• Performance tuning of SQL tuning


    Syntax based optimization and simple query conditions. Syntax based optimization refers to the selection of words and the order of writing in SQL statements without considering any non grammatical factors (such as index, table size and storage). general rule In this section, I’ll look at some general rules that you need to pay attention to […]

  • SQL Server batch modify database table PK name to PK table name


    1. When we create the primary key of the data table of SQL server, sometimes a string of random strings will be added, as shown in the figure:   2. If you have obsessive-compulsive disorder, you can use the following SQL script to modify the name of the primary key to the PK UU table […]

  • View MySQL execution plan


    1. MySQL syntax MySQL provides the explain syntax for query analysis. Add an “explain” before the SQL statement. By default, MySQL profiling is turned off, so you must first turn on profiling set profiling=”ON” mysql> show variables like “%profi%”; +————————+——-+ | Variable_name | Value | +————————+——-+ | profiling | ON | Show processlist; view the […]

  • Create asp.net mvc5 program step by step [repository + Autofac + automapper + sqlsugar] (XI)


    Preface Guys,Hello, I’m receptor.Recently, the receiver has been busy changing jobs, and there is not much time to update our asp.net MVC 5 series of articles [step by step to create asp.net mvc5 program repository + Autofac + automapper + sqlsugar], until now, I have just squeezed some time to update one, and my friends […]

  • How to set API parameters in Milvus best practice (3)


    In the above “how to set system configuration item (2)” of Milvus best practice, the key system configuration items of Milvus version 0.6.0 are described in detail. In this paper, the key parameters of the API of Milvus version 0.6.0 are described in detail, tested and verified, and suggestions on how to set them are […]

  • One of the ES series takes you to avoid the pit of date type


    Summary Time related fields are the most commonly used fields in elasticssearch (hereinafter referred to as ES). Almost all indexing application scenarios will have time fields, which are generally used in time range based search, aggregation and other scenarios. However, due to the problem of time zone, I believe that many small partners have stepped […]

  • SQL Server view query efficiency test


    I.Test backgroundDevelop a project, the database is SQL server. The data in the account table is one or two million, not big or small. In consideration of whether to use the view and worry about efficiency, Baidu has different opinions. Well, practice is the best proof, so let’s test it. 2、 Test environmentWin8 system, memory […]

  • Principle of cold and hot separation technology for decryption cloud HBase


    Preface HBase is a popular distributed database for mass data storage. Mass data storage often involves a cost problem, how to reduce the cost. The common solution is to manage data through cold and hot separation. Cold data can use higher compression ratio algorithm (zstd), lower replica coding algorithm, and cheaper storage device (HDD, high […]

  • First scene, first mirror


    With the last spring breeze blowing, the air filled with the taste of summer, it’s time to roll to learn.Recently, learning redis, I found a funny thing called the bloon filter. But my level is not enough to study the source code, so I write a simple play. principle Please forgive me for teaching. I […]

  • Kafka log segmentation and message searching


    Kafka is a message middleware (later Kafka gradually turns to kafkastream, a loss processing platform). The final storage of messages is in the log. Kafka’s message is finally sent with the partition under the topic as the final goal, so Kafka’s log storage is also based on the partition. Log.dir parameter in configuration fileThis parameter […]

  • Solr cache best practices for easy tuning


    Background Apache Solr is a widely used open-source search engine. Greenplum text, the full-text search component of Greenplum dB, is based on it: Greenplum text is abbreviated to gptext, which combines Greenplum database with Apache Solrcloud enterprise search and madlib analysis library are closely integrated to provide customers with large-scale analysis processing and business decision […]

  • Lua table


    Table is the only data structure in Lua and has powerful functions. Table type implements that associative array can be indexed not only by integer, but also by string or other types of values (except Nil). In addition, table has no fixed size, and any number of elements can be added to a table dynamically. […]