* Bruce Momjian wrote:
> I think what you are seeing is that the getaddrinfo memory is placed in
> the PGconn structure that isn't freed until PQclear is called. Does
> your test call PQclear()?
s/PQclear/PQfinish/
It does call PQclear on the result, and PQfinish on the connection.
The code is attached.
With postgres doing the dns lookup:
fubar:~# while true; do ps aux|grep -v grep|grep test; sleep 30; done
root 3245 3.6 0.2 4056 1352 pts/3 S+ 10:37 0:01 ./test
root 3245 3.6 0.3 4056 1456 pts/3 S+ 10:37 0:02 ./test
root 3245 3.7 0.3 4184 1560 pts/3 S+ 10:37 0:03 ./test
root 3245 3.7 0.3 4312 1668 pts/3 R+ 10:37 0:04 ./test
root 3245 3.6 0.3 4440 1760 pts/3 S+ 10:37 0:05 ./test
with an output of:
called PQconnectdb: 0x804a008
called PQexec: 0x80dcbe0
calling PQclear: 0x80dcbe0
calling PQfinish: 0x804a008
...
called PQconnectdb: 0x804a008
called PQexec: 0x80dcea0
calling PQclear: 0x80dcea0
calling PQfinish: 0x804a008
...
called PQconnectdb: 0x804a008
called PQexec: 0x80dd620
calling PQclear: 0x80dd620
calling PQfinish: 0x804a008
...
and valgrind complaining about lost blocks:
==3290== 35224 bytes in 1258 blocks are definitely lost in loss record 8 of 8
==3290== at 0x1B90459D: malloc (vg_replace_malloc.c:130)
==3290== by 0x1BC38E3B: (within /lib/tls/i686/cmov/libresolv-2.3.2.so)
==3290== by 0x1BC37B92: __libc_res_nquery (in
/lib/tls/i686/cmov/libresolv-2.3.2.so)
==3290== by 0x1BC38289: (within /lib/tls/i686/cmov/libresolv-2.3.2.so)
==3290== by 0x1BC37E8F: __libc_res_nsearch (in
/lib/tls/i686/cmov/libresolv-2.3.2.so)
==3290== by 0x1BDA307D: ???
==3290== by 0x1B9EFA65: (within /lib/tls/i686/cmov/libc-2.3.2.so)
==3290== by 0x1B9F0673: getaddrinfo (in /lib/tls/i686/cmov/libc-2.3.2.so)
==3290== by 0x1B925701: getaddrinfo_all (in /usr/lib/libpq.so.3.1)
==3290== by 0x1B916F0B: (within /usr/lib/libpq.so.3.1)
==3290== by 0x1B9164B9: PQconnectStart (in /usr/lib/libpq.so.3.1)
==3290== by 0x1B916441: PQconnectdb (in /usr/lib/libpq.so.3.1)
With the IP in the host field:
fubar:~# while true; do ps aux|grep -v grep|grep test; sleep 30; done
root 3312 1.4 0.2 3872 1092 pts/3 S+ 10:42 0:00 ./test
root 3312 1.6 0.2 3872 1092 pts/3 S+ 10:42 0:00 ./test
root 3312 1.9 0.2 3872 1092 pts/3 S+ 10:42 0:01 ./test
root 3312 2.0 0.2 3872 1092 pts/3 S+ 10:42 0:01 ./test
root 3312 2.0 0.2 3872 1092 pts/3 S+ 10:42 0:02 ./test
output:
called PQconnectdb: 0x804a008
called PQexec: 0x80525b8
calling PQclear: 0x80525b8
calling PQfinish: 0x804a008
...
called PQconnectdb: 0x804a008
called PQexec: 0x80525b8
calling PQclear: 0x80525b8
calling PQfinish: 0x804a008
...
called PQconnectdb: 0x804a008
called PQexec: 0x80525b8
calling PQclear: 0x80525b8
calling PQfinish: 0x804a008
...
and no leaking output from valgrind.
Best regards,
Karsten Desler
#include <postgresql/libpq-fe.h>
#include <stdio.h>
// gcc -lpq -o test test.c
static const char *conninfo = "host=xxx.xxx.xx.xx port=5432 dbname=xxx user=xxx password=xxx connect_timeout=30";
// static const char *conninfo = "host=db.xxx.de port=5432 dbname=xxx user=xxx password=xxx connect_timeout=30";
static int fetch_from_database(void)
{
PGconn *conn;
PGresult *res;
char sql[32768];
int c_username, c_ip;
int ret = -1;
unsigned int max, i;
conn = PQconnectdb(conninfo);
printf("called PQconnectdb: %p\n", conn);
if (!conn) {
printf("connection failed\n");
goto out_finish;
}
snprintf(sql, sizeof(sql), "SELECT username,ip FROM extras WHERE server=(SELECT id FROM servers WHERE IP='xxx.xxx.xx.xx') ORDER BY username");
res = PQexec(conn, sql);
printf("called PQexec: %p\n", res);
if (PQresultStatus(res) != PGRES_TUPLES_OK) {
printf("couldn't get data\n");
goto out;
}
max = (unsigned int)PQntuples(res);
if (max == 0) {
ret = 0;
goto out;
}
if (max > 64) {
printf("too many results\n");
goto out;
}
c_username = PQfnumber(res, "username");
c_ip = PQfnumber(res, "ip");
if (c_username == -1 || c_ip == -1) {
printf("weird table structure found\n");
goto out;
}
for (i = 0; i < max; i++) {
(void)PQgetvalue(res, i, c_username);
(void)PQgetvalue(res, i, c_ip);
}
ret = 0;
out:
printf("calling PQclear: %p\n", res);
PQclear(res);
out_finish:
printf("calling PQfinish: %p\n", conn);
PQfinish(conn);
res = NULL;
conn = NULL;
return ret;
}
int main(void)
{
while(fetch_from_database() == 0);
return 0;
}
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