MySQL : Open-Source, Relational Database Management System

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For two triggers(before insert and after insert),is it allowed for you to use where in the NEW keyword

I have two triggers.One after insert trigger and the other before insert trigger.The two triggers are using the NEW keyword to get the last inserted message. Both triggers are watching a table called ...
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1answer
26 views

Multiple User Types - DB Design Advice

I'm developing a web application that will support user authentication with corresponding roles for each user. Also, my users can be of different types and have different fields associated with them. ...
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21 views

Is it possible to enforce a Unique Constraint on a Dataset comprised of joins

I am playing around with an idea to describe friendships in a system, and I am wondering about constraints. I currently have a database that looks like this: Users: ...
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40 views

How to generate a sequence in mysql

Consider this table in mysql create table numbers (number int); insert into numbers values (3), (2), (9); select * from numbers; +--------+ | number | +--------+ | 3 | | 2 | | 9 | ...
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21 views

Replicate/Sync Production database with Development database (no Master/Slave)

I currently use ClearDB MySQL DaaS for my production database, and a local MySQL database on my dev server for development. I need to have the production database replicated/copied/synced to the dev ...
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27 views

Packet and N-SubPacket Msql query ( same as catgeory and N sub catgeory )

First of i am PHP Developer , and working on huge project alone .i think i have made many mistake in creating table. and below is one of those. I am making packet type system when in my Packet Table ...
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2answers
41 views

Top 10 in MySQL

Following a load test of my website I am trying to find the slowest performing web objects of my application. I have a field called 'path' with the applications object path along with a field called ...
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1answer
20 views

How can I move a MySQL database from 5.1 to 5.6?

I have pretty big database, like with 5 000 000 rows in total. It is located in a remote server. I want to copy this database to my personal computer, for testing purposes. However I don't know the ...
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23 views

mysql combine tables

I have three tables which has the same schema. all of them has 10000000+ rows and has unique data as well as duplicate keys but with a datetime column can differentiate them and get the newest row. I ...
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13 views

mysql update a table from another table - performance

I have two mysql tables, table_A = 2500000+ (rows) table_B = 6000000+ (rows) I need to update rows in table_A from data in table_B (using a multithreaded application) What is the fastest way ...
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13 views

Query from database a set of infomation and sorting them out while mataining its structure

I am currently using mysql 5.5.32. Below is my database design. It is used for storing student infomation, however each student have 61 "entries" or more(some schools might have more options), eg. ...
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137 views

MySQL does not start - Ubuntu 14.04 LTS after migration to new disk

I have installed in a Virtualbox VM a 64-bit desktop version of Ubuntu 14.04 LTS and MySQL Server 5.6. I had some databases in the machine's main virtual hard disk but then I was going to open a SQL ...
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36 views

MySQL GRANT requiring additional permissions

I have a MySQL user (rundeck) that is being used as part of a deployment process. Its purpose is to create a new database, create a new user, and grant permissions to the new user for the new ...
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13 views

Running MySQL Test Suite against an external server requires blank root password

Running MySQL Test Suite 5.5 on Ubuntu 14.04 against an external MySQL on port 3307. Several tests (main.connect, innodb.innodb-semi-consistent, sys_vars.autocommit_func to name a few) seem to require ...
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1answer
95 views

MySQL slave taking too long on “Queueing master event to the relay log”

I have two mysql mysql slave servers. The DB version is: mysql> show variables like '%version%'; +-------------------------+-----------------------------------------------------+ | Variable_name ...
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1answer
36 views

MySql Condition not working in trigger

I am developing a social networking website, where I have 3 tables - 1st for users(userid- pk,auto increment,username,etc.), 2nd for Album(albumid - auto increment,userid - of person who owns the ...
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1answer
32 views

can i use percona to do the mapreduce job?

i am wondering that percona might can do mapreduce job like mongo, it has a handlersocket implementation isnt it? is it can do a mapreduce job? actually what i want to do is the i have to process ...
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1answer
23 views

Access denied to user ODBC, but trying to login as root

I'm trying to do a backup of a MySQL database on Windows, but for some reason it's trying to log me in as ODBC instead of root - does anyone know why? As you can see below the red line, I can login ...
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1answer
42 views

How can I optimize this Cross Table COUNT() mysql query?

I am trying to cut down the retrieval speed of this MySQL query. All instances of COUNT() point to the PRIMARY key of each field. Currently this query makes my MySQL hang. It seems ridiculous as I'm ...
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13 views

See indices implicitly created for foreign key constaints in MySQL

When I add a foreign key constraint to my table, SHOW INDEX doesn't show any new indices, but the overall space used by the indices in that table increases. Apparently, the index for the field I put a ...
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1answer
29 views

MySQL my.cnf: innodb_log_file_size is missing

How to set innodb_log_file_size to MySQL database if there is no innodb_log_file_size in my.cnf configuration file? I'd like to backup via Percona Xtrabackup and the backup crashes at this point ...
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14 views

Usermanagement and a database pr user

Is there any easy way to manage users? Let's say, I need another user called user2. This user needs a database called user2 aswell - With only privileges to THIS database. It's easy to do, just by ...
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45 views

mysql join not working as expected

i want to select schedule of specific teacher for a given day .... statement should assume that a teacher may teach in elementary and high school here is my statement `select class.name as ...
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50 views

How to upload 1.5GB sql file on mysql?

Whenever I tried to import file in MySql on my Linux Mint system, "You probably tried to upload a file that is too large. Please refer to documentation for a workaround for this limit." this message ...
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19 views

innodb_buffer_pool & innodb_buffer_pool_instances

I have a database dedicated server with one quad-core cpu and 48GB Memory. Total database size is about 6GB and my ultimate goal is to get the maximum performance out of this system. At First, to ...
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16 views

MySQL Query logic for filters for wordpress site

I'm a WordPress (PHP) developer, however I have not done a lot of complex MySQL queries. I am working on an events website and want to create filters: User should be able to filter events by the ...
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70 views

Complicated data

I have a requirement i got from my father. He gave me a table and wanted me to digitalis it. So that he can the system can do all the dirty jobs for him ( that's why there are developers in the world, ...
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25 views

Is it safe to delete the innodb schema on a new Amazon RDS instance?

As per the title, I'm struggling to find out if it's safe to delete the innodb schema that's created on a fresh Amazon RDS instance. mysql> SHOW DATABASES; +--------------------+ | Database ...
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74 views

Almost identical queries but large time difference in execution

Exhibit A SELECT SUM(value) FROM Credits RIGHT JOIN calendar ON datefield = DATE(FROM_UNIXTIME(created_at)) WHERE confirm = 1 && reason = 1 && country = 'it' && created_at ...
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30 views

Mysql server stops responding quickly after +- 200 connections

We have a mysql instance, 5.5.28. Its working as intended, it has during normal operations perhaps around 200 to 300 connections on it. These connections are usually "idle" waiting for something to ...
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59 views

Select all rows with multiple conditions in another table

Here is my simplified database scheme -- ----------------------------------------------------- -- Table `products` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS ...
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1answer
28 views

Creating a FIFO List in MySQL

I work in Transportation/Freight and we have these things called "PRO" numbers or freight bill numbers, which you can think about as and Invoice and Tracking number for a shipment. Our carriers send ...
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33 views

mysql-udf-http http_get function Linux

I want to insert into MYSQL UDF function "http_get". Currently I have a "mysql-udf-http.so" file that I import the function in the program, but to run it I get the error message: ERROR 2013 (HY000): ...
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22 views

MySQL replication - independent data update on slave

I have an unusual situation where I am migrating websites and their corresponding databases from one server to another. I have a database that is hosted on one server, A, where new records are ...
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1answer
37 views

Can I replicate slaves without a dump?

I have setup a new slave in a set and I just want to allow it to naturally cach up to the master and start using the binary log once it has caught up. However, I cannot seem to find anything on this, ...
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45 views

Configuration to stop mysql sleep

I am trying to configure a mariadb / mysql instance to stop sleeping when there is no activity for a while. The reason being is that I keep getting the following exception in my java logs when nobody ...
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42 views

Performance difference between two MariaDB slaves

I have a pool of MariaDB servers like this : master (5.5.38-MariaDB-log) slave1 (5.5.38-MariaDB-log) slave2 (5.5.38-MariaDB-log) The two slaves servers run on the exact same hardware (Dell ...
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2answers
394 views

Is Data Warehousing possible in MySQL and PostgresSQL [closed]

I am fairly new to DB design and development. My requirement is simple drilldown/slicing based on time and language of words (in a language on a particular day). However, my db is mysql. But so far I ...
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1answer
35 views

How can I transfer Mysql data to another computer and add it to an exist database

I'm trying to transfer Mysql data to another computer and add it to an exist database Here is the condition: 1. Computer A, A has a database named 'Test'; 2. Computer B, B has a database named ...
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1answer
15 views

How much memory will allocated for a mysql view

How much memory will allocated for a mysql view,if not how it works,if allocated how much will be allocated.
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MySQL: Is there any possible way to get notified about mysql-server FOREIGN KEY CONSTRAINT violation during INSERT, if FOREIGN_KEY_CHECKS=0 ?

Plese don't bite me, i'm a newbie here ... So here is the question: Is there any possible way to get notified about mysql-server FOREIGN KEY CONSTRAINT violation during INSERT, if ...
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21 views

Mysql performance tunning [closed]

I have 2 VM : one x.x.x.22 "16G RAM" and "Intel(R) Xeon(R) CPU E5620 @ 2.40GHz 8Core " and one x.x.x.21 "8G RAM" and "Intel(R) Xeon(R) CPU E5620 @ 2.40GHz 8core" Now , app is installed ...
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38 views

what is the difference between mysql community server and mysql cluster

I am starting to look into different database's for different use cases. I see there is a mysql community server and mysql cluster. What is the difference between the two? Are they both database ...
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51 views

is this dead simple query too slow?

I have added and removed a few indexes from my user table and, while testing, didn't see the performance gains I had hoped. As a result, I removed the indexes and tried a simple query to see what my ...
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3answers
59 views

Query to compare the structure of two tables in MySQL

To automate the backup process of one of my MySQL databases, I would like to compare the structure of two tables (current version vs old version). Can you think of a query that can compare two ...
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23 views

(libmysql): (filename not available): mysql_query

Hi everybody im running a game server connected to mysql and it crashes only because of mysql connection with the error in title.. when i dont use mysql and save data as files on harddrive it dont ...
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(libmysql): (filename not available): mysql_query [duplicate]

Hi everybody im running a game server connected to mysql and it crashes only because of mysql connection when i dont use mysql and save data as files on harddrive it dont crash at all but i cant ...
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13 views

MySql full text query with truncate sign strange behaviour

I'm implementing a search mechanism on a customer site. I need to find products with "full-text" matching description. However, I noticed a strange behavior. Taking for example two records: (A) ...
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1answer
273 views

Is there any performance difference in using a unique index on primary key?

I know there are lost of similar questions to this one, but none that really answers this: Is there ANY difference in performance in using an unique index in a primary key, using a MyISAM table on a ...
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2answers
49 views

How do you update a large MySQL table that's on a server?

I have an application on a web server. The PHP front end for the application queries a MySQL database which has a table that contains 60 million taken domain names. My application queries this ...