customNum=100 orderNum=200 rm tmp rm custom.sql for i in `seq $customNum`; do uuid=$(uuidgen) echo $uuid >> tmp done ## custom.sql文件为向t_custom表插入数据的sql awk -v LINE_NUM=$customNum 'BEGIN{ srand(); for(i=1;i<=LINE_NUM;i++) { a[i]=int(rand()*10000%100); ...
比如下图中的store_sales.ss_sold_date_sk列就是只用于连接条件。 对于输出列信息中还有一点需要说明的是,某些需要经过计算的表达式列,比如下图19号算子中的sum表达式列,在19号算子中每个DN计算了这个表达式的结果,在上层18号streaming算子中只是引用19号算子的结果进行重分布数据,不对其进行计算,所以在18号算子中在...
承接上一篇博客《GaussDB(DWS)性能调优系列基础篇一:万物之始analyze统计信息》,在GaussDB(DWS)的优化器根据analyze统计信息生成计划后,这里继续介绍如何详细解读计划以及计划的执行过程,从中发现可能存在的性能瓶颈点及其产生的原因。 前言 执行计划(又称解释计划)是数据库执行SQL语句的具体步骤,例如通过索引还是全表扫描...
当项目的SQL查询慢得像蜗牛爬行时,用户的耐心也在一点点被消耗,作为研发,我们可不想看到这样的事。这篇文章将结合行云部署项目的实践经验,带你走进SQL优化的奇妙世界,一起探索如何让那… 京东云 面试系列 Explain详解与索引实践 介绍一下explian字段/如何判断索引生效/如何分析一条SQL的索引使用情况 1. id列 SQL执...
<sql_operation>:識別將在節點上執行的 SQL 命令。<location permanent="false" distribution="AllDistributions">Compute</location> <sql_operation type="statement">CREATE TABLE [tempdb].[dbo]. [Q_[TEMP_ID_259]]_ [PARTITION_ID]]]([dist_date] DATE) WITH (DISTRIBUTION = HASH([dist_date]),...
(AWR) SQL Tuning Set (STS) SQL Plan Baseline (SPM) Using the EXPLAIN PLAN Command and the DBMS_XPLAN.DISPLAY Function The following examples illustrate how to generate and display an execution plan for our original SQL statement using the different functions provided in the DBMS_...
QSM-01030 materialized view, string, has PL/SQL functions in ENFORCED integrity mode Cause: A materialized view with PL/SQL functions in its definition cannot be used for query rewrite when query rewrite integrity is set to ENFORCED. Action: Consider running the query in STALE TOLERATED mode. ...
I get a spill error when i paste =UNIQUE(RANDARRAY(100,1,9788723527370120,9788723527370990,TRUE)) in a clean sheet at a1 cell. Am i doing something wrong? Ohayonson No, it appears to be a bug. Paste the formula into any other cell - it should work. ...
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Return the current time/date in various formats (Golang Playground) go run time.go Return pseudo random integer values (Golang Playground) go run random.go Concat strings in two different ways (Golang Playground) go run cat.go Modulo operation finds the remainder of division (Golang Playground...