mirror/postgresql
2
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2024-12-27 08:39:28 +08:00
Code Issues Packages Projects Releases Wiki Activity
1b3d4cefe8
postgresql/contrib/dblink/dblink.c

2049 lines
49 KiB
C
Raw Blame History

/*
* dblink.c
*
* Functions returning results from a remote database
*
* Joe Conway <mail@joeconway.com>
*
* Copyright (c) 2001, 2002 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 "dblink.h"
/*
* Internal declarations
*/
static dblink_results *init_dblink_results(MemoryContext fn_mcxt);
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 dblink_results *get_res_ptr(int32 res_id_index);
static void append_res_ptr(dblink_results * results);
static void remove_res_ptr(dblink_results * results);
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;
#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)
/*
* Create a persistent connection to another database
*/
PG_FUNCTION_INFO_V1(dblink_connect);
Datum
dblink_connect(PG_FUNCTION_ARGS)
{
char *connstr = GET_STR(PG_GETARG_TEXT_P(0));
char *msg;
text *result_text;
MemoryContext oldcontext;
if (persistent_conn != NULL)
PQfinish(persistent_conn);
oldcontext = MemoryContextSwitchTo(TopMemoryContext);
persistent_conn = PQconnectdb(connstr);
MemoryContextSwitchTo(oldcontext);
if (PQstatus(persistent_conn) == CONNECTION_BAD)
{
msg = pstrdup(PQerrorMessage(persistent_conn));
PQfinish(persistent_conn);
persistent_conn = NULL;
elog(ERROR, "dblink_connect: connection error: %s", msg);
}
result_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum("OK")));
PG_RETURN_TEXT_P(result_text);
}
/*
* Clear a persistent connection to another database
*/
PG_FUNCTION_INFO_V1(dblink_disconnect);
Datum
dblink_disconnect(PG_FUNCTION_ARGS)
{
text *result_text;
if (persistent_conn != NULL)
PQfinish(persistent_conn);
persistent_conn = NULL;
result_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum("OK")));
PG_RETURN_TEXT_P(result_text);
}
/*
* 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;
text *result_text;
char *curname = GET_STR(PG_GETARG_TEXT_P(0));
char *sql = GET_STR(PG_GETARG_TEXT_P(1));
StringInfo str = makeStringInfo();
if (persistent_conn != NULL)
conn = persistent_conn;
else
elog(ERROR, "dblink_open: no connection available");
res = PQexec(conn, "BEGIN");
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
msg = pstrdup(PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
persistent_conn = NULL;
elog(ERROR, "dblink_open: begin error: %s", msg);
}
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))
{
msg = pstrdup(PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
persistent_conn = NULL;
elog(ERROR, "dblink: sql error: %s", msg);
}
result_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum("OK")));
PG_RETURN_TEXT_P(result_text);
}
/*
* closes a cursor
*/
PG_FUNCTION_INFO_V1(dblink_close);
Datum
dblink_close(PG_FUNCTION_ARGS)
{
PGconn *conn = NULL;
PGresult *res = NULL;
char *curname = GET_STR(PG_GETARG_TEXT_P(0));
StringInfo str = makeStringInfo();
text *result_text;
char *msg;
if (persistent_conn != NULL)
conn = persistent_conn;
else
elog(ERROR, "dblink_close: no connection available");
appendStringInfo(str, "CLOSE %s", curname);
/* close the cursor */
res = PQexec(conn, str->data);
if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
{
msg = pstrdup(PQerrorMessage(conn));
PQclear(res);
PQfinish(persistent_conn);
persistent_conn = NULL;
elog(ERROR, "dblink_close: sql error: %s", msg);
}
PQclear(res);
/* commit the transaction */
res = PQexec(conn, "COMMIT");
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
msg = pstrdup(PQerrorMessage(conn));
PQclear(res);
PQfinish(persistent_conn);
persistent_conn = NULL;
elog(ERROR, "dblink_close: commit error: %s", msg);
}
PQclear(res);
result_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum("OK")));
PG_RETURN_TEXT_P(result_text);
}
/*
* 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;
/* 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 = GET_STR(PG_GETARG_TEXT_P(0));
int howmany = PG_GETARG_INT32(1);
/* 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 (persistent_conn != NULL)
conn = persistent_conn;
else
elog(ERROR, "dblink_fetch: no connection available");
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))
{
msg = pstrdup(PQerrorMessage(conn));
PQclear(res);
PQfinish(persistent_conn);
persistent_conn = NULL;
elog(ERROR, "dblink_fetch: sql error: %s", msg);
}
else if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
/* cursor does not exist - closed already or bad name */
PQclear(res);
elog(ERROR, "dblink_fetch: 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)
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 if (functyptype == 'b')
elog(ERROR, "dblink_fetch: invalid kind of return type specified for function");
else
elog(ERROR, "dblink_fetch: unknown kind of return type specified for function");
/* 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;
/* 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;
/* 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 (fcinfo->nargs == 2)
{
connstr = GET_STR(PG_GETARG_TEXT_P(0));
sql = GET_STR(PG_GETARG_TEXT_P(1));
conn = PQconnectdb(connstr);
if (PQstatus(conn) == CONNECTION_BAD)
{
msg = pstrdup(PQerrorMessage(conn));
PQfinish(conn);
elog(ERROR, "dblink: connection error: %s", msg);
}
}
else if (fcinfo->nargs == 1)
{
sql = GET_STR(PG_GETARG_TEXT_P(0));
if (persistent_conn != NULL)
conn = persistent_conn;
else
elog(ERROR, "dblink: no connection available");
}
else
elog(ERROR, "dblink: wrong number of arguments");
res = PQexec(conn, sql);
if (!res || (PQresultStatus(res) != PGRES_COMMAND_OK && PQresultStatus(res) != PGRES_TUPLES_OK))
{
msg = pstrdup(PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
if (fcinfo->nargs == 1)
persistent_conn = NULL;
elog(ERROR, "dblink: sql error: %s", msg);
}
else
{
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 (fcinfo->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 if (functyptype == 'b')
elog(ERROR, "Invalid kind of return type specified for function");
else
elog(ERROR, "Unknown kind of return type specified for function");
}
/* 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;
char *sql_cmd_status = NULL;
TupleDesc tupdesc = NULL;
text *result_text;
PGconn *conn = NULL;
char *connstr = NULL;
char *sql = NULL;
if (fcinfo->nargs == 2)
{
connstr = GET_STR(PG_GETARG_TEXT_P(0));
sql = GET_STR(PG_GETARG_TEXT_P(1));
conn = PQconnectdb(connstr);
if (PQstatus(conn) == CONNECTION_BAD)
{
msg = pstrdup(PQerrorMessage(conn));
PQfinish(conn);
elog(ERROR, "dblink_exec: connection error: %s", msg);
}
}
else if (fcinfo->nargs == 1)
{
sql = GET_STR(PG_GETARG_TEXT_P(0));
if (persistent_conn != NULL)
conn = persistent_conn;
else
elog(ERROR, "dblink_exec: no connection available");
}
else
elog(ERROR, "dblink_exec: wrong number of arguments");
res = PQexec(conn, sql);
if (!res || (PQresultStatus(res) != PGRES_COMMAND_OK && PQresultStatus(res) != PGRES_TUPLES_OK))
{
msg = pstrdup(PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
if (fcinfo->nargs == 1)
persistent_conn = NULL;
elog(ERROR, "dblink_exec: sql error: %s", msg);
}
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, false);
/*
* and save a copy of the command status string to return as
* our result tuple
*/
sql_cmd_status = 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 (fcinfo->nargs == 2)
PQfinish(conn);
result_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(sql_cmd_status)));
PG_RETURN_TEXT_P(result_text);
}
/*
* Note: this original version of dblink is DEPRECATED;
* it *will* be removed in favor of the new version on next release
*/
PG_FUNCTION_INFO_V1(dblink);
Datum
dblink(PG_FUNCTION_ARGS)
{
PGconn *conn = NULL;
PGresult *res = NULL;
dblink_results *results;
char *optstr;
char *sqlstatement;
char *execstatement;
char *msg;
int ntuples = 0;
ReturnSetInfo *rsi;
if (fcinfo->resultinfo == NULL || !IsA(fcinfo->resultinfo, ReturnSetInfo))
elog(ERROR, "dblink: function called in context that does not accept a set result");
optstr = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(PG_GETARG_TEXT_P(0))));
sqlstatement = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(PG_GETARG_TEXT_P(1))));
if (fcinfo->flinfo->fn_extra == NULL)
{
conn = PQconnectdb(optstr);
if (PQstatus(conn) == CONNECTION_BAD)
{
msg = pstrdup(PQerrorMessage(conn));
PQfinish(conn);
elog(ERROR, "dblink: connection error: %s", msg);
}
execstatement = (char *) palloc(strlen(sqlstatement) + 1);
if (execstatement != NULL)
{
strcpy(execstatement, sqlstatement);
strcat(execstatement, "\0");
}
else
elog(ERROR, "dblink: insufficient memory");
res = PQexec(conn, execstatement);
if (!res || (PQresultStatus(res) != PGRES_COMMAND_OK && PQresultStatus(res) != PGRES_TUPLES_OK))
{
msg = pstrdup(PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
elog(ERROR, "dblink: sql error: %s", msg);
}
else
{
/*
* got results, start fetching them
*/
ntuples = PQntuples(res);
/*
* increment resource index
*/
res_id_index++;
results = init_dblink_results(fcinfo->flinfo->fn_mcxt);
results->tup_num = 0;
results->res_id_index = res_id_index;
results->res = res;
/*
* Append node to res_id to hold pointer to results. Needed by
* dblink_tok to access the data
*/
append_res_ptr(results);
/*
* save pointer to results for the next function manager call
*/
fcinfo->flinfo->fn_extra = (void *) results;
/* close the connection to the database and cleanup */
PQfinish(conn);
rsi = (ReturnSetInfo *) fcinfo->resultinfo;
rsi->isDone = ExprMultipleResult;
PG_RETURN_INT32(res_id_index);
}
}
else
{
/*
* check for more results
*/
results = fcinfo->flinfo->fn_extra;
results->tup_num++;
res_id_index = results->res_id_index;
ntuples = PQntuples(results->res);
if (results->tup_num < ntuples)
{
/*
* fetch them if available
*/
rsi = (ReturnSetInfo *) fcinfo->resultinfo;
rsi->isDone = ExprMultipleResult;
PG_RETURN_INT32(res_id_index);
}
else
{
/*
* or if no more, clean things up
*/
results = fcinfo->flinfo->fn_extra;
remove_res_ptr(results);
PQclear(results->res);
pfree(results);
fcinfo->flinfo->fn_extra = NULL;
rsi = (ReturnSetInfo *) fcinfo->resultinfo;
rsi->isDone = ExprEndResult;
PG_RETURN_NULL();
}
}
PG_RETURN_NULL();
}
/*
* Note: dblink_tok is DEPRECATED;
* it *will* be removed in favor of the new version on next release
*
* dblink_tok
* parse dblink output string
* return fldnum item (0 based)
* based on provided field separator
*/
PG_FUNCTION_INFO_V1(dblink_tok);
Datum
dblink_tok(PG_FUNCTION_ARGS)
{
dblink_results *results;
int fldnum;
text *result_text;
char *result;
int nfields = 0;
int text_len = 0;
results = get_res_ptr(PG_GETARG_INT32(0));
if (results == NULL)
{
if (res_id != NIL)
{
freeList(res_id);
res_id = NIL;
res_id_index = 0;
}
elog(ERROR, "dblink_tok: function called with invalid resource id");
}
fldnum = PG_GETARG_INT32(1);
if (fldnum < 0)
elog(ERROR, "dblink_tok: field number < 0 not permitted");
nfields = PQnfields(results->res);
if (fldnum > (nfields - 1))
elog(ERROR, "dblink_tok: field number %d does not exist", fldnum);
if (PQgetisnull(results->res, results->tup_num, fldnum) == 1)
PG_RETURN_NULL();
else
{
text_len = PQgetlength(results->res, results->tup_num, fldnum);
result = (char *) palloc(text_len + 1);
if (result != NULL)
{
strcpy(result, PQgetvalue(results->res, results->tup_num, fldnum));
strcat(result, "\0");
}
else
elog(ERROR, "dblink: insufficient memory");
result_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(result)));
PG_RETURN_TEXT_P(result_text);
}
}
/*
* 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);
}
/*
* Note: dblink_last_oid is DEPRECATED;
* it *will* be removed on next release
*
* dblink_last_oid
* return last inserted oid
*/
PG_FUNCTION_INFO_V1(dblink_last_oid);
Datum
dblink_last_oid(PG_FUNCTION_ARGS)
{
dblink_results *results;
results = get_res_ptr(PG_GETARG_INT32(0));
if (results == NULL)
{
if (res_id != NIL)
{
freeList(res_id);
res_id = NIL;
res_id_index = 0;
}
elog(ERROR, "dblink_tok: function called with invalid resource id");
}
PG_RETURN_OID(PQoidValue(results->res));
}
#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;
text *sql_text;
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);
/*
* Make it into TEXT for return to the client
*/
sql_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(sql)));
/*
* And send it
*/
PG_RETURN_TEXT_P(sql_text);
}
/*
* 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;
text *sql_text;
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);
/*
* Make it into TEXT for return to the client
*/
sql_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(sql)));
/*
* And send it
*/
PG_RETURN_TEXT_P(sql_text);
}
/*
* 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;
text *sql_text;
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);
/*
* Make it into TEXT for return to the client
*/
sql_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(sql)));
/*
* And send it
*/
PG_RETURN_TEXT_P(sql_text);
}
/*
* 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)
{
text *result_text;
result_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(debug_query_string)));
PG_RETURN_TEXT_P(result_text);
}
/*************************************************************
* internal functions
*/
/*
* init_dblink_results
* - create an empty dblink_results data structure
*/
static dblink_results *
init_dblink_results(MemoryContext fn_mcxt)
{
MemoryContext oldcontext;
dblink_results *retval;
oldcontext = MemoryContextSwitchTo(fn_mcxt);
retval = (dblink_results *) palloc0(sizeof(dblink_results));
retval->tup_num = -1;
retval->res_id_index = -1;
retval->res = NULL;
MemoryContextSwitchTo(oldcontext);
return retval;
}
/*
* 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 dblink_results *
get_res_ptr(int32 res_id_index)
{
List *ptr;
/*
* short circuit empty list
*/
if (res_id == NIL)
return NULL;
/*
* OK, should be good to go
*/
foreach(ptr, res_id)
{
dblink_results *this_res_id = (dblink_results *) lfirst(ptr);
if (this_res_id->res_id_index == res_id_index)
return this_res_id;
}
return NULL;
}
/*
* Add node to global List res_id
*/
static void
append_res_ptr(dblink_results * results)
{
res_id = lappend(res_id, results);
}
/*
* Remove node from global List
* using res_id_index
*/
static void
remove_res_ptr(dblink_results * results)
{
res_id = lremove(results, res_id);
if (res_id == NIL)
res_id_index = 0;
}
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;
}
Reference in New Issue View Git Blame Copy Permalink