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  MySQL is blocked due to MDL read lock select

  Thread 1, begin; update table; no commit, no rollback operation thread2, create index on this table at this time client timeout interrupts connection again session query this table is blocked, unable to query thread3, query sele

  2022-06-01 06:36:24 Views: 270
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  MongoDB installation

  MongoDB can be installed using a binary package, or you can use rpm or yum to install yum: take installing MongoDB3.4 version as example 1, create MongoDB yum source vim / etc/yum.repos.d/mongo

  2022-06-01 06:36:24 Views: 217
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  Mysql multi-instance deployment

  1. Modify my.cnf [mysql] [mysqld_multi] mysqld = / usr/local/mysql/bin/mysqld_safe mysqladmin = / usr/local/my

  2022-06-01 06:36:23 Views: 253
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  Ten methods for finding the maximum value of grouping by mysql

  "How to solve the same problem in 10 different ways" .One of the common problems to solve in SQL is "

  2022-06-01 06:36:23 Views: 215
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  View mysql logs and log encoding issues

  This article solves the following problems: the directory of mysql log files, how to view binaries, and how to view binary garbled. [@ more@] 1. View the file mysql > show binary logs;+-+

  2022-06-01 06:36:22 Views: 228
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  Oracle 19c RAC on Linux 7.6 installation manual

  Directory Oracle 19c RAC on Linux installation manual. 2 instructions. 21 OS environment check. 32 turn off THP, open Hugepages 42.1 disable transparent large page:. 42

  2022-06-01 06:36:22 Views: 217
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  Giant sequoia database and Lenovo Xinchuang server complete compatible authentication

  Recently, the giant sequoia database and Lenovo completed technical compatibility and certification work. After rigorous testing by both sides, SequoiaDB Giant Sequoia database V3.4 and Lenovo Xinchuang server ThinkSystem SR358F V2 run stably, safe and reliable, and excellent performance.

  2022-06-01 06:36:21 Views: 256
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  SQL Optimization case-using with as to optimize Subquery Unnesting (7)

  The use of no_unnest hint allows the execution plan to generate filter, that is, no expansion, but in general, using unnest hint does not eliminate filter. SQL below to find out the non-unique index in the library, then you might write SQL:SE like this

  2022-06-01 06:36:06 Views: 262
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  Introduction of characters and bytes in Dameng Database

  Parameters introduction when initializing the database with DMINIT, we have the following two character set-related parameters, UNICODE_FLAG and LENGTH_IN_CHAR. UNICODE_FALG: this parameter represents the words of all the data in the database

  2022-06-01 06:35:57 Views: 276
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  Specify an ID to find the upper and lower range

  But not complex requirements: implementation idea: given an ID, such as 272944, if the ID in the table is greater than this value, the custom variable is incremented by one, if the ID in the table is less than this value, subtract the ID in the table, and if the ID in the table is equal to this value, it is 0SELECTa

  2022-06-01 06:35:53 Views: 211
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  Spool command about oracle

  Use the spool command to copy the results of the output in sql*plus to a specified file, or send the results of the query to the printer, directly using the spool off command. The syntax of the spool command is as follows: spool [file_na

  2022-06-01 06:35:47 Views: 264
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  Redis source code installation and start and stop

  Installation steps: $cd / opt $wget http://download.redis.io/releases/redis-3.2.8.tar.gz $tar xzf redis-3.2.8.tar

  2022-06-01 06:35:47 Views: 297
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  [AlwaysOn2017] DMV and DMF-Sys.availability_replicas of AlwaysOn

  7 、 Sys. Availability_replicas returns a row for each availability copy that belongs to any AlwaysOn availability group in the WSFC failover cluster. If the local server instance cannot contact the WSFC failover cluster, for example, due to

  2022-06-01 06:35:38 Views: 273
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  Using Connect By to construct sequence

  Select rownum from dual connect by rownum < = 12SELECT '2016 rownum' | | substr ('0' | | to_char (rownum),-2mem2) yym

  2022-06-01 06:35:38 Views: 236
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  Upgrade from oracle for windows 11.2.0.1 to 11.2.0.4

  Upgrading from oracle for windows 11.2.0.1 to 11.2.0.4 is simple, but there are still a lot of details to pay attention to, otherwise there may be unpredictable disasters. Oracle for windows 11.2.

  2022-06-01 06:35:38 Views: 300
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  Online redefinition? Convert a regular table to a partitioned table

  -- collect table statistics exec dbms_stats.gather_table_stats ('kcpt',' TH_VEHICLE_MEDIA', cascade = > true);-- create temporary partitions

  2022-06-01 06:35:37 Views: 218
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  ORA-00845: MEMORY_TARGET not supported on this system error resolution

  ORA-00845: MEMORY_TARGET not supported on this system error resolution was embarrassed when importing oracle data files today. Because the environment is in a virtual machine, and then I start the virtual

  2022-06-01 06:35:37 Views: 298
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  Oracle storage methods compete with each other

  First, the file system (the simplest way) allocates some space from local storage to provide storage for data. 1. How to use it: ① formats this area (this is the name of windows. In Linux and Unix systems, it is called creating a file system. ) ② to the disk

  2022-06-01 06:35:37 Views: 279
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  PostgreSQL DBA (5)-PG 11 New Features#2

  PG 11 is about to be officially released, and this section provides a brief introduction to some of the new features of PG 11, including enhancements to SQL statements. 1. SQL statement VACUUM/ANALYZE supports simultaneous operation of multiple Table VACUUMtestdb=# vacu

  2022-06-01 06:35:36 Views: 246
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  LVB Review | delivery of TDSQL

  Tencent Cloud Database domestic database online technology salon is in full swing. 0622 Bi Hanbin's sharing has ended. For those who have not had time to participate, don't worry. Here is the live video and text review. Follow the official account of "Tencent Cloud Database" and reply "0622 Bi Hanbin".

  2022-06-01 06:35:32 Views: 301