Database Administrator

1. even if the autoReconnect = true parameter is added to the url when Mysql is created, communication will still occur if the connection time exceeds the wait_timeout time limit on the server side: the last packet successfully received from the

1. analysis table and index (analyze does not rebuild the index) Analyze table tablename compute statisticsEquivalent to analyze table tablename compute statistics for table for all indexes for all columns For table statistics exist in views:

Profile usually refers to the configuration file. crs_profile is the configuration file for managing the cluster. In systlele RAC, all CRS resources are stored on the OCR disk. OCR is more similar to Windows registry. We know that the Windows

Summary by year, statistics: Select sum (mymoney) as totalmoney, count (*) as sheets from mytable group by date_format (col, '% y '); Monthly summary, statistics: Select sum (mymoney) as totalmoney, count (*) as sheets from mytable group by

Today, to_char is used in the stored procedure to query the day of the week. I thought there was no problem, and I didn't want it. Select to_char (sysdate, 'day', 'nls _ DATE_LANGUAGE = AMERICAN ') day Into v_day From dual; Note: The returned values

In the Oracle RAC cluster, the management of various resources also has the owner and permission issues. Crs_getperm and crs_setperm are a pair of commands used to view and modify the owner, group, and permissions of resources in the cluster. The

The following is my first complicated MySQL stored procedure, which is hereby recorded: -- Delete a stored procedure Drop procedure if exists proc_update_term_group; -- Create a stored procedure DELIMITER // Create procedure

Record PCM lock information in GRD It is located in the SGA of each instance However, each instance only contains part of GRD, And the GRD of all instances is a complete GRD. PCM lock has three main attributes: Mode, Role, and PI. ① Mode -- S -- X --

The select statement in Oracle can use the start with... connect by prior clause to implement recursive queries. The connect by clause is used in structured queries. Its basic syntax is as follows: Select... from Where Start with Connect by ; :

1. view the current DB2 copy on the system: [Root @ localhost home] # db2ls   Install Path Level Fix Pack Special Install Number Install Date Installer UID Bytes ----------------------------------------------------------------------------------------

OCILIB is a cross-platform Oracle driver that provides fast and reliable access to Oracle databases. It provides a rich, fully functional, and easy-to-use API. OCILIB supports all running Oracle platforms. # Include "ocilib. h" Int main (int argc,

PhpMyAdmin 3.x must be php5.2 or above, and be prefixed with a Checksum. If you choose the wrong one, the problem will be difficult to solve. PhpMyAdmin is a MySQL management tool that manages MySQL directly from the web. 1: Upload

Recently, a telecom company has implemented a project to migrate the original Oracle database to the PPAS of EnterpriseDB. It is very busy to get back the dump file of oracle and write down the installation and migration process. First, list the

Problem: In Oracle, how does one combine two tables with different rows into one table? SQL: Select s. stagename sname, Sum (nworkhours) nworkhours, Sum (OVERHOURS) OVERHOURS, Sum (nworkhours + OVERHOURS) From T_WorkDetails w, T_stage s Where w.

On MySQL, the index Merge function is added, and two indexes can be used for one SQL statement. The following is an example: Mysql> select * from t; + ------ + | A | B | + ------ + | 1 | 24 | | 4 | 1 | | 1 | 20 | | 4 | 26 | | 5 | 10 | | 4

Memcached is a distributed memory object cache system, which is usually used for dynamic Web applications to reduce database load. Memcached is a hashmap based on a storage key pair. When the table is full, it is replaced by the LRU (least recently

1 Requirement Send the important database AWR to the DBA mail on a regular basis every day. After receiving the AWR mail, the DBA simply checks whether the database has abnormal waiting tasks and abnormal SQL statements, try to avoid analyzing

Delete the Oracle database first ~~ SQL> shutdown immediate; SQL> startup mount; SQL> alter system enable restricted session; SQL> drop database; Start manual Oracle database creation Vi. bash_profile Source. bash_profile (it is second in

You do not need to limit the expiration time of your account during development, so you need to make some settings. 1. Check the user's proifle, which is generally default: SELECT username, profile from dba_users; 2. view the password validity

I. Overview Prior to Oracle9i, DBA is responsible for collecting object statistics. By default, the database does not provide object statistics. At oracle10g, a job is created and scheduled to periodically collect object statistics when you create a