Database Administrator

Latency index and paging Optimization for MySQL Optimization What is delayed indexing? Use the index to query the data, and then connect the query results to the data in the same table to improve the query speed! Paging is a common feature. select **

New Oracle 12C performance summary Basic RAC Maintenance 1) Check RAC status [Grid @ rac01 ~] $ Crsctl check crs CRS-4638: Oracle High Availability Services is online CRS-4537: Cluster Ready Services is online CRS-4529: Cluster Synchronization

Oracle user name and password Modification After the Oracle database is copied or cloned, you often need to modify the user name and password. The following describes the modification methods and steps: 1. query the table USER $ Select name, USER

Grouping statistics using MapReduce in MongoDB Grouping statistics using MapReduce in MongoDB Recently, when calculating the number of url deduplication for a certain period of time, an error is reported due to the large amount of data. The prompt

Oracle Database Advanced subquery Oracle Database Advanced subquery ① SubqueryA subquery is another SELECT statement nested in an SQL statement.Subquery (internal query) is executed before the master query is executed.Main query (external query)

Innobackupex full backup database For MySQL Database Hot backup, xtrabackup is the best choice except MySQL enterprise backup. This tool provides Hot Backup Based on the innodb Storage engine, supports full, Incremental backup, partial backup, point-

ORA-600 [13013] handling process Record one ORA-600 [13013] Process A ORA-600 [13013] error was found in the alert Log after a database exception was completed Thu Mar 08 23:29:37 2012 Errors infile/opt/Oracle/diag/rdbms/chf/trace/chf_smon_24137.trc

Deploy custom Observer Coprocessor in Hbase0.98.4 Hbase supports Coprocessor (Coprocessor) Since 0.92. It is designed to enable users to run their code on the regionserver, that is, to move the computing program to the location where the data is

PL/SQL flow control statements PL/SQL flow control statements This section describes PL/SQL flow control statements, including the following three types:Control statement: IF statementLOOP statement: LOOP statement and EXIT statementSequential

Oracle user and permission management Oracle permission Classification 1. system permissions: database operation permissions, including but not limited: CREATE TABLE CREATE VIEW CREATE SESSION CREATE SEQUENCE CREATE PROCEDURE ...... 2. object

Oracle 11g system automatically collects statistics Before the 11g period, when the table's data volume was modified to more than 10% of the total data volume, statistics will be automatically collected at night. How to Determine the 10% data volume

Oracle uses handles for non-Backup Recovery in specific scenarios In dba's work, backup is the foundation of all work. If there is no backup, it would be difficult to recover the data easily. If the business data requirements are high, resulting in

Simple Hibernate Access Database Demo, hibernate access data Recently I am studying SSH. Now I have seen Hibernate and implemented a simple Demo. I have a preliminary understanding of the functions and usage of Hibernate. 1. Copy the Hibernate jar

The instance cannot be started after the second node of rac _ restarts: dismount of the disk group, racdismount Original Works are from the blog of "Deep Blue blog". You are welcome to reprint them. Please note the following source when reprinting

Oracle Database lock Table query and unlock process, oracle au I unlockOracle Database lock Table query and unlock ProcessIn Oracle Database Operations, we sometimes use lock table queries and unlock and kill processes. How do we implement these

Basic SQLite operations, sqlite operationsSQLite basic operations: database creation, table creation, data insertion, data modification, data deletion, table deletion, and database deletion. 1. Enter sqlite3 test in the command line to create a

Talking about triggers and stored procedures, talking about triggers   When I first came to know SQL databases last year, I came into contact with two concepts. However, there is almost nothing to do with the role of these two siblings. I slowly

Use lvm-snapshot to back up the mysql database and lvm-snapshotmysql Prerequisites: Transaction logs and data files must be on the same volume; Before creating a snapshot volume, you must request the Global lock of MySQL. After the snapshot is

Deferred_segment_creation and deferred of the 11g Parameter Deferred_segment_creation Boolean The default value is true. This parameter is not found in 10gR2, and is available in 11g. It can also be seen from the literal meaning that when this

Database Operations-query (continued), database-Query1. Common query conditions:(1) Comparison =,>, =, (not equal to),!> (Not greater ),! (2) determine the range between and, not between and(3) determine the set in, not in(4) character matching