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Absrtact: paging query is required to turn the page of posts, and paging query is also required to search goods. When there are tens of millions or hundreds of millions of data, how can we quickly pull the full amount of data? This article is shared from Huawei cloud community< Paging query for large data volume performance optimization &g ...

13.MyBatis caching mechanism 1. Why cache? When users frequently query some fixed data, they query these data from the database for the first time and save them in the cache. When users query these data again, they do not need to query through the database, but query in the cache. Reduce the loss caused by network connection and database quer ...

Before that, we learned the global configuration file of mybatis. Now we begin to learn the mapping file of mybatis. In the mapping file, you can write the following top-level element labels: cache – Cache configuration for this namespace. cache-ref – Cache configuration that references other namespaces. resultMap – Describing how to load obje ...

For single process implementation @RequestMapping("/miaosha1") @ResponseBody public String miaosha1() { synchronized (this){ Map<String,Object> mapListmaps = new HashMap<>(); //Get inventory value in redis int kucun = Integer.valueOf(redisUtil.getStrKV("kucun").toString()) ...

JMM memory model 1. Computer structure Input device: our mouse and keyboard Memory: corresponding to our memory, cache The arithmetic unit and controller together constitute the cpu Output devices, such as display screens and printers. Let's focus on caching: 2. Cache In fact, when we say that computers are inefficient and slow, they ...

1. Install redis for Ubuntu / CentOS (redis5.0.8 does not need to update gcc) https://blog.csdn.net/qq_34246965/article/details/115269542 2. Start redis service and verify If it is in the bin directory under the redis file, the command: redis-server /etc/redis/redis.conf # start redis service If it is in the redis file /bin/redis-server /et ...

redis pipeline Beer theory, for example, there are 24 bottles of beer in the store. You can't take one bottle home and drink another. You need to find a box to carry the beer home together The buffer mechanism can also be understood in this way to avoid calling back and forth A request / response server can handle new requests even ...

1, Analysis of shopping cart data model in E-commerce Functions realized in shopping cart: add shopping cart, view shopping cart, edit shopping cart sku, edit commodity data, select multiple commodities in shopping cart to settle, view the total number of commodities in shopping cart, delete shopping cart, share shopping cart, etc Current sho ...

1, Redis installation download Redis 1. Decompress, compile and install # Decompress, compile and install (odc) [mca@clu01 software]$ tar -xvf redis-6.2.6.tar.gz (odc) [mca@clu01 software]$ cd redis-6.2.6/ (odc) [mca@clu01 redis-6.2.6]$ make (odc) [mca@clu01 redis-6.2.6]$ cd src (odc) [mca@clu01 src]$ sudo make install 2. Director ...

concept Keep alive yes Vue When it wraps dynamic components, it caches inactive component instances instead of destroying them. Similar to transition, keep alive is an abstract component: it does not render itself as a DOM element or appear in the parent component chain. effect In the process of component switching, the switched components a ...