15 CHAR_LENGTH, CHARACTER_LENGTH ............................................................ 426 HASH ................................................................................................. ..................................................................................... 664 RDB$FUNCTIONS ............................................................................................... | | | | <hash-item> ::= SORT () ::= JOIN (, [,

COT() DATEADD() DATEDIFF() DECODE() EXP() EXTRACT() MILLISECOND WEEK FLOOR() GEN_ID() GEN_UUID() HASH() IIF() LEFT() LN() LOG() LOG10() LOWER() LPAD() MAXVALUE() MINVALUE() MOD() NULLIF() OCTET_LENGTH() Операторы и предикаты (утверждения); • Агрегатные функции; • Встроенные функции; • UDF (User Defined Functions — функции, определённые пользователем. Также известные как внешние функции). Полная документация DATA DATEADD DATEDIFF DECODE DELETING DIFFERENCE EXP FIRST FIRSTNAME FLOOR GEN_UUID GENERATED GRANTED HASH IIF INSERTING LAST LASTNAME LEAVE LIST LN LOCK LOG LOG10 LPAD MAPPING MATCHED MATCHING MAXVALUE MIDDLENAME

способ поддержать все возможности стандарта и сохранить все расширения ClickHouse! 2021: Window Functions, ANY/ALL, EXISTS, GROUPING SETS... 2022: Correlated Subqueries Отсутствие оптимизаций JOIN 18 учитывается сортировка таблицы для JOIN • Нет cost based optimizer для переупорядочивания JOIN • Нет grace hash алгоритма для JOIN • Нет shuffle для распределённых JOIN • И вообще распределённые JOIN плохо работают

способ поддержать все возможности стандарта и сохранить все расширения ClickHouse! 2021: Window Functions, ANY/ALL, EXISTS, GROUPING SETS... 2022: Correlated Subqueries Отсутствие оптимизаций JOIN 18 учитывается сортировка таблицы для JOIN • Нет cost based optimizer для переупорядочивания JOIN • Нет grace hash алгоритма для JOIN • Нет shuffle для распределённых JOIN • И вообще распределённые JOIN плохо работают

двойки. Медленное деление даже с constant switch, libdivide но есть ещё fastrange size_t place = hash & (size - 1) Выбор load factor 18 18 0.5 хороший вариант для линейных проб с шагом 1 ClickHouse 011 сек. std::unordered_map 44.758 сек. Бенчмарки 28 28 perf stat -e cache-misses:u ./integer_hash_tables_and_hashes Хеш-таблица Cache misses ClickHouse HashMap 329,664,616 Google DenseMap 383,350 1. Hash 2. Allocator 3. Cell 4. Grower (интерфейс для ресайза) 5. HashTable С++ дизайн хэш-таблицы 33 33 Hash Такой же как std::hash. С++ дизайн хэш-таблицы 34 34 Hash Такой же как std::hash. С++

URL, so you don't need !includeurl • Some features (like %date%) have been replaced by builtin functions (for example %date()) • When calling a legacy !definelong macro with no arguments, you do have Function names must start with a $ • Argument names must start with a $ • Void functions can call other void functions Example: @startuml !function msg($source, $destination) $source --> $destination языку PlantUML (1.2019.9) 147 / 172 19.5 Return function 19 PREPROCESSING Variables defined in functions are local. It means that the variable is destroyed when the function ends. 19.5 Return function

URL, so you don't need !includeurl • Some features (like %date%) have been replaced by builtin functions (for example %date()) • When calling a legacy !definelong macro with no arguments, you do have Boolean builtin functions [%false(), %true(), %not()] For convenience, you can use those boolean builtin functions: • %false() • %true() • %not() [See also Builtin functions] 20.4 Conditions function that you can call: • directly in variable definition or in diagram text • from other return functions • from procedures • Function name should start with a $ • Argument names should start with a

URL, so you don't need !includeurl • Some features (like %date%) have been replaced by builtin functions (for example %date()) • When calling a legacy !definelong macro with no arguments, you do have Boolean builtin functions [%false(), %true(), %not()] For convenience, you can use those boolean builtin functions: • %false() • %true() • %not() [See also Builtin functions] 20.4 Conditions function that you can call: • directly in variable definition or in diagram text • from other return functions • from procedures • Function name should start with a $ • Argument names should start with a

URL, so you don't need !includeurl • Some features (like %date%) have been replaced by builtin functions (for example %date()) • When calling a legacy !definelong macro with no arguments, you do have created outside function are global, that is you can access to them from everywhere (including from functions). You can emphasize this by using the optional global keyword when defining a variable. @startuml Function name should start by a $ • Argument names should start by a $ • Void functions can call other void functions Example: @startuml !function msg($source, $destination) $source --> $destination

URL, so you don’t need !includeurl • Some features (like %date%) have been replaced by builtin functions (for example %date()) • When calling a legacy !definelong macro with no arguments, you do have Boolean builtin functions [%false(), %true(), %not()] For convenience, you can use those boolean builtin functions: • %false() • %true() • %not() [See also Builtin functions] 25.4 Conditions function that you can call: • directly in variable definition or in diagram text • from other return functions • from procedures • Function name should start with a $ • Argument names should start with a