Database Administrator

Various load file methods and time for MySQL and PostgreSQL are evaluated on virtual machines. Because it is the evaluation on the virtual machine, so the time is only for reference, don't be too real, just look at it.MySQL tool:1. built-in

In my opinion, since ORACLE has set Automatic scaling, it must have its own intention. How can we use it manually or automatically in the production environment? It mainly depends on the production environment.The first is to check the data volume

The relationships in relational databases must meet certain requirements, that is, they must meet different paradigms. Currently, relational databases have six paradigms: 1NF, 2NF, 3NF, 4NF, and 5NF) and the sixth paradigm (6NF ). The first paradigm

Example: update users set classes = '1' where id in ('u001', 'u002', 'u002', 'u002 '); update users set classes = '2' where id in ('u005 ', 'u006', 'u007 '); the users table content is as follows: + ------ + ----------- + ------------ + ------ + ----

After the oracle database is started normally, it can be accessed locally, but sqldevelop cannot be accessed remotely. The system prompts ORA 12505 Listener does not currently know of SID given in connection descriptor. Before this problem is solved,

MongoDB logs are growing rapidly, and the space of/var is immediately full. Even if you switch to another disk partition to save the logs, the logs are still growing rapidly, and the disk is about to be closed. There is a good way to use rotating

The problem is as follows: Assume that the information is stored in the mysql database. As shown in the following figure, the information heap of Table A is A million-level information heap (each piece of information is not long and generally 20

For multi-dimensional analysis, the rough and fast solution is to use ROLAP (Relational OLAP. Data is stored in MySQL after dimensional modeling. The ROLAP engine (such as the open-source Mondrian) is responsible for converting OLAP requests into

The CNT option makes the Oracle client attempt to use your current Windows domain credentials to authenticate you with the Oracle server. This cocould fail for a couple of reasons:-The Oracle server is not configured to support Windows

-- Create tablecreate table policycompany (ID VARCHAR2 (32) default SYS_GUID () not null, FLOWID VARCHAR2 (50), conpanyid number, ISCOMMUNICATION VARCHAR2 (10 )) tablespace USERS pctfree 10 initrans 1 maxtrans 255 storage (initial 64 K minextents 1

Password 420b http://yunpan.cn/QNXXpjP9aBy6v accessIf you want to use sqlplus in Unix or Linux environments, you can turn pages up and down like windows.What should we do?First, check that the OS is installed with the readline tool. Otherwise,

1. delimiterDelimiter is the mysql separator, and the default delimiter In the mysql client is semicolon (;). If many statements are input at a time and there is a semicolon in the middle of the statement, a special separator needs to be specified.2.

-- The trace file is read INTO the table for analysis. SELECT * into zgsjyfrom fn_trace_gettable ('e: \ wxxcdbprofiler. trc ', default); -- SQLselect TOP 100 SUBSTRING (Textdata, 1,660) as 'name', count (*) as 'number' in a certain period of time ',

Find the listener. ora file: My Oracle is installed on the F disk, Path: F: \ oracle \ product \ 10.2.0 \ db_1 \ network \ admin \ listener. ora: # Listener. ora Network Configuration File: F: \ oracle \ product \ 10.2.0 \ db_1 \ network \ admin \

Today is. At noon today, I received a question from a user in Tianjin about how to install gi, and a character set question asked by a user: sort it out here. Question 1: Gi installation problems: Problem description: When installing gi, the system

The most confusing order of composite indexes is the order of index columns, which depends not only on queries using this index, but also on sorting and grouping. Some time ago I posted a post: where condition order and compound index field order.

Test Table 1 DROP TABLE IF EXISTS test; CREATE TABLE test ( id bigint(11) unsigned NOT NULL AUTO_INCREMENT, name varchar(100) NOT NULL DEFAULT '', type varchar(100), create_time datetime,

Because the data capacity is smaller than 20 GB, using mysqldump for full-Database Export has little impact on the business. Therefore, this mode is used to build a slave database: PS: master-data = 1, record the Master_Log_File and Read_Master_Log_

Index rebuilding is a topic that is constantly under discussion. Of course, Oracle also has its own opinions. Many of our DBAs follow this rule to rebuild indexes, that is, we recommend that you re-create an index when the index depth exceeds 4 and

13. View the Exhibit that sets the threshold for the Current Open Cursors Count metric. Why is Significance Level threshold type not available in the threshold setting? A. because AWR baseline is not enabled B. because Current Open Cursors