• Original | how do I solve the oom problem of POI parsing excel?


    background Before, I took over a project to parse excel, which was parsed by the POI component in Java, but oom often appeared during parsing. Later, I optimized it from the following aspects and solved 99% of the problems. Yes, you are right, only 99% of them are solved. Solution 1. Adjust the heap memory […]

  • Spark research


    Learning materials https://blog.csdn.net/rlnLo2pNEfx9c/article/details/78738084 http://dblab.xmu.edu.cn/blog/1264/ Database Laboratory of Xiamen University Miscellaneous problems Element: one behavior one element Example: flatmap (x = > (x to 5)) element row splitting can be used to split words Reduce() two operations isomorphism Fold () is the same as reduce, but has an initial value aggregate() : It first aggregates the […]

  • For translation Node.js Write memory efficient applications


    Software applications run in the main memory of a computer, which we call random access memory (RAM). JavaScript, especially nodejs (server side JS), allows us to write small to large software projects for end users. Processor memory is always a tricky issue because poor implementation can block all other applications running on a given server […]

  • How to view the memory of MAC device? How to quickly view apple notebook memory


    Many friends want to know how big the memory of their apple notebook is, and the view method is very simple. Here is a brief introduction: Quick view of apple notebook memory method 1. Click the apple Icon on the MAC menu bar 2. Click about this machine 3. Click more information 4. Click memory […]

  • C learning notes (6) — common body, deep bit field


    1. Union:   A common body is a special data type that allows you to store different data types in the same memory location. You can define a common body with multiple members, but only one member can have a value at any time. A common body provides an efficient way to use the same […]

  • lab1 part one


    lab1 Start process BIOS(saved on ROM) from theboot sectorRead upbootloader(under boot folder) program code to memory 0x7c00 to 0x7dff Bootloader program consists of two files: boot / boot. S and boot / main. C. boot / boot. S is to switch processor from real mode to real mode (the switched process can be readIa32-3a section […]

  • An advanced IOS interview question (runtime direction)


        When it comes to IOS, it’s either a small company with 3 people and no interview. Others, I think it’s better for you to show off 18 kinds of martial arts, such as swords, guns, sticks and clubs. Among them, if there is ioser in the enemy’s camp, there is a great probability […]

  • Conscience tool recommendation! Free online mind map, offline without advertising


    Technical editor: Zong en from sifou newoffice SegmentFault has he reported the official account number: SegmentFault Mindmaps may be a better choice. Mindmaps is a mind mapping application based on HTML 5. It can help you use simple mind map in browser. Using mind map through browser can not only save the storage space of […]

  • 200 IOS interview questions. There are all the questions needed by the bottom and technology companies


    A collection of interview questions from 100 well-known enterprises in IOS this year: You want everything here; There are also what enterprises want here; From the beginning of the foundation to the advanced level and to the bottom Sort out 188 interview questions. They’re all dry goods Catalog display: 1. The difference between swift and […]

  • Talk about the heap size setting of Flink jobmanager


    order This paper mainly studies the heap size setting of the flick job manager JobManagerOptions flink-core-1.7.1-sources.jar!/org/apache/flink/configuration/JobManagerOptions.java @PublicEvolving public class JobManagerOptions { //…… /** * JVM heap size for the JobManager with memory size. */ @Documentation.CommonOption(position = Documentation.CommonOption.POSITION_MEMORY) public static final ConfigOption<String> JOB_MANAGER_HEAP_MEMORY = key(“jobmanager.heap.size”) .defaultValue(“1024m”) .withDescription(“JVM heap size for the JobManager.”); /** * JVM heap […]

  • Comparison between Memcache and redis cache and why I choose redis


    Comparative conclusion 1. Performance: The performance is excellent. To be specific, because redis only uses a single core and memcached can use multiple cores, the average performance of redis on each core is higher than memcached when storing small data. Among the data above 100k, the performance of memcached is higher than that of redis. […]

  • Redis3.2 source code analysis – integer set intset


    Intset is one of the underlying implementations of redis set. When integer set is stored and the amount of data is small, redis will use intset as the underlying implementation of set. When the amount of data is large or the set element is a string, the set is implemented with dict.Intset stores the integer […]