionByName(conname_or_str); \
if(rcon) \
{ \
conn = rcon->con; \
freeconn = false; \
} \
else \
{ \
connstr = conname_or_str; \
conn = PQconnectdb(connstr); \
if (PQstatus(conn) == CONNECTION_BAD) \
{ \
msg = pstrdup(PQerrorMessage(conn)); \
PQfinish(conn); \
elog(ERROR, "%s: connection error: %s", p1, msg); \
} \
} \
} 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 *rcon = NULL;
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)
rcon=(remoteConn *) palloc(sizeof(remoteConn));
conn = PQconnectdb(connstr);
MemoryContextSwitchTo(oldcontext);
if (PQstatus(conn) == CONNECTION_BAD)
{
msg = pstrdup(PQerrorMessage(conn));
PQfinish(conn);
if(rcon)
pfree(rcon);
elog(ERROR, "dblink_connect: connection error: %s", msg);
}
if(connname)
{
rcon->con = conn;
if(createNewConnection(connname, rcon) == false)
{
PQfinish(conn);
pfree(rcon);
elog(ERROR, "dblink_connect: cannot save named connection");
}
}
else
persistent_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 *str = NULL;
remoteConn *rcon = NULL;
PGconn *conn = NULL;
if (PG_NARGS() ==1 )
{
str = GET_STR(PG_GETARG_TEXT_P(0));
rcon = getConnectionByName(str);
if (rcon)
conn = rcon->con;
}
else
conn = persistent_conn;
if (!conn)
{
if (str)
elog(ERROR,"dblink_disconnect: connection named \"%s\" not found",
str);
else
elog(ERROR,"dblink_disconnect: connection not found");
}
PQfinish(conn);
if (rcon)
{
deleteConnection(str);
pfree(rcon);
}
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 *rcon = NULL;
if(PG_NARGS() == 2)
{
curname = GET_STR(PG_GETARG_TEXT_P(0));
sql = GET_STR(PG_GETARG_TEXT_P(1));
conn = persistent_conn;
}
else if(PG_NARGS() == 3)
{
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
sql = GET_STR(PG_GETARG_TEXT_P(2));
rcon = getConnectionByName(conname);
if (rcon)
conn = rcon->con;
}
if (!conn)
DBLINK_CONN_NOT_AVAIL("dblink_open");
res = PQexec(conn, "BEGIN");
if (PQresultStatus(res) != PGRES_COMMAND_OK)
DBLINK_RES_ERROR("dblink_open", "begin error");
PQclear(res);
appendStringInfo(str, "DECLARE %s CURSOR FOR %s", curname, sql);
res = PQexec(conn, str->data);
if (!res ||
(PQresultStatus(res) != PGRES_COMMAND_OK &&
PQresultStatus(res) != PGRES_TUPLES_OK))
DBLINK_RES_ERROR("dblink_open", "sql 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 *rcon = NULL;
if (PG_NARGS() == 1)
{
curname = GET_STR(PG_GETARG_TEXT_P(0));
conn = persistent_conn;
}
else if (PG_NARGS()==2)
{
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
rcon = getConnectionByName(conname);
if(rcon)
conn = rcon->con;
}
if (!conn)
DBLINK_CONN_NOT_AVAIL("dblink_close");
appendStringInfo(str, "CLOSE %s", curname);
/* close the cursor */
res = PQexec(conn, str->data);
if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
DBLINK_RES_ERROR("dblink_close", "sql error");
PQclear(res);
/* commit the transaction */
res = PQexec(conn, "COMMIT");
if (PQresultStatus(res) != PGRES_COMMAND_OK)
DBLINK_RES_ERROR("dblink_close", "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;
TupleTableSlot *slot;
AttInMetadata *attinmeta;
char *msg;
PGresult *res = NULL;
MemoryContext oldcontext;
char *conname = NULL;
remoteConn *rcon=NULL;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
Oid functypeid;
char functyptype;
Oid funcid = fcinfo->flinfo->fn_oid;
PGconn *conn = NULL;
StringInfo str = makeStringInfo();
char *curname = NULL;
int howmany = 0;
if (PG_NARGS() == 3)
{
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
howmany = PG_GETARG_INT32(2);
rcon = getConnectionByName(conname);
if(rcon)
conn = rcon->con;
}
else if (PG_NARGS() == 2)
{
curname = GET_STR(PG_GETARG_TEXT_P(0));
howmany = PG_GETARG_INT32(1);
conn = persistent_conn;
}
if(!conn)
DBLINK_CONN_NOT_AVAIL("dblink_fetch");
/* 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))
{
DBLINK_RES_ERROR("dblink_fetch", "sql error");
}
else if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
/* cursor does not exist - closed already or bad name */
PQclear(res);
elog(ERROR, "dblink_fetch: cursor not found: %s", 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)
SRF_RETURN_DONE(funcctx);
/* check typtype to see if we have a predetermined return type */
functypeid = get_func_rettype(funcid);
functyptype = get_typtype(functypeid);
if (functyptype == 'c')
tupdesc = TypeGetTupleDesc(functypeid, NIL);
else if (functyptype == 'p' && functypeid == RECORDOID)
tupdesc = pgresultGetTupleDesc(res);
else
elog(ERROR, "dblink_fetch: return type must be a row type");
/* store needed metadata for subsequent calls */
slot = TupleDescGetSlot(tupdesc);
funcctx->slot = slot;
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;
slot = funcctx->slot;
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 = TupleGetDatum(slot, 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;
TupleTableSlot *slot;
AttInMetadata *attinmeta;
char *msg;
PGresult *res = NULL;
bool is_sql_cmd = false;
char *sql_cmd_status = NULL;
MemoryContext oldcontext;
bool freeconn = true;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
Oid functypeid;
char functyptype;
Oid funcid = fcinfo->flinfo->fn_oid;
PGconn *conn = NULL;
char *connstr = NULL;
char *sql = NULL;
char *conname = NULL;
remoteConn *rcon=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);
if (PG_NARGS() == 2)
{
DBLINK_GET_CONN("dblink");
sql = GET_STR(PG_GETARG_TEXT_P(1));
}
else if (PG_NARGS() == 1)
{
conn = persistent_conn;
sql = GET_STR(PG_GETARG_TEXT_P(0));
}
else
elog(ERROR, "dblink: wrong number of arguments");
if(!conn)
DBLINK_CONN_NOT_AVAIL("dblink_record");
res = PQexec(conn, sql);
if (!res || (PQresultStatus(res) != PGRES_COMMAND_OK && PQresultStatus(res) != PGRES_TUPLES_OK))
DBLINK_RES_ERROR("dblink", "sql error");
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, false);
/*
* 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 && PG_NARGS() == 2)
PQfinish(conn);
/* fast track when no results */
if (funcctx->max_calls < 1)
SRF_RETURN_DONE(funcctx);
/* check typtype to see if we have a predetermined return type */
functypeid = get_func_rettype(funcid);
functyptype = get_typtype(functypeid);
if (!is_sql_cmd)
{
if (functyptype == 'c')
tupdesc = TypeGetTupleDesc(functypeid, NIL);
else if (functyptype == 'p' && functypeid == RECORDOID)
tupdesc = pgresultGetTupleDesc(res);
else
elog(ERROR, "dblink: return type must be a row type");
}
/* store needed metadata for subsequent calls */
slot = TupleDescGetSlot(tupdesc);
funcctx->slot = slot;
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;
slot = funcctx->slot;
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 = TupleGetDatum(slot, 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 *rcon=NULL;
bool freeconn = true;
if (PG_NARGS() == 2)
{
DBLINK_GET_CONN("dblink_exec");
sql = GET_STR(PG_GETARG_TEXT_P(1));
}
else if (PG_NARGS() == 1)
{
conn = persistent_conn;
sql = GET_STR(PG_GETARG_TEXT_P(0));
}
else
elog(ERROR, "dblink_exec: wrong number of arguments");
if(!conn)
DBLINK_CONN_NOT_AVAIL("dblink_exec");
res = PQexec(conn, sql);
if (!res ||
(PQresultStatus(res) != PGRES_COMMAND_OK &&
PQresultStatus(res) != PGRES_TUPLES_OK))
DBLINK_RES_ERROR("dblink_exec", "sql error");
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, false);
/*
* and save a copy of the command status string to return as
* our result tuple
*/
sql_cmd_status = GET_TEXT(PQcmdStatus(res));
}
else
elog(ERROR, "dblink_exec: queries returning results not allowed");
PQclear(res);
/* if needed, close the connection to the database and cleanup */
if (freeconn && fcinfo->nargs == 2)
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;
TupleTableSlot *slot;
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))
elog(ERROR, "dblink_get_pkey: relation does not exist");
/*
* need a tuple descriptor representing one INT and one TEXT
* column
*/
tupdesc = CreateTemplateTupleDesc(2, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "position",
INT4OID, -1, 0, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "colname",
TEXTOID, -1, 0, false);
/* allocate a slot for a tuple with this tupdesc */
slot = TupleDescGetSlot(tupdesc);
/* assign slot to function context */
funcctx->slot = slot;
/*
* 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;
slot = funcctx->slot;
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 = TupleGetDatum(slot, 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;
int16 *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))
elog(ERROR, "dblink_build_sql_insert: relation does not exist");
pkattnums = (int16 *) PG_GETARG_POINTER(1);
pknumatts_tmp = PG_GETARG_INT32(2);
if (pknumatts_tmp <= SHRT_MAX)
pknumatts = pknumatts_tmp;
else
elog(ERROR, "Bad input value for pknumatts; too large");
/*
* There should be at least one key attribute
*/
if (pknumatts == 0)
elog(ERROR, "dblink_build_sql_insert: 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)
elog(ERROR, "dblink_build_sql_insert: source key array length does not 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)
elog(ERROR, "dblink_build_sql_insert: target key array length does not 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;
int16 *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))
elog(ERROR, "dblink_build_sql_delete: relation does not exist");
pkattnums = (int16 *) PG_GETARG_POINTER(1);
pknumatts_tmp = PG_GETARG_INT32(2);
if (pknumatts_tmp <= SHRT_MAX)
pknumatts = pknumatts_tmp;
else
elog(ERROR, "Bad input value for pknumatts; too large");
/*
* There should be at least one key attribute
*/
if (pknumatts == 0)
elog(ERROR, "dblink_build_sql_insert: 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)
elog(ERROR, "dblink_build_sql_insert: target key array length does not 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;
int16 *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))
elog(ERROR, "dblink_build_sql_update: relation does not exist");
pkattnums = (int16 *) PG_GETARG_POINTER(1);
pknumatts_tmp = PG_GETARG_INT32(2);
if (pknumatts_tmp <= SHRT_MAX)
pknumatts = pknumatts_tmp;
else
elog(ERROR, "Bad input value for pknumatts; too large");
/*
* There should be one source array key values for each key attnum
*/
if (pknumatts == 0)
elog(ERROR, "dblink_build_sql_insert: 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)
elog(ERROR, "dblink_build_sql_insert: source key array length does not 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)
elog(ERROR, "dblink_build_sql_insert: target key array length does not 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_openr(IndexRelationName, AccessShareLock);
ScanKeyEntryInitialize(&entry, 0, Anum_pg_index_indrelid,
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)
{
i = 0;
while (index->indkey[i++] != 0)
(*numatts)++;
if (*numatts > 0)
{
result = (char **) palloc(*numatts * sizeof(char *));
for (i = 0; i < *numatts; i++)
result[i] = SPI_fname(tupdesc, index->indkey[i]);
}
break;
}
}
heap_endscan(scan);
heap_close(indexRelation, AccessShareLock);
relation_close(rel, AccessShareLock);
return result;
}
static char *
get_sql_insert(Oid relid, int16 *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)
elog(ERROR, "dblink_build_sql_insert: 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, int16 *pkattnums, int16 pknumatts, char **tgt_pkattvals)
{
Relation rel;
char *relname;
TupleDesc tupdesc;
int natts;
StringInfo str = makeStringInfo();
char *sql;
char *val;
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[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
{
elog(ERROR, "Target key array must not be NULL");
val = NULL; /* keep compiler quiet */
}
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, int16 *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)
elog(ERROR, "dblink_build_sql_update: 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[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(int16 *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[i])
return i;
return -1;
}
static HeapTuple
get_tuple_of_interest(Oid relid, int16 *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)
elog(ERROR, "get_tuple_of_interest: SPI_connect 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[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))
elog(ERROR, "get_tuple_of_interest: Source criteria may not match more than one record.");
else if (ret == SPI_OK_SELECT && SPI_processed == 1)
{
SPITupleTable *tuptable = SPI_tuptable;
tuple = SPI_copytuple(tuptable->vals[0]);
return tuple;
}
else
{
/*
* no qualifying tuples
*/
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, "get_relid_from_relname"));
rel = heap_openrv(relvar, AccessShareLock);
relid = RelationGetRelid(rel);
relation_close(rel, AccessShareLock);
return relid;
}
static TupleDesc
pgresultGetTupleDesc(PGresult *res)
{
int natts;
AttrNumber attnum;
TupleDesc desc;
char *attname;
int32 atttypmod;
int attdim;
bool attisset;
Oid atttypid;
int i;
/*
* allocate a new tuple descriptor
*/
natts = PQnfields(res);
if (natts < 1)
elog(ERROR, "cannot create a description for empty results");
desc = CreateTemplateTupleDesc(natts, false);
attnum = 0;
for (i = 0; i < natts; i++)
{
/*
* for each field, get the name and type information from the
* query result and have TupleDescInitEntry fill in the attribute
* information we need.
*/
attnum++;
attname = PQfname(res, i);
atttypid = PQftype(res, i);
atttypmod = PQfmod(res, i);
if (PQfsize(res, i) != get_typlen(atttypid))
elog(ERROR, "Size of remote field \"%s\" does not match size "
"of local type \"%s\"",
attname,
format_type_with_typemod(atttypid, atttypmod));
attdim = 0;
attisset = false;
TupleDescInitEntry(desc, attnum, attname, atttypid,
atttypmod, attdim, attisset);
}
return desc;
}
/*
* 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 of relation %u failed", 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->rcon);
return(NULL);
}
static HTAB *
createConnHash(void)
{
HASHCTL ctl;
HTAB *ptr;
ctl.keysize = NAMEDATALEN;
ctl.entrysize = sizeof(remoteConnHashEnt);
ptr=hash_create("Remote Con hash", NUMCONN, &ctl, HASH_ELEM);
if(!ptr)
elog(ERROR,"Can not create connections hash table. Out of memory");
return(ptr);
}
static bool
createNewConnection(const char *name, remoteConn *con)
{
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(!hentry)
elog(ERROR, "failed to create connection");
if(found)
{
elog(NOTICE, "cannot use a connection name more than once");
return false;
}
hentry->rcon = con;
strncpy(hentry->name, name, NAMEDATALEN - 1);
return true;
}
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)
elog(WARNING,"Trying to delete a connection that does not exist");
}
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