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Use RMAN to restore the (lost or damaged) control file

Control File Recovery The loss of the control file divided into two situations, one is one of the control file is damaged or missed, the other is all the control files are missing. Based on the first case, only the good control file copy in case of damage or loss of the control file path. … Continue reading

Oracle Database Recovery – in summary

Oracle Database Recovery Determine whether you need to perform a recovery Access different interfaces (such as Enterprise Manager and the command line) Describe and use the available programs such as Recovery Manager (RMAN) and data recovery guide perform recovery for the following files: Control file Redo log files Data File Open Database To open an … Continue reading

Oracle Performance Analysis Section2: TKPROF Introduction

Oracle’s own tkprof is a command-line tool, the main role is to trace the original files into formatted text file, the easiest use is as follows: tkprof with many parameters, in most cases, the use of your analysis of these parameters would be helpful tkprof parameters Without any parameters tkprof, it will print out the … Continue reading

Oracle performance Analysis Section1: Open SQL trace file tracking and acquisition

When Oracle query efficiency problems arise, we often need to understand the problem, so as to give solutions for the problem. Oracle provides SQL execution trace information, which includes the text of the SQL statement, the implementation of some statistical information, the process of waiting, and an analysis phase (such as the execution plan) generated. … Continue reading

Clustered Index and Non-Clustered Index

As developers, we often use the clustering index and non-clustered index, if I ask most people the following two questions may have few satisfactory answers. What is the clustering index (clustered index) / What is non-clustering index (nonclustered index)? clustered index and non-clustered index What is the difference? In fact, the index can be understood … Continue reading

Oracle Database Index – Basic

Index is a relational database table for storing a record position of each object, the main purpose is to speed up the data read speed and data integrity checks. Indexing is a very demanding technical work. General database design phase must take into account how to design and create the index. Create an index The … Continue reading

T-SQL (1)

Using Variables Like C language, variables are divided into: Local variables: Local variables must be marked with @ as a prefix, such asage Use of local variables is the first statement, and then the assignment Global variables: Global variables must mark @@ as a prefix, such as @@version Global variables, we can only be read … Continue reading

Four advanced features SQL Server index

Index Building Filter (filter when the index is created) There are some very inefficient index, such as regular query the status of ongoing orders, order 99% of the state is complete, one percent is in progress, so we built an index on the order status field, performance is improved, but the feeling in the index … Continue reading

RAID-Detailed technical principles

RAID Description RAID is a Redundant Array of Inexpensive Disks. Simply put, RAID is a way to multiple independent hard disk (physical disk) combined in different ways to form a disk group (logical drives), thereby providing a single higher hard disk storage performance ratio and provide data backup technology. Disk array composed of different ways … Continue reading

Sybase ASE Knowledge summary Section1 – Sybase ASE Basics

A client / server architecture Sybase is built on a client / server architecture of the database management system. What is a client / server architecture? From a hardware perspective, the client / server architecture refers to a task between two or more machines are allocated where the client (Client) is used to provide a … Continue reading