Re: [libdbi-devel] Memory leak in dbi_result.c

[Markus H. <mar...@mh...>]

Hi Tom,

thank you for sharing the patch. The patched sources pass the tests  
without problems, but I'd like to set up your test case to make sure  
the patch indeed fixes a problem on my OS as well. I'll take care of  
this shortly.

regards,
Markus

Quoting Tom Lane <tg...@ss...>:

> A loop such as the following leaks memory in libdbi 0.8.3:
>
>
> 	for (n = 0; n < 100000; n++) {
>
> 	res = dbi_conn_query(conn, "SELECT * FROM foo;");
>
> 	if (!dbi_result_first_row(res)) {
> 		fprintf(stderr, "dbi_result_first_row() failed.\n");
> 		exit(1);
> 	}
>
> 	for (i = 0; i < 2; i++) {
> 		do {
> 			val = dbi_result_get_int(res, "val");
> 			if (n == 0)
> 			  printf("val: %d\n", val);
>
> 		} while (dbi_result_next_row(res));
>
> 		/* Rewind for the next iteration of the for() loop */
> 		if (!dbi_result_first_row(res)) {
> 			fprintf(stderr, "dbi_result_first_row() failed.\n");
> 			exit(1);
> 		}
> 	}
>
> 	dbi_result_free(res);
>
> 	}
>
>
> This patch appears to fix it:
>
>
> diff -Naur libdbi-0.8.3.orig/src/dbi_result.c libdbi-0.8.3/src/dbi_result.c
> --- libdbi-0.8.3.orig/src/dbi_result.c	2008-01-23 11:37:36.000000000 -0500
> +++ libdbi-0.8.3/src/dbi_result.c	2011-09-06 20:51:34.610449576 -0400
> @@ -1533,7 +1533,7 @@
>  }
>
>  static int _is_row_fetched(dbi_result_t *result, unsigned long long row) {
> -  if (!result->rows || (row >= result->numrows_matched)) return -1;
> +  if (!result->rows || (row > result->numrows_matched)) return -1;
>    return !(result->rows[row] == NULL);
>  }
>
>
>
> This was discovered by some folks at Bull, who also deserve credit for
> the patch, but I don't have a full name.
>
> 			regards, tom lane
>
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-- 
Markus Hoenicka
http://www.mhoenicka.de
AQ score 38