Database Administrator

More about AWR AWR is a new feature of Oracle 10g version. Its full name is Automatic Workload Repository-Automatic load information library. AWR compares the statistics collected by snapshot twice, to generate report data. The generated report

Mondiran creates a connection and mondiran creates a connection.The url used to create a connection using jdbc is in the following format: jdbc: mysql: // hostname: port/database? Key1 = value1 & key2 = value2, which must start with "jabc: mysql" in

DRP problem series -- The Network Adapter cocould not establish the connection, drpestablish After the last problem is solved, another new problem occurs. There will always be too many disappointments in life. Let's take a look at the problem

Replication_Error: Relay log write failure: cocould not queue event from master, eventqueue Mysql Version: 5.6.16 OS Version: CentOS release 6.4 (Final) Replication: Master-Master Just now I suddenly found that the DB Master1 (currently read/

[Java] itoo project practices: optimized collection of millions of data queries and itoo data queries 1. To optimize the query, you should consider creating an index on the columns involved in where and order.   2. Try to avoid null value

Excel reads database tables and excel reads Databases The following code is used to read the table fields of a database using an Excel macro. Public Sub getdata () Dim cnn As New ADODB. connection, sh As Worksheet Dim rs As New ADODB. recordset Dim

Detailed description of pessimistic locks and optimistic locks in the database; Detailed description of the Database There are two types of locks in data: Pessimistic locks and optimistic locks, as well as table-level locks and row-level

PL/SQL Developer functions of various windows, pldeveloper Understanding the functions of each window is the primary condition for the correct use of PL/SQL Developer. The following briefly describes the functions of PL/SQL Developer

Mysql Master/Slave configuration for read/write splitting and mysql Master/Slave read/write splitting In order to solve a large number of concurrent accesses to large websites, distributed load balancing is far from enough. At the data service

Ora-01445: unable to select ROWID or sampling from the join view of a table without reserved keywords, ora-01445rowid When you query a view today, the query contains the rowid field, and an error is returned:     Two simple table tests:

Add, delete, modify, and query hibernate associated objects ------ query, hibernate ------ This blog post is the addition, deletion, modification, and query of hibernate-related objects in the previous blog. the settings of this Code have been

Convert multiple columns into one row, and convert multiple columns into one row. A friend asked me how to convert multiple columns into one row in Impala. In fact, the built-in functions in Impala can be implemented without using custom

MySQL (16) ----------- suggestions for massive data volumes, mysql ----------- The following are some important suggestions:1. Select the Correct storage engineTaking MySQL as an example, there are two storage engines MyISAM and InnoDB, each of

MYSQL import and export, mysql Import and Export Database Export all data in the entire database 1. Enter the following in the linux Command Line:? 1 mysqldump -u userName -p  dabaseName  > fileName.sql FileName. It is best to add

New Feature of oracle11g-Adaptive Cursor Sharing (ACS) and oracle11gadaptive 1. ACS Overview Oracle Database 11g provides the Adaptive Cursor Sharing (ACS) function to overcome the possibility of Sharing a Cursor that should not be shared in the

HBase learning Summary (2): HBase introduction and basic operations, hbase basic operations (HBase is a type of Database: Hadoop database, which is a NoSQL storage system designed to quickly read and write large-scale data at random. This document

[Hibernate] Hibernate multi-Table query and hibernate Table query In [Hibernate] Hibernate's difference in clustering query, grouping query, sorting, and time (click to open the link), we have already talked about how to replace SQL statements with

[Oracle error highlights]: PLSQL cannot directly connect 64-bit Oracle11g database, plsqloracle11g After the Oracle 11g Database is installed today, plsql cannot be used to connect to the database. The Database drop-down box in the plsql client

Win or win? Pig vs Hive !!!, Pighive From: http://www.aptibook.com/Articles/Pig-and-hive-advantages-disadvantages-features This article discusses the features of pig and hive. Developers usually choose a technical system that meets their business

When the database resource consumption is high, two SQL statements that are simple and useful to quickly identify possible causes of problems, resource consumption SQL 1. view the SQL statement being executed (1) SQL statement: Selectdistinct s. sid,