From: oetiker Date: Fri, 26 Sep 2008 05:10:25 +0000 (+0000) Subject: This patch ensures that the "FLUSH" command will write the updates out to X-Git-Url: https://git.octo.it/?p=rrdtool.git;a=commitdiff_plain;h=a78dbfc073725a76ca28f8ae9f7a7ae9df34d2d3 This patch ensures that the "FLUSH" command will write the updates out to RRD before returning to the user. Before, it returned when the update was "dequeued"; updates were not necessarily on disk. Also, for new nodes, the cache_lock is not held while we are setting up the new node. We don't want to be holding the lock if the stat() blocks. -- kevin brintnal git-svn-id: svn://svn.oetiker.ch/rrdtool/trunk/program@1527 a5681a0c-68f1-0310-ab6d-d61299d08faa --- diff --git a/doc/rrdcached.pod b/doc/rrdcached.pod index 3505728..bf289c5 100644 --- a/doc/rrdcached.pod +++ b/doc/rrdcached.pod @@ -187,9 +187,8 @@ The downside of caching values is that they won't show up in graphs generated from the RRDEfiles. To get around this, the daemon provides the "flush command" to flush specific files. This means that the file is inserted at the B of the update queue or moved there if it is already enqueued. The flush -command will return after the update thread has dequeued the file, so there is -a good chance that the file has been updated by the time the client receives -the response from the daemon, but there is no guarantee. +command will return only after the file's pending updates have been written +to disk. +------+ +------+ +------+ ! head ! ! root ! ! tail ! diff --git a/doc/rrdflush.pod b/doc/rrdflush.pod index a593821..514bd35 100644 --- a/doc/rrdflush.pod +++ b/doc/rrdflush.pod @@ -12,9 +12,7 @@ S<[B<--daemon> I
]> The B function connects to L, the RRD caching daemon, and issues a "flush" command for the given file. The daemon will put this file to the head of the update queue so it is written "soon". The status will be -returned after the node has been B by the update thread. By the time -execution of this command ends it is very likely that the update thread has -just updated the requested file, though this is not guaranteed. +returned only after the file's pending updates have been written to disk. =over 8 diff --git a/src/rrd_daemon.c b/src/rrd_daemon.c index c438028..1c02a49 100644 --- a/src/rrd_daemon.c +++ b/src/rrd_daemon.c @@ -119,7 +119,7 @@ struct cache_item_s #define CI_FLAGS_IN_TREE (1<<0) #define CI_FLAGS_IN_QUEUE (1<<1) int flags; - + pthread_cond_t flushed; cache_item_t *next; }; @@ -165,8 +165,6 @@ static cache_item_t *cache_queue_tail = NULL; static pthread_mutex_t cache_lock = PTHREAD_MUTEX_INITIALIZER; static pthread_cond_t cache_cond = PTHREAD_COND_INITIALIZER; -static pthread_cond_t flush_cond = PTHREAD_COND_INITIALIZER; - static int config_write_interval = 300; static int config_write_jitter = 0; static int config_flush_interval = 3600; @@ -640,6 +638,7 @@ static void *queue_thread_main (void *args __attribute__((unused))) /* {{{ */ } journal_write("wrote", file); + pthread_cond_broadcast(&ci->flushed); for (i = 0; i < values_num; i++) free (values[i]); @@ -656,7 +655,6 @@ static void *queue_thread_main (void *args __attribute__((unused))) /* {{{ */ } pthread_mutex_lock (&cache_lock); - pthread_cond_broadcast (&flush_cond); /* We're about to shut down, so lets flush the entire tree. */ if ((do_shutdown != 0) && (cache_queue_head == NULL)) @@ -751,23 +749,9 @@ static int flush_file (const char *filename) /* {{{ */ enqueue_cache_item (ci, HEAD); pthread_cond_signal (&cache_cond); - while ((ci->flags & CI_FLAGS_IN_QUEUE) != 0) - { - ci = NULL; - - pthread_cond_wait (&flush_cond, &cache_lock); - - ci = g_tree_lookup (cache_tree, filename); - if (ci == NULL) - { - RRDD_LOG (LOG_ERR, "flush_file: Tree node went away " - "while waiting for flush."); - pthread_mutex_unlock (&cache_lock); - return (-1); - } - } + pthread_cond_wait(&ci->flushed, &cache_lock); + pthread_mutex_unlock(&cache_lock); - pthread_mutex_unlock (&cache_lock); return (0); } /* }}} int flush_file */ @@ -1043,17 +1027,19 @@ static int handle_request_update (int fd, /* {{{ */ pthread_mutex_unlock(&stats_lock); pthread_mutex_lock (&cache_lock); - ci = g_tree_lookup (cache_tree, file); + if (ci == NULL) /* {{{ */ { struct stat statbuf; + /* don't hold the lock while we setup; stat(2) might block */ + pthread_mutex_unlock(&cache_lock); + memset (&statbuf, 0, sizeof (statbuf)); status = stat (file, &statbuf); if (status != 0) { - pthread_mutex_unlock (&cache_lock); RRDD_LOG (LOG_NOTICE, "handle_request_update: stat (%s) failed.", file); status = errno; @@ -1067,16 +1053,12 @@ static int handle_request_update (int fd, /* {{{ */ } if (!S_ISREG (statbuf.st_mode)) { - pthread_mutex_unlock (&cache_lock); - snprintf (answer, sizeof (answer), "-1 Not a regular file: %s\n", file); RRDD_UPDATE_SEND; return (0); } if (access(file, R_OK|W_OK) != 0) { - pthread_mutex_unlock (&cache_lock); - snprintf (answer, sizeof (answer), "-1 Cannot read/write %s: %s\n", file, rrd_strerror(errno)); RRDD_UPDATE_SEND; @@ -1086,7 +1068,6 @@ static int handle_request_update (int fd, /* {{{ */ ci = (cache_item_t *) malloc (sizeof (cache_item_t)); if (ci == NULL) { - pthread_mutex_unlock (&cache_lock); RRDD_LOG (LOG_ERR, "handle_request_update: malloc failed."); strncpy (answer, "-1 malloc failed.\n", sizeof (answer)); @@ -1098,7 +1079,6 @@ static int handle_request_update (int fd, /* {{{ */ ci->file = strdup (file); if (ci->file == NULL) { - pthread_mutex_unlock (&cache_lock); free (ci); RRDD_LOG (LOG_ERR, "handle_request_update: strdup failed."); @@ -1110,6 +1090,7 @@ static int handle_request_update (int fd, /* {{{ */ _wipe_ci_values(ci, now); ci->flags = CI_FLAGS_IN_TREE; + pthread_mutex_lock(&cache_lock); g_tree_insert (cache_tree, (void *) ci->file, (void *) ci); } /* }}} */ assert (ci != NULL);