Do not force internal collectors to call rrdset_next. (#13926)

* Remove calls to rrdset_next().

* Rm checks plugin

* Update documentantion

* Call rrdset_next from within rrdset_done

This wraps up the removal of rrdset_next from internal collectors, which
removes a lot of unecessary code and the need for if/else clauses in
every place.

The pluginsd parser is the only component that calls rrdset_next*()
functions because it's not strictly speaking a collector but more of a
collector manager/proxy.

With the current changes it's possible to simplify the API we expose
from RRD significantly, but this will be follow-up work in the future.

* Remove stale reference to checks.plugin

* Fix RRD unit test

rrdset_next is not meant to be called from these tests.

* Fix db engine unit test.

* Schedule rrdset_next when we have completed at least one collection.

* Mark chart creation clauses as unlikely.

* Add missing brace to fix FreeBSD plugin.

1 files changed, 0 insertions, 2 deletions

diff --git a/collectors/proc.plugin/proc_sys_kernel_random_entropy_avail.c b/collectors/proc.plugin/proc_sys_kernel_random_entropy_avail.c
index 20d2116ceb..a04d43039a 100644
--- a/collectors/proc.plugin/proc_sys_kernel_random_entropy_avail.c
+++ b/collectors/proc.plugin/proc_sys_kernel_random_entropy_avail.c
@@ -40,10 +40,8 @@ int do_proc_sys_kernel_random_entropy_avail(int update_every, usec_t dt) {
 
         rd = rrddim_add(st, "entropy", NULL, 1, 1, RRD_ALGORITHM_ABSOLUTE);
     }
-    else rrdset_next(st);
 
     rrddim_set_by_pointer(st, rd, entropy);
     rrdset_done(st);
-
     return 0;
 }