Tag：Data Volume
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Time：2021-1-19
There are three implementations: foreach, spring transaction, and ExecutorType.BATCH . 1. Foreach mode This way is actually to splice SQL statements, generate a long SQL, and bind many variables. If the amount of data is small (less than 1000), this method can be used. If the amount of data is too large, the database may […]
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Time：2021-1-17
For the use of distinct and group by:1. When the performance of the system is high and the amount of data is large, group by is used2. When the performance of the system is not high and the amount of data used is small, both can be used3. Try to use group by Simple example: […]
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Time：2021-1-13
Related blogs: Row in SQL_ A comparison between number and apple in dealing with top n and other similar problems SQL Server – focus on apply operator (27) Do you really know how to play SQL? Top and apply in the cold There are the following application scenarios When we use row_ When doing group […]
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Time：2021-1-8
As we all know, the efficiency of like is very low. If there is a large amount of data, it will be very slow. Today, we found a built-in function instr() which is more efficient than like SELECT * FROM msg_ List where title like ‘ Can be replaced by: SELECT * FROM msg_ List […]
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Time：2021-1-7
In the past, the corresponding English word for business analysis was business analysis, and the analysis tool we used was excel. Later, with a large amount of data, excel could not cope with it (the maximum number of rows supported by Excel was 1048576). People began to turn to analysis tools such as Python and […]
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Time：2021-1-6
Demand background In some cases, we want to modify the schema of a database, but there is no existing statement. If we create a new schema and import the data, the operation will be very slow in the case of large amount of data. At this time, we can use the rename table command to […]
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Time：2021-1-2
Abstract:The surge of massive data promotes the continuous upgrading and expansion of big data clusters. In order to reduce data relocation and avoid cross cluster usage, the emergence of big clusters is inevitable. With the digital process of all walks of life, data will grow exponentially in the next few years. It is predicted that […]
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Time：2020-12-28
GrapeAll videos: https://segmentfault.com/a/11… Intset is a kind of data structure in redis. Its status is similar to ziplist and dict. What is the definition of intset? Intset is one of the underlying implementations of redis set. When all the added data are integers, intset will be used; otherwise, dict will be used. In particular, when […]
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Time：2020-12-10
Video link: https://developer.aliyun.com/live/1548?spm=a2c6h.12873581.0.0.71671566Xloy3Z&groupCode=apachespark PPT information: https://www.slidestalk.com/AliSpark/SparkRelationalCache2019_ fifty-seven thousand nine hundred and twenty-seven This sharing is mainly divided into the following four aspects: Project introduction technical analysis How to use it performance analysis 1、 Project introduction Project background Alibaba cloud EMR is an open source big data solution. At present, many open source components have been […]
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Time：2020-11-29
Property table_ Props) has the following structure Data volume above 800W Field name type explain id int id pn_id int Property type pv_id int Property value product_id int Product ID Among them, product_ ID and PN_ id,pv_ ID is a one to many relationship.The data is similar to this: product_id pn_id pv_id 10970 5 (model) […]
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Time：2020-11-17
hello everyone! This is Sean! Linux performance monitoring commands that have been running for 3 days, continue with iostat! I’ve been in touch with iostat for a long time. I’m an old friend with him! Next, I’d like to introduce this old friend to you! Iostat (monitor the usage of system input / output devices […]
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Time：2020-11-15
For large-scale data projects, large-scale data development is often encountered. Usually, a large amount of data needs to be rendered by the front end, and we usually use table to render it. stick out a mile. Many people may ask, isn’t the current component library very mature? There are all kinds of components with powerful […]
