SQL Server Performance Tuning 2-Index creation

Preface Indexes are one of the most important objects in relational databases. They can significantly reduce disk I/O and logical read consumption and improve the query performance of SELECT statements. However, it is a double-edged sword. Improper

In-depth understanding of Java and MySQL garbled characters

Recently, we used tomcat and MySQL to build a Java Web server and deploy the game server logic on it.   Shortly after the game was launched, we found a large number of garbled characters in the database. This is a very serious problem and must be

11gDG switchover: incorrect, ORA-00274 illegal recovery option SEESION

The following error occurs during DG switching:   ORA-00274: illegal recovery option SEESION   Problem description: When I run the switch statement on the master database and then switch the slave database to the master database, this problem occurs:

Simple REDO file corruption error ORA-00333 REDO log read Block Error

I. fault description First, the REDO file required for instance recovery is damaged. Ii. Solution 1. Use the following CLEAR command for non-current REDO or current REDO but no active transactions: Use the CLEAR command to recreate the log file SQL>

Common configuration methods of c3p0

1: The first method is very simple. c3p0.driverClass=com.mysql.jdbc.Driverc3p0.jdbcUrl=jdbc:mysql://localhost:3308/databasec3p0.user=rootc3p0.password=root File Name: c3p0. properties (put under the src directory) // The program I wrote is

Oracle experience (1)

Install: Oracle installation has many tutorials on the Internet, which are explained in detail. I will not go into details here. I only provide two links, which may be helpful: Oracle Installation and simple configuration. free installation of

Simply record a ORA-00600: internal error code, arguments: [4194]

Next, after the resolution of SCN problem, encountered ORA-600 [4194]/[4193] error.Fault symptom: An error is reported when you OPEN the database:ORA-00600: internal error code, arguments: [4194], [], [], [], [], [], [], [] 4193: indicates

How to delete an oracle 11g cluster node in a linux and UNIX environment step by step

 Ing a Cluster Node on Linux and UNIX Systems 1. Check whether the node to be deleted is active or pinned.$ Olsnodes-s-t If pinned, crsctl unpin css-n unpinned corresponding node 2. Disable the application resources and processes of the

How to Set mysql tables to be case insensitive

By default, MySQL installation on Linux is case sensitive to database tables. The modification is simple. You only need to modify the mysql configuration file. Mysql> show tables;+ -------------------------------------- +| Tables_in_cddl |+ ---------

Test the DG Environment

Test the DG Environment Environment Name Master Database Slave Database Host Name Bjsrv Shsrv Software Version RedHat performanise5.5, Oracle 11g 11.2.0.1 RedHat performanise5.5, Oracle 11g 11.2.0.1

Simple record once ORA-00600 kcratr_nab_less_than_odr

The current detailed error message is no longer displayed. Only the corresponding figure is displayed. Refer to the data in an EYGLE article:1. Fault symptom The database version is 11 GB. The error is similar to the following: ORA-00600: Internal

First understanding of UML

Uml-Unified Modeling Language, called the Unified Modeling Language, is a visual Modeling Language used to design software blueprints. It supports the analysis, design, implementation and delivery of object-oriented systems, and supports system

Experience Summary 16--EF local data update

EF provides the function of updating some data of an object while retaining other data. 1. Re-instance an object and give the ID and fields to be modified. Note: The entity here cannot be queried from the database, but can only be a new instance.

EBS-add and Update price lists

 Add and Update price list lines-- Purpose: to add row information based on the existing price list Header-- Restriction: this api has some problems. If the header information is forcibly added, there will be many problems. Therefore, this example

Simply record a ORA-00600: internal error code, arguments: [2662]

Next, REDO error after the OPEN Database and the error ORA-00600: internal error code, arguments: [2662]. The reason is _ allow_resetlogs_uption after resetlogs open the database, we may encounter ORA-00600 2662 error due to inconsistent SCN, here

Sum over usage, and difference with group

1. sum over usage Sum (col1) over (partition by col2 order by col3) The above function can be understood as: grouping by col2 (partition), sorting by col3 (order), and continuous addition (sum) Table a has the following content:B C D02 02 102 03 202

How to Avoid N + 1 Problems in Rails

N + 1 Problems N + 1 is the most common performance problem in database access. First, let's introduce what N + 1 is: For example, there are two tables in our database: MERs and Orders. Orders contains a foreign key mermer_id pointing to the

Single-row conversion functions of ORACLE Functions

Required bytes 1 ASCIISTR Format:ASCIISTR (C) Note:Converts a string C to an ASCII string, meaning that the ASCII characters in C remain unchanged, but non-ASCII characters are returned in ASCII format. Example: SQL> select asciistr ('AB? CDE

MongoDB study Note 1: download and install MongoDB

MongoDB study Note 1: download and install MongoDB Taking advantage of these few days, I am ready to learn about the MongoDB database. Today I have simply learned how to download and install MongoDB and created a data warehouse that stores MongoDB.

& Quot; crsctl check crs & quot; command hangs at EVMD check

Zookeeper Pre-11gR2: "crsctl check crs" command hangs at EVMD check (Document ID 1578875.1)Applies:Oracle Database-Enterprise Edition-Version 10.2.0.3 to 11.1.0.7 [Release 10.2 to 11.1]Information in this document applies to any platform.SYMPTOMSIn

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