4 files changed, 131 insertions, 0 deletions
diff --git a/web/api/queries/incremental_sum/Makefile.am b/web/api/queries/incremental_sum/Makefile.am
new file mode 100644
index 00000000..161784b8
--- /dev/null
+++ b/web/api/queries/incremental_sum/Makefile.am
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+AUTOMAKE_OPTIONS = subdir-objects
+MAINTAINERCLEANFILES = $(srcdir)/Makefile.in
+
+dist_noinst_DATA = \
+    README.md \
+    $(NULL)
diff --git a/web/api/queries/incremental_sum/README.md b/web/api/queries/incremental_sum/README.md
new file mode 100644
index 00000000..c882acba
--- /dev/null
+++ b/web/api/queries/incremental_sum/README.md
@@ -0,0 +1,45 @@
+<!--
+title: "Incremental Sum (`incremental_sum`)"
+sidebar_label: "Incremental Sum (`incremental_sum`)"
+custom_edit_url: https://github.com/netdata/netdata/edit/master/web/api/queries/incremental_sum/README.md
+learn_status: "Published"
+learn_topic_type: "References"
+learn_rel_path: "Developers/Web/Api/Queries"
+-->
+
+# Incremental Sum (`incremental_sum`)
+
+This modules finds the incremental sum of a period, which `last value - first value`.
+
+The result may be positive (rising) or negative (falling) depending on the first and last values.
+
+## how to use
+
+Use it in alerts like this:
+
+```
+ alarm: my_alert
+    on: my_chart
+lookup: incremental_sum -1m unaligned of my_dimension
+  warn: $this > 1000
+```
+
+`incremental_sum` does not change the units. For example, if the chart units is `requests/sec`, the result
+will be again expressed in the same units. 
+
+It can also be used in APIs and badges as `&group=incremental_sum` in the URL.
+
+## Examples
+
+Examining last 1 minute `successful` web server responses:
+
+-   ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=min&after=-60&label=min)
+-   ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=average&after=-60&label=average)
+-   ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=max&after=-60&label=max)
+-   ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=incremental_sum&after=-60&label=incremental+sum&value_color=orange)
+
+## References
+
+-   none
+
+
diff --git a/web/api/queries/incremental_sum/incremental_sum.c b/web/api/queries/incremental_sum/incremental_sum.c
new file mode 100644
index 00000000..88072f29
--- /dev/null
+++ b/web/api/queries/incremental_sum/incremental_sum.c
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "incremental_sum.h"
+
+// ----------------------------------------------------------------------------
+// incremental sum
+
diff --git a/web/api/queries/incremental_sum/incremental_sum.h b/web/api/queries/incremental_sum/incremental_sum.h
new file mode 100644
index 00000000..f110c586
--- /dev/null
+++ b/web/api/queries/incremental_sum/incremental_sum.h
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef NETDATA_API_QUERY_INCREMENTAL_SUM_H
+#define NETDATA_API_QUERY_INCREMENTAL_SUM_H
+
+#include "../query.h"
+#include "../rrdr.h"
+
+struct tg_incremental_sum {
+    NETDATA_DOUBLE first;
+    NETDATA_DOUBLE last;
+    size_t count;
+};
+
+// resets when switches dimensions
+// so, clear everything to restart
+static inline void tg_incremental_sum_reset(RRDR *r) {
+    struct tg_incremental_sum *g = (struct tg_incremental_sum *)r->time_grouping.data;
+    g->first = NAN;
+    g->last = NAN;
+    g->count = 0;
+}
+
+static inline void tg_incremental_sum_create(RRDR *r, const char *options __maybe_unused) {
+    r->time_grouping.data = onewayalloc_mallocz(r->internal.owa, sizeof(struct tg_incremental_sum));
+    tg_incremental_sum_reset(r);
+}
+
+static inline void tg_incremental_sum_free(RRDR *r) {
+    onewayalloc_freez(r->internal.owa, r->time_grouping.data);
+    r->time_grouping.data = NULL;
+}
+
+static inline void tg_incremental_sum_add(RRDR *r, NETDATA_DOUBLE value) {
+    struct tg_incremental_sum *g = (struct tg_incremental_sum *)r->time_grouping.data;
+
+    if(unlikely(!g->count)) {
+        if(isnan(g->first))
+            g->first = value;
+        else
+            g->last = value;
+
+        g->count++;
+    }
+    else {
+        g->last = value;
+        g->count++;
+    }
+}
+
+static inline NETDATA_DOUBLE tg_incremental_sum_flush(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr) {
+    struct tg_incremental_sum *g = (struct tg_incremental_sum *)r->time_grouping.data;
+
+    NETDATA_DOUBLE value;
+
+    if(unlikely(!g->count || isnan(g->first) || isnan(g->last))) {
+        value = 0.0;
+        *rrdr_value_options_ptr |= RRDR_VALUE_EMPTY;
+    }
+    else {
+        value = g->last - g->first;
+    }
+
+    g->first = g->last;
+    g->last = NAN;
+    g->count = 0;
+
+    return value;
+}
+
+#endif //NETDATA_API_QUERY_INCREMENTAL_SUM_H