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  The difference between SQL Association query Direct join and subquery

  My colleagues in the operation group recently put forward a request to count the users and orders of the system, so we naturally wrote a statistical SQL, user table user and itinerary direct join, and made a group for the itinerary, but the execution speed of SQL was surprisingly slow. E

  2022-06-01 10:29:41 Views: 278
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  Query statements commonly used in Oracle

  SELECT * from user_views where view_name='v$session';SELECT * FROM ALL_USERS where username like's%

  2022-06-01 10:29:40 Views: 226
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  Package installation of linux

  ! Command: execute linux commands under other systems: for example: #! pwd: view path under lftp command: (subcommand: single file download: get; directory download: mirror; multi-file download: mget; exit: bye) I. package composition: package composition: (

  2022-06-01 10:29:40 Views: 256
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  Three methods of current limiting by redis

  Today, the editor shares with you the three ways to achieve current limitation in redis. I believe many people don't know much about it. In order to make you understand better, I summarized the following contents for you. Let's look down together. I'm sure you'll get something. The first is the operation of Redis-based setnx.

  2022-06-01 10:29:40 Views: 267
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  Automatic backup of mysql database based on shell learning

  First log in to mysql:mysql-u root-p Note: it is not the password of the system root. After mysql is installed, the default root password is empty > set password for 'root'@'localhost' =

  2022-06-01 10:29:33 Views: 298
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  Redis Sentinel Cluster

  Redis's sentinel is often used to manage multiple Redis servers. It mainly performs the following three tasks: Monitoring: sentinel will constantly check your Master and S

  2022-06-01 10:29:33 Views: 232
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  Performance Optimization of Oracle Learning (2) Vernier

  Cursor is the Chinese translation of cursor, so what exactly is cursor? It is described in Oracle Concept as follows: When an application issues a SQL statement, the

  2022-06-01 10:29:30 Views: 227
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  Oracle query temporary tablespace usage

  Select h.tablespace_name tablespace_name,f.autoextensible,round (sum (nvl (p.bytes_used, 0)) / power (2

  2022-06-01 10:29:29 Views: 212
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  Mongodb migrates sharding, shuts down or removes the sharding of the table

  For MongoDB's Shard cluster, it's easy to add a shard, just AddShard. But reducing clusters (removing shards) is rarely used, but in some scenarios, the data on it must be automatically migrated to other Shard. Mongodb migration

  2022-06-01 10:29:25 Views: 232
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  Optimize mount file system parameters and IO scheduling settings

  Reference blog: https://blog.csdn.net/helloanthea/article/details/50464800 reference blog: http://wubx.net/21ways-optimize-

  2022-06-01 10:29:25 Views: 249
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  My process of getting data from a remote oracle view

  Three oracle objects are involved here, one is the customer's view, one is the oracle on the transfer station server provided by the customer, and the other is the oracle of our own development machine. Finally, we develop and use the oracle data of our own development machine for development, and the development is completed.

  2022-06-01 10:28:55 Views: 300
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  ORACLE RAC load balancing

  Oracle cluster database sometimes does not achieve automatic load balancing, and almost all business is on a certain node, so it is easy to cause downtime of a certain node. In view of this situation, we need to configure load balancer manually for a period of time. There are both server-side and client-side configurations for load balancing.

  2022-06-01 10:28:55 Views: 202
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  19 resize tablespaces in Oracletized Admins

  The storage settings of Oracle database can be divided into three levels: at the global scope, at the tablespace level, and at the segment level. With the growth of data, some table spaces may be running out, while others may be idle for a long time, which requires the size of the table space.

  2022-06-01 10:28:26 Views: 222
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  Mongodb series of tutorials

  Mongodb series tutorials ttlsa tutorials series mongodb- (1) mongodb introduction to ttlsa tutorials series mongodb-- (2) mongodb installation ttlsa tutorial series mongodb-- (3) mongod

  2022-06-01 10:28:25 Views: 249
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  Oracle unknown host specified solution

  Today, when we restore oracle 11G to oracle 10G, there is a version mismatch first. Use the workaround in http://hundage.blog.51cto.com/3779401/1285465 for this problem

  2022-06-01 10:28:25 Views: 227
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  Query the number of snapshots

  SELECT A. SNAPPhID Today Char (B.END_INTERVAL_TIME, 'mm-dd_hh34:mi') SNAP_TIME,SUM (DECODE (A.STAT_NAME,' lo)

  2022-06-01 10:28:25 Views: 241
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  Data queried by SQL is inserted into Excel version 2007

  INSERT INTO-insert OPENROWSET-open ('Microsoft.Ace.OleDb.12.0'-OLEDB driver

  2022-06-01 10:28:25 Views: 297
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  The third part of Oracle Hint Learning

  Hint related to the table join order: execution order emp-jobs-deptSQL > select / * + ordered * / e.enamedepartment j.jobpape.salre d.deptno from emp eJob

  2022-06-01 10:28:24 Views: 210
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  MySQL manages long-running queries

  The most commonly used query select concat ('kill', id,';') from information_schema.processlist where time > = 2-

  2022-06-01 10:28:13 Views: 225
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  Oracle 11.2.0.4 RAC installation database software does not recognize the host

  In the afternoon, colleagues sent to Wechat to say that when installing RAC of Oracle 11.2.0.4, GI has been installed normally. However, when installing the database software, the graphical interface does not show the hostnames of the two hosts, so there is no way to continue the installation. Because they are not together, so look at the corresponding articles from Baidu.

  2022-06-01 10:28:13 Views: 258