Tag：plan
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Time：2021-4-14
In our existing system, the importance of database is self-evident. In order to avoid data loss caused by data downtime or misoperation, it is necessary to backup the database regularly. The following will introduce the database backup method of SQL server, hoping to help you solve the problem of daily backup. Step 1: login Database […]
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Time：2021-2-24
Author: cybertecLei Yanliang, a PostgreSQL database technology enthusiast, 10g & 11g OCM, Ogg Certified Expert, works in Hangao basic software Co., Ltd Monitoring PostgreSQL execution planpg_ show_ Plans is a free PostgreSQL tool that allows you to monitor execution plans in real time. So far, the query plan cannot be monitored while the SQL statement […]
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Time：2021-2-18
Absrtact: This paper mainly introduces the overall structure of the query layer, and introduces the flow through the four main modules of the query layer through an ngql statement. 1、 Overview Compared with version 1.0, the distributed graph database version 2.0 has a big change. The most obvious change is that in version 1.0, the […]
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Time：2021-2-12
Today, let’s share some common SQL errors (improper) usage of MySQL. As a beginner, we probably didn’t pay attention to these problems when we were writing SQL, which led to the inefficiency of the SQL statements. So we can also introspect ourselves. Common SQL error usage 1. Limit statement Paging query is one of the […]
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Time：2021-2-5
Absrtact: This paper introduces another function of gaussdb (DWS), plan hint, which can generate human intervention plan. preface When database users write SQL statements, they will try their best to write high-performance SQL statements according to their known situation. However, when a large number of SQL statements need to be written, and the logic of […]
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Time：2021-2-1
? 2001, 2014 don gray and Dan Starr Near the Blue Ridge Mountains in North Carolina, not far from where you should think, there is a small town called Mayberry. Although the main road bypassed the town a few years ago, Mayberry is the name of the popular 1960s TV series, and it’s still a […]
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Time：2021-1-23
In Oracle database, the optimizer needs to collect the statistical information of related objects in order to produce the optimal execution plan. The database can collect the execution plan automatically or use the package DBMS_ Stats for manual collection, this article does not explain the collection of conventional statistical information, but focuses on the collection […]
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Time：2021-1-22
Introduction to AQE fromspark configurationAs early as in spark version 1.6, AQE has been established; in spark version 2. X, Intel big data team has carried out corresponding prototype development and practice; in spark 3.0 era, databricks and Intel have contributed new AQE to the community together Configuration of AQE in spark 3.0.1 Configuration item […]
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Time：2021-1-22
numerical calculation 1. Overflow and underflow The first problem in numerical computation is numerical overflow and numerical underflow. Overflow refers to the value is very large, overflow is Nan value, and underflow refers to the value is very small, underflow is 0. Numerical overflow is likely to lead to numerical calculation problems, so corresponding solutions […]
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Time：2021-1-20
preface Recently, I’ve been busy with all kinds of work. Even reading spring source code has been suspended, and DOC view has put plans on hold. Although I want to have many functions, I always have to take my time. Several small partners also mentioned issues in GitHub: Hope to support idea 2020.3 There is […]
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Time：2021-1-8
Partition expansion For example, the theme “user”_ “Order” is currently one partition. Here, increase the number of theme partitions to six, and observe the modification results kafka-topics.sh –partitions 6 –alter –zookeeper dn1:2181,dn2:2181,dn3:2181 –topic user_order This is just to modify the number of partitions, but the data has not been migrated Use the tool Kafka reassign […]
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Time：2021-1-6
catalog Types and properties of indexes Single key index General single key index Index subdocument fields unique index Composite index Multi key index Expired index Hash indices Geolocation index Text index Index operation method View existing index Lists all indexes of the database Delete index Re index Parameters for creating an index Index rules query […]
