Database Administrator

Oracle 11g Active standby uard Log applications and database read-only queries in log uard are mutually exclusive. If logs need to be applied, the database can only use the recover managed standby database disconnect from session in the Mount state

Two Methods for patching Grid Infrastructure are described in detail. Patching is an important task for system administrators. Oracle Grid Infrastructure is currently a complex cluster management middleware. In the case of various strange problems,

Small files automatically merged and output based on Hive Optimization   1. First set the small file standard in the hive-site.xml.   hive. merge. smallfiles. avgsize 536870912 When the average output file size of a job is less than this number,

Oracle 11g result set cache restrictions There is a small table with a data volume larger than one million. This is similar to IP address range lookup. the number of queries to a table is large. the number is generated in real time, and sometimes

PostgreSQL source code customization: online global read only Based on a certain functional requirement on the cloud, a function similar to MySQL global read only has been recently implemented. PostgreSQL's read only function does not need to be

How to obtain the SELECT result value in a Shell script Sometimes we may need to execute the SELECT statement in the Shell script and assign the result to a variable. In this case, we can use the following methods to achieve the goal. #! /Bin/ksh##

"Fatal NI connect error 12170" error in Alert Log Regular inspection of Database alert log information is an important means of routine database maintenance, inspection and troubleshooting. Database Systems "Run with illness" and "Run with injury"

Programmer's path to quantitative transaction (17) -- Cointrader's Temporal entity (5); programmer's path to quantitative transaction Reprint need to note: http://blog.csdn.net/minimicall,http://cloudtrader.top/ This section describes a time entity

Difference between truncate and delete: truncatedelete Truncate table players; equivalent to delete from players; or delete players. * from players; 1. truncate is fast. If the rollback command is available, delete will be revoked, but truncate

Mysql function 2 Iv. Conditional judgment functions 1. if (expr, v1, v2): returns the result v1. Otherwise, select id, if (grade> = 60, 'pass', 'fail ') from t; 2. IFNULL (V1, V2) function: If v2 is empty, otherwise v1 is displayed, for example:

PL/SQL: Use pragma restrict_references to restrict package permissions and references When looking at other people's code, we found the following compilation instructions,Pragma restrict_references (get_attribute_name, wnds );   Get_attribute_name

SQL query beginner's Guide Reading Notes (5) collection operations and multi-Table query introduction, beginner's Guide Reading Notes Part iii: Thinking in SetsCHAPTER7 Thinking in Sets The three mostcommon set operations are as follows.

How to enable or disable the foreign key constraint in mysql.Method for starting and disabling foreign key constraints in mysql (FOREIGN_KEY_CHECKS) When a table or a piece of data is deleted in MySQL [Err] 1451-Cannot delete or update a parent

Detailed description of the latest Hive Data Operations (super detailed) and latest hive dataThe data operation capability of zookeeper is crucial to big data analysis. Data operations include exchange, moving, sorting, and transforming ). Hive

Problems with mac XAMPP mysql, xamppmysql After installing XAMPP on Mac, I encountered a series of problems. I sorted out the issues and updated them later. 1. MySQl cannot be started using the client. No reason is found yet. Solution: import the

RMAN and rman backup Original script, zombie Http://blog.csdn.net/ashic/article/details/46311573 -H: View help information [Oracle @ gc1 ~] $ Sh backup. sh-hThe following information teach you how to use this scriptBackup. sh -- fullBackup. sh --

The difference between Mysql and Oracle group by is that mysqloracle This article is original freas_1990, reprint please indicate the source: http://blog.csdn.net/freas_1990/article/details/46310145 In Oracle, grouping and aggregation must appear

SQL simple query, limited query and sorting, SQL query limited sorting Structured Query Language (structured Query Language) is a database Query and programming Language used to access data and Query, update, and manage relational database systems.

In SQL Server replication, large transactions are divided into small transactions for distribution. In SQL server replication, when a large transaction is executed in the published database, for example, 100,000 or more data is operated at a time.

When the database is updated, you will suffer. Do not do this during database update. What is this? Please come with me. Earlier in the year, the customer sent the text "XX, XXXXXXXX has a 0.1 million account not received, help add it ." I