X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=src%2Frrdtool.c;h=161037caf347596ced034fac0ed9ab004348aa8a;hb=1b3e36851fc2a6535379718674c1473b148202b4;hp=ea96290555670542dfdcd116f90006dc85cf1c50;hpb=7293eb23871200cea4de5c594610fe782891339a;p=collectd.git

diff --git a/src/rrdtool.c b/src/rrdtool.c
index ea962905..161037ca 100644
--- a/src/rrdtool.c
+++ b/src/rrdtool.c
@@ -24,6 +24,8 @@
 #include "common.h"
 #include "utils_avltree.h"
 
+#include <rrd.h>
+
 #if HAVE_PTHREAD_H
 # include <pthread.h>
 #endif
@@ -37,9 +39,21 @@ struct rrd_cache_s
 	char **values;
 	time_t first_value;
 	time_t last_value;
+	enum
+	{
+		FLAG_NONE   = 0x00,
+		FLAG_QUEUED = 0x01
+	} flags;
 };
 typedef struct rrd_cache_s rrd_cache_t;
 
+struct rrd_queue_s
+{
+	char *filename;
+	struct rrd_queue_s *next;
+};
+typedef struct rrd_queue_s rrd_queue_t;
+
 /*
  * Private variables
  */
@@ -77,25 +91,54 @@ static const char *config_keys[] =
 };
 static int config_keys_num = STATIC_ARRAY_SIZE (config_keys);
 
+/* If datadir is zero, the daemon's basedir is used. If stepsize or heartbeat
+ * is zero a default, depending on the `interval' member of the value list is
+ * being used. */
 static char   *datadir   = NULL;
 static int     stepsize  = 0;
 static int     heartbeat = 0;
 static int     rrarows   = 1200;
 static double  xff       = 0.1;
 
+/* XXX: If you need to lock both, cache_lock and queue_lock, at the same time,
+ * ALWAYS lock `cache_lock' first! */
 static int         cache_timeout = 0;
 static int         cache_flush_timeout = 0;
 static time_t      cache_flush_last;
-static avl_tree_t *cache = NULL;
+static c_avl_tree_t *cache = NULL;
 static pthread_mutex_t cache_lock = PTHREAD_MUTEX_INITIALIZER;
 
+static rrd_queue_t    *queue_head = NULL;
+static rrd_queue_t    *queue_tail = NULL;
+static pthread_t       queue_thread = 0;
+static pthread_mutex_t queue_lock = PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t  queue_cond = PTHREAD_COND_INITIALIZER;
+
+#if !HAVE_THREADSAFE_LIBRRD
+static pthread_mutex_t librrd_lock = PTHREAD_MUTEX_INITIALIZER;
+#endif
+
+static int do_shutdown = 0;
+
 /* * * * * * * * * *
  * WARNING:  Magic *
  * * * * * * * * * */
-static int rra_get (char ***ret)
+
+static void rra_free (int rra_num, char **rra_def)
+{
+	int i;
+
+	for (i = 0; i < rra_num; i++)
+	{
+		sfree (rra_def[i]);
+	}
+	sfree (rra_def);
+} /* void rra_free */
+
+static int rra_get (char ***ret, const value_list_t *vl)
 {
-	static char **rra_def = NULL;
-	static int rra_num = 0;
+	char **rra_def;
+	int rra_num;
 
 	int *rts;
 	int  rts_num;
@@ -110,10 +153,21 @@ static int rra_get (char ***ret)
 
 	char buffer[64];
 
-	if ((rra_num != 0) && (rra_def != NULL))
+	/* The stepsize we use here: If it is user-set, use it. If not, use the
+	 * interval of the value-list. */
+	int ss;
+
+	if (rrarows <= 0)
+	{
+		*ret = NULL;
+		return (-1);
+	}
+
+	ss = (stepsize > 0) ? stepsize : vl->interval;
+	if (ss <= 0)
 	{
-		*ret = rra_def;
-		return (rra_num);
+		*ret = NULL;
+		return (-1);
 	}
 
 	/* Use the configured timespans or fall back to the built-in defaults */
@@ -133,29 +187,24 @@ static int rra_get (char ***ret)
 	if ((rra_def = (char **) malloc ((rra_max + 1) * sizeof (char *))) == NULL)
 		return (-1);
 	memset (rra_def, '\0', (rra_max + 1) * sizeof (char *));
-
-	if ((stepsize <= 0) || (rrarows <= 0))
-	{
-		*ret = NULL;
-		return (-1);
-	}
+	rra_num = 0;
 
 	cdp_len = 0;
 	for (i = 0; i < rts_num; i++)
 	{
 		span = rts[i];
 
-		if ((span / stepsize) < rrarows)
+		if ((span / ss) < rrarows)
 			continue;
 
 		if (cdp_len == 0)
 			cdp_len = 1;
 		else
 			cdp_len = (int) floor (((double) span)
-					/ ((double) (rrarows * stepsize)));
+					/ ((double) (rrarows * ss)));
 
 		cdp_num = (int) ceil (((double) span)
-				/ ((double) (cdp_len * stepsize)));
+				/ ((double) (cdp_len * ss)));
 
 		for (j = 0; j < rra_types_num; j++)
 		{
@@ -182,7 +231,7 @@ static int rra_get (char ***ret)
 
 	*ret = rra_def;
 	return (rra_num);
-}
+} /* int rra_get */
 
 static void ds_free (int ds_num, char **ds_def)
 {
@@ -194,7 +243,7 @@ static void ds_free (int ds_num, char **ds_def)
 	free (ds_def);
 }
 
-static int ds_get (char ***ret, const data_set_t *ds)
+static int ds_get (char ***ret, const data_set_t *ds, const value_list_t *vl)
 {
 	char **ds_def;
 	int ds_num;
@@ -236,7 +285,7 @@ static int ds_get (char ***ret, const data_set_t *ds)
 
 		if (isnan (d->min))
 		{
-			strcpy (min, "U");
+			sstrncpy (min, "U", sizeof (min));
 		}
 		else
 		{
@@ -246,7 +295,7 @@ static int ds_get (char ***ret, const data_set_t *ds)
 
 		if (isnan (d->max))
 		{
-			strcpy (max, "U");
+			sstrncpy (max, "U", sizeof (max));
 		}
 		else
 		{
@@ -256,7 +305,8 @@ static int ds_get (char ***ret, const data_set_t *ds)
 
 		status = snprintf (buffer, sizeof (buffer),
 				"DS:%s:%s:%i:%s:%s",
-				d->name, type, heartbeat,
+				d->name, type,
+				(heartbeat > 0) ? heartbeat : (2 * vl->interval),
 				min, max);
 		if ((status < 1) || (status >= sizeof (buffer)))
 			break;
@@ -283,7 +333,144 @@ static int ds_get (char ***ret, const data_set_t *ds)
 	return (ds_num);
 }
 
-static int rrd_create_file (char *filename, const data_set_t *ds)
+#if HAVE_THREADSAFE_LIBRRD
+static int srrd_create (char *filename, unsigned long pdp_step, time_t last_up,
+		int argc, char **argv)
+{
+	int status;
+
+	optind = 0; /* bug in librrd? */
+	rrd_clear_error ();
+
+	status = rrd_create_r (filename, pdp_step, last_up, argc, (void *) argv);
+
+	if (status != 0)
+	{
+		WARNING ("rrdtool plugin: rrd_create_r (%s) failed: %s",
+				filename, rrd_get_error ());
+	}
+
+	return (status);
+} /* int srrd_create */
+
+static int srrd_update (char *filename, char *template, int argc, char **argv)
+{
+	int status;
+
+	optind = 0; /* bug in librrd? */
+	rrd_clear_error ();
+
+	status = rrd_update_r (filename, template, argc, (void *) argv);
+
+	if (status != 0)
+	{
+		WARNING ("rrdtool plugin: rrd_update_r (%s) failed: %s",
+				filename, rrd_get_error ());
+	}
+
+	return (status);
+} /* int srrd_update */
+/* #endif HAVE_THREADSAFE_LIBRRD */
+
+#else /* !HAVE_THREADSAFE_LIBRRD */
+static int srrd_create (char *filename, unsigned long pdp_step, time_t last_up,
+		int argc, char **argv)
+{
+	int status;
+
+	int new_argc;
+	char **new_argv;
+
+	char pdp_step_str[16];
+	char last_up_str[16];
+
+	new_argc = 6 + argc;
+	new_argv = (char **) malloc ((new_argc + 1) * sizeof (char *));
+	if (new_argv == NULL)
+	{
+		ERROR ("rrdtool plugin: malloc failed.");
+		return (-1);
+	}
+
+	if (last_up == 0)
+		last_up = time (NULL) - 10;
+
+	snprintf (pdp_step_str, sizeof (pdp_step_str), "%lu", pdp_step);
+	pdp_step_str[sizeof (pdp_step_str) - 1] = '\0';
+	snprintf (last_up_str, sizeof (last_up_str), "%u", (unsigned int) last_up);
+	last_up_str[sizeof (last_up_str) - 1] = '\0';
+
+	new_argv[0] = "create";
+	new_argv[1] = filename;
+	new_argv[2] = "-s";
+	new_argv[3] = pdp_step_str;
+	new_argv[4] = "-b";
+	new_argv[5] = last_up_str;
+
+	memcpy (new_argv + 6, argv, argc * sizeof (char *));
+	new_argv[new_argc] = NULL;
+	
+	pthread_mutex_lock (&librrd_lock);
+	optind = 0; /* bug in librrd? */
+	rrd_clear_error ();
+
+	status = rrd_create (new_argc, new_argv);
+	pthread_mutex_unlock (&librrd_lock);
+
+	if (status != 0)
+	{
+		WARNING ("rrdtool plugin: rrd_create (%s) failed: %s",
+				filename, rrd_get_error ());
+	}
+
+	sfree (new_argv);
+
+	return (status);
+} /* int srrd_create */
+
+static int srrd_update (char *filename, char *template, int argc, char **argv)
+{
+	int status;
+
+	int new_argc;
+	char **new_argv;
+
+	assert (template == NULL);
+
+	new_argc = 2 + argc;
+	new_argv = (char **) malloc ((new_argc + 1) * sizeof (char *));
+	if (new_argv == NULL)
+	{
+		ERROR ("rrdtool plugin: malloc failed.");
+		return (-1);
+	}
+
+	new_argv[0] = "update";
+	new_argv[1] = filename;
+
+	memcpy (new_argv + 2, argv, argc * sizeof (char *));
+	new_argv[new_argc] = NULL;
+
+	pthread_mutex_lock (&librrd_lock);
+	optind = 0; /* bug in librrd? */
+	rrd_clear_error ();
+
+	status = rrd_update (new_argc, new_argv);
+	pthread_mutex_unlock (&librrd_lock);
+
+	if (status != 0)
+	{
+		WARNING ("rrdtool plugin: rrd_update_r failed: %s: %s",
+				argv[1], rrd_get_error ());
+	}
+
+	sfree (new_argv);
+
+	return (status);
+} /* int srrd_update */
+#endif /* !HAVE_THREADSAFE_LIBRRD */
+
+static int rrd_create_file (char *filename, const data_set_t *ds, const value_list_t *vl)
 {
 	char **argv;
 	int argc;
@@ -291,26 +478,24 @@ static int rrd_create_file (char *filename, const data_set_t *ds)
 	int rra_num;
 	char **ds_def;
 	int ds_num;
-	int i, j;
-	char stepsize_str[16];
 	int status = 0;
 
 	if (check_create_dir (filename))
 		return (-1);
 
-	if ((rra_num = rra_get (&rra_def)) < 1)
+	if ((rra_num = rra_get (&rra_def, vl)) < 1)
 	{
 		ERROR ("rrd_create_file failed: Could not calculate RRAs");
 		return (-1);
 	}
 
-	if ((ds_num = ds_get (&ds_def, ds)) < 1)
+	if ((ds_num = ds_get (&ds_def, ds, vl)) < 1)
 	{
 		ERROR ("rrd_create_file failed: Could not calculate DSes");
 		return (-1);
 	}
 
-	argc = ds_num + rra_num + 4;
+	argc = ds_num + rra_num;
 
 	if ((argv = (char **) malloc (sizeof (char *) * (argc + 1))) == NULL)
 	{
@@ -320,36 +505,19 @@ static int rrd_create_file (char *filename, const data_set_t *ds)
 		return (-1);
 	}
 
-	status = snprintf (stepsize_str, sizeof (stepsize_str),
-			"%i", stepsize);
-	if ((status < 1) || (status >= sizeof (stepsize_str)))
-	{
-		ERROR ("rrdtool plugin: snprintf failed.");
-		return (-1);
-	}
+	memcpy (argv, ds_def, ds_num * sizeof (char *));
+	memcpy (argv + ds_num, rra_def, rra_num * sizeof (char *));
+	argv[ds_num + rra_num] = NULL;
 
-	argv[0] = "create";
-	argv[1] = filename;
-	argv[2] = "-s";
-	argv[3] = stepsize_str;
-
-	j = 4;
-	for (i = 0; i < ds_num; i++)
-		argv[j++] = ds_def[i];
-	for (i = 0; i < rra_num; i++)
-		argv[j++] = rra_def[i];
-	argv[j] = NULL;
-
-	optind = 0; /* bug in librrd? */
-	rrd_clear_error ();
-	if (rrd_create (argc, argv) == -1)
-	{
-		ERROR ("rrd_create failed: %s: %s", filename, rrd_get_error ());
-		status = -1;
-	}
+	assert (vl->time > 10);
+	status = srrd_create (filename,
+			(stepsize > 0) ? stepsize : vl->interval,
+			vl->time - 10,
+			argc, argv);
 
 	free (argv);
 	ds_free (ds_num, ds_def);
+	rra_free (rra_num, rra_def);
 
 	return (status);
 }
@@ -361,7 +529,7 @@ static int value_list_to_string (char *buffer, int buffer_len,
 	int status;
 	int i;
 
-	memset (buffer, '\0', sizeof (buffer_len));
+	memset (buffer, '\0', buffer_len);
 
 	status = snprintf (buffer, buffer_len, "%u", (unsigned int) vl->time);
 	if ((status < 1) || (status >= buffer_len))
@@ -434,138 +602,109 @@ static int value_list_to_filename (char *buffer, int buffer_len,
 	return (0);
 } /* int value_list_to_filename */
 
-static rrd_cache_t *rrd_cache_insert (const char *filename,
-		const char *value, time_t value_time)
+static void *rrd_queue_thread (void *data)
 {
-	rrd_cache_t *rc = NULL;
-	int new_rc = 0;
-
-	if (cache != NULL)
-		avl_get (cache, filename, (void *) &rc);
-
-	if (rc == NULL)
-	{
-		rc = (rrd_cache_t *) malloc (sizeof (rrd_cache_t));
-		if (rc == NULL)
-			return (NULL);
-		rc->values_num = 0;
-		rc->values = NULL;
-		rc->first_value = 0;
-		rc->last_value = 0;
-		new_rc = 1;
-	}
-
-	if (rc->last_value >= value_time)
-	{
-		WARNING ("rrdtool plugin: (rc->last_value = %u) >= (value_time = %u)",
-				(unsigned int) rc->last_value,
-				(unsigned int) value_time);
-		return (NULL);
-	}
-
-	rc->values = (char **) realloc ((void *) rc->values,
-			(rc->values_num + 1) * sizeof (char *));
-	if (rc->values == NULL)
+	while (42)
 	{
-		char errbuf[1024];
-		ERROR ("rrdtool plugin: realloc failed: %s",
-				sstrerror (errno, errbuf, sizeof (errbuf)));
-		if (cache != NULL)
+		rrd_queue_t *queue_entry;
+		rrd_cache_t *cache_entry;
+		char **values;
+		int    values_num;
+		int    i;
+
+		/* XXX: If you need to lock both, cache_lock and queue_lock, at
+		 * the same time, ALWAYS lock `cache_lock' first! */
+
+		/* wait until an entry is available */
+		pthread_mutex_lock (&queue_lock);
+		while ((queue_head == NULL) && (do_shutdown == 0))
+			pthread_cond_wait (&queue_cond, &queue_lock);
+
+		/* We're in the shutdown phase */
+		if (queue_head == NULL)
 		{
-			void *cache_key = NULL;
-			avl_remove (cache, filename, &cache_key, NULL);
-			sfree (cache_key);
+			pthread_mutex_unlock (&queue_lock);
+			break;
 		}
-		free (rc);
-		return (NULL);
-	}
 
-	rc->values[rc->values_num] = strdup (value);
-	if (rc->values[rc->values_num] != NULL)
-		rc->values_num++;
+		/* Dequeue the first entry */
+		queue_entry = queue_head;
+		if (queue_head == queue_tail)
+			queue_head = queue_tail = NULL;
+		else
+			queue_head = queue_head->next;
 
-	if (rc->values_num == 1)
-		rc->first_value = value_time;
-	rc->last_value = value_time;
+		/* Unlock the queue again */
+		pthread_mutex_unlock (&queue_lock);
 
-	/* Insert if this is the first value */
-	if ((cache != NULL) && (new_rc == 1))
-	{
-		void *cache_key = strdup (filename);
+		/* We now need the cache lock so the entry isn't updated while
+		 * we make a copy of it's values */
+		pthread_mutex_lock (&cache_lock);
 
-		if (cache_key == NULL)
-		{
-			char errbuf[1024];
-			ERROR ("rrdtool plugin: strdup failed: %s",
-					sstrerror (errno, errbuf, sizeof (errbuf)));
-			sfree (rc->values[0]);
-			sfree (rc->values);
-			sfree (rc);
-			return (NULL);
-		}
+		c_avl_get (cache, queue_entry->filename, (void *) &cache_entry);
 
-		avl_insert (cache, cache_key, rc);
-	}
+		values = cache_entry->values;
+		values_num = cache_entry->values_num;
 
-	DEBUG ("rrd_cache_insert (%s, %s, %u) = %p", filename, value,
-			(unsigned int) value_time, (void *) rc);
+		cache_entry->values = NULL;
+		cache_entry->values_num = 0;
+		cache_entry->flags = FLAG_NONE;
 
-	return (rc);
-} /* rrd_cache_t *rrd_cache_insert */
+		pthread_mutex_unlock (&cache_lock);
 
-static int rrd_write_cache_entry (const char *filename, rrd_cache_t *rc)
-{
-	char **argv;
-	int    argc;
+		/* Write the values to the RRD-file */
+		srrd_update (queue_entry->filename, NULL, values_num, values);
+		DEBUG ("rrdtool plugin: queue thread: Wrote %i values to %s",
+				values_num, queue_entry->filename);
 
-	char *fn;
-	int status;
+		for (i = 0; i < values_num; i++)
+		{
+			sfree (values[i]);
+		}
+		sfree (values);
+		sfree (queue_entry->filename);
+		sfree (queue_entry);
+	} /* while (42) */
 
-	int i;
+	pthread_mutex_lock (&cache_lock);
+	c_avl_destroy (cache);
+	cache = NULL;
+	pthread_mutex_unlock (&cache_lock);
 
-	if (rc->values_num < 1)
-		return (0);
+	pthread_exit ((void *) 0);
+	return ((void *) 0);
+} /* void *rrd_queue_thread */
+
+static int rrd_queue_cache_entry (const char *filename)
+{
+	rrd_queue_t *queue_entry;
 
-	argc = rc->values_num + 2;
-	argv = (char **) malloc ((argc + 1) * sizeof (char *));
-	if (argv == NULL)
+	queue_entry = (rrd_queue_t *) malloc (sizeof (rrd_queue_t));
+	if (queue_entry == NULL)
 		return (-1);
 
-	fn = strdup (filename);
-	if (fn == NULL)
+	queue_entry->filename = strdup (filename);
+	if (queue_entry->filename == NULL)
 	{
-		free (argv);
+		free (queue_entry);
 		return (-1);
 	}
 
-	argv[0] = "update";
-	argv[1] = fn;
-	memcpy (argv + 2, rc->values, rc->values_num * sizeof (char *));
-	argv[argc] = NULL;
+	queue_entry->next = NULL;
 
-	DEBUG ("rrd_update (argc = %i, argv = %p)", argc, (void *) argv);
-
-	optind = 0; /* bug in librrd? */
-	rrd_clear_error ();
-	status = rrd_update (argc, argv);
-	if (status != 0)
-	{
-		WARNING ("rrd_update failed: %s: %s",
-				filename, rrd_get_error ());
-		status = -1;
-	}
+	pthread_mutex_lock (&queue_lock);
+	if (queue_tail == NULL)
+		queue_head = queue_entry;
+	else
+		queue_tail->next = queue_entry;
+	queue_tail = queue_entry;
+	pthread_cond_signal (&queue_cond);
+	pthread_mutex_unlock (&queue_lock);
 
-	free (argv);
-	free (fn);
-	/* Free the value list of `rc' */
-	for (i = 0; i < rc->values_num; i++)
-		free (rc->values[i]);
-	free (rc->values);
-	rc->values = NULL;
-	rc->values_num = 0;
+	DEBUG ("rrdtool plugin: Put `%s' into the update queue", filename);
 
-	return (status);
-} /* int rrd_write_cache_entry */
+	return (0);
+} /* int rrd_queue_cache_entry */
 
 static void rrd_cache_flush (int timeout)
 {
@@ -576,69 +715,203 @@ static void rrd_cache_flush (int timeout)
 	int    keys_num = 0;
 
 	char *key;
-	avl_iterator_t *iter;
+	c_avl_iterator_t *iter;
 	int i;
 
-	if (cache == NULL)
-		return;
-
-	DEBUG ("Flushing cache, timeout = %i", timeout);
+	DEBUG ("rrdtool plugin: Flushing cache, timeout = %i", timeout);
 
 	now = time (NULL);
 
 	/* Build a list of entries to be flushed */
-	iter = avl_get_iterator (cache);
-	while (avl_iterator_next (iter, (void *) &key, (void *) &rc) == 0)
+	iter = c_avl_get_iterator (cache);
+	while (c_avl_iterator_next (iter, (void *) &key, (void *) &rc) == 0)
 	{
-		DEBUG ("key = %s; age = %i;", key, now - rc->first_value);
-		if ((now - rc->first_value) >= timeout)
+		if (rc->flags == FLAG_QUEUED)
+			continue;
+		else if ((now - rc->first_value) < timeout)
+			continue;
+		else if (rc->values_num > 0)
 		{
-			keys = (char **) realloc ((void *) keys,
+			if (rrd_queue_cache_entry (key) == 0)
+				rc->flags = FLAG_QUEUED;
+		}
+		else /* ancient and no values -> waste of memory */
+		{
+			char **tmp = (char **) realloc ((void *) keys,
 					(keys_num + 1) * sizeof (char *));
-			if (keys == NULL)
+			if (tmp == NULL)
 			{
 				char errbuf[1024];
 				ERROR ("rrdtool plugin: "
 						"realloc failed: %s",
 						sstrerror (errno, errbuf,
 							sizeof (errbuf)));
-				avl_iterator_destroy (iter);
+				c_avl_iterator_destroy (iter);
+				sfree (keys);
 				return;
 			}
+			keys = tmp;
 			keys[keys_num] = key;
 			keys_num++;
 		}
-	} /* while (avl_iterator_next) */
-	avl_iterator_destroy (iter);
+	} /* while (c_avl_iterator_next) */
+	c_avl_iterator_destroy (iter);
 	
 	for (i = 0; i < keys_num; i++)
 	{
-		if (avl_remove (cache, keys[i], (void *) &key, (void *) &rc) != 0)
+		if (c_avl_remove (cache, keys[i], (void *) &key, (void *) &rc) != 0)
 		{
-			DEBUG ("avl_remove (%s) failed.", keys[i]);
+			DEBUG ("rrdtool plugin: c_avl_remove (%s) failed.", keys[i]);
 			continue;
 		}
 
-		rrd_write_cache_entry (keys[i], rc);
-		/* rc's value-list is free's by `rrd_write_cache_entry' */
+		assert (rc->values == NULL);
+		assert (rc->values_num == 0);
+
 		sfree (rc);
 		sfree (key);
 		keys[i] = NULL;
 	} /* for (i = 0..keys_num) */
 
-	free (keys);
-	DEBUG ("Flushed %i value(s)", keys_num);
+	sfree (keys);
 
 	cache_flush_last = now;
 } /* void rrd_cache_flush */
 
+static int rrd_cache_insert (const char *filename,
+		const char *value, time_t value_time)
+{
+	rrd_cache_t *rc = NULL;
+	int new_rc = 0;
+	char **values_new;
+
+	pthread_mutex_lock (&cache_lock);
+
+	c_avl_get (cache, filename, (void *) &rc);
+
+	if (rc == NULL)
+	{
+		rc = (rrd_cache_t *) malloc (sizeof (rrd_cache_t));
+		if (rc == NULL)
+			return (-1);
+		rc->values_num = 0;
+		rc->values = NULL;
+		rc->first_value = 0;
+		rc->last_value = 0;
+		rc->flags = FLAG_NONE;
+		new_rc = 1;
+	}
+
+	if (rc->last_value >= value_time)
+	{
+		pthread_mutex_unlock (&cache_lock);
+		WARNING ("rrdtool plugin: (rc->last_value = %u) >= (value_time = %u)",
+				(unsigned int) rc->last_value,
+				(unsigned int) value_time);
+		return (-1);
+	}
+
+	values_new = (char **) realloc ((void *) rc->values,
+			(rc->values_num + 1) * sizeof (char *));
+	if (values_new == NULL)
+	{
+		char errbuf[1024];
+		void *cache_key = NULL;
+
+		sstrerror (errno, errbuf, sizeof (errbuf));
+
+		c_avl_remove (cache, filename, &cache_key, NULL);
+		pthread_mutex_unlock (&cache_lock);
+
+		ERROR ("rrdtool plugin: realloc failed: %s", errbuf);
+
+		sfree (cache_key);
+		sfree (rc->values);
+		sfree (rc);
+		return (-1);
+	}
+	rc->values = values_new;
+
+	rc->values[rc->values_num] = strdup (value);
+	if (rc->values[rc->values_num] != NULL)
+		rc->values_num++;
+
+	if (rc->values_num == 1)
+		rc->first_value = value_time;
+	rc->last_value = value_time;
+
+	/* Insert if this is the first value */
+	if (new_rc == 1)
+	{
+		void *cache_key = strdup (filename);
+
+		if (cache_key == NULL)
+		{
+			char errbuf[1024];
+			sstrerror (errno, errbuf, sizeof (errbuf));
+
+			pthread_mutex_unlock (&cache_lock);
+
+			ERROR ("rrdtool plugin: strdup failed: %s", errbuf);
+
+			sfree (rc->values[0]);
+			sfree (rc->values);
+			sfree (rc);
+			return (-1);
+		}
+
+		c_avl_insert (cache, cache_key, rc);
+	}
+
+	DEBUG ("rrdtool plugin: rrd_cache_insert: file = %s; "
+			"values_num = %i; age = %u;",
+			filename, rc->values_num,
+			rc->last_value - rc->first_value);
+
+	if ((rc->last_value - rc->first_value) >= cache_timeout)
+	{
+		/* XXX: If you need to lock both, cache_lock and queue_lock, at
+		 * the same time, ALWAYS lock `cache_lock' first! */
+		if (rc->flags != FLAG_QUEUED)
+		{
+			if (rrd_queue_cache_entry (filename) == 0)
+				rc->flags = FLAG_QUEUED;
+		}
+		else
+		{
+			DEBUG ("rrdtool plugin: `%s' is already queued.", filename);
+		}
+	}
+
+	if ((cache_timeout > 0) &&
+			((time (NULL) - cache_flush_last) > cache_flush_timeout))
+		rrd_cache_flush (cache_flush_timeout);
+
+
+	pthread_mutex_unlock (&cache_lock);
+
+	return (0);
+} /* int rrd_cache_insert */
+
+static int rrd_compare_numeric (const void *a_ptr, const void *b_ptr)
+{
+	int a = *((int *) a_ptr);
+	int b = *((int *) b_ptr);
+
+	if (a < b)
+		return (-1);
+	else if (a > b)
+		return (1);
+	else
+		return (0);
+} /* int rrd_compare_numeric */
+
 static int rrd_write (const data_set_t *ds, const value_list_t *vl)
 {
 	struct stat  statbuf;
 	char         filename[512];
 	char         values[512];
-	rrd_cache_t *rc;
-	time_t       now;
+	int          status;
 
 	if (value_list_to_filename (filename, sizeof (filename), ds, vl) != 0)
 		return (-1);
@@ -650,7 +923,7 @@ static int rrd_write (const data_set_t *ds, const value_list_t *vl)
 	{
 		if (errno == ENOENT)
 		{
-			if (rrd_create_file (filename, ds))
+			if (rrd_create_file (filename, ds, vl))
 				return (-1);
 		}
 		else
@@ -669,37 +942,9 @@ static int rrd_write (const data_set_t *ds, const value_list_t *vl)
 		return (-1);
 	}
 
-	pthread_mutex_lock (&cache_lock);
-	rc = rrd_cache_insert (filename, values, vl->time);
-	if (rc == NULL)
-	{
-		pthread_mutex_unlock (&cache_lock);
-		return (-1);
-	}
-
-	if (cache == NULL)
-	{
-		rrd_write_cache_entry (filename, rc);
-		/* rc's value-list is free's by `rrd_write_cache_entry' */
-		sfree (rc);
-		pthread_mutex_unlock (&cache_lock);
-		return (0);
-	}
-
-	now = time (NULL);
-
-	DEBUG ("age (%s) = %i", filename, now - rc->first_value);
-
-	/* `rc' is not free'd here, because we'll likely reuse it. If not, then
-	 * the next flush will remove this entry.  */
-	if ((now - rc->first_value) >= cache_timeout)
-		rrd_write_cache_entry (filename, rc);
+	status = rrd_cache_insert (filename, values, vl->time);
 
-	if ((now - cache_flush_last) >= cache_flush_timeout)
-		rrd_cache_flush (cache_flush_timeout);
-
-	pthread_mutex_unlock (&cache_lock);
-	return (0);
+	return (status);
 } /* int rrd_write */
 
 static int rrd_config (const char *key, const char *value)
@@ -748,25 +993,15 @@ static int rrd_config (const char *key, const char *value)
 	}
 	else if (strcasecmp ("StepSize", key) == 0)
 	{
-		int tmp = atoi (value);
-		if (tmp <= 0)
-		{
-			fprintf (stderr, "rrdtool: `StepSize' must "
-					"be greater than 0.\n");
-			return (1);
-		}
-		stepsize = tmp;
+		stepsize = atoi (value);
+		if (stepsize < 0)
+			stepsize = 0;
 	}
 	else if (strcasecmp ("HeartBeat", key) == 0)
 	{
-		int tmp = atoi (value);
-		if (tmp <= 0)
-		{
-			fprintf (stderr, "rrdtool: `HeartBeat' must "
-					"be greater than 0.\n");
-			return (1);
-		}
-		heartbeat = tmp;
+		heartbeat = atoi (value);
+		if (heartbeat < 0)
+			heartbeat = 0;
 	}
 	else if (strcasecmp ("RRARows", key) == 0)
 	{
@@ -809,6 +1044,12 @@ static int rrd_config (const char *key, const char *value)
 			if (rra_timespans_custom[rra_timespans_custom_num] != 0)
 				rra_timespans_custom_num++;
 		} /* while (strtok_r) */
+
+		qsort (/* base = */ rra_timespans_custom,
+				/* nmemb  = */ rra_timespans_custom_num,
+				/* size   = */ sizeof (rra_timespans_custom[0]),
+				/* compar = */ rrd_compare_numeric);
+
 		free (value_copy);
 	}
 	else if (strcasecmp ("XFF", key) == 0)
@@ -833,47 +1074,70 @@ static int rrd_shutdown (void)
 {
 	pthread_mutex_lock (&cache_lock);
 	rrd_cache_flush (-1);
-	if (cache != NULL)
-		avl_destroy (cache);
-	cache = NULL;
 	pthread_mutex_unlock (&cache_lock);
 
+	pthread_mutex_lock (&queue_lock);
+	do_shutdown = 1;
+	pthread_cond_signal (&queue_cond);
+	pthread_mutex_unlock (&queue_lock);
+
+	/* Wait for all the values to be written to disk before returning. */
+	if (queue_thread != 0)
+	{
+		pthread_join (queue_thread, NULL);
+		queue_thread = 0;
+		DEBUG ("rrdtool plugin: queue_thread exited.");
+	}
+
 	return (0);
 } /* int rrd_shutdown */
 
 static int rrd_init (void)
 {
-	if (stepsize <= 0)
-		stepsize = interval_g;
+	int status;
+
+	if (stepsize < 0)
+		stepsize = 0;
 	if (heartbeat <= 0)
-		heartbeat = 2 * interval_g;
+		heartbeat = 2 * stepsize;
 
-	if (heartbeat < interval_g)
+	if ((heartbeat > 0) && (heartbeat < interval_g))
 		WARNING ("rrdtool plugin: Your `heartbeat' is "
 				"smaller than your `interval'. This will "
 				"likely cause problems.");
-	else if (stepsize < interval_g)
+	else if ((stepsize > 0) && (stepsize < interval_g))
 		WARNING ("rrdtool plugin: Your `stepsize' is "
 				"smaller than your `interval'. This will "
 				"create needlessly big RRD-files.");
 
+	/* Set the cache up */
 	pthread_mutex_lock (&cache_lock);
+
+	cache = c_avl_create ((int (*) (const void *, const void *)) strcmp);
+	if (cache == NULL)
+	{
+		ERROR ("rrdtool plugin: c_avl_create failed.");
+		return (-1);
+	}
+
+	cache_flush_last = time (NULL);
 	if (cache_timeout < 2)
 	{
 		cache_timeout = 0;
 		cache_flush_timeout = 0;
 	}
-	else
-	{
-		if (cache_flush_timeout < cache_timeout)
-			cache_flush_timeout = 10 * cache_timeout;
+	else if (cache_flush_timeout < cache_timeout)
+		cache_flush_timeout = 10 * cache_timeout;
 
-		cache = avl_create ((int (*) (const void *, const void *)) strcmp);
-		cache_flush_last = time (NULL);
-		plugin_register_shutdown ("rrdtool", rrd_shutdown);
-	}
 	pthread_mutex_unlock (&cache_lock);
 
+	status = pthread_create (&queue_thread, NULL, rrd_queue_thread, NULL);
+	if (status != 0)
+	{
+		ERROR ("rrdtool plugin: Cannot create queue-thread.");
+		return (-1);
+	}
+
 	DEBUG ("rrdtool plugin: rrd_init: datadir = %s; stepsize = %i;"
 			" heartbeat = %i; rrarows = %i; xff = %lf;",
 			(datadir == NULL) ? "(null)" : datadir,
@@ -888,4 +1152,5 @@ void module_register (void)
 			config_keys, config_keys_num);
 	plugin_register_init ("rrdtool", rrd_init);
 	plugin_register_write ("rrdtool", rrd_write);
+	plugin_register_shutdown ("rrdtool", rrd_shutdown);
 }