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Histogram, a special type of statistical information of columns, can provide more detailed data distribution information of columns in the table. Histogram stores values in buckets. Based on the number of different values and the distribution of data, the database selects the type of histogram to be created. The types of histogram are as follow ...

Production environment Oracle RAC cluster test best method (support Oracle 11g/12c/18c/19c RAC installation post test process) 1, Oracle RAC cluster test background A large and medium-sized manufacturing company has built a set of business system ERP system for new projects. The database environment of this system is Oracle RAC (RHEL Linux7+O ...

1 Build MySQL Server1.1 Question This case requires familiarity with the use of MySQL's official installation package to quickly build a database server: Install MySQL-server, MySQl-client packagesModify the password of the database user rootConfirm MySQL service program is running and root is controllable 1.2 Program This course will use the ...

1. Suggest users and groups su root　　#Switch to root groupadd oinstall　　#Create user group oinstall groupadd dba　　#Create user group dba useradd -g oinstall -g dba -m oracle　　#Create oracle users and join oinstall and dba user groups passwd oracle　　#Set the login password of the user oracle, do not set the password, unable to login i ...

RandomAccessFile class is a java provided access class for file content, which can read or write files. The RandomAccessFile class supports random access to files, that is, any location where files can be accessed. (1)java's file model The files on the hard disk are stored in byte, which is a collection of data (2) There are two modes to op ...

If the server is powered off and restarted or restarted within the plan, the database instance and monitoring need to be started manually after the server's operating system is started. This paper introduces how to configure the start and shutdown of Oracle database as a system service, and automatically start / shut down the Oracle instance a ...

Table of contents Preface Custom parameters Log output mode file network transmission data base Scientific use Reference documents   Preface A year ago, I wrote an introduction to NLog NLog log framework use inquiry-1 , this article briefly introduces the basic use of NLog and ho ...

New tablespaces and corresponding users in Oracle Database Create tablespace and temporary tablespace data files Create a tablespace data file SQL> CREATE TABLESPACE rec_news LOGGING DATAFILE '/home/oracle/OracleDB/user/rec_news/rec_news.dbf' SIZE 100M AUTOEXTEND ON NEXT 100M MAXSIZE 5120M EXTENT MANAGEMENT LOCAL; Ta ...

Problem phenomenon Business level The power of the computer room is cut off abnormally, and the access of the business system is slow after the database is restored. Database level Check the instance and find that only one instance is open and the other instance is not started. RAC cluster level View CR ...

synchronized + wait + notify is saved using an array. Arrays are run by empty producers, and then invoked by notify to wake consumers and wait for them. Consumers complete consumption, wake up producers and wait for themselves. ReentrantLock reenters the lock. ReentrantLock is still used at the bottom of BlockingQueue https://docs.orac ...