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1. Open Slow Query - View show variables like 'slow_query%'; show variables like 'long_query_time'; show variables like 'log_queries_not_using_indexes'; Temporarily open slow log - Open+Set uses root user, after closing the connection, re-query to see the modified value, only valid for the current service, configuration w ...

Preface In the work, the business requirements encounter MYSQL recursion, and most of the online data are copied back and forth, although the code can indeed run. But Mengxin really can't understand what this SQL writes. Looking at the comments below, many people didn't reply to their questions. He ...

1, Oracle 19c alarm log 2020-01-19 20:40:26.193000 +08:00 Warning: ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE has been deprecated. Warning: ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE has been deprecated. alter database recover managed standby database using current logfile disconnect from s ...

Get ready I use docker deployment on CentOS, so I need to prepare docker related operations in advance docker CentOS installation To configure mapping A host has multiple virtual machines, so it needs to use different named configuration folders, such as / etc/mysql/my.cnf.d/master01, to distingu ...

target Series 3 The basic AST traversal is done in. Before deep extraction of table name and column name in SQL, we need to solve the two remaining practical problems in Chapter 3, semicolon and case Semicolon problem The performance of the semicolon problem is the automatically generated HiveParser ...

Get mysql image ➜ ~ docker pull mysql ➜ ~ docker images REPOSITORY TAG IMAGE ID CREATED SIZE mysql latest d435eee2caa5 3 weeks ago 456MB mysql ...

1.JDBC introduction jdbc(java database connectivity) provides a unified programming interface for java developers to use the database. It consists of a set of java classes and interfaces. The classes and interfaces needed for JDBC are: DriverManager,Connection,Statement,ResultSet            2. Download MySQL connector Java The mysql version of ...

I wrote an article yesterday Why don't many people want to use hibernate? Blog, with the majority of ape friends to discuss the advantages and disadvantages of hibernate and the way to connect to the database, go home to study, found that Spring JdbcTemplate is very useful, made a summary, share to you. Disclaimer: This article is just a littl ...

The caching of mybatis refers to caching query results. When using the same sql statement and passing in the same parameters to query in the future, the query results can be obtained directly from the local caching of mybatis without querying the database. mybatis's cache includes the first level cache and the second level cache. The first leve ...

(1) Different products come from the same brand. This question requires that the sales of each brand should be calculated and aggregated WITH c as ( SELECT a.logday, b.brand_name, SUM(a.sale_amt) as sum_sales FROM a INNER JOIN b ON a.SKU_ID = b.SKU_ID WHERE a.logday BETWEEN '2017-01-01' AND '2017-12-31' AND ...