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Preface Share some common data cleaning methods of Mongdb Note: "Exceeded memory limit for $group, but didn't allow external sort. Pass allowDiskUse:true to opt in." causes and solutions: Reason During big data calculation and data statistics, each calculation task (job or task) will use independent and limited memory space. mongod ...

SSM framework integration in general Configure the web.xml file <!-- read applicationContext-*.xml configuration file --> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext-jdbc.xml</param-value> </context-param> <!-- Set ...

Catalog 1. My blog test 1.1 sub title of my blog My blog test 1. My blog test Information retrieval is an important part of Internet applications, 1.1 sub title of my blog It is closely related to people's daily life, and web application as a text form is still the mainstream application of the Internet. How to retriev ...

Customize JAVA class and inherit BaseRegionObserver package com.charley.example.hbase2es; import org.apache.hadoop.hbase.Cell; import org.apache.hadoop.hbase.CellUtil; import org.apache.hadoop.hbase.CoprocessorEnvironment; import org.apache.hadoop.hbase.client.Durability; import org.apache.hadoop.hbase.client.Put; import ...

I. histogram Box office histogram 1 import matplotlib.pyplot as plt import numpy as np # Set matplotlib to display Chinese and minus sign normally matplotlib.rcParams['font.sans-serif']=['SimHei'] matplotlib.rcParams['axes.unicode_minus']=False # Create canvas plt.figure(figsi ...

Demand: count how many pieces of data there are every day and the average value of a field. 1. Use datehistograggregationbuilder to count by day, and then embed aggs to take the average value. If you want to sort the results, add. Order (histogram. Order. Count? DESC) to AggregationBuilders AvgAggregationBuilder avgA ...

A simple example of Deferred class code in openTSDB source code details 1. example 1 1.1 code /** * simplest with only 1 defer * In the simplest case, there is only one defer */ public static void test1() { try { //Deferred deferred = new deferred(); - > no parameters are passed, and direct n ...

Docker Network Settings Docker creates a bridged network card [docker 0]. docker has two mappings, one is random mapping and the other is specified mapping Production scenarios generally do not use random mapping The advantage of random mapping is that ports are allocated by docker and do not conflict Install nginx specified port docker pull ...

Reference link: https://www.cnblogs.com/linjiqin/p/8003838.html 1: Introduction There are three ways to implement distributed lock: 1. Optimistic database lock; 2. redis based; 3. zookeeper based. redis server is a single thread operation, which perfectly avoids the problem of multithreading synchronization and realizes atomicity. First of all, ...

Ranking function 1. Row Ou number: returns a sequential sort, regardless of whether the values are equal or not2.rank: rows with equal values have the same order, and the order value then jumps3. Deny u rank: rows with equal values are ordered the same, and the sequence number is consecutive Experiment table create table chengji(sno number,km ...