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Here's a small patch for dblink:

Browse Source 
- fixed dblink invalid pointer causing corrupt elog message
   - fixed dblink_tok improper handling of null results
   - fixed examples in README.dblink

Joe Conway
This commit is contained in:
Bruce Momjian 2001-06-18 19:09:50 +00:00
parent ec96f1dacd
commit 10b5f0bea8
2 changed files with 34 additions and 20 deletions
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18
contrib/dblink/README.dblink
View File

@ -24,12 +24,18 @@
*
*/
Version 0.2 (29 May, 2001):
Version 0.3 (14 June, 2001):
Function to test returning data set from remote database
Tested under Linux (Red Hat 6.2 and 7.0) and PostgreSQL 7.1 and 7.2devel
Release Notes:
Version 0.3
- fixed dblink invalid pointer causing corrupt elog message
- fixed dblink_tok improper handling of null results
- fixed examples in README.dblink
Version 0.2
- initial release
@ -124,11 +130,11 @@ to 'fake' a UNION, e.g.
'hostaddr=127.0.0.1 port=5432 dbname=mydb user=postgres password=mypasswd'
,'select f1, f2 from mytable'
) as dblink_p
union
select null,null where false
union all
select null where false
) as t1
where
f1 = 'mycriteria';
dblink_tok(t1.dblink_p,0) = 'mycriteria';
in order to work around an issue with the query optimizer. A more convenient way to approach
this problem is to create a view:
@ -143,8 +149,8 @@ this problem is to create a view:
'hostaddr=127.0.0.1 port=5432 dbname=mydb user=postgres password=mypasswd'
,'select f1, f2 from mytable'
) as dblink_p
union
select null,null where false
union all
select null where false
) as t1;
Then you can simply write:

36
contrib/dblink/dblink.c
View File

@ -57,7 +57,7 @@ dblink(PG_FUNCTION_ARGS)
conn = PQconnectdb(optstr);
if (PQstatus(conn) == CONNECTION_BAD)
{
msg = PQerrorMessage(conn);
msg = pstrdup(PQerrorMessage(conn));
PQfinish(conn);
elog(ERROR, "dblink: connection error: %s", msg);
}
@ -65,7 +65,7 @@ dblink(PG_FUNCTION_ARGS)
res = PQexec(conn, "BEGIN");
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
msg = PQerrorMessage(conn);
msg = pstrdup(PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
elog(ERROR, "dblink: begin error: %s", msg);
@ -84,7 +84,7 @@ dblink(PG_FUNCTION_ARGS)
res = PQexec(conn, execstatement);
if (!res || (PQresultStatus(res) != PGRES_COMMAND_OK && PQresultStatus(res) != PGRES_TUPLES_OK))
{
msg = PQerrorMessage(conn);
msg = pstrdup(PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
elog(ERROR, "dblink: sql error: %s", msg);
@ -96,7 +96,7 @@ dblink(PG_FUNCTION_ARGS)
res = PQexec(conn, "FETCH ALL in mycursor");
if (!res || PQresultStatus(res) != PGRES_TUPLES_OK) {
msg = PQerrorMessage(conn);
msg = pstrdup(PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
elog(ERROR, "dblink: sql error: %s", msg);
@ -230,20 +230,28 @@ dblink_tok(PG_FUNCTION_ARGS)
elog(ERROR, "dblink: field number %d does not exist", fldnum);
}
text_len = PQgetlength(results->res, results->tup_num, fldnum);
if (PQgetisnull(results->res, results->tup_num, fldnum) == 1) {
result = (char *) palloc(text_len + 1);
PG_RETURN_NULL();
if (result != NULL) {
strcpy(result, PQgetvalue(results->res, results->tup_num, fldnum));
strcat(result, "\0");
} else {
elog(ERROR, "dblink: insufficient memory" );
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);
}
result_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(result)));
PG_RETURN_TEXT_P(result_text);
}