Merging upstream version 1.36.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

25 files changed, 370 insertions, 311 deletions

diff --git a/exporting/aws_kinesis/aws_kinesis.c b/exporting/aws_kinesis/aws_kinesis.c
index fe4181e3a..1d89cc79a 100644
--- a/exporting/aws_kinesis/aws_kinesis.c
+++ b/exporting/aws_kinesis/aws_kinesis.c
@@ -45,6 +45,7 @@ int init_aws_kinesis_instance(struct instance *instance)
         instance->metric_formatting = format_dimension_stored_json_plaintext;
 
     instance->end_chart_formatting = NULL;
+    instance->variables_formatting = NULL;
     instance->end_host_formatting = flush_host_labels;
     instance->end_batch_formatting = NULL;
 
diff --git a/exporting/check_filters.c b/exporting/check_filters.c
index f7eba22db..726fd02a1 100644
--- a/exporting/check_filters.c
+++ b/exporting/check_filters.c
@@ -2,6 +2,14 @@
 
 #include "exporting_engine.h"
 
+
+bool exporting_labels_filter_callback(const char *name, const char *value, RRDLABEL_SRC ls, void *data) {
+    (void)name;
+    (void)value;
+    struct instance *instance = (struct instance *)data;
+    return should_send_label(instance, ls);
+}
+
 /**
  * Check if the connector instance should export the host metrics
  *
diff --git a/exporting/clean_connectors.c b/exporting/clean_connectors.c
index 4af1219a6..e93563741 100644
--- a/exporting/clean_connectors.c
+++ b/exporting/clean_connectors.c
@@ -33,7 +33,7 @@ static void clean_instance_config(struct instance_config *config)
 void clean_instance(struct instance *instance)
 {
     clean_instance_config(&instance->config);
-    buffer_free(instance->labels);
+    buffer_free(instance->labels_buffer);
 
     uv_cond_destroy(&instance->cond_var);
     // uv_mutex_destroy(&instance->mutex);
diff --git a/exporting/exporting.conf b/exporting/exporting.conf
index 314e1541e..f2ec56a52 100644
--- a/exporting/exporting.conf
+++ b/exporting/exporting.conf
@@ -45,6 +45,7 @@
     # send names instead of ids = yes
     # send charts matching = *
     # send hosts matching = localhost *
+    # send variables = no
 
 # [kinesis:my_kinesis_instance]
     # enabled = no
diff --git a/exporting/exporting_engine.h b/exporting/exporting_engine.h
index 20f260c15..2141caa41 100644
--- a/exporting/exporting_engine.h
+++ b/exporting/exporting_engine.h
@@ -4,7 +4,6 @@
 #define NETDATA_EXPORTING_ENGINE_H 1
 
 #include "daemon/common.h"
-
 #include <uv.h>
 
 #define exporter_get(section, name, value) expconfig_get(&exporting_config, section, name, value)
@@ -27,7 +26,8 @@ typedef enum exporting_options {
     EXPORTING_OPTION_SEND_AUTOMATIC_LABELS  = (1 << 4),
     EXPORTING_OPTION_USE_TLS                = (1 << 5),
 
-    EXPORTING_OPTION_SEND_NAMES             = (1 << 16)
+    EXPORTING_OPTION_SEND_NAMES             = (1 << 16),
+    EXPORTING_OPTION_SEND_VARIABLES         = (1 << 17)
 } EXPORTING_OPTIONS;
 
 #define EXPORTING_OPTIONS_SOURCE_BITS                                                                                  \
@@ -40,11 +40,13 @@ extern const char *global_exporting_prefix;
 #define sending_labels_configured(instance)                                                                            \
     (instance->config.options & (EXPORTING_OPTION_SEND_CONFIGURED_LABELS | EXPORTING_OPTION_SEND_AUTOMATIC_LABELS))
 
-#define should_send_label(instance, label)                                                                             \
+#define should_send_label(instance, label_source)                                                                      \
     ((instance->config.options & EXPORTING_OPTION_SEND_CONFIGURED_LABELS &&                                            \
-      label->label_source == LABEL_SOURCE_NETDATA_CONF) ||                                                             \
+      label_source & RRDLABEL_SRC_CONFIG) ||                                                                           \
      (instance->config.options & EXPORTING_OPTION_SEND_AUTOMATIC_LABELS &&                                             \
-      label->label_source != LABEL_SOURCE_NETDATA_CONF))
+      label_source & RRDLABEL_SRC_AUTO))
+
+#define should_send_variables(instance) (instance->config.options & EXPORTING_OPTION_SEND_VARIABLES)
 
 typedef enum exporting_connector_types {
     EXPORTING_CONNECTOR_TYPE_UNKNOWN,                 // Invalid type
@@ -205,7 +207,7 @@ struct instance {
     int skip_host;
     int skip_chart;
 
-    BUFFER *labels;
+    BUFFER *labels_buffer;
 
     time_t after;
     time_t before;
@@ -220,6 +222,7 @@ struct instance {
     int (*start_chart_formatting)(struct instance *instance, RRDSET *st);
     int (*metric_formatting)(struct instance *instance, RRDDIM *rd);
     int (*end_chart_formatting)(struct instance *instance, RRDSET *st);
+    int (*variables_formatting)(struct instance *instance, RRDHOST *host);
     int (*end_host_formatting)(struct instance *instance, RRDHOST *host);
     int (*end_batch_formatting)(struct instance *instance);
 
@@ -270,7 +273,8 @@ int rrdset_is_exportable(struct instance *instance, RRDSET *st);
 
 extern EXPORTING_OPTIONS exporting_parse_data_source(const char *source, EXPORTING_OPTIONS exporting_options);
 
-calculated_number exporting_calculate_value_from_stored_data(
+NETDATA_DOUBLE
+exporting_calculate_value_from_stored_data(
     struct instance *instance,
     RRDDIM *rd,
     time_t *last_timestamp);
@@ -280,6 +284,7 @@ void start_host_formatting(struct engine *engine, RRDHOST *host);
 void start_chart_formatting(struct engine *engine, RRDSET *st);
 void metric_formatting(struct engine *engine, RRDDIM *rd);
 void end_chart_formatting(struct engine *engine, RRDSET *st);
+void variables_formatting(struct engine *engine, RRDHOST *host);
 void end_host_formatting(struct engine *engine, RRDHOST *host);
 void end_batch_formatting(struct engine *engine);
 int flush_host_labels(struct instance *instance, RRDHOST *host);
diff --git a/exporting/graphite/graphite.c b/exporting/graphite/graphite.c
index 84d4febf1..8ca094b3b 100644
--- a/exporting/graphite/graphite.c
+++ b/exporting/graphite/graphite.c
@@ -37,6 +37,7 @@ int init_graphite_instance(struct instance *instance)
         instance->metric_formatting = format_dimension_stored_graphite_plaintext;
 
     instance->end_chart_formatting = NULL;
+    instance->variables_formatting = NULL;
     instance->end_host_formatting = flush_host_labels;
     instance->end_batch_formatting = simple_connector_end_batch;
 
@@ -71,7 +72,7 @@ int init_graphite_instance(struct instance *instance)
  * @param len the maximum number of characters copied.
  */
 
-void sanitize_graphite_label_value(char *dst, char *src, size_t len)
+void sanitize_graphite_label_value(char *dst, const char *src, size_t len)
 {
     while (*src != '\0' && len) {
         if (isspace(*src) || *src == ';' || *src == '~')
@@ -91,29 +92,18 @@ void sanitize_graphite_label_value(char *dst, char *src, size_t len)
  * @param host a data collecting host.
  * @return Always returns 0.
  */
+
 int format_host_labels_graphite_plaintext(struct instance *instance, RRDHOST *host)
 {
-    if (!instance->labels)
-        instance->labels = buffer_create(1024);
+    if (!instance->labels_buffer)
+        instance->labels_buffer = buffer_create(1024);
 
     if (unlikely(!sending_labels_configured(instance)))
         return 0;
 
-    rrdhost_check_rdlock(host);
-    netdata_rwlock_rdlock(&host->labels.labels_rwlock);
-    for (struct label *label = host->labels.head; label; label = label->next) {
-        if (!should_send_label(instance, label))
-            continue;
-
-        char value[CONFIG_MAX_VALUE + 1];
-        sanitize_graphite_label_value(value, label->value, CONFIG_MAX_VALUE);
-
-        if (*value) {
-            buffer_strcat(instance->labels, ";");
-            buffer_sprintf(instance->labels, "%s=%s", label->key, value);
-        }
-    }
-    netdata_rwlock_unlock(&host->labels.labels_rwlock);
+    rrdlabels_to_buffer(host->host_labels, instance->labels_buffer, ";", "=", "", "",
+                        exporting_labels_filter_callback, instance,
+                        NULL, sanitize_graphite_label_value);
 
     return 0;
 }
@@ -151,7 +141,7 @@ int format_dimension_collected_graphite_plaintext(struct instance *instance, RRD
         dimension_name,
         (host->tags) ? ";" : "",
         (host->tags) ? host->tags : "",
-        (instance->labels) ? buffer_tostring(instance->labels) : "",
+        (instance->labels_buffer) ? buffer_tostring(instance->labels_buffer) : "",
         rd->last_collected_value,
         (unsigned long long)rd->last_collected_time.tv_sec);
 
@@ -183,21 +173,21 @@ int format_dimension_stored_graphite_plaintext(struct instance *instance, RRDDIM
         RRD_ID_LENGTH_MAX);
 
     time_t last_t;
-    calculated_number value = exporting_calculate_value_from_stored_data(instance, rd, &last_t);
+    NETDATA_DOUBLE value = exporting_calculate_value_from_stored_data(instance, rd, &last_t);
 
     if(isnan(value))
         return 0;
 
     buffer_sprintf(
         instance->buffer,
-        "%s.%s.%s.%s%s%s%s " CALCULATED_NUMBER_FORMAT " %llu\n",
+        "%s.%s.%s.%s%s%s%s " NETDATA_DOUBLE_FORMAT " %llu\n",
         instance->config.prefix,
         (host == localhost) ? instance->config.hostname : host->hostname,
         chart_name,
         dimension_name,
         (host->tags) ? ";" : "",
         (host->tags) ? host->tags : "",
-        (instance->labels) ? buffer_tostring(instance->labels) : "",
+        (instance->labels_buffer) ? buffer_tostring(instance->labels_buffer) : "",
         value,
         (unsigned long long)last_t);
 
diff --git a/exporting/graphite/graphite.h b/exporting/graphite/graphite.h
index 993c12e57..79f87e46e 100644
--- a/exporting/graphite/graphite.h
+++ b/exporting/graphite/graphite.h
@@ -7,7 +7,7 @@
 
 int init_graphite_instance(struct instance *instance);
 
-void sanitize_graphite_label_value(char *dst, char *src, size_t len);
+void sanitize_graphite_label_value(char *dst, const char *src, size_t len);
 int format_host_labels_graphite_plaintext(struct instance *instance, RRDHOST *host);
 
 int format_dimension_collected_graphite_plaintext(struct instance *instance, RRDDIM *rd);
diff --git a/exporting/init_connectors.c b/exporting/init_connectors.c
index 69ea0685c..bfb6525ea 100644
--- a/exporting/init_connectors.c
+++ b/exporting/init_connectors.c
@@ -117,7 +117,7 @@ static size_t base64_encode(unsigned char *input, size_t input_size, char *outpu
         return 0;
     }
     size_t count = 0;
-    while (input_size > 3) {
+    while (input_size >= 3) {
         value = ((input[0] << 16) + (input[1] << 8) + input[2]) & 0xffffff;
         output[0] = lookup[value >> 18];
         output[1] = lookup[(value >> 12) & 0x3f];
@@ -138,6 +138,7 @@ static size_t base64_encode(unsigned char *input, size_t input_size, char *outpu
             output[3] = '=';
             //error("Base-64 encode (%06x) -> %c %c %c %c\n", (value>>2)&0xffff, output[0], output[1], output[2], output[3]);
             count += 4;
+            output[4] = '\0';
             break;
         case 1:
             value = input[0] << 4;
@@ -147,10 +148,13 @@ static size_t base64_encode(unsigned char *input, size_t input_size, char *outpu
             output[3] = '=';
             //error("Base-64 encode (%06x) -> %c %c %c %c\n", value, output[0], output[1], output[2], output[3]);
             count += 4;
+            output[4] = '\0';
             break;
         case 0:
+            output[0] = '\0';
             break;
     }
+
     return count;
 }
 
@@ -199,7 +203,7 @@ void simple_connector_init(struct instance *instance)
         char *encoded_credentials = callocz(1, encoded_size);
 
         base64_encode((unsigned char*)buffer_tostring(auth_string), buffer_strlen(auth_string), encoded_credentials, encoded_size);
-       
+
         buffer_flush(auth_string);
         buffer_sprintf(auth_string, "Authorization: Basic %s\n", encoded_credentials);
 
diff --git a/exporting/json/json.c b/exporting/json/json.c
index 50278c5b8..45a8c9d9f 100644
--- a/exporting/json/json.c
+++ b/exporting/json/json.c
@@ -29,6 +29,7 @@ int init_json_instance(struct instance *instance)
         instance->metric_formatting = format_dimension_stored_json_plaintext;
 
     instance->end_chart_formatting = NULL;
+    instance->variables_formatting = NULL;
     instance->end_host_formatting = flush_host_labels;
     instance->end_batch_formatting = simple_connector_end_batch;
 
@@ -87,6 +88,7 @@ int init_json_http_instance(struct instance *instance)
         instance->metric_formatting = format_dimension_stored_json_plaintext;
 
     instance->end_chart_formatting = NULL;
+    instance->variables_formatting = NULL;
     instance->end_host_formatting = flush_host_labels;
     instance->end_batch_formatting = close_batch_json_http;
 
@@ -113,34 +115,20 @@ int init_json_http_instance(struct instance *instance)
  * @param host a data collecting host.
  * @return Always returns 0.
  */
+
 int format_host_labels_json_plaintext(struct instance *instance, RRDHOST *host)
 {
-    if (!instance->labels)
-        instance->labels = buffer_create(1024);
+    if (!instance->labels_buffer)
+        instance->labels_buffer = buffer_create(1024);
 
     if (unlikely(!sending_labels_configured(instance)))
         return 0;
 
-    buffer_strcat(instance->labels, "\"labels\":{");
-
-    int count = 0;
-    rrdhost_check_rdlock(host);
-    netdata_rwlock_rdlock(&host->labels.labels_rwlock);
-    for (struct label *label = host->labels.head; label; label = label->next) {
-        if (!should_send_label(instance, label))
-            continue;
-
-        char value[CONFIG_MAX_VALUE * 2 + 1];
-        sanitize_json_string(value, label->value, CONFIG_MAX_VALUE);
-        if (count > 0)
-            buffer_strcat(instance->labels, ",");
-        buffer_sprintf(instance->labels, "\"%s\":\"%s\"", label->key, value);
-
-        count++;
-    }
-    netdata_rwlock_unlock(&host->labels.labels_rwlock);
-
-    buffer_strcat(instance->labels, "},");
+    buffer_strcat(instance->labels_buffer, "\"labels\":{");
+    rrdlabels_to_buffer(host->host_labels, instance->labels_buffer, "", ":", "\"", ",",
+                        exporting_labels_filter_callback, instance,
+                        NULL, sanitize_json_string);
+    buffer_strcat(instance->labels_buffer, "},");
 
     return 0;
 }
@@ -203,7 +191,7 @@ int format_dimension_collected_json_plaintext(struct instance *instance, RRDDIM
         tags_pre,
         tags,
         tags_post,
-        instance->labels ? buffer_tostring(instance->labels) : "",
+        instance->labels_buffer ? buffer_tostring(instance->labels_buffer) : "",
 
         st->id,
         st->name,
@@ -238,7 +226,7 @@ int format_dimension_stored_json_plaintext(struct instance *instance, RRDDIM *rd
     RRDHOST *host = st->rrdhost;
 
     time_t last_t;
-    calculated_number value = exporting_calculate_value_from_stored_data(instance, rd, &last_t);
+    NETDATA_DOUBLE value = exporting_calculate_value_from_stored_data(instance, rd, &last_t);
 
     if(isnan(value))
         return 0;
@@ -279,7 +267,7 @@ int format_dimension_stored_json_plaintext(struct instance *instance, RRDDIM *rd
 
         "\"id\":\"%s\","
         "\"name\":\"%s\","
-        "\"value\":" CALCULATED_NUMBER_FORMAT ","
+        "\"value\":" NETDATA_DOUBLE_FORMAT ","
 
         "\"timestamp\": %llu}",
 
@@ -288,7 +276,7 @@ int format_dimension_stored_json_plaintext(struct instance *instance, RRDDIM *rd
         tags_pre,
         tags,
         tags_post,
-        instance->labels ? buffer_tostring(instance->labels) : "",
+        instance->labels_buffer ? buffer_tostring(instance->labels_buffer) : "",
 
         st->id,
         st->name,
diff --git a/exporting/mongodb/mongodb.c b/exporting/mongodb/mongodb.c
index aab1770d2..850d07fb3 100644
--- a/exporting/mongodb/mongodb.c
+++ b/exporting/mongodb/mongodb.c
@@ -99,6 +99,7 @@ int init_mongodb_instance(struct instance *instance)
         instance->metric_formatting = format_dimension_stored_json_plaintext;
 
     instance->end_chart_formatting = NULL;
+    instance->variables_formatting = NULL;
     instance->end_host_formatting = flush_host_labels;
     instance->end_batch_formatting = format_batch_mongodb;
 
diff --git a/exporting/opentsdb/opentsdb.c b/exporting/opentsdb/opentsdb.c
index 7ed88fd6d..282de2e6b 100644
--- a/exporting/opentsdb/opentsdb.c
+++ b/exporting/opentsdb/opentsdb.c
@@ -38,6 +38,7 @@ int init_opentsdb_telnet_instance(struct instance *instance)
         instance->metric_formatting = format_dimension_stored_opentsdb_telnet;
 
     instance->end_chart_formatting = NULL;
+    instance->variables_formatting = NULL;
     instance->end_host_formatting = flush_host_labels;
     instance->end_batch_formatting = simple_connector_end_batch;
 
@@ -94,6 +95,7 @@ int init_opentsdb_http_instance(struct instance *instance)
         instance->metric_formatting = format_dimension_stored_opentsdb_http;
 
     instance->end_chart_formatting = NULL;
+    instance->variables_formatting = NULL;
     instance->end_host_formatting = flush_host_labels;
     instance->end_batch_formatting = close_batch_json_http;
 
@@ -124,13 +126,14 @@ int init_opentsdb_http_instance(struct instance *instance)
  * @param len the maximum number of characters copied.
  */
 
-void sanitize_opentsdb_label_value(char *dst, char *src, size_t len)
+void sanitize_opentsdb_label_value(char *dst, const char *src, size_t len)
 {
     while (*src != '\0' && len) {
-        if (isalpha(*src) || isdigit(*src) || *src == '-' || *src == '_' || *src == '.' || *src == '/' || IS_UTF8_BYTE(*src))
+        if (isalpha(*src) || isdigit(*src) || *src == '-' || *src == '.' || *src == '/' || IS_UTF8_BYTE(*src))
             *dst++ = *src;
         else
             *dst++ = '_';
+
         src++;
         len--;
     }
@@ -144,28 +147,18 @@ void sanitize_opentsdb_label_value(char *dst, char *src, size_t len)
  * @param host a data collecting host.
  * @return Always returns 0.
  */
-int format_host_labels_opentsdb_telnet(struct instance *instance, RRDHOST *host)
-{
-    if (!instance->labels)
-        instance->labels = buffer_create(1024);
+
+int format_host_labels_opentsdb_telnet(struct instance *instance, RRDHOST *host) {
+    if(!instance->labels_buffer)
+        instance->labels_buffer = buffer_create(1024);
 
     if (unlikely(!sending_labels_configured(instance)))
         return 0;
 
-    rrdhost_check_rdlock(host);
-    netdata_rwlock_rdlock(&host->labels.labels_rwlock);
-    for (struct label *label = host->labels.head; label; label = label->next) {
-        if (!should_send_label(instance, label))
-            continue;
-
-        char value[CONFIG_MAX_VALUE + 1];
-        sanitize_opentsdb_label_value(value, label->value, CONFIG_MAX_VALUE);
-
-        if (*value)
-            buffer_sprintf(instance->labels, " %s=%s", label->key, value);
-    }
-    netdata_rwlock_unlock(&host->labels.labels_rwlock);
-
+    buffer_strcat(instance->labels_buffer, " ");
+    rrdlabels_to_buffer(host->host_labels, instance->labels_buffer, "", "=", "", " ",
+                        exporting_labels_filter_callback, instance,
+                        NULL, sanitize_opentsdb_label_value);
     return 0;
 }
 
@@ -204,7 +197,7 @@ int format_dimension_collected_opentsdb_telnet(struct instance *instance, RRDDIM
         (host == localhost) ? instance->config.hostname : host->hostname,
         (host->tags) ? " " : "",
         (host->tags) ? host->tags : "",
-        (instance->labels) ? buffer_tostring(instance->labels) : "");
+        (instance->labels_buffer) ? buffer_tostring(instance->labels_buffer) : "");
 
     return 0;
 }
@@ -234,14 +227,14 @@ int format_dimension_stored_opentsdb_telnet(struct instance *instance, RRDDIM *r
         RRD_ID_LENGTH_MAX);
 
     time_t last_t;
-    calculated_number value = exporting_calculate_value_from_stored_data(instance, rd, &last_t);
+    NETDATA_DOUBLE value = exporting_calculate_value_from_stored_data(instance, rd, &last_t);
 
     if(isnan(value))
         return 0;
 
     buffer_sprintf(
         instance->buffer,
-        "put %s.%s.%s %llu " CALCULATED_NUMBER_FORMAT " host=%s%s%s%s\n",
+        "put %s.%s.%s %llu " NETDATA_DOUBLE_FORMAT " host=%s%s%s%s\n",
         instance->config.prefix,
         chart_name,
         dimension_name,
@@ -250,7 +243,7 @@ int format_dimension_stored_opentsdb_telnet(struct instance *instance, RRDDIM *r
         (host == localhost) ? instance->config.hostname : host->hostname,
         (host->tags) ? " " : "",
         (host->tags) ? host->tags : "",
-        (instance->labels) ? buffer_tostring(instance->labels) : "");
+        (instance->labels_buffer) ? buffer_tostring(instance->labels_buffer) : "");
 
     return 0;
 }
@@ -287,33 +280,17 @@ void opentsdb_http_prepare_header(struct instance *instance)
  * @param host a data collecting host.
  * @return Always returns 0.
  */
-int format_host_labels_opentsdb_http(struct instance *instance, RRDHOST *host)
-{
-    if (!instance->labels)
-        instance->labels = buffer_create(1024);
+
+int format_host_labels_opentsdb_http(struct instance *instance, RRDHOST *host) {
+    if (!instance->labels_buffer)
+        instance->labels_buffer = buffer_create(1024);
 
     if (unlikely(!sending_labels_configured(instance)))
         return 0;
 
-    rrdhost_check_rdlock(host);
-    netdata_rwlock_rdlock(&host->labels.labels_rwlock);
-    for (struct label *label = host->labels.head; label; label = label->next) {
-        if (!should_send_label(instance, label))
-            continue;
-
-        char escaped_value[CONFIG_MAX_VALUE * 2 + 1];
-        sanitize_json_string(escaped_value, label->value, CONFIG_MAX_VALUE);
-
-        char value[CONFIG_MAX_VALUE + 1];
-        sanitize_opentsdb_label_value(value, escaped_value, CONFIG_MAX_VALUE);
-
-        if (*value) {
-            buffer_strcat(instance->labels, ",");
-            buffer_sprintf(instance->labels, "\"%s\":\"%s\"", label->key, value);
-        }
-    }
-    netdata_rwlock_unlock(&host->labels.labels_rwlock);
-
+    rrdlabels_to_buffer(host->host_labels, instance->labels_buffer, ",", ":", "\"", "",
+                        exporting_labels_filter_callback, instance,
+                        NULL, sanitize_opentsdb_label_value);
     return 0;
 }
 
@@ -362,7 +339,7 @@ int format_dimension_collected_opentsdb_http(struct instance *instance, RRDDIM *
         (host == localhost) ? instance->config.hostname : host->hostname,
         (host->tags) ? " " : "",
         (host->tags) ? host->tags : "",
-        instance->labels ? buffer_tostring(instance->labels) : "");
+        instance->labels_buffer ? buffer_tostring(instance->labels_buffer) : "");
 
     return 0;
 }
@@ -392,7 +369,7 @@ int format_dimension_stored_opentsdb_http(struct instance *instance, RRDDIM *rd)
         RRD_ID_LENGTH_MAX);
 
     time_t last_t;
-    calculated_number value = exporting_calculate_value_from_stored_data(instance, rd, &last_t);
+    NETDATA_DOUBLE value = exporting_calculate_value_from_stored_data(instance, rd, &last_t);
 
     if(isnan(value))
         return 0;
@@ -405,7 +382,7 @@ int format_dimension_stored_opentsdb_http(struct instance *instance, RRDDIM *rd)
         "{"
         "\"metric\":\"%s.%s.%s\","
         "\"timestamp\":%llu,"
-        "\"value\":"CALCULATED_NUMBER_FORMAT","
+        "\"value\":" NETDATA_DOUBLE_FORMAT ","
         "\"tags\":{"
         "\"host\":\"%s%s%s\"%s"
         "}"
@@ -418,7 +395,7 @@ int format_dimension_stored_opentsdb_http(struct instance *instance, RRDDIM *rd)
         (host == localhost) ? instance->config.hostname : host->hostname,
         (host->tags) ? " " : "",
         (host->tags) ? host->tags : "",
-        instance->labels ? buffer_tostring(instance->labels) : "");
+        instance->labels_buffer ? buffer_tostring(instance->labels_buffer) : "");
 
     return 0;
 }
diff --git a/exporting/opentsdb/opentsdb.h b/exporting/opentsdb/opentsdb.h
index d53a5054f..b544ba8c1 100644
--- a/exporting/opentsdb/opentsdb.h
+++ b/exporting/opentsdb/opentsdb.h
@@ -8,7 +8,7 @@
 int init_opentsdb_telnet_instance(struct instance *instance);
 int init_opentsdb_http_instance(struct instance *instance);
 
-void sanitize_opentsdb_label_value(char *dst, char *src, size_t len);
+void sanitize_opentsdb_label_value(char *dst, const char *src, size_t len);
 int format_host_labels_opentsdb_telnet(struct instance *instance, RRDHOST *host);
 int format_host_labels_opentsdb_http(struct instance *instance, RRDHOST *host);
 
diff --git a/exporting/process_data.c b/exporting/process_data.c
index c77b7ad4a..d5138b787 100644
--- a/exporting/process_data.c
+++ b/exporting/process_data.c
@@ -64,7 +64,7 @@ int mark_scheduled_instances(struct engine *engine)
  * @param last_timestamp the timestamp that should be reported to the exporting connector instance.
  * @return Returns the value, calculated over the given period.
  */
-calculated_number exporting_calculate_value_from_stored_data(
+NETDATA_DOUBLE exporting_calculate_value_from_stored_data(
     struct instance *instance,
     RRDDIM *rd,
     time_t *last_timestamp)
@@ -77,11 +77,10 @@ calculated_number exporting_calculate_value_from_stored_data(
     time_t before = instance->before;
 
     // find the edges of the rrd database for this chart
-    time_t first_t = rd->state->query_ops.oldest_time(rd);
-    time_t last_t = rd->state->query_ops.latest_time(rd);
+    time_t first_t = rd->tiers[0]->query_ops.oldest_time(rd->tiers[0]->db_metric_handle);
+    time_t last_t = rd->tiers[0]->query_ops.latest_time(rd->tiers[0]->db_metric_handle);
     time_t update_every = st->update_every;
     struct rrddim_query_handle handle;
-    storage_number n;
 
     // step back a little, to make sure we have complete data collection
     // for all metrics
@@ -124,23 +123,21 @@ calculated_number exporting_calculate_value_from_stored_data(
     *last_timestamp = before;
 
     size_t counter = 0;
-    calculated_number sum = 0;
+    NETDATA_DOUBLE sum = 0;
 
-    for (rd->state->query_ops.init(rd, &handle, after, before); !rd->state->query_ops.is_finished(&handle);) {
-        time_t curr_t;
-        n = rd->state->query_ops.next_metric(&handle, &curr_t);
+    for (rd->tiers[0]->query_ops.init(rd->tiers[0]->db_metric_handle, &handle, after, before, TIER_QUERY_FETCH_SUM); !rd->tiers[0]->query_ops.is_finished(&handle);) {
+        STORAGE_POINT sp = rd->tiers[0]->query_ops.next_metric(&handle);
 
-        if (unlikely(!does_storage_number_exist(n))) {
+        if (unlikely(storage_point_is_empty(sp))) {
             // not collected
             continue;
         }
 
-        calculated_number value = unpack_storage_number(n);
-        sum += value;
-
-        counter++;
+        sum += sp.sum;
+        counter += sp.count;
     }
-    rd->state->query_ops.finalize(&handle);
+    rd->tiers[0]->query_ops.finalize(&handle);
+
     if (unlikely(!counter)) {
         debug(
             D_EXPORTING,
@@ -156,7 +153,7 @@ calculated_number exporting_calculate_value_from_stored_data(
     if (unlikely(EXPORTING_OPTIONS_DATA_SOURCE(instance->config.options) == EXPORTING_SOURCE_DATA_SUM))
         return sum;
 
-    return sum / (calculated_number)counter;
+    return sum / (NETDATA_DOUBLE)counter;
 }
 
 /**
@@ -262,6 +259,27 @@ void end_chart_formatting(struct engine *engine, RRDSET *st)
 }
 
 /**
+ * Format variables for every connector instance's buffer
+ *
+ * @param engine an engine data structure.
+ * @param host a data collecting host.
+  */
+void variables_formatting(struct engine *engine, RRDHOST *host)
+{
+    for (struct instance *instance = engine->instance_root; instance; instance = instance->next) {
+        if (instance->scheduled && !instance->skip_host && should_send_variables(instance)) {
+            if (instance->variables_formatting && instance->variables_formatting(instance, host) != 0){ 
+                error("EXPORTING: cannot format variables for %s", instance->config.name);
+                disable_instance(instance);
+                continue;
+            }
+            // sum all variables as one metrics
+            instance->stats.buffered_metrics++;
+        }
+    }
+}
+
+/**
  * End host formatting for every connector instance's buffer
  *
  * @param engine an engine data structure.
@@ -337,7 +355,7 @@ void prepare_buffers(struct engine *engine)
             end_chart_formatting(engine, st);
             rrdset_unlock(st);
         }
-
+        variables_formatting(engine, host);
         end_host_formatting(engine, host);
         rrdhost_unlock(host);
     }
@@ -358,8 +376,8 @@ int flush_host_labels(struct instance *instance, RRDHOST *host)
 {
     (void)host;
 
-    if (instance->labels)
-        buffer_flush(instance->labels);
+    if (instance->labels_buffer)
+        buffer_flush(instance->labels_buffer);
 
     return 0;
 }
diff --git a/exporting/prometheus/prometheus.c b/exporting/prometheus/prometheus.c
index c7f3f1d38..7d632164f 100644
--- a/exporting/prometheus/prometheus.c
+++ b/exporting/prometheus/prometheus.c
@@ -290,35 +290,44 @@ inline char *prometheus_units_copy(char *d, const char *s, size_t usable, int sh
  * @param instance an instance data structure.
  * @param host a data collecting host.
  */
-void format_host_labels_prometheus(struct instance *instance, RRDHOST *host)
-{
-    if (unlikely(!sending_labels_configured(instance)))
-        return;
 
-    if (!instance->labels)
-        instance->labels = buffer_create(1024);
+struct format_prometheus_label_callback {
+    struct instance *instance;
+    size_t count;
+};
 
-    int count = 0;
-    rrdhost_check_rdlock(host);
-    netdata_rwlock_rdlock(&host->labels.labels_rwlock);
-    for (struct label *label = host->labels.head; label; label = label->next) {
-        if (!should_send_label(instance, label))
-            continue;
+static int format_prometheus_label_callback(const char *name, const char *value, RRDLABEL_SRC ls, void *data) {
+    struct format_prometheus_label_callback *d = (struct format_prometheus_label_callback *)data;
 
-        char key[PROMETHEUS_ELEMENT_MAX + 1];
-        char value[PROMETHEUS_ELEMENT_MAX + 1];
+    if (!should_send_label(d->instance, ls)) return 0;
 
-        prometheus_name_copy(key, label->key, PROMETHEUS_ELEMENT_MAX);
-        prometheus_label_copy(value, label->value, PROMETHEUS_ELEMENT_MAX);
+    char k[PROMETHEUS_ELEMENT_MAX + 1];
+    char v[PROMETHEUS_ELEMENT_MAX + 1];
 
-        if (*key && *value) {
-            if (count > 0)
-                buffer_strcat(instance->labels, ",");
-            buffer_sprintf(instance->labels, "%s=\"%s\"", key, value);
-            count++;
-        }
+    prometheus_name_copy(k, name, PROMETHEUS_ELEMENT_MAX);
+    prometheus_label_copy(v, value, PROMETHEUS_ELEMENT_MAX);
+
+    if (*k && *v) {
+        if (d->count > 0) buffer_strcat(d->instance->labels_buffer, ",");
+        buffer_sprintf(d->instance->labels_buffer, "%s=\"%s\"", k, v);
+        d->count++;
     }
-    netdata_rwlock_unlock(&host->labels.labels_rwlock);
+    return 1;
+}
+
+void format_host_labels_prometheus(struct instance *instance, RRDHOST *host)
+{
+    if (unlikely(!sending_labels_configured(instance)))
+        return;
+
+    if (!instance->labels_buffer)
+        instance->labels_buffer = buffer_create(1024);
+
+    struct format_prometheus_label_callback tmp = {
+        .instance = instance,
+        .count = 0
+    };
+    rrdlabels_walkthrough_read(host->host_labels, format_prometheus_label_callback, &tmp);
 }
 
 struct host_variables_callback_options {
@@ -353,7 +362,7 @@ static int print_host_variables(RRDVAR *rv, void *data)
             }
         }
 
-        calculated_number value = rrdvar2number(rv);
+        NETDATA_DOUBLE value = rrdvar2number(rv);
         if (isnan(value) || isinf(value)) {
             if (opts->output_options & PROMETHEUS_OUTPUT_HELP)
                 buffer_sprintf(
@@ -374,7 +383,7 @@ static int print_host_variables(RRDVAR *rv, void *data)
         if (opts->output_options & PROMETHEUS_OUTPUT_TIMESTAMPS)
             buffer_sprintf(
                 opts->wb,
-                "%s_%s%s%s%s " CALCULATED_NUMBER_FORMAT " %llu\n",
+                "%s_%s%s%s%s " NETDATA_DOUBLE_FORMAT " %llu\n",
                 opts->prefix,
                 opts->name,
                 label_pre,
@@ -385,7 +394,7 @@ static int print_host_variables(RRDVAR *rv, void *data)
         else
             buffer_sprintf(
                 opts->wb,
-                "%s_%s%s%s%s " CALCULATED_NUMBER_FORMAT "\n",
+                "%s_%s%s%s%s " NETDATA_DOUBLE_FORMAT "\n",
                 opts->prefix,
                 opts->name,
                 label_pre,
@@ -474,9 +483,9 @@ static void generate_as_collected_prom_metric(BUFFER *wb, struct gen_parameters
     if (prometheus_collector)
         buffer_sprintf(
             wb,
-            CALCULATED_NUMBER_FORMAT,
-            (calculated_number)p->rd->last_collected_value * (calculated_number)p->rd->multiplier /
-                (calculated_number)p->rd->divisor);
+            NETDATA_DOUBLE_FORMAT,
+            (NETDATA_DOUBLE)p->rd->last_collected_value * (NETDATA_DOUBLE)p->rd->multiplier /
+                (NETDATA_DOUBLE)p->rd->divisor);
     else
         buffer_sprintf(wb, COLLECTED_NUMBER_FORMAT, p->rd->last_collected_value);
 
@@ -516,77 +525,29 @@ static void rrd_stats_api_v1_charts_allmetrics_prometheus(
 
     format_host_labels_prometheus(instance, host);
 
+    buffer_sprintf(
+        wb,
+        "netdata_info{instance=\"%s\",application=\"%s\",version=\"%s\"",
+        hostname,
+        host->program_name,
+        host->program_version);
+
+    if (instance->labels_buffer && *buffer_tostring(instance->labels_buffer)) {
+        buffer_sprintf(wb, ",%s", buffer_tostring(instance->labels_buffer));
+    }
+
     if (output_options & PROMETHEUS_OUTPUT_TIMESTAMPS)
-        buffer_sprintf(
-            wb,
-            "netdata_info{instance=\"%s\",application=\"%s\",version=\"%s\"} 1 %llu\n",
-            hostname,
-            host->program_name,
-            host->program_version,
-            now_realtime_usec() / USEC_PER_MS);
+        buffer_sprintf(wb, "} 1 %llu\n", now_realtime_usec() / USEC_PER_MS);
     else
-        buffer_sprintf(
-            wb,
-            "netdata_info{instance=\"%s\",application=\"%s\",version=\"%s\"} 1\n",
-            hostname,
-            host->program_name,
-            host->program_version);
+        buffer_sprintf(wb, "} 1\n");
 
     char labels[PROMETHEUS_LABELS_MAX + 1] = "";
     if (allhosts) {
-        if (instance->labels && buffer_tostring(instance->labels)) {
-            if (output_options & PROMETHEUS_OUTPUT_TIMESTAMPS) {
-                buffer_sprintf(
-                    wb,
-                    "netdata_host_tags_info{instance=\"%s\",%s} 1 %llu\n",
-                    hostname,
-                    buffer_tostring(instance->labels),
-                    now_realtime_usec() / USEC_PER_MS);
-
-                // deprecated, exists only for compatibility with older queries
-                buffer_sprintf(
-                    wb,
-                    "netdata_host_tags{instance=\"%s\",%s} 1 %llu\n",
-                    hostname,
-                    buffer_tostring(instance->labels),
-                    now_realtime_usec() / USEC_PER_MS);
-            } else {
-                buffer_sprintf(
-                    wb, "netdata_host_tags_info{instance=\"%s\",%s} 1\n", hostname, buffer_tostring(instance->labels));
-
-                // deprecated, exists only for compatibility with older queries
-                buffer_sprintf(
-                    wb, "netdata_host_tags{instance=\"%s\",%s} 1\n", hostname, buffer_tostring(instance->labels));
-            }
-        }
-
         snprintfz(labels, PROMETHEUS_LABELS_MAX, ",instance=\"%s\"", hostname);
-    } else {
-        if (instance->labels && buffer_tostring(instance->labels)) {
-            if (output_options & PROMETHEUS_OUTPUT_TIMESTAMPS) {
-                buffer_sprintf(
-                    wb,
-                    "netdata_host_tags_info{%s} 1 %llu\n",
-                    buffer_tostring(instance->labels),
-                    now_realtime_usec() / USEC_PER_MS);
-
-                // deprecated, exists only for compatibility with older queries
-                buffer_sprintf(
-                    wb,
-                    "netdata_host_tags{%s} 1 %llu\n",
-                    buffer_tostring(instance->labels),
-                    now_realtime_usec() / USEC_PER_MS);
-            } else {
-                buffer_sprintf(wb, "netdata_host_tags_info{%s} 1\n", buffer_tostring(instance->labels));
-
-                // deprecated, exists only for compatibility with older queries
-                buffer_sprintf(wb, "netdata_host_tags{%s} 1\n", buffer_tostring(instance->labels));
-            }
-        }
-    }
+     }
 
-    if (instance->labels)
-        buffer_flush(instance->labels);
+    if (instance->labels_buffer)
+        buffer_flush(instance->labels_buffer);
 
     // send custom variables set for the host
     if (output_options & PROMETHEUS_OUTPUT_VARIABLES) {
@@ -723,7 +684,7 @@ static void rrd_stats_api_v1_charts_allmetrics_prometheus(
 
                         time_t first_time = instance->after;
                         time_t last_time = instance->before;
-                        calculated_number value = exporting_calculate_value_from_stored_data(instance, rd, &last_time);
+                        NETDATA_DOUBLE value = exporting_calculate_value_from_stored_data(instance, rd, &last_time);
 
                         if (!isnan(value) && !isinf(value)) {
                             if (EXPORTING_OPTIONS_DATA_SOURCE(exporting_options) == EXPORTING_SOURCE_DATA_AVERAGE)
@@ -755,7 +716,7 @@ static void rrd_stats_api_v1_charts_allmetrics_prometheus(
                             if (output_options & PROMETHEUS_OUTPUT_TIMESTAMPS)
                                 buffer_sprintf(
                                     wb,
-                                    "%s_%s%s%s{chart=\"%s\",family=\"%s\",dimension=\"%s\"%s} " CALCULATED_NUMBER_FORMAT
+                                    "%s_%s%s%s{chart=\"%s\",family=\"%s\",dimension=\"%s\"%s} " NETDATA_DOUBLE_FORMAT
                                     " %llu\n",
                                     prefix,
                                     context,
@@ -770,7 +731,7 @@ static void rrd_stats_api_v1_charts_allmetrics_prometheus(
                             else
                                 buffer_sprintf(
                                     wb,
-                                    "%s_%s%s%s{chart=\"%s\",family=\"%s\",dimension=\"%s\"%s} " CALCULATED_NUMBER_FORMAT
+                                    "%s_%s%s%s{chart=\"%s\",family=\"%s\",dimension=\"%s\"%s} " NETDATA_DOUBLE_FORMAT
                                     "\n",
                                     prefix,
                                     context,
diff --git a/exporting/prometheus/remote_write/remote_write.c b/exporting/prometheus/remote_write/remote_write.c
index 59a488e1b..03feb2c08 100644
--- a/exporting/prometheus/remote_write/remote_write.c
+++ b/exporting/prometheus/remote_write/remote_write.c
@@ -97,6 +97,7 @@ int init_prometheus_remote_write_instance(struct instance *instance)
     instance->start_chart_formatting = format_chart_prometheus_remote_write;
     instance->metric_formatting = format_dimension_prometheus_remote_write;
     instance->end_chart_formatting = NULL;
+    instance->variables_formatting = format_variables_prometheus_remote_write;
     instance->end_host_formatting = NULL;
     instance->end_batch_formatting = format_batch_prometheus_remote_write;
 
@@ -134,6 +135,25 @@ int init_prometheus_remote_write_instance(struct instance *instance)
     return 0;
 }
 
+struct format_remote_write_label_callback {
+    struct instance *instance;
+    void *write_request;
+};
+
+static int format_remote_write_label_callback(const char *name, const char *value, RRDLABEL_SRC ls, void *data) {
+    struct format_remote_write_label_callback *d = (struct format_remote_write_label_callback *)data;
+
+    if (!should_send_label(d->instance, ls)) return 0;
+
+    char k[PROMETHEUS_ELEMENT_MAX + 1];
+    char v[PROMETHEUS_ELEMENT_MAX + 1];
+
+    prometheus_name_copy(k, name, PROMETHEUS_ELEMENT_MAX);
+    prometheus_label_copy(v, value, PROMETHEUS_ELEMENT_MAX);
+    add_label(d->write_request, k, v);
+    return 1;
+}
+
 /**
  * Format host data for Prometheus Remote Write connector
  *
@@ -157,23 +177,13 @@ int format_host_prometheus_remote_write(struct instance *instance, RRDHOST *host
     add_host_info(
         connector_specific_data->write_request,
         "netdata_info", hostname, host->program_name, host->program_version, now_realtime_usec() / USEC_PER_MS);
-
+    
     if (unlikely(sending_labels_configured(instance))) {
-        rrdhost_check_rdlock(host);
-        netdata_rwlock_rdlock(&host->labels.labels_rwlock);
-        for (struct label *label = host->labels.head; label; label = label->next) {
-            if (!should_send_label(instance, label))
-                continue;
-
-            char key[PROMETHEUS_ELEMENT_MAX + 1];
-            prometheus_name_copy(key, label->key, PROMETHEUS_ELEMENT_MAX);
-
-            char value[PROMETHEUS_ELEMENT_MAX + 1];
-            prometheus_label_copy(value, label->value, PROMETHEUS_ELEMENT_MAX);
-
-            add_label(connector_specific_data->write_request, key, value);
-        }
-        netdata_rwlock_unlock(&host->labels.labels_rwlock);
+        struct format_remote_write_label_callback tmp = {
+            .write_request = connector_specific_data->write_request,
+            .instance = instance
+        };
+        rrdlabels_walkthrough_read(host->host_labels, format_remote_write_label_callback, &tmp);
     }
 
     return 0;
@@ -284,7 +294,7 @@ int format_dimension_prometheus_remote_write(struct instance *instance, RRDDIM *
             // we need average or sum of the data
 
             time_t last_t = instance->before;
-            calculated_number value = exporting_calculate_value_from_stored_data(instance, rd, &last_t);
+            NETDATA_DOUBLE value = exporting_calculate_value_from_stored_data(instance, rd, &last_t);
 
             if (!isnan(value) && !isinf(value)) {
                 if (EXPORTING_OPTIONS_DATA_SOURCE(instance->config.options) == EXPORTING_SOURCE_DATA_AVERAGE)
@@ -311,6 +321,49 @@ int format_dimension_prometheus_remote_write(struct instance *instance, RRDDIM *
     return 0;
 }
 
+int format_variable_prometheus_remote_write_callback(RRDVAR *rv, void *data) {
+    struct prometheus_remote_write_variables_callback_options *opts = data;
+
+    if (rv->options & (RRDVAR_OPTION_CUSTOM_HOST_VAR | RRDVAR_OPTION_CUSTOM_CHART_VAR)) {        
+        RRDHOST *host = opts->host;
+        struct instance *instance = opts->instance;
+        struct simple_connector_data *simple_connector_data =
+            (struct simple_connector_data *)instance->connector_specific_data;
+        struct prometheus_remote_write_specific_data *connector_specific_data =
+            (struct prometheus_remote_write_specific_data *)simple_connector_data->connector_specific_data;
+
+        char name[PROMETHEUS_LABELS_MAX + 1];
+        char *suffix = "";
+
+        prometheus_name_copy(context, rv->name, PROMETHEUS_ELEMENT_MAX);
+        snprintf(name, PROMETHEUS_LABELS_MAX, "%s_%s%s", instance->config.prefix, context, suffix);
+
+        NETDATA_DOUBLE value = rrdvar2number(rv);
+        add_variable(connector_specific_data->write_request, name,
+            (host == localhost) ? instance->config.hostname : host->hostname, value, opts->now / USEC_PER_MS);
+    }
+
+    return 0;
+}
+
+/**
+ * Format a variable for Prometheus Remote Write connector
+ * 
+ * @param rv a variable.
+ * @param instance an instance data structure.
+ * @return Always returns 0.
+ */ 
+int format_variables_prometheus_remote_write(struct instance *instance, RRDHOST *host)
+{
+    struct prometheus_remote_write_variables_callback_options opt = {
+        .host = host,
+        .instance = instance,
+        .now = now_realtime_usec(),
+    };
+
+    return foreach_host_variable_callback(host, format_variable_prometheus_remote_write_callback, &opt);
+}
+
 /**
  * Format a batch for Prometheus Remote Write connector
  *
@@ -339,7 +392,6 @@ int format_batch_prometheus_remote_write(struct instance *instance)
         return 1;
     }
     buffer->len = data_size;
-    instance->stats.buffered_bytes = (collected_number)buffer_strlen(buffer);
 
     simple_connector_end_batch(instance);
 
diff --git a/exporting/prometheus/remote_write/remote_write.h b/exporting/prometheus/remote_write/remote_write.h
index d738f5126..4740772d0 100644
--- a/exporting/prometheus/remote_write/remote_write.h
+++ b/exporting/prometheus/remote_write/remote_write.h
@@ -11,12 +11,19 @@ struct prometheus_remote_write_specific_data {
     void *write_request;
 };
 
+struct prometheus_remote_write_variables_callback_options {
+    RRDHOST *host;
+    time_t now;
+    struct instance *instance;
+};
+
 int init_prometheus_remote_write_instance(struct instance *instance);
 extern void clean_prometheus_remote_write(struct instance *instance);
 
 int format_host_prometheus_remote_write(struct instance *instance, RRDHOST *host);
 int format_chart_prometheus_remote_write(struct instance *instance, RRDSET *st);
 int format_dimension_prometheus_remote_write(struct instance *instance, RRDDIM *rd);
+int format_variables_prometheus_remote_write(struct instance *instance, RRDHOST *host);
 int format_batch_prometheus_remote_write(struct instance *instance);
 
 void prometheus_remote_write_prepare_header(struct instance *instance);
diff --git a/exporting/prometheus/remote_write/remote_write_request.cc b/exporting/prometheus/remote_write/remote_write_request.cc
index cfd61271e..ecfa11fa8 100644
--- a/exporting/prometheus/remote_write/remote_write_request.cc
+++ b/exporting/prometheus/remote_write/remote_write_request.cc
@@ -138,6 +138,38 @@ void add_metric(
 }
 
 /**
+ * Adds a metric to a write request
+ *
+ * @param write_request_p the write request
+ * @param name the name of the metric
+ * @param instance the name of the host, the metric belongs to
+ * @param value the value of the metric
+ * @param timestamp the timestamp for the metric in milliseconds
+ */
+void add_variable(
+    void *write_request_p, const char *name, const char *instance, const double value, const int64_t timestamp)
+{
+    WriteRequest *write_request = (WriteRequest *)write_request_p;
+    TimeSeries *timeseries;
+    Sample *sample;
+    Label *label;
+
+    timeseries = write_request->add_timeseries();
+
+    label = timeseries->add_labels();
+    label->set_name("__name__");
+    label->set_value(name);
+
+    label = timeseries->add_labels();
+    label->set_name("instance");
+    label->set_value(instance);
+
+    sample = timeseries->add_samples();
+    sample->set_value(value);
+    sample->set_timestamp(timestamp);
+}
+
+/**
  * Gets the size of a write request
  *
  * @param write_request_p the write request
diff --git a/exporting/prometheus/remote_write/remote_write_request.h b/exporting/prometheus/remote_write/remote_write_request.h
index 5f242b941..b25370133 100644
--- a/exporting/prometheus/remote_write/remote_write_request.h
+++ b/exporting/prometheus/remote_write/remote_write_request.h
@@ -20,6 +20,9 @@ void add_metric(
     const char *name, const char *chart, const char *family, const char *dimension,
     const char *instance, const double value, const int64_t timestamp);
 
+void add_variable(
+    void *write_request_p, const char *name, const char *instance, const double value, const int64_t timestamp);
+
 size_t get_write_request_size(void *write_request_p);
 
 int pack_and_clear_write_request(void *write_request_p, char *buffer, size_t *size);
diff --git a/exporting/pubsub/pubsub.c b/exporting/pubsub/pubsub.c
index 5a5afbdc2..b218338f1 100644
--- a/exporting/pubsub/pubsub.c
+++ b/exporting/pubsub/pubsub.c
@@ -23,6 +23,7 @@ int init_pubsub_instance(struct instance *instance)
         instance->metric_formatting = format_dimension_stored_json_plaintext;
 
     instance->end_chart_formatting = NULL;
+    instance->variables_formatting = NULL;
     instance->end_host_formatting = flush_host_labels;
     instance->end_batch_formatting = NULL;
 
diff --git a/exporting/read_config.c b/exporting/read_config.c
index b834e867d..1cba16826 100644
--- a/exporting/read_config.c
+++ b/exporting/read_config.c
@@ -399,6 +399,11 @@ struct engine *read_exporting_config()
         else
             tmp_instance->config.options &= ~EXPORTING_OPTION_SEND_NAMES;
 
+        if (exporter_get_boolean(instance_name, "send variables", CONFIG_BOOLEAN_YES))
+            tmp_instance->config.options |= EXPORTING_OPTION_SEND_VARIABLES;
+        else 
+            tmp_instance->config.options &= ~EXPORTING_OPTION_SEND_VARIABLES;
+
         if (tmp_instance->config.type == EXPORTING_CONNECTOR_TYPE_PROMETHEUS_REMOTE_WRITE) {
             struct prometheus_remote_write_specific_config *connector_specific_config =
                 callocz(1, sizeof(struct prometheus_remote_write_specific_config));
diff --git a/exporting/tests/exporting_doubles.c b/exporting/tests/exporting_doubles.c
index b8c9f3756..75ab7ba43 100644
--- a/exporting/tests/exporting_doubles.c
+++ b/exporting/tests/exporting_doubles.c
@@ -52,11 +52,11 @@ int __wrap_mark_scheduled_instances(struct engine *engine)
     return mock_type(int);
 }
 
-calculated_number __real_exporting_calculate_value_from_stored_data(
+NETDATA_DOUBLE __real_exporting_calculate_value_from_stored_data(
     struct instance *instance,
     RRDDIM *rd,
     time_t *last_timestamp);
-calculated_number __wrap_exporting_calculate_value_from_stored_data(
+NETDATA_DOUBLE __wrap_exporting_calculate_value_from_stored_data(
     struct instance *instance,
     RRDDIM *rd,
     time_t *last_timestamp)
@@ -67,7 +67,7 @@ calculated_number __wrap_exporting_calculate_value_from_stored_data(
     *last_timestamp = 15052;
 
     function_called();
-    return mock_type(calculated_number);
+    return mock_type(NETDATA_DOUBLE);
 }
 
 int __real_prepare_buffers(struct engine *engine);
@@ -156,6 +156,14 @@ int __mock_end_chart_formatting(struct instance *instance, RRDSET *st)
     return mock_type(int);
 }
 
+int __mock_variables_formatting(struct instance *instance, RRDHOST *host)
+{
+    function_called();
+    check_expected_ptr(instance);
+    check_expected_ptr(host);
+    return mock_type(int);
+}
+
 int __mock_end_host_formatting(struct instance *instance, RRDHOST *host)
 {
     function_called();
diff --git a/exporting/tests/exporting_fixtures.c b/exporting/tests/exporting_fixtures.c
index 501fc405c..aae1c53fb 100644
--- a/exporting/tests/exporting_fixtures.c
+++ b/exporting/tests/exporting_fixtures.c
@@ -41,17 +41,9 @@ int setup_rrdhost()
 
     localhost->tags = strdupz("TAG1=VALUE1 TAG2=VALUE2");
 
-    struct label *label = calloc(1, sizeof(struct label));
-    label->key = strdupz("key1");
-    label->value = strdupz("value1");
-    label->label_source = LABEL_SOURCE_NETDATA_CONF;
-    localhost->labels.head = label;
-
-    label = calloc(1, sizeof(struct label));
-    label->key = strdupz("key2");
-    label->value = strdupz("value2");
-    label->label_source = LABEL_SOURCE_AUTO;
-    localhost->labels.head->next = label;
+    localhost->host_labels = rrdlabels_create();
+    rrdlabels_add(localhost->host_labels, "key1", "value1", RRDLABEL_SRC_CONFIG);
+    rrdlabels_add(localhost->host_labels, "key2", "value2", RRDLABEL_SRC_CONFIG);
 
     localhost->rrdset_root = calloc(1, sizeof(RRDSET));
     RRDSET *st = localhost->rrdset_root;
@@ -71,13 +63,13 @@ int setup_rrdhost()
     rd->collections_counter++;
     rd->next = NULL;
 
-    rd->state = calloc(1, sizeof(*rd->state));
-    rd->state->query_ops.oldest_time = __mock_rrddim_query_oldest_time;
-    rd->state->query_ops.latest_time = __mock_rrddim_query_latest_time;
-    rd->state->query_ops.init = __mock_rrddim_query_init;
-    rd->state->query_ops.is_finished = __mock_rrddim_query_is_finished;
-    rd->state->query_ops.next_metric = __mock_rrddim_query_next_metric;
-    rd->state->query_ops.finalize = __mock_rrddim_query_finalize;
+    rd->tiers[0] = calloc(1, sizeof(struct rrddim_tier));
+    rd->tiers[0]->query_ops.oldest_time = __mock_rrddim_query_oldest_time;
+    rd->tiers[0]->query_ops.latest_time = __mock_rrddim_query_latest_time;
+    rd->tiers[0]->query_ops.init = __mock_rrddim_query_init;
+    rd->tiers[0]->query_ops.is_finished = __mock_rrddim_query_is_finished;
+    rd->tiers[0]->query_ops.next_metric = __mock_rrddim_query_next_metric;
+    rd->tiers[0]->query_ops.finalize = __mock_rrddim_query_finalize;
 
     return 0;
 }
@@ -87,19 +79,14 @@ int teardown_rrdhost()
     RRDDIM *rd = localhost->rrdset_root->dimensions;
     free((void *)rd->name);
     free((void *)rd->id);
-    free(rd->state);
+    free(rd->tiers[0]);
     free(rd);
 
     RRDSET *st = localhost->rrdset_root;
     free((void *)st->name);
     free(st);
 
-    free(localhost->labels.head->next->key);
-    free(localhost->labels.head->next->value);
-    free(localhost->labels.head->next);
-    free(localhost->labels.head->key);
-    free(localhost->labels.head->value);
-    free(localhost->labels.head);
+    rrdlabels_destroy(localhost->host_labels);
 
     free((void *)localhost->tags);
     free(localhost);
@@ -124,7 +111,7 @@ int teardown_initialized_engine(void **state)
     struct engine *engine = *state;
 
     teardown_rrdhost();
-    buffer_free(engine->instance_root->labels);
+    buffer_free(engine->instance_root->labels_buffer);
     buffer_free(engine->instance_root->buffer);
     teardown_configured_engine(state);
 
diff --git a/exporting/tests/netdata_doubles.c b/exporting/tests/netdata_doubles.c
index a9a184336..ee36e887a 100644
--- a/exporting/tests/netdata_doubles.c
+++ b/exporting/tests/netdata_doubles.c
@@ -177,7 +177,7 @@ const char *rrd_memory_mode_name(RRD_MEMORY_MODE id)
     return RRD_MEMORY_MODE_NONE_NAME;
 }
 
-calculated_number rrdvar2number(RRDVAR *rv)
+NETDATA_DOUBLE rrdvar2number(RRDVAR *rv)
 {
     (void)rv;
     return 0;
@@ -196,26 +196,27 @@ void rrdset_update_heterogeneous_flag(RRDSET *st)
     (void)st;
 }
 
-time_t __mock_rrddim_query_oldest_time(RRDDIM *rd)
+time_t __mock_rrddim_query_oldest_time(STORAGE_METRIC_HANDLE *db_metric_handle)
 {
-    (void)rd;
+    (void)db_metric_handle;
 
     function_called();
     return mock_type(time_t);
 }
 
-time_t __mock_rrddim_query_latest_time(RRDDIM *rd)
+time_t __mock_rrddim_query_latest_time(STORAGE_METRIC_HANDLE *db_metric_handle)
 {
-    (void)rd;
+    (void)db_metric_handle;
 
     function_called();
     return mock_type(time_t);
 }
 
-void __mock_rrddim_query_init(RRDDIM *rd, struct rrddim_query_handle *handle, time_t start_time, time_t end_time)
+void __mock_rrddim_query_init(STORAGE_METRIC_HANDLE *db_metric_handle, struct rrddim_query_handle *handle, time_t start_time, time_t end_time, TIER_QUERY_FETCH tier_query_fetch_type)
 {
-    (void)rd;
+    (void)db_metric_handle;
     (void)handle;
+    (void)tier_query_fetch_type;
 
     function_called();
     check_expected(start_time);
@@ -230,13 +231,14 @@ int __mock_rrddim_query_is_finished(struct rrddim_query_handle *handle)
     return mock_type(int);
 }
 
-storage_number __mock_rrddim_query_next_metric(struct rrddim_query_handle *handle, time_t *current_time)
+STORAGE_POINT __mock_rrddim_query_next_metric(struct rrddim_query_handle *handle)
 {
     (void)handle;
-    (void)current_time;
 
     function_called();
-    return mock_type(storage_number);
+
+    STORAGE_POINT sp = {};
+    return sp;    
 }
 
 void __mock_rrddim_query_finalize(struct rrddim_query_handle *handle)
@@ -245,3 +247,11 @@ void __mock_rrddim_query_finalize(struct rrddim_query_handle *handle)
 
     function_called();
 }
+
+void sql_store_chart_label(uuid_t *chart_uuid, int source_type, char *label, char *value)
+{
+    (void)chart_uuid;
+    (void)source_type;
+    (void)label;
+    (void)value;
+}
diff --git a/exporting/tests/test_exporting_engine.c b/exporting/tests/test_exporting_engine.c
index 6bb7d2efd..56a28059f 100644
--- a/exporting/tests/test_exporting_engine.c
+++ b/exporting/tests/test_exporting_engine.c
@@ -307,19 +307,17 @@ static void test_exporting_calculate_value_from_stored_data(void **state)
     expect_function_call(__mock_rrddim_query_is_finished);
     will_return(__mock_rrddim_query_is_finished, 0);
     expect_function_call(__mock_rrddim_query_next_metric);
-    will_return(__mock_rrddim_query_next_metric, pack_storage_number(27, SN_DEFAULT_FLAGS));
 
     expect_function_call(__mock_rrddim_query_is_finished);
     will_return(__mock_rrddim_query_is_finished, 0);
     expect_function_call(__mock_rrddim_query_next_metric);
-    will_return(__mock_rrddim_query_next_metric, pack_storage_number(45, SN_DEFAULT_FLAGS));
 
     expect_function_call(__mock_rrddim_query_is_finished);
     will_return(__mock_rrddim_query_is_finished, 1);
 
     expect_function_call(__mock_rrddim_query_finalize);
 
-    assert_int_equal(__real_exporting_calculate_value_from_stored_data(instance, rd, &timestamp), 36);
+    assert_float_equal(__real_exporting_calculate_value_from_stored_data(instance, rd, &timestamp), 36, 0.1);
 }
 
 static void test_prepare_buffers(void **state)
@@ -381,7 +379,7 @@ static void test_prepare_buffers(void **state)
     expect_value(__mock_end_batch_formatting, instance, instance);
     will_return(__mock_end_batch_formatting, 0);
 
-    assert_int_equal(__real_prepare_buffers(engine), 0);
+    __real_prepare_buffers(engine);
 
     assert_int_equal(instance->stats.buffered_metrics, 1);
 
@@ -393,7 +391,7 @@ static void test_prepare_buffers(void **state)
     instance->end_chart_formatting = NULL;
     instance->end_host_formatting = NULL;
     instance->end_batch_formatting = NULL;
-    assert_int_equal(__real_prepare_buffers(engine), 0);
+    __real_prepare_buffers(engine);
 
     assert_int_equal(instance->scheduled, 0);
     assert_int_equal(instance->after, 2);
@@ -705,7 +703,7 @@ static void test_format_host_labels_json_plaintext(void **state)
     instance->config.options |= EXPORTING_OPTION_SEND_AUTOMATIC_LABELS;
 
     assert_int_equal(format_host_labels_json_plaintext(instance, localhost), 0);
-    assert_string_equal(buffer_tostring(instance->labels), "\"labels\":{\"key1\":\"value1\",\"key2\":\"value2\"},");
+    assert_string_equal(buffer_tostring(instance->labels_buffer), "\"labels\":{\"key1\":\"value1\",\"key2\":\"value2\"},");
 }
 
 static void test_format_host_labels_graphite_plaintext(void **state)
@@ -717,7 +715,7 @@ static void test_format_host_labels_graphite_plaintext(void **state)
     instance->config.options |= EXPORTING_OPTION_SEND_AUTOMATIC_LABELS;
 
     assert_int_equal(format_host_labels_graphite_plaintext(instance, localhost), 0);
-    assert_string_equal(buffer_tostring(instance->labels), ";key1=value1;key2=value2");
+    assert_string_equal(buffer_tostring(instance->labels_buffer), ";key1=value1;key2=value2");
 }
 
 static void test_format_host_labels_opentsdb_telnet(void **state)
@@ -729,7 +727,7 @@ static void test_format_host_labels_opentsdb_telnet(void **state)
     instance->config.options |= EXPORTING_OPTION_SEND_AUTOMATIC_LABELS;
 
     assert_int_equal(format_host_labels_opentsdb_telnet(instance, localhost), 0);
-    assert_string_equal(buffer_tostring(instance->labels), " key1=value1 key2=value2");
+    assert_string_equal(buffer_tostring(instance->labels_buffer), " key1=value1 key2=value2");
 }
 
 static void test_format_host_labels_opentsdb_http(void **state)
@@ -741,7 +739,7 @@ static void test_format_host_labels_opentsdb_http(void **state)
     instance->config.options |= EXPORTING_OPTION_SEND_AUTOMATIC_LABELS;
 
     assert_int_equal(format_host_labels_opentsdb_http(instance, localhost), 0);
-    assert_string_equal(buffer_tostring(instance->labels), ",\"key1\":\"value1\",\"key2\":\"value2\"");
+    assert_string_equal(buffer_tostring(instance->labels_buffer), ",\"key1\":\"value1\",\"key2\":\"value2\"");
 }
 
 static void test_flush_host_labels(void **state)
@@ -749,12 +747,12 @@ static void test_flush_host_labels(void **state)
     struct engine *engine = *state;
     struct instance *instance = engine->instance_root;
 
-    instance->labels = buffer_create(12);
-    buffer_strcat(instance->labels, "check string");
-    assert_int_equal(buffer_strlen(instance->labels), 12);
+    instance->labels_buffer = buffer_create(12);
+    buffer_strcat(instance->labels_buffer, "check string");
+    assert_int_equal(buffer_strlen(instance->labels_buffer), 12);
 
     assert_int_equal(flush_host_labels(instance, localhost), 0);
-    assert_int_equal(buffer_strlen(instance->labels), 0);
+    assert_int_equal(buffer_strlen(instance->labels_buffer), 0);
 }
 
 static void test_create_main_rusage_chart(void **state)
@@ -1048,7 +1046,7 @@ static void test_format_host_labels_prometheus(void **state)
     instance->config.options |= EXPORTING_OPTION_SEND_AUTOMATIC_LABELS;
 
     format_host_labels_prometheus(instance, localhost);
-    assert_string_equal(buffer_tostring(instance->labels), "key1=\"value1\",key2=\"value2\"");
+    assert_string_equal(buffer_tostring(instance->labels_buffer), "key1=\"value1\",key2=\"value2\"");
 }
 
 static void rrd_stats_api_v1_charts_allmetrics_prometheus(void **state)
@@ -1071,9 +1069,7 @@ static void rrd_stats_api_v1_charts_allmetrics_prometheus(void **state)
 
     assert_string_equal(
         buffer_tostring(buffer),
-        "netdata_info{instance=\"test_hostname\",application=\"(null)\",version=\"(null)\"} 1\n"
-        "netdata_host_tags_info{key1=\"value1\",key2=\"value2\"} 1\n"
-        "netdata_host_tags{key1=\"value1\",key2=\"value2\"} 1\n"
+        "netdata_info{instance=\"test_hostname\",application=\"(null)\",version=\"(null)\",key1=\"value1\",key2=\"value2\"} 1\n"
         "test_prefix_test_context{chart=\"chart_id\",family=\"test_family\",dimension=\"dimension_id\"} 690565856.0000000\n");
 
     buffer_flush(buffer);
@@ -1089,9 +1085,7 @@ static void rrd_stats_api_v1_charts_allmetrics_prometheus(void **state)
 
     assert_string_equal(
         buffer_tostring(buffer),
-        "netdata_info{instance=\"test_hostname\",application=\"(null)\",version=\"(null)\"} 1\n"
-        "netdata_host_tags_info{key1=\"value1\",key2=\"value2\"} 1\n"
-        "netdata_host_tags{key1=\"value1\",key2=\"value2\"} 1\n"
+        "netdata_info{instance=\"test_hostname\",application=\"(null)\",version=\"(null)\",key1=\"value1\",key2=\"value2\"} 1\n"
         "# TYPE test_prefix_test_context gauge\n"
         "test_prefix_test_context{chart=\"chart_name\",family=\"test_family\",dimension=\"dimension_name\"} 690565856.0000000\n");
 
@@ -1107,9 +1101,7 @@ static void rrd_stats_api_v1_charts_allmetrics_prometheus(void **state)
 
     assert_string_equal(
         buffer_tostring(buffer),
-        "netdata_info{instance=\"test_hostname\",application=\"(null)\",version=\"(null)\"} 1\n"
-        "netdata_host_tags_info{instance=\"test_hostname\",key1=\"value1\",key2=\"value2\"} 1\n"
-        "netdata_host_tags{instance=\"test_hostname\",key1=\"value1\",key2=\"value2\"} 1\n"
+        "netdata_info{instance=\"test_hostname\",application=\"(null)\",version=\"(null)\",key1=\"value1\",key2=\"value2\"} 1\n"
         "test_prefix_test_context{chart=\"chart_id\",family=\"test_family\",dimension=\"dimension_id\",instance=\"test_hostname\"} 690565856.0000000\n");
 
     free(localhost->rrdset_root->context);
diff --git a/exporting/tests/test_exporting_engine.h b/exporting/tests/test_exporting_engine.h
index 800be1b99..ae0b7df9a 100644
--- a/exporting/tests/test_exporting_engine.h
+++ b/exporting/tests/test_exporting_engine.h
@@ -30,7 +30,14 @@
 #include <stddef.h>
 #include <setjmp.h>
 #include <stdint.h>
+
+#ifndef UNIT_TESTING
+#include <cmocka.h>
+#else
+#undef UNIT_TESTING
 #include <cmocka.h>
+#define UNIT_TESTING
+#endif
 
 #define MAX_LOG_LINE 1024
 extern char log_line[];
@@ -50,11 +57,11 @@ int __wrap_connect_to_one_of(
 void __rrdhost_check_rdlock(RRDHOST *host, const char *file, const char *function, const unsigned long line);
 void __rrdset_check_rdlock(RRDSET *st, const char *file, const char *function, const unsigned long line);
 void __rrd_check_rdlock(const char *file, const char *function, const unsigned long line);
-time_t __mock_rrddim_query_oldest_time(RRDDIM *rd);
-time_t __mock_rrddim_query_latest_time(RRDDIM *rd);
-void __mock_rrddim_query_init(RRDDIM *rd, struct rrddim_query_handle *handle, time_t start_time, time_t end_time);
+time_t __mock_rrddim_query_oldest_time(STORAGE_METRIC_HANDLE *db_metric_handle);
+time_t __mock_rrddim_query_latest_time(STORAGE_METRIC_HANDLE *db_metric_handle);
+void __mock_rrddim_query_init(STORAGE_METRIC_HANDLE *db_metric_handle, struct rrddim_query_handle *handle, time_t start_time, time_t end_time, TIER_QUERY_FETCH tier_query_fetch_type);
 int __mock_rrddim_query_is_finished(struct rrddim_query_handle *handle);
-storage_number __mock_rrddim_query_next_metric(struct rrddim_query_handle *handle, time_t *current_time);
+STORAGE_POINT __mock_rrddim_query_next_metric(struct rrddim_query_handle *handle);
 void __mock_rrddim_query_finalize(struct rrddim_query_handle *handle);
 
 // -----------------------------------------------------------------------
@@ -81,11 +88,11 @@ int __wrap_init_connectors(struct engine *engine);
 int __real_mark_scheduled_instances(struct engine *engine);
 int __wrap_mark_scheduled_instances(struct engine *engine);
 
-calculated_number __real_exporting_calculate_value_from_stored_data(
+NETDATA_DOUBLE __real_exporting_calculate_value_from_stored_data(
     struct instance *instance,
     RRDDIM *rd,
     time_t *last_timestamp);
-calculated_number __wrap_exporting_calculate_value_from_stored_data(
+NETDATA_DOUBLE __wrap_exporting_calculate_value_from_stored_data(
     struct instance *instance,
     RRDDIM *rd,
     time_t *last_timestamp);
@@ -113,6 +120,7 @@ int __mock_start_host_formatting(struct instance *instance, RRDHOST *host);
 int __mock_start_chart_formatting(struct instance *instance, RRDSET *st);
 int __mock_metric_formatting(struct instance *instance, RRDDIM *rd);
 int __mock_end_chart_formatting(struct instance *instance, RRDSET *st);
+int __mock_variables_formatting(struct instance *instance, RRDHOST *host);
 int __mock_end_host_formatting(struct instance *instance, RRDHOST *host);
 int __mock_end_batch_formatting(struct instance *instance);