| Volkan YAZICI 2005-04-18, 8:24 pm |
| Hi all,
Could anybody help me to figure out the reason of the endless loop
after pg_query() line:
/tmp$ cat example-copy.php
<?php
$conn = pg_connect("user=knt dbname=template1")
or die("Connection failed!\nRelated error message: ".
pg_last_error($conn)
);
$res = pg_query($conn, "COPY ornektablo FROM stdin");
/*
* If a pg_end_copy() call won't make in here, it will stuck to this
* line of the code with an endless loop (and a 100% CPU usage in
* the proccess side).
*/
if ( pg_result_status($re
s) != PGSQL_COPY_IN )
die("An unexpected result occured!\n");
pg_close($conn);
?>
/tmp$ php example-copy.php
# Waiting and waiting `n waiting...
# (CPU Usage: 99%-100%)
The same program written using libpq works without any problem:
/tmp$ cat example-copy.c
#include <libpq-fe.h>
#include <stdlib.h>
#include <libpq-fe.h>
int main(void)
{
PGconn *conn;
PGresult *res;
conn = PQconnectdb("dbname=template1");
if ( PQstatus(conn) != CONNECTION_OK ) {
fprintf(stderr, "Connection failed!\n");
fprintf(stderr, "Related error message: %s",
PQerrorMessage(conn)
);
PQfinish(conn);
exit(1);
}
res = PQexec(conn, "COPY ornektablo FROM stdin");
if ( PQresultStatus(res) != PGRES_COPY_IN ) {
fprintf(stderr, "An unexpected result occured!\n");
PQclear(res);
PQfinish(conn);
exit(1);
}
PQfinish(conn);
return 0;
}
/tmp$ gcc -Wall -lpq example-copy.c && ./a.out
/tmp$ _
# Program ends normally.
It seems like a PHP bug related with the handling of stdin between
PostgreSQL and PHP. (I executed above PHP script from the command
line, but the result is same when you'd use a web server too.) When I
look at the source code of pg_query() function, it just makes a simple
call to PQexec() after controlling taken input. Also, that encouraged
me to think about stdin handling once more.
Any comments are welcome.
Regards.
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