diff options
Diffstat (limited to 'web/api/queries/median')
| -rw-r--r-- | web/api/queries/median/Makefile.am | 8 | ||||
| -rw-r--r-- | web/api/queries/median/README.md | 64 | ||||
| -rw-r--r-- | web/api/queries/median/median.c | 6 | ||||
| -rw-r--r-- | web/api/queries/median/median.h | 143 |
4 files changed, 0 insertions, 221 deletions
diff --git a/web/api/queries/median/Makefile.am b/web/api/queries/median/Makefile.am deleted file mode 100644 index 161784b8f..000000000 --- a/web/api/queries/median/Makefile.am +++ /dev/null @@ -1,8 +0,0 @@ -# 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/median/README.md b/web/api/queries/median/README.md deleted file mode 100644 index f1fb3a61c..000000000 --- a/web/api/queries/median/README.md +++ /dev/null @@ -1,64 +0,0 @@ -<!-- -title: "Median" -sidebar_label: "Median" -description: "Use median in API queries and health entities to find the 'middle' value from a sample, eliminating any unwanted spikes in the returned metrics." -custom_edit_url: https://github.com/netdata/netdata/edit/master/web/api/queries/median/README.md -learn_status: "Published" -learn_topic_type: "References" -learn_rel_path: "Developers/Web/Api/Queries" ---> - -# Median - -The median is the value separating the higher half from the lower half of a data sample -(a population or a probability distribution). For a data set, it may be thought of as the -"middle" value. - -`median` is not an accurate average. However, it eliminates all spikes, by sorting -all the values in a period, and selecting the value in the middle of the sorted array. - -Netdata also supports `trimmed-median`, which trims a percentage of the smaller and bigger values prior to finding the -median. The following `trimmed-median` functions are defined: - -- `trimmed-median1` -- `trimmed-median2` -- `trimmed-median3` -- `trimmed-median5` -- `trimmed-median10` -- `trimmed-median15` -- `trimmed-median20` -- `trimmed-median25` - -The function `trimmed-median` is an alias for `trimmed-median5`. - -## how to use - -Use it in alerts like this: - -``` - alarm: my_alert - on: my_chart -lookup: median -1m unaligned of my_dimension - warn: $this > 1000 -``` - -`median` 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=median` in the URL. Additionally, a percentage may be given with -`&group_options=` to trim all small and big values before finding the median. - -## Examples - -Examining last 1 minute `successful` web server responses: - --  --  --  --  - -## References - -- <https://en.wikipedia.org/wiki/Median>. - - diff --git a/web/api/queries/median/median.c b/web/api/queries/median/median.c deleted file mode 100644 index 9865b485c..000000000 --- a/web/api/queries/median/median.c +++ /dev/null @@ -1,6 +0,0 @@ -// SPDX-License-Identifier: GPL-3.0-or-later - -#include "median.h" - -// ---------------------------------------------------------------------------- -// median diff --git a/web/api/queries/median/median.h b/web/api/queries/median/median.h deleted file mode 100644 index 3d6d35925..000000000 --- a/web/api/queries/median/median.h +++ /dev/null @@ -1,143 +0,0 @@ -// SPDX-License-Identifier: GPL-3.0-or-later - -#ifndef NETDATA_API_QUERIES_MEDIAN_H -#define NETDATA_API_QUERIES_MEDIAN_H - -#include "../query.h" -#include "../rrdr.h" - -struct tg_median { - size_t series_size; - size_t next_pos; - NETDATA_DOUBLE percent; - - NETDATA_DOUBLE *series; -}; - -static inline void tg_median_create_internal(RRDR *r, const char *options, NETDATA_DOUBLE def) { - long entries = r->view.group; - if(entries < 10) entries = 10; - - struct tg_median *g = (struct tg_median *)onewayalloc_callocz(r->internal.owa, 1, sizeof(struct tg_median)); - 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 > 50.0) g->percent = 50.0; - } - - g->percent = g->percent / 100.0; - r->time_grouping.data = g; -} - -static inline void tg_median_create(RRDR *r, const char *options) { - tg_median_create_internal(r, options, 0.0); -} -static inline void tg_median_create_trimmed_1(RRDR *r, const char *options) { - tg_median_create_internal(r, options, 1.0); -} -static inline void tg_median_create_trimmed_2(RRDR *r, const char *options) { - tg_median_create_internal(r, options, 2.0); -} -static inline void tg_median_create_trimmed_3(RRDR *r, const char *options) { - tg_median_create_internal(r, options, 3.0); -} -static inline void tg_median_create_trimmed_5(RRDR *r, const char *options) { - tg_median_create_internal(r, options, 5.0); -} -static inline void tg_median_create_trimmed_10(RRDR *r, const char *options) { - tg_median_create_internal(r, options, 10.0); -} -static inline void tg_median_create_trimmed_15(RRDR *r, const char *options) { - tg_median_create_internal(r, options, 15.0); -} -static inline void tg_median_create_trimmed_20(RRDR *r, const char *options) { - tg_median_create_internal(r, options, 20.0); -} -static inline void tg_median_create_trimmed_25(RRDR *r, const char *options) { - tg_median_create_internal(r, options, 25.0); -} - -// resets when switches dimensions -// so, clear everything to restart -static inline void tg_median_reset(RRDR *r) { - struct tg_median *g = (struct tg_median *)r->time_grouping.data; - g->next_pos = 0; -} - -static inline void tg_median_free(RRDR *r) { - struct tg_median *g = (struct tg_median *)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_median_add(RRDR *r, NETDATA_DOUBLE value) { - struct tg_median *g = (struct tg_median *)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_median_flush(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr) { - struct tg_median *g = (struct tg_median *)r->time_grouping.data; - - size_t available_slots = g->next_pos; - NETDATA_DOUBLE value; - - 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); - - size_t start_slot = 0; - size_t end_slot = available_slots - 1; - - if(g->percent > 0.0) { - NETDATA_DOUBLE min = g->series[0]; - NETDATA_DOUBLE max = g->series[available_slots - 1]; - NETDATA_DOUBLE delta = (max - min) * g->percent; - - NETDATA_DOUBLE wanted_min = min + delta; - NETDATA_DOUBLE wanted_max = max - delta; - - for (start_slot = 0; start_slot < available_slots; start_slot++) - if (g->series[start_slot] >= wanted_min) break; - - for (end_slot = available_slots - 1; end_slot > start_slot; end_slot--) - if (g->series[end_slot] <= wanted_max) break; - } - - if(start_slot == end_slot) - value = g->series[start_slot]; - else - value = median_on_sorted_series(&g->series[start_slot], end_slot - start_slot + 1); - } - - 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, "median"); - - g->next_pos = 0; - - return value; -} - -#endif //NETDATA_API_QUERIES_MEDIAN_H |