MYSQL-- data modification

MYSQL data modification 1 add single column an ALTER TABLE list name ADD parameter name (such as age) content (e.g. 21); [at the bottom of all columns] b ALTER TABLE list name ADD parameter name to add (such as year)

2022-06-01 Database 我要分享

Sqoop Chinese Handbook

1. Overview this document mainly explains the use of SQOOP, and the reference is mainly from the official documentation of Cloudera SQOOP. In order to describe the meaning of the parameters more clearly in Chinese, almost all the instructions for the use of the parameters in this document have been verified by me.

2022-06-01 Database 我要分享

The COMPRESSION parameter compression ratio of Oracle 11g version EXPDP is comparable to that of "gzip-9".

This compression ratio is comparable to that of the operating system "gzip-9" and may be more efficient than gzip in some special cases. Experience it for reference. Description of the COMPRESSION parameter secooler in the expdp help page in 1.Oracle 11g

2022-06-02 Servers 我要分享

[EXPDP] the COMPRESSION parameter compression ratio of 11g version EXPDP is comparable to that of "gzip-9"

This compression ratio is comparable to that of the operating system "gzip-9" and may be more efficient than gzip in some special cases. Experience it for reference. Description of the COMPRESSION parameter secooler in the expdp help page in 1.Oracle 11g

2022-06-02 Servers 我要分享

The method of configuring Parameter tmp_table_size in MySQL

This article will explain in detail the method of configuring MySQL parameter tmp_table_size for you. The editor thinks it is very practical, so I share it for you as a reference. I hope you can get something after reading this article. MySQL configuration parameters [tmp_table

2022-06-01 Database 我要分享

Lower_case_table_names of the MySQL parameter

Lower_case_table_names parameter MySQL library table case. Default is 00. Database table is sensitive and case sensitive. The specified case saves the file 1. The library table is insensitive and not case sensitive. The file system is saved in lowercase 2 using create

2022-06-01 Database 我要分享

MySQL 5.7Database parameter optimization

Connection related parameter max_connections: the maximum number of concurrent connections allowed by the client. The default value is 151.This parameter is generally set to 300-1000max_connect_errors: if the client attempts to connect more than this number of errors

2022-06-01 Database 我要分享

Oracle11g installs example users

Environment operating system: RHEL 6.4 x86_64DB:oracle 11.2.0.3 is a test library. I forgot to install example when installing and building the library. Sometimes it is not easy to test without these users, for example, there are no scott users.

2022-06-01 Database 我要分享

The use of records_per_block parameter

1. BLOCK is the smallest storage and processing unit in the database, including the header information data or PL/SQL code of the block itself. The RECORDS_PER_BLOCK parameter is used to set the maximum number of records in each BLOCK, which is first found in all BLOCK of the current table.

2022-06-01 Database 我要分享

MySQL parameter adjustment method

This article mainly explains the "MySQL parameter adjustment method", the content of the article is simple and clear, easy to learn and understand, now please follow the editor's train of thought slowly in depth, together to study and learn "MySQL parameter adjustment method"! 1 MySQL parameter adjustment 1.1 tx

2022-05-31 Database 我要分享

Best practices for collecting statistics of Oracle 12c database optimizer (1)

Original text link http://www.oracle.com/technetwork/database/bi-datawarehousing/twp-bp-for-stats-gather-12c-19673

2022-06-01 Database 我要分享

DBMS_REDEFINITION for online redefinition of Oracle

11g detailed description of DBMS_REDEFINITION in official document: *

2022-06-01 Database 我要分享

SQL table-valued function

1. Multi-statement table-valued function-- =-- Author:-- Create date:-- De

2022-06-01 Database 我要分享

IMP-00009: abnormal termination of file export solution

Original text: introduction to https://www.enmotech.com/web/detail/1/788/1.html: this article comes from the contribution of the reader "cheer for Little Leopard (screen name)". It is mainly about the use of imp to import files to appear IMP-00009.

2022-06-01 Database 我要分享

Oracle table join operation-- under Hash Join (hash join)

Hash Join is a kind of connection method that often appears in the Oracle CBO era, and it often appears in the execution plan when dealing with massive data. The first part of this article (http://space.itpub.net/17203031/viewspace

2022-06-02 Servers 我要分享

Lookup from library data and parameter slave_rows_search_alg

In this section, we assume that the parameter binlog_row_image is set to 'FULL', which is the default value. First, starting from a column, before we start, we assume that the parameter 'slave_rows_search_algorithms' is the default, that is, TA.

2022-06-01 Database 我要分享

MySQL online DDL & quot;gh-ost"

Most of the changes to the DDL of the large table are pt-online-schema-change using Percona. This article explains the use of another tool, gh-ost: it does not rely on triggers because it simulates the slave library in row binlog.

2022-06-01 Database 我要分享

How to use DDL gh-ost in MySQL

This article is about how to use DDL gh-ost in MySQL. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look. Background: as a DBA, most of the changes to the DDL of a large table are using Per

2022-05-31 Database 我要分享

Detailed explanation of new configuration parameters for MySQL8.0

MySQL8.0 adds or improves data dictionaries, atomic DDL, security and accounts, resource management, InnoDB enhancements, character set support, JSON enhancements, field type support, optimizer, generic expressions, window functions, regular expression support, internal temporary tables, logs, backup locks

2022-06-01 Database 我要分享

[EXPDP] estimated size when backing up data using EXPDP-- ESTIMATE parameter

When using EXPDP to complete the data export, you can use the ESTIMATE parameter to evaluate the size of the database object to be exported, which is briefly demonstrated for reference. 1. View help information about ESTIMATE parameters 1) View command line help information ora10g@secDB

2022-06-02 Servers 我要分享