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Data type analysis of Redis source code - DICT The current Redis analysis version is 6.2, which should be noted. DICT, dictionary data structure, is essentially a hash table. Related documents mainly include dict.h and dict.c. Infrastructure dictEntry is a hash node and a key value pair, in which the value adopts the union v. it can be seen ...

Transfer case of JDBC control transaction Preface This exercise is from a black horse programmer class case 1. Title requirements Zhangngsan and lisi each have 1,000 yuan. Please transfer 500 yuan from zhangsan to lisiAnd try if you add an error code, will the transfer change? (The answer appears in the code as a comment) 🥑 Quick ...

preface As mentioned earlier, after practicing for a long time, I found that the official brought its own demo, followed by the official website again, and learned more operators. Then I'll see if I have time to practice some more Learning method: before running those topics with specific values, you can imagine the approximate values in ...

1, Introduction shardingsphere is a product of Apache, mainly including Sharding JDBC and Sharding Proxy. The former can be regarded as an enhanced version of JDBC, and the latter is an independent proxy system without coupling in the code. In this regard, it is very similar to Mycat 2, What did ShardingJDBC do for me? When using Shardi ...

catalogue Actions to be implemented:   mysql database image storage read_image or write_image mysql database image storage mysql_write mysql database image storage mysql_read   Completed code demonstration and results reflection Actions to be implemented:   Prepare a picture and read it.xxx,xxx， mysql_write_imagemysql ...

1. Function introduction Using Dameng database job management tool, you can complete fixed daily work such as regularly backing up the database and regularly generating data statistical reports. These repetitive tasks can be completed automatically, which is convenient for database administrators to improve work efficiency. DM's operating syst ...

1. Introduction to Mycat A completely open source large database cluster for enterprise application developmentSupport transaction, ACID and enhanced database that can replace MySQLAn enterprise database that can be regarded as a MySQL Cluster is used to replace the expensive Oracle clusterA new SQL Server integrating memory cache technology, ...

L2 cache principle 1. L2 cache 1.1 definitions L2 cache is also called application level cache. Different from L1 cache, its scope is the whole application and can be used across threads. Therefore, L2 cache has a higher hit rate and is suitable for caching some data with less modification. When it comes to L2 cache, let's briefly talk ...

Business scenario: balance shared by different business systems, hjmallind_user and ims_cjdc_user two tables have different balance fields, but share the balance value. Trigger definition: DROP TRIGGER IF EXISTS `test-up_ds_wallet`; CREATE  TRIGGER `test-up_ds_wallet` AFTER UPDATE ON `ims_cjdc_user`      FOR EACH ROW      BEGIN         DECLAR ...

1. Services 1.1 concept of transaction Transaction: a transaction consists of one or more SQL statements in a single unit, in which each MySQL statement is interdependent. The whole single cell is an inseparable whole. If an SQL statement in the cell fails or generates an error, the whole cell will be rolled back. All affected data will be re ...