Tag:data file

  • Oracle create database and user, table space, manage table space and data file


    introduce A table space is a logical part of a database Physically: the database data is stored in the data file Logically, the database is stored in the table space A table space consists of one or more data files   Logical structure of database Introduction: Logical structure in Oracle includes table space, segment, zone, […]

  • Redis and Memcache


    1. The difference between redis and Memcache Redis supports complex data structures Redis supports native cluster mode Redis only uses a single core, while Memcache can use multiple cores. So on average, the efficiency of storing small data on each core is higher than that of Memcache. For data storage above 100k, Memcache is more […]

  • Installing Oracle database with docker under virtual machine (alicloud source)


    Environmental preparation Docker environment Install docker Create a new virtual machine without installing the docker environment. Execute the following command to install it:yum install docker -yyum updateUpgrade the machine to the latest version~Execute after installationdocker –versionTo see the docker installation versionDocker version 1.13.1, build cccb291/1.13.1 Start docker rootThe user executes the command:systemctl start docker.servicesystemctl enable […]

  • Introduction to Apache Hudi


    Introduction to Apache Hudi [TOC] Real time data processing and real time data processing Real time is divided into processing real-time and data real-timeAd hoc analysis requires real-time data processing, and the corresponding results should be obtained immediatelyFlink and spark streaming are used for real-time processing of real-time dataThe scene where the data is not […]

  • Deep dry goods | how to achieve rapid recovery of Oracle backup with cloud native?


    Introduction:DBS Oracle backup product is a cloud backup product developed by Alibaba cloud itself, combined with years of Oracle database production experience of Alibaba group. It not only provides the Oracle backup capability provided by traditional backup, but also realizes the intrusion free streaming backup capability. At the same time, it deeply combines with cloud […]

  • MySQL — 1 — general structure and execution process


    Introduction of MySQL structure Simplified version of MySQL structure diagram: MySQL logic architecture is divided into three layers 1. Client: not unique to MySQL, such as connection processing, authorization authentication, security and other functions are processed in this layer 2. Core services: including query parsing, analysis, optimization, caching, built-in functions (such as time, mathematics, encryption, […]

  • Oracle table space expansion


    1. Table space capacity index query SELECT TABLESPACE_ Name “table space,”, To_char(Round(BYTES / 1024, 2), ‘99990.00’) ||It’s true, To_char(Round(FREE / 1024, 2), ‘99990.00’) ||’g’ “existing,”, To_char(Round(( BYTES – FREE ) / 1024, 2), ‘99990.00’) ||’g’ “use”, To_char(Round(10000 * USED / BYTES) / 100, ‘99990.00’) ||’%’ “proportion” FROM (SELECT A.TABLESPACE_NAME TABLESPACE_NAME, Floor(A.BYTES / ( 1024 * […]

  • Hive: a data warehouse tool based on Hadoop


    Hive function Hive is a set of data warehouse analysis system based on Hadoop. It provides rich SQL query methods to analyze the data stored in Hadoop distributed file system: it can map the structured data file to a database table and provide complete SQL query function; it can convert the SQL statement into MapReduce […]

  • [20210225] recovery of full serial number of control file.txt


    [20210225] recovery of full serial number of control file.txt –//Continue yesterday’s test, today is mainly test recovery–//I want to add a little bit of difficulty to myself, that is, open it with noresetlogs, because the reconstructed control file needs to read redo, and the data file needs to be re opened–//Backfill some information. In fact, […]

  • [20210224] analysis of full serial number of control file.txt


    [20210224] analysis of full serial number of control file.txt –//I read the link in the morning: https://blog.csdn.net/enmotech/article/details/113855641 I have never met the situation that the serial number of the control file is full–//Nothing in the afternoon, to see if it can be demonstrated in the test environment repeated failure–//Pay attention not to do such a […]

  • Examples of using SQL queries on files


    Data files are often processed in data analysis business. We know that for the data in the database, using SQL to query is very convenient, so it is easy to think of importing the file data into the database first, and then using SQL to query. But the file data into the database itself is […]

  • Use redis data reveal (RDR) to view the memory space occupied by the key in redis


    The response speed of the project is relatively high, so redis cache is used for all the projects, which also leads to cache failure. It is necessary to analyze the memory usage of various keys for optimization. Although redisclient can easily operate redis, it can’t view the memory occupied by the corresponding key, and can’t […]