Boost dbengine (#14832)

* configure extent cache size

* workers can now execute up to 10 jobs in a run, boosting query prep and extent reads

* fix dispatched and executing counters

* boost to the max

* increase libuv worker threads

* query prep always get more prio than extent reads; stop processing in batch when dbengine is queue is critical

* fix accounting of query prep

* inlining of time-grouping functions, to speed up queries with billions of points

* make switching based on a local const variable

* print one pending contexts loading message per iteration

* inlined store engine query API

* inlined storage engine data collection api

* inlined all storage engine query ops

* eliminate and inline data collection ops

* simplified query group-by

* more error handling

* optimized partial trimming of group-by queries

* preparative work to support multiple passes of group-by

* more preparative work to support multiple passes of group-by (accepts multiple group-by params)

* unified query timings

* unified query timings - weights endpoint

* query target is no longer a static thread variable - there is a list of cached query targets, each of which of freed every 1000 queries

* fix query memory accounting

* added summary.dimension[].pri and sorted summary.dimensions based on priority and then name

* limit max ACLK WEB response size to 30MB

* the response type should be text/plain

* more preparative work for multiple group-by passes

* create functions for generating group by keys, ids and names

* multiple group-by passes are now supported

* parse group-by options array also with an index

* implemented percentage-of-instance group by function

* family is now merged in multi-node contexts

* prevent uninitialized use

1 files changed, 162 insertions, 13 deletions

diff --git a/web/api/queries/percentile/percentile.h b/web/api/queries/percentile/percentile.h
index 65e335c110..0532f9d3f0 100644
--- a/web/api/queries/percentile/percentile.h
+++ b/web/api/queries/percentile/percentile.h
@@ -6,18 +6,167 @@
 #include "../query.h"
 #include "../rrdr.h"
 
-void grouping_create_percentile25(RRDR *r, const char *options);
-void grouping_create_percentile50(RRDR *r, const char *options);
-void grouping_create_percentile75(RRDR *r, const char *options);
-void grouping_create_percentile80(RRDR *r, const char *options);
-void grouping_create_percentile90(RRDR *r, const char *options);
-void grouping_create_percentile95(RRDR *r, const char *options);
-void grouping_create_percentile97(RRDR *r, const char *options);
-void grouping_create_percentile98(RRDR *r, const char *options);
-void grouping_create_percentile99(RRDR *r, const char *options );
-void grouping_reset_percentile(RRDR *r);
-void grouping_free_percentile(RRDR *r);
-void grouping_add_percentile(RRDR *r, NETDATA_DOUBLE value);
-NETDATA_DOUBLE grouping_flush_percentile(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr);
+struct tg_percentile {
+    size_t series_size;
+    size_t next_pos;
+    NETDATA_DOUBLE percent;
+
+    NETDATA_DOUBLE *series;
+};
+
+static inline void tg_percentile_create_internal(RRDR *r, const char *options, NETDATA_DOUBLE def) {
+    long entries = r->view.group;
+    if(entries < 10) entries = 10;
+
+    struct tg_percentile *g = (struct tg_percentile *)onewayalloc_callocz(r->internal.owa, 1, sizeof(struct tg_percentile));
+    g->series = onewayalloc_mallocz(r->internal.owa, entries * sizeof(NETDATA_DOUBLE));
+    g->series_size = (size_t)entries;
+
+    g->percent = def;
+    if(options && *options) {
+        g->percent = str2ndd(options, NULL);
+        if(!netdata_double_isnumber(g->percent)) g->percent = 0.0;
+        if(g->percent < 0.0) g->percent = 0.0;
+        if(g->percent > 100.0) g->percent = 100.0;
+    }
+
+    g->percent = g->percent / 100.0;
+    r->time_grouping.data = g;
+}
+
+static inline void tg_percentile_create_25(RRDR *r, const char *options) {
+    tg_percentile_create_internal(r, options, 25.0);
+}
+static inline void tg_percentile_create_50(RRDR *r, const char *options) {
+    tg_percentile_create_internal(r, options, 50.0);
+}
+static inline void tg_percentile_create_75(RRDR *r, const char *options) {
+    tg_percentile_create_internal(r, options, 75.0);
+}
+static inline void tg_percentile_create_80(RRDR *r, const char *options) {
+    tg_percentile_create_internal(r, options, 80.0);
+}
+static inline void tg_percentile_create_90(RRDR *r, const char *options) {
+    tg_percentile_create_internal(r, options, 90.0);
+}
+static inline void tg_percentile_create_95(RRDR *r, const char *options) {
+    tg_percentile_create_internal(r, options, 95.0);
+}
+static inline void tg_percentile_create_97(RRDR *r, const char *options) {
+    tg_percentile_create_internal(r, options, 97.0);
+}
+static inline void tg_percentile_create_98(RRDR *r, const char *options) {
+    tg_percentile_create_internal(r, options, 98.0);
+}
+static inline void tg_percentile_create_99(RRDR *r, const char *options) {
+    tg_percentile_create_internal(r, options, 99.0);
+}
+
+// resets when switches dimensions
+// so, clear everything to restart
+static inline void tg_percentile_reset(RRDR *r) {
+    struct tg_percentile *g = (struct tg_percentile *)r->time_grouping.data;
+    g->next_pos = 0;
+}
+
+static inline void tg_percentile_free(RRDR *r) {
+    struct tg_percentile *g = (struct tg_percentile *)r->time_grouping.data;
+    if(g) onewayalloc_freez(r->internal.owa, g->series);
+
+    onewayalloc_freez(r->internal.owa, r->time_grouping.data);
+    r->time_grouping.data = NULL;
+}
+
+static inline void tg_percentile_add(RRDR *r, NETDATA_DOUBLE value) {
+    struct tg_percentile *g = (struct tg_percentile *)r->time_grouping.data;
+
+    if(unlikely(g->next_pos >= g->series_size)) {
+        g->series = onewayalloc_doublesize( r->internal.owa, g->series, g->series_size * sizeof(NETDATA_DOUBLE));
+        g->series_size *= 2;
+    }
+
+    g->series[g->next_pos++] = value;
+}
+
+static inline NETDATA_DOUBLE tg_percentile_flush(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr) {
+    struct tg_percentile *g = (struct tg_percentile *)r->time_grouping.data;
+
+    NETDATA_DOUBLE value;
+    size_t available_slots = g->next_pos;
+
+    if(unlikely(!available_slots)) {
+        value = 0.0;
+        *rrdr_value_options_ptr |= RRDR_VALUE_EMPTY;
+    }
+    else if(available_slots == 1) {
+        value = g->series[0];
+    }
+    else {
+        sort_series(g->series, available_slots);
+
+        NETDATA_DOUBLE min = g->series[0];
+        NETDATA_DOUBLE max = g->series[available_slots - 1];
+
+        if (min != max) {
+            size_t slots_to_use = (size_t)((NETDATA_DOUBLE)available_slots * g->percent);
+            if(!slots_to_use) slots_to_use = 1;
+
+            NETDATA_DOUBLE percent_to_use = (NETDATA_DOUBLE)slots_to_use / (NETDATA_DOUBLE)available_slots;
+            NETDATA_DOUBLE percent_delta = g->percent - percent_to_use;
+
+            NETDATA_DOUBLE percent_interpolation_slot = 0.0;
+            NETDATA_DOUBLE percent_last_slot = 0.0;
+            if(percent_delta > 0.0) {
+                NETDATA_DOUBLE percent_to_use_plus_1_slot = (NETDATA_DOUBLE)(slots_to_use + 1) / (NETDATA_DOUBLE)available_slots;
+                NETDATA_DOUBLE percent_1slot = percent_to_use_plus_1_slot - percent_to_use;
+
+                percent_interpolation_slot = percent_delta / percent_1slot;
+                percent_last_slot = 1 - percent_interpolation_slot;
+            }
+
+            int start_slot, stop_slot, step, last_slot, interpolation_slot;
+            if(min >= 0.0 && max >= 0.0) {
+                start_slot = 0;
+                stop_slot = start_slot + (int)slots_to_use;
+                last_slot = stop_slot - 1;
+                interpolation_slot = stop_slot;
+                step = 1;
+            }
+            else {
+                start_slot = (int)available_slots - 1;
+                stop_slot = start_slot - (int)slots_to_use;
+                last_slot = stop_slot + 1;
+                interpolation_slot = stop_slot;
+                step = -1;
+            }
+
+            value = 0.0;
+            for(int slot = start_slot; slot != stop_slot ; slot += step)
+                value += g->series[slot];
+
+            size_t counted = slots_to_use;
+            if(percent_interpolation_slot > 0.0 && interpolation_slot >= 0 && interpolation_slot < (int)available_slots) {
+                value += g->series[interpolation_slot] * percent_interpolation_slot;
+                value += g->series[last_slot] * percent_last_slot;
+                counted++;
+            }
+
+            value = value / (NETDATA_DOUBLE)counted;
+        }
+        else
+            value = min;
+    }
+
+    if(unlikely(!netdata_double_isnumber(value))) {
+        value = 0.0;
+        *rrdr_value_options_ptr |= RRDR_VALUE_EMPTY;
+    }
+
+    //log_series_to_stderr(g->series, g->next_pos, value, "percentile");
+
+    g->next_pos = 0;
+
+    return value;
+}
 
 #endif //NETDATA_API_QUERIES_PERCENTILE_H