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The requirements are as follows. There are already generated good spatial data, including date, hour, longitude, latitude, number of people. Use GeoServer to generate heat map. This article uses the PostgreSQL10 database and has added PostGIS support. Create table create table table_test( day varchar(8), hour int, lon nu ...

When did Apache Spark start to support the integrated Hive feature? I believe that as long as readers have used Spark, they will say that this is a long time ago. When does Apache Flink support integration with Hive? Readers may be confused. Haven't they supported it yet, haven't they used it? Or the latest version only supports it, but the fu ...

The original table (order? TBL) is partitioned by dt, and the full order is saved by partition every day (zone 20200321) order_id address trade_time dt 1 Tianjin 20200320 20200321 2 Beijing 20200320 20200321 3 Beijing 20200319 20200321 4 Tianjin 20200319 20200321 5 Beijing 20200321 20200321 6 20200321 20200321 (zone 20200320) ...

Recently, when communicating with a big guy, I mentioned the problem of SQL query. His idea is to query data with the most primitive database driver without ORM. The benefits of doing so are twofold Express SQL semantics clearly for later optimization. Especially in report, data analysis and other complex SQL. Reduce useless encapsulation and ...

In enterprise applications, there are too many scenarios involving modifying state. For example, after an enterprise enters the network, it needs to check its qualification. After the individual receives the task, the enterprise administrator shall review the receiver. In the application management system, usually as shown in the figure below, ...

In order to facilitate the unified management of exceptions, spring mvc provides controlleradvise annotation to deal with exceptions in a unified way. After getting the exception information, you can sit and handle it. For example, it provides a unified web interface to view the exception information, or it sends SMS or email t ...

This paper introduces the operation of adding, deleting, modifying and querying mysql database. 1. Install the database, pay attention to the installation of Connector NET. 2. Introduce MySql.Data.dll and add project reference. The general location of the file is: C:\Program Files (x86)\MySQL\Connector NET xx\Assemblies\v xx (determined by MySQ ...

Preface This paper introduces Redis database from the origin of NoSQL, then demonstrates the process of Redis manual compilation and installation (the system version of the experimental environment is Centos7), and finally introduces the common command tools of Redis. What is NoSQL? NoSQL -- non relational SQL, non relational database. The st ...

I. Introduction Opening the slow query log enables MySQL to record the statements that are queried for more than the specified time. Only by locating and analyzing the bottleneck of performance, can we better optimize the performance of the database system. 2, Parameter description Slow query log slow query on status Slow q ...

Some sql runtime is time-consuming, consumes system resources, and cannot be further optimized, and each time the data is obtained, it does not change much. Then the information obtained by this sql statement will be cached for the next execution This saves system resources very much View query cache size mysql> selec ...