Guard for null host when sending node instances (#14673)

* guard for null host when sending node instances

* also add a default value when migrating

3 files changed, 7 insertions, 2 deletions

diff --git a/aclk/aclk.c b/aclk/aclk.c
index e808972213..9e03e04c8c 100644
--- a/aclk/aclk.c
+++ b/aclk/aclk.c
@@ -870,6 +870,11 @@ void aclk_send_node_instances()
             uuid_unparse_lower(list->host_id, host_id);
 
             RRDHOST *host = rrdhost_find_by_guid(host_id);
+            if (unlikely(!host)) {
+                freez((void*)node_state_update.node_id);
+                freez(query);
+                continue;
+            }
             node_state_update.capabilities = aclk_get_node_instance_capas(host);
 
             rrdhost_aclk_state_lock(localhost);
diff --git a/database/sqlite/sqlite_db_migration.c b/database/sqlite/sqlite_db_migration.c
index fad3c57643..3132ae2d05 100644
--- a/database/sqlite/sqlite_db_migration.c
+++ b/database/sqlite/sqlite_db_migration.c
@@ -49,7 +49,7 @@ static int column_exists_in_table(const char *table, const char *column)
 }
 
 const char *database_migrate_v1_v2[] = {
-    "ALTER TABLE host ADD hops INTEGER;",
+    "ALTER TABLE host ADD hops INTEGER NOT NULL DEFAULT 0;",
     NULL
 };
 
diff --git a/database/sqlite/sqlite_functions.c b/database/sqlite/sqlite_functions.c
index 3bd11f1ae1..bdfcd7f6ed 100644
--- a/database/sqlite/sqlite_functions.c
+++ b/database/sqlite/sqlite_functions.c
@@ -771,7 +771,7 @@ failed:
 }
 
 #define SQL_GET_NODE_INSTANCE_LIST "select ni.node_id, ni.host_id, h.hostname " \
-    "from node_instance ni, host h where ni.host_id = h.host_id;"
+    "from node_instance ni, host h where ni.host_id = h.host_id AND h.hops >=0;"
 
 struct node_instance_list *get_node_list(void)
 {