From: Florian Forster <octo@collectd.org>
Date: Thu, 20 Jul 2017 07:12:14 +0000 (+0200)
Subject: Merge branch 'collectd-5.7'
X-Git-Tag: collectd-5.8.0~112
X-Git-Url: https://git.octo.it/?a=commitdiff_plain;h=c99e3a4d169ada9299c73e20662d17debdc32e1f;hp=af12cc40e48331f8c98294239cef60393218a46d;p=collectd.git

Merge branch 'collectd-5.7'

Conflicts:
	src/rrdtool.c
---

diff --git a/src/collectd.conf.pod b/src/collectd.conf.pod
index 2bf1a558..2566aa19 100644
--- a/src/collectd.conf.pod
+++ b/src/collectd.conf.pod
@@ -7043,14 +7043,20 @@ one (exclusive).
 
 When the C<rrdtool> plugin uses a cache (by setting B<CacheTimeout>, see below)
 it writes all values for a certain RRD-file if the oldest value is older than
-(or equal to) the number of seconds specified. If some RRD-file is not updated
+(or equal to) the number of seconds specified by B<CacheTimeout>.
+That check happens on new values arriwal. If some RRD-file is not updated
 anymore for some reason (the computer was shut down, the network is broken,
-etc.) some values may still be in the cache. If B<CacheFlush> is set, then the
-entire cache is searched for entries older than B<CacheTimeout> seconds and
-written to disk every I<Seconds> seconds. Since this is kind of expensive and
-does nothing under normal circumstances, this value should not be too small.
-900 seconds might be a good value, though setting this to 7200 seconds doesn't
-normally do much harm either.
+etc.) some values may still be in the cache. If B<CacheFlush> is set, then
+every I<Seconds> seconds the entire cache is searched for entries older than
+B<CacheTimeout> + B<RandomTimeout> seconds. The entries found are written to
+disk. Since scanning the entire cache is kind of expensive and does nothing
+under normal circumstances, this value should not be too small. 900 seconds
+might be a good value, though setting this to 7200 seconds doesn't normally
+do much harm either.
+
+Defaults to 10x B<CacheTimeout>.
+B<CacheFlush> must be larger than or equal to B<CacheTimeout>, otherwise the
+above default is used.
 
 =item B<CacheTimeout> I<Seconds>
 
diff --git a/src/rrdtool.c b/src/rrdtool.c
index 41289058..2dfa87a0 100644
--- a/src/rrdtool.c
+++ b/src/rrdtool.c
@@ -87,7 +87,7 @@ static rrdcreate_config_t rrdcreate_config = {
  * ALWAYS lock `cache_lock' first! */
 static cdtime_t cache_timeout = 0;
 static cdtime_t cache_flush_timeout = 0;
-static cdtime_t random_timeout = TIME_T_TO_CDTIME_T_STATIC(1);
+static cdtime_t random_timeout = 0;
 static cdtime_t cache_flush_last;
 static c_avl_tree_t *cache = NULL;
 static pthread_mutex_t cache_lock = PTHREAD_MUTEX_INITIALIZER;
@@ -505,7 +505,6 @@ static void rrd_cache_flush(cdtime_t timeout) {
         CDTIME_T_TO_DOUBLE(timeout));
 
   now = cdtime();
-  timeout = TIME_T_TO_CDTIME_T(timeout);
 
   /* Build a list of entries to be flushed */
   iter = c_avl_get_iterator(cache);
@@ -606,23 +605,10 @@ static int rrd_cache_flush_identifier(cdtime_t timeout,
 } /* int rrd_cache_flush_identifier */
 
 static int64_t rrd_get_random_variation(void) {
-  long min;
-  long max;
-
   if (random_timeout == 0)
     return 0;
 
-  /* Assure that "cache_timeout + random_variation" is never negative. */
-  if (random_timeout > cache_timeout) {
-    INFO("rrdtool plugin: Adjusting \"RandomTimeout\" to %.3f seconds.",
-         CDTIME_T_TO_DOUBLE(cache_timeout));
-    random_timeout = cache_timeout;
-  }
-
-  max = (long)(random_timeout / 2);
-  min = max - ((long)random_timeout);
-
-  return (int64_t)cdrand_range(min, max);
+  return (int64_t)cdrand_range(-random_timeout, random_timeout);
 } /* int64_t rrd_get_random_variation */
 
 static int rrd_cache_insert(const char *filename, const char *value,
@@ -740,7 +726,7 @@ static int rrd_cache_insert(const char *filename, const char *value,
 
   if ((cache_timeout > 0) &&
       ((cdtime() - cache_flush_last) > cache_flush_timeout))
-    rrd_cache_flush(cache_flush_timeout);
+    rrd_cache_flush(cache_timeout + random_timeout);
 
   pthread_mutex_unlock(&cache_lock);
 
@@ -877,7 +863,7 @@ static int rrd_config(const char *key, const char *value) {
     }
     cache_timeout = DOUBLE_TO_CDTIME_T(tmp);
   } else if (strcasecmp("CacheFlush", key) == 0) {
-    int tmp = atoi(value);
+    double tmp = atof(value);
     if (tmp < 0) {
       fprintf(stderr, "rrdtool: `CacheFlush' must "
                       "be greater than 0.\n");
@@ -885,7 +871,7 @@ static int rrd_config(const char *key, const char *value) {
             "be greater than 0.\n");
       return 1;
     }
-    cache_flush_timeout = tmp;
+    cache_flush_timeout = DOUBLE_TO_CDTIME_T(tmp);
   } else if (strcasecmp("DataDir", key) == 0) {
     char *tmp;
     size_t len;
@@ -1065,9 +1051,23 @@ static int rrd_init(void) {
 
   cache_flush_last = cdtime();
   if (cache_timeout == 0) {
+    random_timeout = 0;
     cache_flush_timeout = 0;
-  } else if (cache_flush_timeout < cache_timeout)
+  } else if (cache_flush_timeout < cache_timeout) {
+    INFO("rrdtool plugin: \"CacheFlush %.3f\" is less than \"CacheTimeout %.3f\". "
+         "Ajusting \"CacheFlush\" to %.3f seconds.",
+         CDTIME_T_TO_DOUBLE(cache_flush_timeout),
+         CDTIME_T_TO_DOUBLE(cache_timeout),
+         CDTIME_T_TO_DOUBLE(cache_timeout * 10));
     cache_flush_timeout = 10 * cache_timeout;
+  }
+
+  /* Assure that "cache_timeout + random_variation" is never negative. */
+  if (random_timeout > cache_timeout) {
+    INFO("rrdtool plugin: Adjusting \"RandomTimeout\" to %.3f seconds.",
+         CDTIME_T_TO_DOUBLE(cache_timeout));
+    random_timeout = cache_timeout;
+  }
 
   pthread_mutex_unlock(&cache_lock);