ClickHouse create temporary structure in memory like this: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 SELECT array_1, array_2, x FROM ( SELECT [1, 2, 3, 4, 5] AS array_1, [1, 2, 3, 4, 5] AS array_2 ) ARRAY JOIN arrayEnumerate(array_1) AS x ┌─array_1─────...
Why arrayMap, arrayFilter, arrayJoin use so much memory? arrayMap-like functions memory usage calculation. In order to calculate arrayMap or similar array* functions ClickHouse temporarily does arrayJoin-like operation, which in certain conditions can lead to huge memory usage for big arrays. So fo...
arrayMap是ClickHouse里处理数组的实用工具,适合需要批量处理数组元素的场景。它的核心逻辑是对数组内每个元素执行相同操作,生成新数组,类似编程中的map函数。 基本结构长这样: arrayMap(func, arr1 [, arr2...]) 三个关键点: 1.func是处理元素的函数,通常用lambda表达式,比如x-> x2 ...
我是Clickhouse的新手，所以对于专家来说这可能是一个简单的问题;)！
arrayMap(x, y->floor(x/y,3), threshold, l) threshold_percent, does not handle some corner case correctly or there's a bug somewhere in sh scripts that generate data for this query, it's hard to tell. https://clickhouse-test-reports.s3.yandex.net/31391/a13ed01c05b90edd9408fe33b80c...
ClickHouse create temporary structure in memory like this: SELECT array_1,array_2,x FROM(SELECT [1,2,3,4,5] AS array_1,[1,2,3,4,5] AS array_2)ARRAY JOINarrayEnumerate(array_1)AS x ┌─array_1─────┬─array_2─────┬─x─┐ ...
ClickHouse create temporary structure in memory like this: SELECT array_1, array_2, x FROM ( SELECT [1, 2, 3, 4, 5]ASarray_1, [1, 2, 3, 4, 5]ASarray_2 ) ARRAYJOINarrayEnumerate(array_1)ASx ┌─array_1─────┬─array_2─────┬─x─┐ ...
ClickHouse create temporary structure in memory like this: AI检测代码解析 SELECT array_1, array_2, x FROM ( SELECT [1, 2, 3, 4, 5] AS array_1, [1, 2, 3, 4, 5] AS array_2 ) ARRAY JOIN arrayEnumerate(array_1) AS x