[ http://issues.apache.org/jira/brows...244
7666 ]

Jim Gallacher commented on MODPYTHON-184:
-----------------------------------------


[[ Old comment, sent by email on Wed, 16 Aug 2006 17:44:21 -0400 ]]


Actually I don't think apr_pool_destroy() in table_dealloc is actually
destroying the pool. I've been poking around in the code and there is
something odd going on here.

I tried registering a cleanup in MpTable_New() using:

apr_pool_cleanup_register(t->pool,
"pool cleanup called", 							   cleanup_test,
apr_pool_cleaunp_null);

The cleanup_test callback just logs the "pool cleanup called" message to
a file.

apr_pool_destroy() is getting called in table_dealloc, but cleanup_test
never gets called which indicates that the pool is *not* being
destroyed, and hence our memory leak.

I tried your trick of immediately calling apr_pool_destroy in
MpTable_New(), and cleanup_test does get called there.

So, the big question is... why is the pool not being destroyed?

Can anyone offer some insight here?

The attached diff is for trunk if anyone wants to play around with it.

Jim
Index: tableobject.c
 ========================================
===========================
--- tableobject.c	(revision 431994)
+++ tableobject.c	(working copy)
@@ -59,6 +59,19 @@
return (PyObject *)result;
}

+
+
+apr_status_t cleanup_test(void *msg)
+{
+    FILE *f;
+    f = fopen("/tmp/debug_table.log", "a+");
+    fprintf(f, "%s\n", (char *)msg);
+    fclose(f);
+
+    return 0;
+}
+
+
/**
** MpTable_New
**
@@ -78,6 +91,8 @@
tableobject *t;
apr_pool_t *p;

+    cleanup_test("MpTable_New() called");
+
/* XXX need second arg abort function to report mem error */
apr_pool_create_ex(&p, NULL, NULL, NULL);

@@ -86,7 +101,12 @@

/* remember the pointer to our own pool */
t->pool = p;
+    apr_pool_cleanup_register(p, "  pool cleanup called", cleanup_test, apr
_pool_cleanup_null);

+    /* Uncomment this to test that cleanup_test is getting called correctly
.
+    apr_pool_destroy(t->pool);
+    */
+
return (PyObject *)t;

}
@@ -99,10 +119,13 @@

static void table_dealloc(register tableobject *self)
{
+    cleanup_test("table_dealloc:");

if (MpTable_Check(self)) {
-        if (self->pool)
+        if (self->pool) {
+            cleanup_test("  preparing to destroy the pool");
apr_pool_destroy(self->pool);
+        }
PyObject_Del(self);
}
else


> Memory leak apache.table()
> --------------------------
>
>                 Key: MODPYTHON-184
>                 URL: http://issues.apache.org/jira/browse/MODPYTHON-184
>             Project: mod_python
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 3.3, 3.2.10
>            Reporter: Jim Gallacher
>         Assigned To: Jim Gallacher
>             Fix For: 3.3
>
>         Attachments: MP184-2006-08-25-grahamd-1.diff
>
>
> There is a memory leak in apache.table().
> from mod_python import apache
> def handler(req):
>     req.content_type = 'text/plain'
>     t = apache.make_table()
>     req.write('ok table:')
>     return apache.OK
> Using mpm-worker with StartServers 2, and 20000 requests results in memory
 consumption going from 1.2% to 9.3% per process. (ie approx 8k per request)
> This will have an impact on FieldStorage which makes use of apache.make_table(), w
hich is the deprecated name for apache.table()

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