X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=src%2Frrdtool.c;h=debb7bd4ff4416386d5881ec814e1dbd63f7313a;hb=6597f3a6584704f92f824f3cf7bac3369102e8a0;hp=4d4b87cbeaa38b63201dcb12153596caaa04a1dc;hpb=27f6db4769cac5727888c327dbbf1b88da4f3ca6;p=collectd.git

diff --git a/src/rrdtool.c b/src/rrdtool.c
index 4d4b87cb..debb7bd4 100644
--- a/src/rrdtool.c
+++ b/src/rrdtool.c
@@ -1,6 +1,6 @@
 /**
  * collectd - src/rrdtool.c
- * Copyright (C) 2006,2007  Florian octo Forster
+ * Copyright (C) 2006-2008  Florian octo Forster
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
@@ -23,6 +23,9 @@
 #include "plugin.h"
 #include "common.h"
 #include "utils_avltree.h"
+#include "utils_rrdcreate.h"
+
+#include <rrd.h>
 
 #if HAVE_PTHREAD_H
 # include <pthread.h>
@@ -40,11 +43,19 @@ struct rrd_cache_s
 	enum
 	{
 		FLAG_NONE   = 0x00,
-		FLAG_QUEUED = 0x01
+		FLAG_QUEUED = 0x01,
+		FLAG_FLUSHQ = 0x02
 	} flags;
 };
 typedef struct rrd_cache_s rrd_cache_t;
 
+enum rrd_queue_dir_e
+{
+  QUEUE_INSERT_FRONT,
+  QUEUE_INSERT_BACK
+};
+typedef enum rrd_queue_dir_e rrd_queue_dir_t;
+
 struct rrd_queue_s
 {
 	char *filename;
@@ -55,27 +66,6 @@ typedef struct rrd_queue_s rrd_queue_t;
 /*
  * Private variables
  */
-static int rra_timespans[] =
-{
-	3600,
-	86400,
-	604800,
-	2678400,
-	31622400
-};
-static int rra_timespans_num = STATIC_ARRAY_SIZE (rra_timespans);
-
-static int *rra_timespans_custom = NULL;
-static int rra_timespans_custom_num = 0;
-
-static char *rra_types[] =
-{
-	"AVERAGE",
-	"MIN",
-	"MAX"
-};
-static int rra_types_num = STATIC_ARRAY_SIZE (rra_types);
-
 static const char *config_keys[] =
 {
 	"CacheTimeout",
@@ -85,322 +75,116 @@ static const char *config_keys[] =
 	"HeartBeat",
 	"RRARows",
 	"RRATimespan",
-	"XFF"
+	"XFF",
+	"WritesPerSecond"
 };
 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;
+static char *datadir   = NULL;
+static double write_rate = 0.0;
+static rrdcreate_config_t rrdcreate_config =
+{
+	/* stepsize = */ 0,
+	/* heartbeat = */ 0,
+	/* rrarows = */ 1200,
+	/* xff = */ 0.1,
+
+	/* timespans = */ NULL,
+	/* timespans_num = */ 0,
+
+	/* consolidation_functions = */ NULL,
+	/* consolidation_functions_num = */ 0
+};
 
 /* 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 rrd_queue_t    *flushq_head = NULL;
+static rrd_queue_t    *flushq_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;
 
-static int do_shutdown = 0;
-
-/* * * * * * * * * *
- * WARNING:  Magic *
- * * * * * * * * * */
-
-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)
-{
-	char **rra_def;
-	int rra_num;
-
-	int *rts;
-	int  rts_num;
-
-	int rra_max;
-
-	int span;
-
-	int cdp_num;
-	int cdp_len;
-	int i, j;
-
-	char buffer[64];
-
-	/* 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 = NULL;
-		return (-1);
-	}
-
-	/* Use the configured timespans or fall back to the built-in defaults */
-	if (rra_timespans_custom_num != 0)
-	{
-		rts = rra_timespans_custom;
-		rts_num = rra_timespans_custom_num;
-	}
-	else
-	{
-		rts = rra_timespans;
-		rts_num = rra_timespans_num;
-	}
-
-	rra_max = rts_num * rra_types_num;
-
-	if ((rra_def = (char **) malloc ((rra_max + 1) * sizeof (char *))) == NULL)
-		return (-1);
-	memset (rra_def, '\0', (rra_max + 1) * sizeof (char *));
-	rra_num = 0;
-
-	cdp_len = 0;
-	for (i = 0; i < rts_num; i++)
-	{
-		span = rts[i];
-
-		if ((span / ss) < rrarows)
-			continue;
-
-		if (cdp_len == 0)
-			cdp_len = 1;
-		else
-			cdp_len = (int) floor (((double) span)
-					/ ((double) (rrarows * ss)));
-
-		cdp_num = (int) ceil (((double) span)
-				/ ((double) (cdp_len * ss)));
-
-		for (j = 0; j < rra_types_num; j++)
-		{
-			if (rra_num >= rra_max)
-				break;
-
-			if (snprintf (buffer, sizeof (buffer), "RRA:%s:%3.1f:%u:%u",
-						rra_types[j], xff,
-						cdp_len, cdp_num) >= sizeof (buffer))
-			{
-				ERROR ("rra_get: Buffer would have been truncated.");
-				continue;
-			}
-
-			rra_def[rra_num++] = sstrdup (buffer);
-		}
-	}
-
-#if COLLECT_DEBUG
-	DEBUG ("rra_num = %i", rra_num);
-	for (i = 0; i < rra_num; i++)
-		DEBUG ("  %s", rra_def[i]);
+#if !HAVE_THREADSAFE_LIBRRD
+static pthread_mutex_t librrd_lock = PTHREAD_MUTEX_INITIALIZER;
 #endif
 
-	*ret = rra_def;
-	return (rra_num);
-} /* int rra_get */
-
-static void ds_free (int ds_num, char **ds_def)
-{
-	int i;
-
-	for (i = 0; i < ds_num; i++)
-		if (ds_def[i] != NULL)
-			free (ds_def[i]);
-	free (ds_def);
-}
+static int do_shutdown = 0;
 
-static int ds_get (char ***ret, const data_set_t *ds, const value_list_t *vl)
+#if HAVE_THREADSAFE_LIBRRD
+static int srrd_update (char *filename, char *template,
+		int argc, const char **argv)
 {
-	char **ds_def;
-	int ds_num;
-
-	char min[32];
-	char max[32];
-	char buffer[128];
-
-	DEBUG ("ds->ds_num = %i", ds->ds_num);
-
-	ds_def = (char **) malloc (ds->ds_num * sizeof (char *));
-	if (ds_def == NULL)
-	{
-		char errbuf[1024];
-		ERROR ("rrdtool plugin: malloc failed: %s",
-				sstrerror (errno, errbuf, sizeof (errbuf)));
-		return (-1);
-	}
-	memset (ds_def, '\0', ds->ds_num * sizeof (char *));
-
-	for (ds_num = 0; ds_num < ds->ds_num; ds_num++)
-	{
-		data_source_t *d = ds->ds + ds_num;
-		char *type;
-		int status;
-
-		ds_def[ds_num] = NULL;
-
-		if (d->type == DS_TYPE_COUNTER)
-			type = "COUNTER";
-		else if (d->type == DS_TYPE_GAUGE)
-			type = "GAUGE";
-		else
-		{
-			ERROR ("rrdtool plugin: Unknown DS type: %i",
-					d->type);
-			break;
-		}
-
-		if (isnan (d->min))
-		{
-			strcpy (min, "U");
-		}
-		else
-		{
-			snprintf (min, sizeof (min), "%lf", d->min);
-			min[sizeof (min) - 1] = '\0';
-		}
-
-		if (isnan (d->max))
-		{
-			strcpy (max, "U");
-		}
-		else
-		{
-			snprintf (max, sizeof (max), "%lf", d->max);
-			max[sizeof (max) - 1] = '\0';
-		}
-
-		status = snprintf (buffer, sizeof (buffer),
-				"DS:%s:%s:%i:%s:%s",
-				d->name, type,
-				(heartbeat > 0) ? heartbeat : (2 * vl->interval),
-				min, max);
-		if ((status < 1) || (status >= sizeof (buffer)))
-			break;
+	int status;
 
-		ds_def[ds_num] = sstrdup (buffer);
-	} /* for ds_num = 0 .. ds->ds_num */
+	optind = 0; /* bug in librrd? */
+	rrd_clear_error ();
 
-#if COLLECT_DEBUG
-{
-	int i;
-	DEBUG ("ds_num = %i", ds_num);
-	for (i = 0; i < ds_num; i++)
-		DEBUG ("  %s", ds_def[i]);
-}
-#endif
+	status = rrd_update_r (filename, template, argc, (void *) argv);
 
-	if (ds_num != ds->ds_num)
+	if (status != 0)
 	{
-		ds_free (ds_num, ds_def);
-		return (-1);
+		WARNING ("rrdtool plugin: rrd_update_r (%s) failed: %s",
+				filename, rrd_get_error ());
 	}
 
-	*ret = ds_def;
-	return (ds_num);
-}
+	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)
+#else /* !HAVE_THREADSAFE_LIBRRD */
+static int srrd_update (char *filename, char *template,
+		int argc, const char **argv)
 {
-	char **argv;
-	int argc;
-	char **rra_def;
-	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, vl)) < 1)
-	{
-		ERROR ("rrd_create_file failed: Could not calculate RRAs");
-		return (-1);
-	}
-
-	if ((ds_num = ds_get (&ds_def, ds, vl)) < 1)
-	{
-		ERROR ("rrd_create_file failed: Could not calculate DSes");
-		return (-1);
-	}
+	int status;
 
-	argc = ds_num + rra_num + 4;
+	int new_argc;
+	char **new_argv;
 
-	if ((argv = (char **) malloc (sizeof (char *) * (argc + 1))) == NULL)
-	{
-		char errbuf[1024];
-		ERROR ("rrd_create failed: %s",
-				sstrerror (errno, errbuf, sizeof (errbuf)));
-		return (-1);
-	}
+	assert (template == NULL);
 
-	status = snprintf (stepsize_str, sizeof (stepsize_str),
-			"%i", (stepsize > 0) ? stepsize : vl->interval);
-	if ((status < 1) || (status >= sizeof (stepsize_str)))
+	new_argc = 2 + argc;
+	new_argv = (char **) malloc ((new_argc + 1) * sizeof (char *));
+	if (new_argv == NULL)
 	{
-		ERROR ("rrdtool plugin: snprintf failed.");
-		free (argv);
-		ds_free (ds_num, ds_def);
-		rra_free (rra_num, rra_def);
+		ERROR ("rrdtool plugin: malloc failed.");
 		return (-1);
 	}
 
-	argv[0] = "create";
-	argv[1] = filename;
-	argv[2] = "-s";
-	argv[3] = stepsize_str;
+	new_argv[0] = "update";
+	new_argv[1] = filename;
 
-	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;
+	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 ();
-	if (rrd_create (argc, argv) == -1)
+
+	status = rrd_update (new_argc, new_argv);
+	pthread_mutex_unlock (&librrd_lock);
+
+	if (status != 0)
 	{
-		ERROR ("rrd_create failed: %s: %s", filename, rrd_get_error ());
-		status = -1;
+		WARNING ("rrdtool plugin: rrd_update_r failed: %s: %s",
+				argv[1], rrd_get_error ());
 	}
 
-	free (argv);
-	ds_free (ds_num, ds_def);
-	rra_free (rra_num, rra_def);
+	sfree (new_argv);
 
 	return (status);
-}
+} /* int srrd_update */
+#endif /* !HAVE_THREADSAFE_LIBRRD */
 
 static int value_list_to_string (char *buffer, int buffer_len,
 		const data_set_t *ds, const value_list_t *vl)
@@ -411,7 +195,7 @@ static int value_list_to_string (char *buffer, int buffer_len,
 
 	memset (buffer, '\0', buffer_len);
 
-	status = snprintf (buffer, buffer_len, "%u", (unsigned int) vl->time);
+	status = ssnprintf (buffer, buffer_len, "%u", (unsigned int) vl->time);
 	if ((status < 1) || (status >= buffer_len))
 		return (-1);
 	offset = status;
@@ -423,10 +207,10 @@ static int value_list_to_string (char *buffer, int buffer_len,
 			return (-1);
 
 		if (ds->ds[i].type == DS_TYPE_COUNTER)
-			status = snprintf (buffer + offset, buffer_len - offset,
+			status = ssnprintf (buffer + offset, buffer_len - offset,
 					":%llu", vl->values[i].counter);
 		else
-			status = snprintf (buffer + offset, buffer_len - offset,
+			status = ssnprintf (buffer + offset, buffer_len - offset,
 					":%lf", vl->values[i].gauge);
 
 		if ((status < 1) || (status >= (buffer_len - offset)))
@@ -439,42 +223,42 @@ static int value_list_to_string (char *buffer, int buffer_len,
 } /* int value_list_to_string */
 
 static int value_list_to_filename (char *buffer, int buffer_len,
-		const data_set_t *ds, const value_list_t *vl)
+		const data_set_t __attribute__((unused)) *ds, const value_list_t *vl)
 {
 	int offset = 0;
 	int status;
 
 	if (datadir != NULL)
 	{
-		status = snprintf (buffer + offset, buffer_len - offset,
+		status = ssnprintf (buffer + offset, buffer_len - offset,
 				"%s/", datadir);
 		if ((status < 1) || (status >= buffer_len - offset))
 			return (-1);
 		offset += status;
 	}
 
-	status = snprintf (buffer + offset, buffer_len - offset,
+	status = ssnprintf (buffer + offset, buffer_len - offset,
 			"%s/", vl->host);
 	if ((status < 1) || (status >= buffer_len - offset))
 		return (-1);
 	offset += status;
 
 	if (strlen (vl->plugin_instance) > 0)
-		status = snprintf (buffer + offset, buffer_len - offset,
+		status = ssnprintf (buffer + offset, buffer_len - offset,
 				"%s-%s/", vl->plugin, vl->plugin_instance);
 	else
-		status = snprintf (buffer + offset, buffer_len - offset,
+		status = ssnprintf (buffer + offset, buffer_len - offset,
 				"%s/", vl->plugin);
 	if ((status < 1) || (status >= buffer_len - offset))
 		return (-1);
 	offset += status;
 
 	if (strlen (vl->type_instance) > 0)
-		status = snprintf (buffer + offset, buffer_len - offset,
-				"%s-%s.rrd", ds->type, vl->type_instance);
+		status = ssnprintf (buffer + offset, buffer_len - offset,
+				"%s-%s.rrd", vl->type, vl->type_instance);
 	else
-		status = snprintf (buffer + offset, buffer_len - offset,
-				"%s.rrd", ds->type);
+		status = ssnprintf (buffer + offset, buffer_len - offset,
+				"%s.rrd", vl->type);
 	if ((status < 1) || (status >= buffer_len - offset))
 		return (-1);
 	offset += status;
@@ -482,44 +266,13 @@ static int value_list_to_filename (char *buffer, int buffer_len,
 	return (0);
 } /* int value_list_to_filename */
 
-static int rrd_write_to_file (char *filename, char **values, int values_num)
+static void *rrd_queue_thread (void __attribute__((unused)) *data)
 {
-	char **argv;
-	int argc;
-	int status;
-
-	if (values_num < 1)
-		return (0);
-
-	argc = values_num + 2;
-	argv = (char **) malloc ((argc + 1) * sizeof (char *));
-	if (argv == NULL)
-		return (-1);
-
-	argv[0] = "update";
-	argv[1] = filename;
-	memcpy (argv + 2, values, values_num * sizeof (char *));
-	argv[argc] = 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;
-	}
+        struct timeval tv_next_update;
+        struct timeval tv_now;
 
-	sfree (argv);
-
-	return (status);
-} /* int rrd_write_cache_entry */
+        gettimeofday (&tv_next_update, /* timezone = */ NULL);
 
-static void *rrd_queue_thread (void *data)
-{
 	while (42)
 	{
 		rrd_queue_t *queue_entry;
@@ -528,27 +281,78 @@ static void *rrd_queue_thread (void *data)
 		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)
-		{
-			pthread_mutex_unlock (&queue_lock);
-			break;
-		}
-
-		/* Dequeue the first entry */
-		queue_entry = queue_head;
-		if (queue_head == queue_tail)
-			queue_head = queue_tail = NULL;
-		else
-			queue_head = queue_head->next;
+                pthread_mutex_lock (&queue_lock);
+                /* Wait for values to arrive */
+                while (true)
+                {
+                  struct timespec ts_wait;
+                  int status;
+
+                  while ((flushq_head == NULL) && (queue_head == NULL)
+                      && (do_shutdown == 0))
+                    pthread_cond_wait (&queue_cond, &queue_lock);
+
+                  if ((flushq_head == NULL) && (queue_head == NULL))
+                    break;
+
+                  /* Don't delay if there's something to flush */
+                  if (flushq_head != NULL)
+                    break;
+
+                  /* Don't delay if we're shutting down */
+                  if (do_shutdown != 0)
+                    break;
+
+                  /* Don't delay if no delay was configured. */
+                  if (write_rate <= 0.0)
+                    break;
+
+                  gettimeofday (&tv_now, /* timezone = */ NULL);
+                  status = timeval_cmp (tv_next_update, tv_now, NULL);
+                  /* We're good to go */
+                  if (status <= 0)
+                    break;
+
+                  /* We're supposed to wait a bit with this update, so we'll
+                   * wait for the next addition to the queue or to the end of
+                   * the wait period - whichever comes first. */
+                  ts_wait.tv_sec = tv_next_update.tv_sec;
+                  ts_wait.tv_nsec = 1000 * tv_next_update.tv_usec;
+
+                  status = pthread_cond_timedwait (&queue_cond, &queue_lock,
+                      &ts_wait);
+                  if (status == ETIMEDOUT)
+                    break;
+                } /* while (true) */
+
+                /* XXX: If you need to lock both, cache_lock and queue_lock, at
+                 * the same time, ALWAYS lock `cache_lock' first! */
+
+                /* We're in the shutdown phase */
+                if ((flushq_head == NULL) && (queue_head == NULL))
+                {
+                  pthread_mutex_unlock (&queue_lock);
+                  break;
+                }
+
+                if (flushq_head != NULL)
+                {
+                  /* Dequeue the first flush entry */
+                  queue_entry = flushq_head;
+                  if (flushq_head == flushq_tail)
+                    flushq_head = flushq_tail = NULL;
+                  else
+                    flushq_head = flushq_head->next;
+                }
+                else /* if (queue_head != NULL) */
+                {
+                  /* Dequeue the first regular entry */
+                  queue_entry = queue_head;
+                  if (queue_head == queue_tail)
+                    queue_head = queue_tail = NULL;
+                  else
+                    queue_head = queue_head->next;
+                }
 
 		/* Unlock the queue again */
 		pthread_mutex_unlock (&queue_lock);
@@ -557,7 +361,7 @@ static void *rrd_queue_thread (void *data)
 		 * we make a copy of it's values */
 		pthread_mutex_lock (&cache_lock);
 
-		avl_get (cache, queue_entry->filename, (void *) &cache_entry);
+		c_avl_get (cache, queue_entry->filename, (void *) &cache_entry);
 
 		values = cache_entry->values;
 		values_num = cache_entry->values_num;
@@ -568,8 +372,25 @@ static void *rrd_queue_thread (void *data)
 
 		pthread_mutex_unlock (&cache_lock);
 
+		/* Update `tv_next_update' */
+		if (write_rate > 0.0) 
+                {
+                  gettimeofday (&tv_now, /* timezone = */ NULL);
+                  tv_next_update.tv_sec = tv_now.tv_sec;
+                  tv_next_update.tv_usec = tv_now.tv_usec
+                    + ((suseconds_t) (1000000 * write_rate));
+                  while (tv_next_update.tv_usec > 1000000)
+                  {
+                    tv_next_update.tv_sec++;
+                    tv_next_update.tv_usec -= 1000000;
+                  }
+                }
+
 		/* Write the values to the RRD-file */
-		rrd_write_to_file (queue_entry->filename, values, values_num);
+		srrd_update (queue_entry->filename, NULL,
+				values_num, (const char **)values);
+		DEBUG ("rrdtool plugin: queue thread: Wrote %i values to %s",
+				values_num, queue_entry->filename);
 
 		for (i = 0; i < values_num; i++)
 		{
@@ -581,7 +402,7 @@ static void *rrd_queue_thread (void *data)
 	} /* while (42) */
 
 	pthread_mutex_lock (&cache_lock);
-	avl_destroy (cache);
+	c_avl_destroy (cache);
 	cache = NULL;
 	pthread_mutex_unlock (&cache_lock);
 
@@ -589,36 +410,79 @@ static void *rrd_queue_thread (void *data)
 	return ((void *) 0);
 } /* void *rrd_queue_thread */
 
-static int rrd_queue_cache_entry (const char *filename)
+static int rrd_queue_enqueue (const char *filename,
+    rrd_queue_t **head, rrd_queue_t **tail)
 {
-	rrd_queue_t *queue_entry;
+  rrd_queue_t *queue_entry;
 
-	queue_entry = (rrd_queue_t *) malloc (sizeof (rrd_queue_t));
-	if (queue_entry == NULL)
-		return (-1);
+  queue_entry = (rrd_queue_t *) malloc (sizeof (rrd_queue_t));
+  if (queue_entry == NULL)
+    return (-1);
 
-	queue_entry->filename = strdup (filename);
-	if (queue_entry->filename == NULL)
-	{
-		free (queue_entry);
-		return (-1);
-	}
+  queue_entry->filename = strdup (filename);
+  if (queue_entry->filename == NULL)
+  {
+    free (queue_entry);
+    return (-1);
+  }
 
-	queue_entry->next = NULL;
+  queue_entry->next = NULL;
 
-	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);
+  pthread_mutex_lock (&queue_lock);
 
-	DEBUG ("rrdtool plugin: Put `%s' into the update queue", filename);
+  if (*tail == NULL)
+    *head = queue_entry;
+  else
+    (*tail)->next = queue_entry;
+  *tail = queue_entry;
 
-	return (0);
-} /* int rrd_queue_cache_entry */
+  pthread_cond_signal (&queue_cond);
+  pthread_mutex_unlock (&queue_lock);
+
+  return (0);
+} /* int rrd_queue_enqueue */
+
+static int rrd_queue_dequeue (const char *filename,
+    rrd_queue_t **head, rrd_queue_t **tail)
+{
+  rrd_queue_t *this;
+  rrd_queue_t *prev;
+
+  pthread_mutex_lock (&queue_lock);
+
+  prev = NULL;
+  this = *head;
+
+  while (this != NULL)
+  {
+    if (strcmp (this->filename, filename) == 0)
+      break;
+    
+    prev = this;
+    this = this->next;
+  }
+
+  if (this == NULL)
+  {
+    pthread_mutex_unlock (&queue_lock);
+    return (-1);
+  }
+
+  if (prev == NULL)
+    *head = this->next;
+  else
+    prev->next = this->next;
+
+  if (this->next == NULL)
+    *tail = prev;
+
+  pthread_mutex_unlock (&queue_lock);
+
+  sfree (this->filename);
+  sfree (this);
+
+  return (0);
+} /* int rrd_queue_dequeue */
 
 static void rrd_cache_flush (int timeout)
 {
@@ -629,53 +493,56 @@ static void rrd_cache_flush (int timeout)
 	int    keys_num = 0;
 
 	char *key;
-	avl_iterator_t *iter;
+	c_avl_iterator_t *iter;
 	int i;
 
-	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 (rc->flags == FLAG_QUEUED)
+		if (rc->flags != FLAG_NONE)
 			continue;
 		else if ((now - rc->first_value) < timeout)
 			continue;
 		else if (rc->values_num > 0)
 		{
-			if (rrd_queue_cache_entry (key) == 0)
+			int status;
+
+			status = rrd_queue_enqueue (key, &queue_head,  &queue_tail);
+			if (status == 0)
 				rc->flags = FLAG_QUEUED;
 		}
 		else /* ancient and no values -> waste of memory */
 		{
-			keys = (char **) realloc ((void *) keys,
+			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;
 		}
 
@@ -687,12 +554,68 @@ static void rrd_cache_flush (int timeout)
 		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_flush_identifier (int timeout, const char *identifier)
+{
+  rrd_cache_t *rc;
+  time_t now;
+  int status;
+  char key[2048];
+
+  if (identifier == NULL)
+  {
+    rrd_cache_flush (timeout);
+    return (0);
+  }
+
+  now = time (NULL);
+
+  if (datadir == NULL)
+    snprintf (key, sizeof (key), "%s.rrd",
+        identifier);
+  else
+    snprintf (key, sizeof (key), "%s/%s.rrd",
+        datadir, identifier);
+  key[sizeof (key) - 1] = 0;
+
+  status = c_avl_get (cache, key, (void *) &rc);
+  if (status != 0)
+  {
+    WARNING ("rrdtool plugin: rrd_cache_flush_identifier: "
+        "c_avl_get (%s) failed. Does that file really exist?",
+        key);
+    return (status);
+  }
+
+  if (rc->flags == FLAG_FLUSHQ)
+  {
+    status = 0;
+  }
+  else if (rc->flags == FLAG_QUEUED)
+  {
+    rrd_queue_dequeue (key, &queue_head, &queue_tail);
+    status = rrd_queue_enqueue (key, &flushq_head, &flushq_tail);
+    if (status == 0)
+      rc->flags = FLAG_FLUSHQ;
+  }
+  else if ((now - rc->first_value) < timeout)
+  {
+    status = 0;
+  }
+  else if (rc->values_num > 0)
+  {
+    status = rrd_queue_enqueue (key, &flushq_head, &flushq_tail);
+    if (status == 0)
+      rc->flags = FLAG_FLUSHQ;
+  }
+
+  return (status);
+} /* int rrd_cache_flush_identifier */
+
 static int rrd_cache_insert (const char *filename,
 		const char *value, time_t value_time)
 {
@@ -702,7 +625,7 @@ static int rrd_cache_insert (const char *filename,
 
 	pthread_mutex_lock (&cache_lock);
 
-	avl_get (cache, filename, (void *) &rc);
+	c_avl_get (cache, filename, (void *) &rc);
 
 	if (rc == NULL)
 	{
@@ -735,7 +658,7 @@ static int rrd_cache_insert (const char *filename,
 
 		sstrerror (errno, errbuf, sizeof (errbuf));
 
-		avl_remove (cache, filename, &cache_key, NULL);
+		c_avl_remove (cache, filename, &cache_key, NULL);
 		pthread_mutex_unlock (&cache_lock);
 
 		ERROR ("rrdtool plugin: realloc failed: %s", errbuf);
@@ -775,19 +698,24 @@ static int rrd_cache_insert (const char *filename,
 			return (-1);
 		}
 
-		avl_insert (cache, cache_key, rc);
+		c_avl_insert (cache, cache_key, rc);
 	}
 
-	DEBUG ("rrd_cache_insert (%s, %s, %u) = %p", filename, value,
-			(unsigned int) value_time, (void *) rc);
+	DEBUG ("rrdtool plugin: rrd_cache_insert: file = %s; "
+			"values_num = %i; age = %lu;",
+			filename, rc->values_num,
+			(unsigned long)(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 (rc->flags == FLAG_NONE)
 		{
-			if (rrd_queue_cache_entry (filename) == 0)
+			int status;
+
+			status = rrd_queue_enqueue (filename, &queue_head, &queue_tail);
+			if (status == 0)
 				rc->flags = FLAG_QUEUED;
 		}
 		else
@@ -800,12 +728,24 @@ static int rrd_cache_insert (const char *filename,
 			((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;
@@ -813,6 +753,11 @@ static int rrd_write (const data_set_t *ds, const value_list_t *vl)
 	char         values[512];
 	int          status;
 
+	if (0 != strcmp (ds->type, vl->type)) {
+		ERROR ("rrdtool plugin: DS type does not match value list type");
+		return -1;
+	}
+
 	if (value_list_to_filename (filename, sizeof (filename), ds, vl) != 0)
 		return (-1);
 
@@ -823,7 +768,9 @@ static int rrd_write (const data_set_t *ds, const value_list_t *vl)
 	{
 		if (errno == ENOENT)
 		{
-			if (rrd_create_file (filename, ds, vl))
+			status = cu_rrd_create_file (filename,
+					ds, vl, &rrdcreate_config);
+			if (status != 0)
 				return (-1);
 		}
 		else
@@ -847,6 +794,21 @@ static int rrd_write (const data_set_t *ds, const value_list_t *vl)
 	return (status);
 } /* int rrd_write */
 
+static int rrd_flush (int timeout, const char *identifier)
+{
+	pthread_mutex_lock (&cache_lock);
+
+	if (cache == NULL) {
+		pthread_mutex_unlock (&cache_lock);
+		return (0);
+	}
+
+	rrd_cache_flush_identifier (timeout, identifier);
+
+	pthread_mutex_unlock (&cache_lock);
+	return (0);
+} /* int rrd_flush */
+
 static int rrd_config (const char *key, const char *value)
 {
 	if (strcasecmp ("CacheTimeout", key) == 0)
@@ -856,6 +818,8 @@ static int rrd_config (const char *key, const char *value)
 		{
 			fprintf (stderr, "rrdtool: `CacheTimeout' must "
 					"be greater than 0.\n");
+			ERROR ("rrdtool: `CacheTimeout' must "
+					"be greater than 0.\n");
 			return (1);
 		}
 		cache_timeout = tmp;
@@ -867,6 +831,8 @@ static int rrd_config (const char *key, const char *value)
 		{
 			fprintf (stderr, "rrdtool: `CacheFlush' must "
 					"be greater than 0.\n");
+			ERROR ("rrdtool: `CacheFlush' must "
+					"be greater than 0.\n");
 			return (1);
 		}
 		cache_flush_timeout = tmp;
@@ -893,15 +859,15 @@ static int rrd_config (const char *key, const char *value)
 	}
 	else if (strcasecmp ("StepSize", key) == 0)
 	{
-		stepsize = atoi (value);
-		if (stepsize < 0)
-			stepsize = 0;
+		int temp = atoi (value);
+		if (temp > 0)
+			rrdcreate_config.stepsize = temp;
 	}
 	else if (strcasecmp ("HeartBeat", key) == 0)
 	{
-		heartbeat = atoi (value);
-		if (heartbeat < 0)
-			heartbeat = 0;
+		int temp = atoi (value);
+		if (temp > 0)
+			rrdcreate_config.heartbeat = temp;
 	}
 	else if (strcasecmp ("RRARows", key) == 0)
 	{
@@ -910,9 +876,11 @@ static int rrd_config (const char *key, const char *value)
 		{
 			fprintf (stderr, "rrdtool: `RRARows' must "
 					"be greater than 0.\n");
+			ERROR ("rrdtool: `RRARows' must "
+					"be greater than 0.\n");
 			return (1);
 		}
-		rrarows = tmp;
+		rrdcreate_config.rrarows = tmp;
 	}
 	else if (strcasecmp ("RRATimespan", key) == 0)
 	{
@@ -931,19 +899,26 @@ static int rrd_config (const char *key, const char *value)
 		{
 			dummy = NULL;
 			
-			tmp_alloc = realloc (rra_timespans_custom,
-					sizeof (int) * (rra_timespans_custom_num + 1));
+			tmp_alloc = realloc (rrdcreate_config.timespans,
+					sizeof (int) * (rrdcreate_config.timespans_num + 1));
 			if (tmp_alloc == NULL)
 			{
 				fprintf (stderr, "rrdtool: realloc failed.\n");
+				ERROR ("rrdtool: realloc failed.\n");
 				free (value_copy);
 				return (1);
 			}
-			rra_timespans_custom = tmp_alloc;
-			rra_timespans_custom[rra_timespans_custom_num] = atoi (ptr);
-			if (rra_timespans_custom[rra_timespans_custom_num] != 0)
-				rra_timespans_custom_num++;
+			rrdcreate_config.timespans = tmp_alloc;
+			rrdcreate_config.timespans[rrdcreate_config.timespans_num] = atoi (ptr);
+			if (rrdcreate_config.timespans[rrdcreate_config.timespans_num] != 0)
+				rrdcreate_config.timespans_num++;
 		} /* while (strtok_r) */
+
+		qsort (/* base = */ rrdcreate_config.timespans,
+				/* nmemb  = */ rrdcreate_config.timespans_num,
+				/* size   = */ sizeof (rrdcreate_config.timespans[0]),
+				/* compar = */ rrd_compare_numeric);
+
 		free (value_copy);
 	}
 	else if (strcasecmp ("XFF", key) == 0)
@@ -953,9 +928,30 @@ static int rrd_config (const char *key, const char *value)
 		{
 			fprintf (stderr, "rrdtool: `XFF' must "
 					"be in the range 0 to 1 (exclusive).");
+			ERROR ("rrdtool: `XFF' must "
+					"be in the range 0 to 1 (exclusive).");
 			return (1);
 		}
-		xff = tmp;
+		rrdcreate_config.xff = tmp;
+	}
+	else if (strcasecmp ("WritesPerSecond", key) == 0)
+	{
+		double wps = atof (value);
+
+		if (wps < 0.0)
+		{
+			fprintf (stderr, "rrdtool: `WritesPerSecond' must be "
+					"greater than or equal to zero.");
+			return (1);
+		}
+		else if (wps == 0.0)
+		{
+			write_rate = 0.0;
+		}
+		else
+		{
+			write_rate = 1.0 / wps;
+		}
 	}
 	else
 	{
@@ -975,6 +971,14 @@ static int rrd_shutdown (void)
 	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 */
 
@@ -982,21 +986,18 @@ static int rrd_init (void)
 {
 	int status;
 
-	if (stepsize < 0)
-		stepsize = 0;
-	if (heartbeat <= 0)
-	{
-		if (stepsize > 0)
-			heartbeat = 2 * stepsize;
-		else
-			heartbeat = 0;
-	}
+	if (rrdcreate_config.stepsize < 0)
+		rrdcreate_config.stepsize = 0;
+	if (rrdcreate_config.heartbeat <= 0)
+		rrdcreate_config.heartbeat = 2 * rrdcreate_config.stepsize;
 
-	if ((heartbeat > 0) && (heartbeat < interval_g))
+	if ((rrdcreate_config.heartbeat > 0)
+			&& (rrdcreate_config.heartbeat < interval_g))
 		WARNING ("rrdtool plugin: Your `heartbeat' is "
 				"smaller than your `interval'. This will "
 				"likely cause problems.");
-	else if ((stepsize > 0) && (stepsize < interval_g))
+	else if ((rrdcreate_config.stepsize > 0)
+			&& (rrdcreate_config.stepsize < interval_g))
 		WARNING ("rrdtool plugin: Your `stepsize' is "
 				"smaller than your `interval'. This will "
 				"create needlessly big RRD-files.");
@@ -1004,10 +1005,10 @@ static int rrd_init (void)
 	/* Set the cache up */
 	pthread_mutex_lock (&cache_lock);
 
-	cache = avl_create ((int (*) (const void *, const void *)) strcmp);
+	cache = c_avl_create ((int (*) (const void *, const void *)) strcmp);
 	if (cache == NULL)
 	{
-		ERROR ("rrdtool plugin: avl_create failed.");
+		ERROR ("rrdtool plugin: c_avl_create failed.");
 		return (-1);
 	}
 
@@ -1032,7 +1033,10 @@ static int rrd_init (void)
 	DEBUG ("rrdtool plugin: rrd_init: datadir = %s; stepsize = %i;"
 			" heartbeat = %i; rrarows = %i; xff = %lf;",
 			(datadir == NULL) ? "(null)" : datadir,
-			stepsize, heartbeat, rrarows, xff);
+			rrdcreate_config.stepsize,
+			rrdcreate_config.heartbeat,
+			rrdcreate_config.rrarows,
+			rrdcreate_config.xff);
 
 	return (0);
 } /* int rrd_init */
@@ -1043,5 +1047,6 @@ void module_register (void)
 			config_keys, config_keys_num);
 	plugin_register_init ("rrdtool", rrd_init);
 	plugin_register_write ("rrdtool", rrd_write);
+	plugin_register_flush ("rrdtool", rrd_flush);
 	plugin_register_shutdown ("rrdtool", rrd_shutdown);
 }