Implemented multihost database (#9556)

* Hard code a node for non-legacy multidb test
Skip dbengine initialization for new incoming children
Add code to switch to multidb ctx when accessing the dbengine

* When a non-legacy streaming connection is detected, use the multidb metadata log context

* Clear the superblock memory to avoid random data written in the metadata log

* Activate the host detection during compaction
Activate the host detection during metadata log chart updates
Keep the host in the user object during replay of the HOST command

* Add defaults for health / rrdpush on HOST metadata replay
Check for legacy status on host creation by checking is_archived and if not conclusive, call is_legacy_child()

Use defaults from the stream.conf

* Count hosts only if not archived
When host switches from archived to active update rrd_hosts_available
Remove archived hosts from charts and info

* Change parameter from "multidb disk space" to "dbengine multihost disk space"
Remove unused variables
Fix compilation error when dbengine is disabled
Fix condition for machine_guid directory creation under cache_dir

* Enable multidb disk space file creation.

* Stop deleting dimensions when rotating archived metrics if the dimension is active in a different database engine.

* Fix old bug in the code that confused obsolete hosts with orphan hosts.

* Do not delete multi-host DB host files.

* Discard dbengine state when a legacy memory mode instantiates to avoid inconsistencies.

* Identify metadata that collide with non-dbengine memory mode hosts and ignore them.

* Handle non-dbengine localhost with dbengine archived charts in localhost and streaming.

* Ignore archived hosts in streaming.

* Add documentation before merging to master.

Co-authored-by: Markos Fountoulakis <markos.fountoulakis.senior@gmail.com>

3 files changed, 3 insertions, 20 deletions

diff --git a/streaming/README.md b/streaming/README.md
index 6891692dae..39693b6819 100644
--- a/streaming/README.md
+++ b/streaming/README.md
@@ -189,7 +189,7 @@ them `/var/lib/netdata/registry/netdata.unique.id`). So, metrics for Netdata `A`
 any number of other Netdata, will have the same `MACHINE_GUID`.
 
 You can also use `default memory mode = dbengine` for an API key or `memory mode = dbengine` for
- a single host. The additional `page cache size` and `dbengine disk space` configuration options
+ a single host. The additional `page cache size` and `dbengine multihost disk space` configuration options
  are inherited from the global Netdata configuration.
 
 ##### allow from
diff --git a/streaming/receiver.c b/streaming/receiver.c
index 73a296eecd..a7f66bede6 100644
--- a/streaming/receiver.c
+++ b/streaming/receiver.c
@@ -287,25 +287,6 @@ static int rrdpush_receive(struct receiver_state *rpt)
         }
         netdata_mutex_unlock(&rpt->host->receiver_lock);
     }
-    else rrdhost_update(rpt->host
-            , rpt->hostname
-            , rpt->registry_hostname
-            , rpt->machine_guid
-            , rpt->os
-            , rpt->timezone
-            , rpt->tags
-            , rpt->program_name
-            , rpt->program_version
-            , rpt->update_every
-            , history
-            , mode
-            , (unsigned int)(health_enabled != CONFIG_BOOLEAN_NO)
-            , (unsigned int)(rrdpush_enabled && rrdpush_destination && *rrdpush_destination && rrdpush_api_key && *rrdpush_api_key)
-            , rrdpush_destination
-            , rrdpush_api_key
-            , rrdpush_send_charts_matching
-            , rpt->system_info);
-
 
     int ssl = 0;
 #ifdef ENABLE_HTTPS
diff --git a/streaming/rrdpush.c b/streaming/rrdpush.c
index a9f06f10ca..1731857f56 100644
--- a/streaming/rrdpush.c
+++ b/streaming/rrdpush.c
@@ -611,6 +611,8 @@ int rrdpush_receiver_thread_spawn(struct web_client *w, char *url) {
      */
     struct receiver_state *rpt = callocz(1, sizeof(*rpt));
     RRDHOST *host = rrdhost_find_by_guid(machine_guid, 0);
+    if (unlikely(host && rrdhost_flag_check(host, RRDHOST_FLAG_ARCHIVED))) /* Ignore archived hosts. */
+        host = NULL;
     if (host) {
         netdata_mutex_lock(&host->receiver_lock);
         if (host->receiver != NULL) {