71.2. Встроенные классы операторов
В базовый дистрибутив Postgres Pro включены классы операторов BRIN, перечисленные в Таблице 71.1.
Классы операторов minmax хранят минимальные и максимальные значения, встречающиеся в индексированном столбце в определённой зоне. Классы операторов inclusion хранят значение, в котором содержатся значения индексированного столбца в определённой зоне. Классы операторов bloom строят фильтр Блума для всех значений в определённой зоне. Классы операторов minmax-multi хранят несколько минимальных и максимальных значений, встречающихся в индексированном столбце в определённой зоне.
Таблица 71.1. Встроенные классы операторов BRIN
| Имя | Индексируемые операторы |
|---|---|
bit_minmax_ops | = (bit,bit) |
< (bit,bit) | |
> (bit,bit) | |
<= (bit,bit) | |
>= (bit,bit) | |
box_inclusion_ops | @> (box,point) |
<< (box,box) | |
&< (box,box) | |
&> (box,box) | |
>> (box,box) | |
<@ (box,box) | |
@> (box,box) | |
~= (box,box) | |
&& (box,box) | |
<<| (box,box) | |
&<| (box,box) | |
|&> (box,box) | |
|>> (box,box) | |
bpchar_bloom_ops | = (character,character) |
bpchar_minmax_ops | = (character,character) |
< (character,character) | |
<= (character,character) | |
> (character,character) | |
>= (character,character) | |
bytea_bloom_ops | = (bytea,bytea) |
bytea_minmax_ops | = (bytea,bytea) |
< (bytea,bytea) | |
<= (bytea,bytea) | |
> (bytea,bytea) | |
>= (bytea,bytea) | |
char_bloom_ops | = ("char","char") |
char_minmax_ops | = ("char","char") |
< ("char","char") | |
<= ("char","char") | |
> ("char","char") | |
>= ("char","char") | |
date_bloom_ops | = (date,date) |
date_minmax_ops | = (date,date) |
< (date,date) | |
<= (date,date) | |
> (date,date) | |
>= (date,date) | |
date_minmax_multi_ops | = (date,date) |
< (date,date) | |
<= (date,date) | |
> (date,date) | |
>= (date,date) | |
float4_bloom_ops | = (float4,float4) |
float4_minmax_ops | = (float4,float4) |
< (float4,float4) | |
> (float4,float4) | |
<= (float4,float4) | |
>= (float4,float4) | |
float4_minmax_multi_ops | = (float4,float4) |
< (float4,float4) | |
> (float4,float4) | |
<= (float4,float4) | |
>= (float4,float4) | |
float8_bloom_ops | = (float8,float8) |
float8_minmax_ops | = (float8,float8) |
< (float8,float8) | |
<= (float8,float8) | |
> (float8,float8) | |
>= (float8,float8) | |
float8_minmax_multi_ops | = (float8,float8) |
< (float8,float8) | |
<= (float8,float8) | |
> (float8,float8) | |
>= (float8,float8) | |
inet_inclusion_ops | << (inet,inet) |
<<= (inet,inet) | |
>> (inet,inet) | |
>>= (inet,inet) | |
= (inet,inet) | |
&& (inet,inet) | |
inet_bloom_ops | = (inet,inet) |
inet_minmax_ops | = (inet,inet) |
< (inet,inet) | |
<= (inet,inet) | |
> (inet,inet) | |
>= (inet,inet) | |
inet_minmax_multi_ops | = (inet,inet) |
< (inet,inet) | |
<= (inet,inet) | |
> (inet,inet) | |
>= (inet,inet) | |
int2_bloom_ops | = (int2,int2) |
int2_minmax_ops | = (int2,int2) |
< (int2,int2) | |
> (int2,int2) | |
<= (int2,int2) | |
>= (int2,int2) | |
int2_minmax_multi_ops | = (int2,int2) |
< (int2,int2) | |
> (int2,int2) | |
<= (int2,int2) | |
>= (int2,int2) | |
int4_bloom_ops | = (int4,int4) |
int4_minmax_ops | = (int4,int4) |
< (int4,int4) | |
> (int4,int4) | |
<= (int4,int4) | |
>= (int4,int4) | |
int4_minmax_multi_ops | = (int4,int4) |
< (int4,int4) | |
> (int4,int4) | |
<= (int4,int4) | |
>= (int4,int4) | |
int8_bloom_ops | = (bigint,bigint) |
int8_minmax_ops | = (bigint,bigint) |
< (bigint,bigint) | |
> (bigint,bigint) | |
<= (bigint,bigint) | |
>= (bigint,bigint) | |
int8_minmax_multi_ops | = (bigint,bigint) |
< (bigint,bigint) | |
> (bigint,bigint) | |
<= (bigint,bigint) | |
>= (bigint,bigint) | |
interval_bloom_ops | = (interval,interval) |
interval_minmax_ops | = (interval,interval) |
< (interval,interval) | |
<= (interval,interval) | |
> (interval,interval) | |
>= (interval,interval) | |
interval_minmax_multi_ops | = (interval,interval) |
< (interval,interval) | |
<= (interval,interval) | |
> (interval,interval) | |
>= (interval,interval) | |
macaddr_bloom_ops | = (macaddr,macaddr) |
macaddr_minmax_ops | = (macaddr,macaddr) |
< (macaddr,macaddr) | |
<= (macaddr,macaddr) | |
> (macaddr,macaddr) | |
>= (macaddr,macaddr) | |
macaddr_minmax_multi_ops | = (macaddr,macaddr) |
< (macaddr,macaddr) | |
<= (macaddr,macaddr) | |
> (macaddr,macaddr) | |
>= (macaddr,macaddr) | |
macaddr8_bloom_ops | = (macaddr8,macaddr8) |
macaddr8_minmax_ops | = (macaddr8,macaddr8) |
< (macaddr8,macaddr8) | |
<= (macaddr8,macaddr8) | |
> (macaddr8,macaddr8) | |
>= (macaddr8,macaddr8) | |
macaddr8_minmax_multi_ops | = (macaddr8,macaddr8) |
< (macaddr8,macaddr8) | |
<= (macaddr8,macaddr8) | |
> (macaddr8,macaddr8) | |
>= (macaddr8,macaddr8) | |
name_bloom_ops | = (name,name) |
name_minmax_ops | = (name,name) |
< (name,name) | |
<= (name,name) | |
> (name,name) | |
>= (name,name) | |
numeric_bloom_ops | = (numeric,numeric) |
numeric_minmax_ops | = (numeric,numeric) |
< (numeric,numeric) | |
<= (numeric,numeric) | |
> (numeric,numeric) | |
>= (numeric,numeric) | |
numeric_minmax_multi_ops | = (numeric,numeric) |
< (numeric,numeric) | |
<= (numeric,numeric) | |
> (numeric,numeric) | |
>= (numeric,numeric) | |
oid_bloom_ops | = (oid,oid) |
oid_minmax_ops | = (oid,oid) |
< (oid,oid) | |
> (oid,oid) | |
<= (oid,oid) | |
>= (oid,oid) | |
oid_minmax_multi_ops | = (oid,oid) |
< (oid,oid) | |
> (oid,oid) | |
<= (oid,oid) | |
>= (oid,oid) | |
pg_lsn_bloom_ops | = (pg_lsn,pg_lsn) |
pg_lsn_minmax_ops | = (pg_lsn,pg_lsn) |
< (pg_lsn,pg_lsn) | |
> (pg_lsn,pg_lsn) | |
<= (pg_lsn,pg_lsn) | |
>= (pg_lsn,pg_lsn) | |
pg_lsn_minmax_multi_ops | = (pg_lsn,pg_lsn) |
< (pg_lsn,pg_lsn) | |
> (pg_lsn,pg_lsn) | |
<= (pg_lsn,pg_lsn) | |
>= (pg_lsn,pg_lsn) | |
range_inclusion_ops | = (anyrange,anyrange) |
< (anyrange,anyrange) | |
<= (anyrange,anyrange) | |
>= (anyrange,anyrange) | |
> (anyrange,anyrange) | |
&& (anyrange,anyrange) | |
@> (anyrange,anyelement) | |
@> (anyrange,anyrange) | |
<@ (anyrange,anyrange) | |
<< (anyrange,anyrange) | |
>> (anyrange,anyrange) | |
&< (anyrange,anyrange) | |
&> (anyrange,anyrange) | |
-|- (anyrange,anyrange) | |
text_bloom_ops | = (text,text) |
text_minmax_ops | = (text,text) |
< (text,text) | |
<= (text,text) | |
> (text,text) | |
>= (text,text) | |
tid_bloom_ops | = (tid,tid) |
tid_minmax_ops | = (tid,tid) |
< (tid,tid) | |
> (tid,tid) | |
<= (tid,tid) | |
>= (tid,tid) | |
tid_minmax_multi_ops | = (tid,tid) |
< (tid,tid) | |
> (tid,tid) | |
<= (tid,tid) | |
>= (tid,tid) | |
timestamp_bloom_ops | = (timestamp,timestamp) |
timestamp_minmax_ops | = (timestamp,timestamp) |
< (timestamp,timestamp) | |
<= (timestamp,timestamp) | |
> (timestamp,timestamp) | |
>= (timestamp,timestamp) | |
timestamp_minmax_multi_ops | = (timestamp,timestamp) |
< (timestamp,timestamp) | |
<= (timestamp,timestamp) | |
> (timestamp,timestamp) | |
>= (timestamp,timestamp) | |
timestamptz_bloom_ops | = (timestamptz,timestamptz) |
timestamptz_minmax_ops | = (timestamptz,timestamptz) |
< (timestamptz,timestamptz) | |
<= (timestamptz,timestamptz) | |
> (timestamptz,timestamptz) | |
>= (timestamptz,timestamptz) | |
timestamptz_minmax_multi_ops | = (timestamptz,timestamptz) |
< (timestamptz,timestamptz) | |
<= (timestamptz,timestamptz) | |
> (timestamptz,timestamptz) | |
>= (timestamptz,timestamptz) | |
time_bloom_ops | = (time,time) |
time_minmax_ops | = (time,time) |
< (time,time) | |
<= (time,time) | |
> (time,time) | |
>= (time,time) | |
time_minmax_multi_ops | = (time,time) |
< (time,time) | |
<= (time,time) | |
> (time,time) | |
>= (time,time) | |
timetz_bloom_ops | = (timetz,timetz) |
timetz_minmax_ops | = (timetz,timetz) |
< (timetz,timetz) | |
<= (timetz,timetz) | |
> (timetz,timetz) | |
>= (timetz,timetz) | |
timetz_minmax_multi_ops | = (timetz,timetz) |
< (timetz,timetz) | |
<= (timetz,timetz) | |
> (timetz,timetz) | |
>= (timetz,timetz) | |
uuid_bloom_ops | = (uuid,uuid) |
uuid_minmax_ops | = (uuid,uuid) |
< (uuid,uuid) | |
> (uuid,uuid) | |
<= (uuid,uuid) | |
>= (uuid,uuid) | |
uuid_minmax_multi_ops | = (uuid,uuid) |
< (uuid,uuid) | |
> (uuid,uuid) | |
<= (uuid,uuid) | |
>= (uuid,uuid) | |
varbit_minmax_ops | = (varbit,varbit) |
< (varbit,varbit) | |
> (varbit,varbit) | |
<= (varbit,varbit) | |
>= (varbit,varbit) |
71.2.1. Параметры класса операторов
Для некоторых встроенных классов операторов можно задавать параметры, влияющие на их поведение, а именно: для классов операторов bloom и minmax-multi. У разных классов операторов разный набор допустимых параметров.
Классы операторов bloom принимают эти параметры:
n_distinct_per_rangeОпределяет предполагаемое количество различных значений (без учёта NULL) в зоне блоков, в зависимости от которого выбирается размер фильтра Блума в BRIN-индексе. Работает аналогично параметру
n_distinctдля ALTER TABLE. Положительное значение непосредственно задаёт предполагаемое количество. Минимальное количество различных значений (без учёта NULL) значений —16. Если заданное значение отрицательно, то количество таких значений линейно зависит от максимального возможного числа кортежей в зоне блоков (один блок может содержать до 290 строк). Коэффициентом зависимости будет модуль этого значения, который не должен превышать 1. Значение по умолчанию —-0.1.false_positive_rateОпределяет ожидаемую долю ложных положительных срабатываний, в зависимости от которой выбирается размер фильтра Блума в BRIN-индексе. Принимаются значения от 0,0001 до 0,25. Значение по умолчанию — 0,01, то есть вероятность ложных положительных срабатываний равна 1%.
Классы операторов minmax-multi принимают эти параметры:
values_per_rangeОпределяет максимальное количество значений, хранимых BRIN-индексами типа minmax для обобщения информации по зоне блоков. Каждое значение может представлять собой либо точку, либо границу интервала. Принимаются значения от 8 до 256, а значение по умолчанию — 32.
71.2. Built-in Operator Classes
The core Postgres Pro distribution includes the BRIN operator classes shown in Table 71.1.
The minmax operator classes store the minimum and the maximum values appearing in the indexed column within the range. The inclusion operator classes store a value which includes the values in the indexed column within the range. The bloom operator classes build a Bloom filter for all values in the range. The minmax-multi operator classes store multiple minimum and maximum values, representing values appearing in the indexed column within the range.
Table 71.1. Built-in BRIN Operator Classes
| Name | Indexable Operators |
|---|---|
bit_minmax_ops | = (bit,bit) |
< (bit,bit) | |
> (bit,bit) | |
<= (bit,bit) | |
>= (bit,bit) | |
box_inclusion_ops | @> (box,point) |
<< (box,box) | |
&< (box,box) | |
&> (box,box) | |
>> (box,box) | |
<@ (box,box) | |
@> (box,box) | |
~= (box,box) | |
&& (box,box) | |
<<| (box,box) | |
&<| (box,box) | |
|&> (box,box) | |
|>> (box,box) | |
bpchar_bloom_ops | = (character,character) |
bpchar_minmax_ops | = (character,character) |
< (character,character) | |
<= (character,character) | |
> (character,character) | |
>= (character,character) | |
bytea_bloom_ops | = (bytea,bytea) |
bytea_minmax_ops | = (bytea,bytea) |
< (bytea,bytea) | |
<= (bytea,bytea) | |
> (bytea,bytea) | |
>= (bytea,bytea) | |
char_bloom_ops | = ("char","char") |
char_minmax_ops | = ("char","char") |
< ("char","char") | |
<= ("char","char") | |
> ("char","char") | |
>= ("char","char") | |
date_bloom_ops | = (date,date) |
date_minmax_ops | = (date,date) |
< (date,date) | |
<= (date,date) | |
> (date,date) | |
>= (date,date) | |
date_minmax_multi_ops | = (date,date) |
< (date,date) | |
<= (date,date) | |
> (date,date) | |
>= (date,date) | |
float4_bloom_ops | = (float4,float4) |
float4_minmax_ops | = (float4,float4) |
< (float4,float4) | |
> (float4,float4) | |
<= (float4,float4) | |
>= (float4,float4) | |
float4_minmax_multi_ops | = (float4,float4) |
< (float4,float4) | |
> (float4,float4) | |
<= (float4,float4) | |
>= (float4,float4) | |
float8_bloom_ops | = (float8,float8) |
float8_minmax_ops | = (float8,float8) |
< (float8,float8) | |
<= (float8,float8) | |
> (float8,float8) | |
>= (float8,float8) | |
float8_minmax_multi_ops | = (float8,float8) |
< (float8,float8) | |
<= (float8,float8) | |
> (float8,float8) | |
>= (float8,float8) | |
inet_inclusion_ops | << (inet,inet) |
<<= (inet,inet) | |
>> (inet,inet) | |
>>= (inet,inet) | |
= (inet,inet) | |
&& (inet,inet) | |
inet_bloom_ops | = (inet,inet) |
inet_minmax_ops | = (inet,inet) |
< (inet,inet) | |
<= (inet,inet) | |
> (inet,inet) | |
>= (inet,inet) | |
inet_minmax_multi_ops | = (inet,inet) |
< (inet,inet) | |
<= (inet,inet) | |
> (inet,inet) | |
>= (inet,inet) | |
int2_bloom_ops | = (int2,int2) |
int2_minmax_ops | = (int2,int2) |
< (int2,int2) | |
> (int2,int2) | |
<= (int2,int2) | |
>= (int2,int2) | |
int2_minmax_multi_ops | = (int2,int2) |
< (int2,int2) | |
> (int2,int2) | |
<= (int2,int2) | |
>= (int2,int2) | |
int4_bloom_ops | = (int4,int4) |
int4_minmax_ops | = (int4,int4) |
< (int4,int4) | |
> (int4,int4) | |
<= (int4,int4) | |
>= (int4,int4) | |
int4_minmax_multi_ops | = (int4,int4) |
< (int4,int4) | |
> (int4,int4) | |
<= (int4,int4) | |
>= (int4,int4) | |
int8_bloom_ops | = (bigint,bigint) |
int8_minmax_ops | = (bigint,bigint) |
< (bigint,bigint) | |
> (bigint,bigint) | |
<= (bigint,bigint) | |
>= (bigint,bigint) | |
int8_minmax_multi_ops | = (bigint,bigint) |
< (bigint,bigint) | |
> (bigint,bigint) | |
<= (bigint,bigint) | |
>= (bigint,bigint) | |
interval_bloom_ops | = (interval,interval) |
interval_minmax_ops | = (interval,interval) |
< (interval,interval) | |
<= (interval,interval) | |
> (interval,interval) | |
>= (interval,interval) | |
interval_minmax_multi_ops | = (interval,interval) |
< (interval,interval) | |
<= (interval,interval) | |
> (interval,interval) | |
>= (interval,interval) | |
macaddr_bloom_ops | = (macaddr,macaddr) |
macaddr_minmax_ops | = (macaddr,macaddr) |
< (macaddr,macaddr) | |
<= (macaddr,macaddr) | |
> (macaddr,macaddr) | |
>= (macaddr,macaddr) | |
macaddr_minmax_multi_ops | = (macaddr,macaddr) |
< (macaddr,macaddr) | |
<= (macaddr,macaddr) | |
> (macaddr,macaddr) | |
>= (macaddr,macaddr) | |
macaddr8_bloom_ops | = (macaddr8,macaddr8) |
macaddr8_minmax_ops | = (macaddr8,macaddr8) |
< (macaddr8,macaddr8) | |
<= (macaddr8,macaddr8) | |
> (macaddr8,macaddr8) | |
>= (macaddr8,macaddr8) | |
macaddr8_minmax_multi_ops | = (macaddr8,macaddr8) |
< (macaddr8,macaddr8) | |
<= (macaddr8,macaddr8) | |
> (macaddr8,macaddr8) | |
>= (macaddr8,macaddr8) | |
name_bloom_ops | = (name,name) |
name_minmax_ops | = (name,name) |
< (name,name) | |
<= (name,name) | |
> (name,name) | |
>= (name,name) | |
numeric_bloom_ops | = (numeric,numeric) |
numeric_minmax_ops | = (numeric,numeric) |
< (numeric,numeric) | |
<= (numeric,numeric) | |
> (numeric,numeric) | |
>= (numeric,numeric) | |
numeric_minmax_multi_ops | = (numeric,numeric) |
< (numeric,numeric) | |
<= (numeric,numeric) | |
> (numeric,numeric) | |
>= (numeric,numeric) | |
oid_bloom_ops | = (oid,oid) |
oid_minmax_ops | = (oid,oid) |
< (oid,oid) | |
> (oid,oid) | |
<= (oid,oid) | |
>= (oid,oid) | |
oid_minmax_multi_ops | = (oid,oid) |
< (oid,oid) | |
> (oid,oid) | |
<= (oid,oid) | |
>= (oid,oid) | |
pg_lsn_bloom_ops | = (pg_lsn,pg_lsn) |
pg_lsn_minmax_ops | = (pg_lsn,pg_lsn) |
< (pg_lsn,pg_lsn) | |
> (pg_lsn,pg_lsn) | |
<= (pg_lsn,pg_lsn) | |
>= (pg_lsn,pg_lsn) | |
pg_lsn_minmax_multi_ops | = (pg_lsn,pg_lsn) |
< (pg_lsn,pg_lsn) | |
> (pg_lsn,pg_lsn) | |
<= (pg_lsn,pg_lsn) | |
>= (pg_lsn,pg_lsn) | |
range_inclusion_ops | = (anyrange,anyrange) |
< (anyrange,anyrange) | |
<= (anyrange,anyrange) | |
>= (anyrange,anyrange) | |
> (anyrange,anyrange) | |
&& (anyrange,anyrange) | |
@> (anyrange,anyelement) | |
@> (anyrange,anyrange) | |
<@ (anyrange,anyrange) | |
<< (anyrange,anyrange) | |
>> (anyrange,anyrange) | |
&< (anyrange,anyrange) | |
&> (anyrange,anyrange) | |
-|- (anyrange,anyrange) | |
text_bloom_ops | = (text,text) |
text_minmax_ops | = (text,text) |
< (text,text) | |
<= (text,text) | |
> (text,text) | |
>= (text,text) | |
tid_bloom_ops | = (tid,tid) |
tid_minmax_ops | = (tid,tid) |
< (tid,tid) | |
> (tid,tid) | |
<= (tid,tid) | |
>= (tid,tid) | |
tid_minmax_multi_ops | = (tid,tid) |
< (tid,tid) | |
> (tid,tid) | |
<= (tid,tid) | |
>= (tid,tid) | |
timestamp_bloom_ops | = (timestamp,timestamp) |
timestamp_minmax_ops | = (timestamp,timestamp) |
< (timestamp,timestamp) | |
<= (timestamp,timestamp) | |
> (timestamp,timestamp) | |
>= (timestamp,timestamp) | |
timestamp_minmax_multi_ops | = (timestamp,timestamp) |
< (timestamp,timestamp) | |
<= (timestamp,timestamp) | |
> (timestamp,timestamp) | |
>= (timestamp,timestamp) | |
timestamptz_bloom_ops | = (timestamptz,timestamptz) |
timestamptz_minmax_ops | = (timestamptz,timestamptz) |
< (timestamptz,timestamptz) | |
<= (timestamptz,timestamptz) | |
> (timestamptz,timestamptz) | |
>= (timestamptz,timestamptz) | |
timestamptz_minmax_multi_ops | = (timestamptz,timestamptz) |
< (timestamptz,timestamptz) | |
<= (timestamptz,timestamptz) | |
> (timestamptz,timestamptz) | |
>= (timestamptz,timestamptz) | |
time_bloom_ops | = (time,time) |
time_minmax_ops | = (time,time) |
< (time,time) | |
<= (time,time) | |
> (time,time) | |
>= (time,time) | |
time_minmax_multi_ops | = (time,time) |
< (time,time) | |
<= (time,time) | |
> (time,time) | |
>= (time,time) | |
timetz_bloom_ops | = (timetz,timetz) |
timetz_minmax_ops | = (timetz,timetz) |
< (timetz,timetz) | |
<= (timetz,timetz) | |
> (timetz,timetz) | |
>= (timetz,timetz) | |
timetz_minmax_multi_ops | = (timetz,timetz) |
< (timetz,timetz) | |
<= (timetz,timetz) | |
> (timetz,timetz) | |
>= (timetz,timetz) | |
uuid_bloom_ops | = (uuid,uuid) |
uuid_minmax_ops | = (uuid,uuid) |
< (uuid,uuid) | |
> (uuid,uuid) | |
<= (uuid,uuid) | |
>= (uuid,uuid) | |
uuid_minmax_multi_ops | = (uuid,uuid) |
< (uuid,uuid) | |
> (uuid,uuid) | |
<= (uuid,uuid) | |
>= (uuid,uuid) | |
varbit_minmax_ops | = (varbit,varbit) |
< (varbit,varbit) | |
> (varbit,varbit) | |
<= (varbit,varbit) | |
>= (varbit,varbit) |
71.2.1. Operator Class Parameters
Some of the built-in operator classes allow specifying parameters affecting behavior of the operator class. Each operator class has its own set of allowed parameters. Only the bloom and minmax-multi operator classes allow specifying parameters:
bloom operator classes accept these parameters:
n_distinct_per_rangeDefines the estimated number of distinct non-null values in the block range, used by BRIN bloom indexes for sizing of the Bloom filter. It behaves similarly to
n_distinctoption for ALTER TABLE. When set to a positive value, each block range is assumed to contain this number of distinct non-null values. When set to a negative value, which must be greater than or equal to -1, the number of distinct non-null values is assumed to grow linearly with the maximum possible number of tuples in the block range (about 290 rows per block). The default value is-0.1, and the minimum number of distinct non-null values is16.false_positive_rateDefines the desired false positive rate used by BRIN bloom indexes for sizing of the Bloom filter. The values must be between 0.0001 and 0.25. The default value is 0.01, which is 1% false positive rate.
minmax-multi operator classes accept these parameters:
values_per_rangeDefines the maximum number of values stored by BRIN minmax indexes to summarize a block range. Each value may represent either a point, or a boundary of an interval. Values must be between 8 and 256, and the default value is 32.
