Table of Contents Storage structure and query performance optimization of ClickHouse primary key index 1. Storage structure of primary key index 2. Query performance optimization methods 2.1. Use primary key index table 2.2. Column storage and data compression 2.3. Merge engine (MergeTree) 2.4. Data copy in conclusion Sample code: Use ClickHouse for e-commerce sales data […]
Tag: dex
[Python Ocean Topic 36] Correlation coefficient of two one-dimensional arrays–preparing for the ocean index
[Python Ocean Topic 36] Correlation coefficient of two one-dimensional arrays – preparing for the ocean index Two sets of data: x = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] A = [41, 63, 83, 71, 94, 62, 60, 42, 55, 67] B = [10, 16, 26, 29, 20, 9, 8, 13, 18, […]
MySQL database indexes and using unique indexes to achieve idempotence
Foreword This article is mainly about MySQL database index and the use of unique indexes to achieve idempotence. If there is anything that needs improvement, please point it out About the author: Hello everyone, I am Qing Jin Blog homepage: CSDN homepage to tell stories Quote of the day: Work harder and be better Table […]
oracle switches temporary table spaces, creates indexes, creates temporary tables, and creates large and small table spaces
1. The temporary table space of the switched database is temp1/the undo table space of the switched database is undotbs01 1. View the table space of the current database select tablespace_name from dba_tablespaces; It was found that there are no above two table spaces. 2. Create temp1 temporary table space and undotbs01 table space #Create […]
AntDB-M high-performance design of hash index dynamic rehash
AntDB-M supports hash index, btree index and other index types. The hash index is implemented in the form of hash table. A simple hash representation is shown in Figure 1. The element nodes under the hash bucket are one-way or two-way linked lists. One or several fields on the data row form an index. The […]
[Python Ocean Topic Thirty-Seven] Ocean Index Drawing Method–Line Chart Style 1
[Python Ocean Topic Thirty-Seven] Ocean Index Drawing Method – Line Chart Style 1 Data: AMO_index Image display: picture Recommended in the past picture [Python Ocean Topic 1] View the attributes of the data nc file and output the attributes to the txt file [Python Ocean Topic 2] Read the water depth nc file and read […]
R Data Analysis: Understanding Net Reclassification (NRI) and Integrated Discriminant Improvement (IDI) Index
Our most common indicator for evaluating the performance of classification prediction models is the ROC curve, which reports AUC. For example, if there are two models, let’s compare the AUCs of the two models to determine the performance of the two models. This is our normal practice. If our research focus is on “Whether the […]
MySQL index pitfalls, who knows who steps on them
The index can be said to be a big heart of the database. If a database lacks an index, then the existence of the database itself will be meaningless, and it is no different from an ordinary file. Therefore, a good index is particularly important for the database system. Today, let’s talk about MySQL index. […]
[ElasticSearch Series-07] ES development scenarios and index sharding settings and optimization
ElasticSearch series overall column Content Link address [1] ElasticSearch download and installation https://zhenghuisheng.blog.csdn.net/article/details/129260827 [2] ElasticSearch concepts and basic operations https://blog.csdn. net/zhenghuishengq/article/details/134121631 [3] ElasticSearch’s advanced query Query DSL https://blog.csdn.net/zhenghuishengq/article/details/134159587 [4] Aggregation query operation of ElasticSearch https://blog.csdn.net/zhenghuishengq/article/details/134159587 [5] SpringBoot integrates elasticSearch https://blog.csdn.net/zhenghuishengq/article/details/134212200 [6] The construction of Es cluster architecture and the core concepts of clusters https: //blog.csdn.net/zhenghuishengq/article/details/134258577 […]
Thoughts on MySQL optimization [storage engine, index]
For SQL optimization, today we first look at the basic knowledge: ? Storage engines. Understanding the characteristics and applicable scenarios of MySQL’s different storage engines can help you make wise decisions in database design and application development. ? Index, when the table does not have an index, querying the data may be a full table […]