MySQL : Open-Source, Relational Database Management System

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What's the advantage of thread pool in MySQL/MariaDB?

MariaDB thread pool MySQL thread pool I've read official document of MySQL/MariaDB thread pool,but I'm still confused about it; As I understand, thread pool has two advantages: 1. limit too many ...
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3answers
44 views

getting MySQL error 1064 but very (absurdly) simple query in MySQLWorkbench

I'm getting a MySQL 1064 error for the simplest query when run with \G at the end. This works: select * from locations; and this doesn't: select * from locations\G hmmm... is there any way to ...
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1answer
93 views

MySQL open_files_limit - cannot change this variable

I'm running into issues because my open_files_limit for mysql is only 1024. Centos 7, MySQL Community Server 5.6.22-log It's actually a vps dedicated to mysql for a WHM server (remote mysql), but ...
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1answer
119 views

MySQL cluster error: “Got error 4009 'Cluster Failure' from NDB. Could not acquire global schema lock”

I am trying to configure MySQL cluster under three Windows 7 machines with disabled firewall, cluster information is like the following: 2 hosts with each running 1 data node 3rd host running ...
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1answer
33 views

Hierarcy Query Mysql

I have a table like this... ========================================================================== UID || PARENT ID || SPONSOR ID ...
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29 views

Using Netscaler datastream and MySQL

I configured MySQL service on a netscaler 10.5. When I perform some MySQL benchmarks using mysqlslap, the first time it runs correctly, the 2nd time I have an error message: When I run it the first ...
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1answer
31 views

Changing mysql root password on Windows after removing mysqld-nt.exe [closed]

I am trying to change password of MySQL root by following the steps here: http://dev.mysql.com/doc/refman/5.0/en/resetting-permissions.html unfortunately the mysqld-nt.exe doesn't exist in Windows ...
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1answer
26 views

Changing mysql root password on Windows after removing mysqld-nt.exe [duplicate]

I am trying to change password of MySQL root by following the steps here: http://dev.mysql.com/doc/refman/5.0/en/resetting-permissions.html unfortunately the mysqld-nt.exe doesn't exist in Windows ...
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creating table syntax error [closed]

I have a problem creating the table. It says unexpected parenthesis at line 3 CREATE DATABASE scl_teachers; USE scl_teachers; CREATE TABLE clteacher ( 'id' INT (10) PRIMARY KEY auto_increment, ...
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31 views

Get all the users that are managed by a targeted manager

I have the following model: Table user: (id, name, direct_manager_id) Table customer: (id, name, managed_by_id) i.e. users can have another user as their direct manager, Customers can be managed ...
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48 views

MySQL InnoDB Deadlock For 2 simple insert queries

I have a deadlock for this two insert queries: insert into PlayerClub (modifiedBy, timeCreated, currentClubId, endingLevelPosition, nextClubId, account_id) values (0, '2014-12-23 15:47:11.596', 180, ...
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45 views

#1025 - Error on rename of table errno: 150 : Table was deleted while tried to assign foreign key

When I tried to assign foreign key to a table named mydb.table1 it was deleted from my database, I could not understand the reason and tried to move on. For this tried to create same table with create ...
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1answer
60 views

Cannot start MySQL service on linux RHEL when pointing datadir to mounted ecryptfs folder

I moved the data directory for MySQL to an ecryptfs encrypted folder. When I run service mysqld start as root, the service will not start. [Warning] Can't create test file ...
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1answer
28 views

Differences between Authentication Types in MySQL Users and Privileges

I noticed that when I create a new account, that there are three different Authentication Typesavailable to choose from in MySQL Users and Privilegeswindow. What I am wondering is: What is the ...
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2answers
95 views

Is there a more efficient way to set up this table

I'm looking to add a new feature in our production site that will show users 25 items they most recently viewed. I already record every view into various tables based on the item type, but querying ...
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2answers
61 views

Minimizing database size (Many small tables)

Our database is interesting in that we have a large amount of tables that take up a correspondingly large amount of space, but when we do a MySQL dump of said database, it is surprisingly small. ...
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1answer
50 views

Pagination, check number of selected records

I am working on pagination for a complex join query and unfortunately I am not sure what's the best way to go... Right now I am thinking about the following solution. Imagine that SELECT id... is the ...
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1answer
40 views

Grant permissions on views, deny select on tables

I have a MySQL user and I want it to view ONLY the views I want and not any other table in the database. I've granted this user permissions only on certain views as following: GRANT SHOW VIEW ON ...
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1answer
43 views

Best way to create materialized view in mysql

I am using mysql 5.6, I am not being able to create materialized view here like oracle. I got one or two solution like flexview and all... Can anybody tell me best way to create materialized view in ...
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1answer
100 views

Converting Heap to MyISAM issue

At work we have a problem that has now occurred more then once. Problem is that query is in state of converting HEAP to MyISAM and it paralyzes our server( query in this state is not able to kill ...
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1answer
19 views

Mysql Master-Master Replication Error

Configured Master-Master Replication But both servers slave shows the below error !! Last_IO_Errno: 1236 Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: ...
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1answer
50 views

How to update a huge MySQL table from a text file

I have a huge MySQL table with 1.3 TB data with InnoDB engine format. Now I have a text file containing updated values of 2.2 GB of records in the 1.3 TB of data. How do I proceed ? I am a newbie ...
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19 views

JDBC4/SQL or Hibernate/ORM?

I have an upcoming thesis project that may be used by the school itself if the system proves to be good. It is a web application (Struts2) for an Online Teacher's Performance Evaluation System. The ...
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1answer
32 views

optimizing a select query of 1.5 million entry

I have the following query: SELECT s0_.id, s0_.lowresimageurl FROM app_instagram_shop_picture s0_ FORCE INDEX ( idx_deleted_shopId ) LEFT JOIN app_instagram_shop s1_ ON s0_.shop_id = s1_.id AND ( ...
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1answer
41 views

Inserting a lot of big numbers into a mysql database

The tutorials online about inserting images and other binary data into a database have you put it in a character buffer and use mysql_real_escape_string() on it. The thing is, characters are 1 byte. ...
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13 views

How can I update the amount on parentid

I'm using MySQL database,This is the first time that i handle this kind of project the Multi-Level Marketing.I am having problem in updating the amount of parentid if he gets paired means he has left ...
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15 views

Best mysql database structure for this data

I need to create a MySQL database that can store the following data for many users: General settings (for each user) 10 url's. 10 words of 20 letters for. ...and more fields like these. Sentences ...
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1answer
44 views

Sorting by two columns conditionally [closed]

Column a has category ids, column b has set orders: +-------------+-----------+ | category_id | set_order | +-------------+-----------+ | 80 | null | | 81 | null | | ...
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1answer
50 views

database design for simple comment

I have a following given scenario. A user can have zero or more item. A user can comment on the item. (Just simple comment listing with name of people who comment, no need hierarchical structure for ...
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2answers
24 views

SQL Query Help to get Quiz statistics

I'm coding a quiz web application and i need help. I've got three tables Nicknames : |USER_ID|NICKNAME| that stores USER_ID(auto increment) and NICKNAME registered to my system. Questions : ...
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1answer
42 views

MySQL column type to boost performance

I'll have a table where: userid (link to user's id in users table) foldername (a varchar, max. 260 char) entry (varchar, max. 1024) data (varchar, max. 20kb) Single user will have several ...
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16 views

Optimal Table Index for hourly data

I have a table that contains ~40,000,000 records and consisting of the following fields: idName - foreign key relationship to another table Date Hour Type (two possible types) Value Currently I ...
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1answer
57 views

MySQL dump - how to order tables?

It seems that mysqldump dumps tables in sequential order - using the same order tables are shown when running: show tables; I would like to reverse that order - is it possible to do without getting ...
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20 views

Insert data from a table and with parameters

I have 2 tables, one feeds data for 2 others but I must add external value too Is this query does the job ? MySqlCommand cmd1 = new MySqlCommand("INSERT INTO tableA (dt1, dt2) SELECT (dt1, dt2) FROM ...
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1answer
19 views

using foreign key as primary key

MySQL: If I have a user table and multiple other tables like seller, buyer etc, is it okay to use user_id foreign key as primary key inside tables like seller, buyer? That'll leave gaps in primary ...
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1answer
21 views

Why storing product fees in another table is preferred?

MySql: What is the benefit of storing several types of fees in another table like Product Table -> (productid...), ProductFee Table -> (productid, feetypeid, feeamount), ProductFeeType -> ...
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2answers
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When is it safe to disable InnoDB doublewrite buffering?

MySQL InnoDB allows us to disable doublewrite buffering by setting innodb_doublewrite = 0. Other databases doesn't seem to allow this setting to be tweaked. How could InnoDB still be able to maintain ...
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3answers
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Why do we use Group by 1 and Group by 1,2,3 in SQL query?

In SQL queries, we do use Group by clause to apply aggregate functions. But what is the purpose behind using numeric value instead of column name with Group by clause? For example: Group by 1.
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Advice on MYSQL DELETE on CASCADE, UPDATE on CASCADE features

I have 2 tables called copyrigihtinfo and sourceinfo and many to many to relationship table cp_src_junction with following data. copyrightinfo table cp_pk cp_info 1 copyright (c) 1991-2000, ...
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35 views

How can I make MySQL client read password from mylogin.cnf?

I'm trying to make the mysql client connect to a mysql server without requiring the password to be given interactively. Steps taken: 1) First create a mylogin.cnf file $ mysql_config_editor set ...
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24 views

Stored Procedure Issue in Simple Select Statement

Here is my Fiddle Here is My Table : CREATE TABLE IF NOT EXISTS `vehicle` ( `AutoID` int(11) NOT NULL AUTO_INCREMENT, `VehicleCode` varchar(20) NOT NULL, `NumberSeats` int(3) NOT NULL, ...
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1answer
24 views

Can we protect data form Database Administrator by encrypting the data?

How can we protect data on my database which is MySQL form database administrator stealing it? Will encrypting it prevent it from being stolen? If yes, how as he already has access to the database ...
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23 views

Large text column slows down whole table

I have a mysql database table table1 with a dozen columns in it. One column is a mediumtext column with lots of data in it and all the other columns are small (ints, timestamps, etc.). The presence ...
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In Forward Engineering I have an error called 'table does not exist'

This is my forward engineering code. -- MySQL Workbench Forward Engineering SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0; SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, ...
0
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1answer
47 views

odbc connection from windows machine to mysql server running on ubuntu?

I was able to install mysql server on an ubuntu machine and set up a test data base, created a user and granted that user access to the database. I also changed the binding address to the IP of the ...
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1answer
28 views

storing query results in a variable in mysql and using it in another query

I have a following query which runs perfectly fine: SELECT count(*) as total,l.state as state FROM db1.table1 cd inner join db2.table2 l ON ...
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Can MySQL Index Merge an Composite index with a single column index?

I am tuning a query and currently have an index as following : Index 1 : (col1, col2) An example query would be : SELECT * FROM t1 WHERE col1 = '1' AND col3 = '2'; I have created an index on ...
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1answer
13 views

Update Trigger in MYSQL

Here is my requirement :- I have a table called "users" and field called "Admin". Field "id" is primary key. Wants to update "Admin" field to "1" if id=1000; Tried this ,but not working.I tried ...
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How to store a 64-digit key of alpha numerical values into MySQL Database

I am student studying in Database Administration (first year), one of our task requires a to design a login form for corporate and regular users. Below are the requirements for the username and ...
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1answer
31 views

Processlist show most of the queries are sending data for select query

I have faced some problem like sending data state in processlist. In my application I used parallel processing which send 50 count at a time, and that will do some MySQL database operation (select and ...