MySQL : Open-Source, Relational Database Management System

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MySQL replication using a lot of IO

I'm having big troubles on a database pool I've setup recently. There is a master, and 4 slaves replicating one DB. All using MyISAM engine. Thing is, during the replication period (when the slave ...
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3 views

MySQL Referential Integrity Issue

I'm having a lot of issues and don't really know where to look. I'm pretty sure it's a referential integrity issue and has something to do with the addition of the Professor table and the Foreign Key ...
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225 views

Inserting empty string on Windows MySQL doesn't use default value

Why inserting '' on a column with default integer value on MYSQL/WINDOWS produces ERROR 1366 (HY000): Incorrect integer value: '' for column 'id' at row 1 The query is: insert into test2 (id,test) ...
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13 views

Problems with foreign keys in a mysql database

I am trying to link both these tables with a foreign key. But I keep getting error message "ERROR 1452: Cannot add or update a child row: a foreign key constraint fails " the foreign key is pwalk_id ...
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1answer
59 views

Installing MySQL in Solaris

I am trying to install MySQL 5.5 on Solaris 10. I executed the code useradd -r -g mysql mysql where a group called mysql is already created using groupadd command. I get the following error : UX: ...
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1answer
9 views

Replication of a remote MySQL database to local MySQL database

I'm the developer of my employers corporate private website, a HTML5/PHP/CSS powered site for company reports etc. The site, hosted on a shared hosting package, connects to a remote read-only MySQL DB ...
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1answer
17 views

Using MySQL Workbench, what is a good way to do development on an alternate server and copy changes to the main server?

This is a noobie question. I'm taking over a database project from someone who recently left the company and I'm looking for advice on how to do some development on a test platform before making ...
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3answers
88 views

Restore large MySQL dump thorugh EasyPHP

I am trying to upload large files on easyphp but as there is limitation on this software and large databases cannot be uploaded. Is there some other software that allows to import large databases? ...
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17 views

How to select complicated query in my sql

I use mysql under Linux. My table is about 8000000 rows. My database is SQL. The table has index(advertiser_id,activity_date),(activity_date,advertiser_id,activity_type). The table is looks as ...
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2answers
44 views

Query to Access a specfic data in the row using python

Am using wordpress and phpmyadmin for handling my database Below is the code I use to view entries on my form using python. In the form I ask users to check/uncheck specific questions. It works as ...
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1answer
45 views

Different column for different conditions when joining

I am using MySQL database and in that two tables, relation is one to many. One table is product table, sample data: +----+----------+ | id | name | +----+----------+ | 1 | product1 | | 2 | ...
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4answers
821 views

How can I replicate some tables without transferring the entire log?

I have a mysql database that contains some tables with private information, and some tables with public information. I would like to replicate only the tables containing public information from one ...
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1answer
47 views

Inconsistent MySQL query execution times

We run tests on two servers: one in production [Old Server] and the other one in tests [New Server]. Both tests used the same database. [New Server] Dedicated MySQL 5.6.17 server on Ubuntu 14.04 ...
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19 views

MySQL Optimisation

I am running mySQL 5.6.16 on a server running Centos with 20Gb RAM ad 1TB disc space. when running SELECT scripts wiht order and group by statements and a number of joins, the results can be very slow ...
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1answer
20 views

Intermittent connection errors

I am experiencing occasional connection errors from my webserver to one of my databases. The code attempts to connect. If it fails, it sleeps for 1 second, then retries, then (if it still fails) ...
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1answer
63 views

Need help optimizing query to prevent full table scans

I have the following query, which while it works, is also doing a full scan on each left joined table (the log* tables). I thought by using a subquery in the FROM that this would eliminate the ...
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14 views

How to make changes to MySQL database settings

I'm a real DBA newbie and have learnt everything in the last day, so need basic guidance on how to implement the recommendations from MySQLTuner (which i eventually managed to do!) >> ...
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3answers
8k views

Why can't this mysql user log in with password?

In phpmyadmin I created a user called "edward" with password and all privileges: Yet when I try to log in via phpmyadmin, it says "Cannot log in to the MySQL Server". When I try to log in on the ...
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2answers
92 views

Find the user with closest taste of mine

I trying to write in SQL the following requirement: Each user can rate as much films as they like. (1= I don't like, 5=I love it) And the system should provide to the current user a list of films ...
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1answer
37 views

Options to include with mysqldump when taking backup of hybrid databases

I'm planning on taking backups of all MySQL databases on a remote production server. The combined database size is around 2 GB. Most of the tables are InnoDB ~1.8 GB and the rest are MyISAM. Now I've ...
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1answer
160 views

Is this amount of disk IO expected with MySQL?

I am running MySQL 5.5.34 on an Amazon EC2 micro instance with EBS (elastic block storage). The instance has been running for around 10 days and according to Amazon I've accumulated around 8.5 ...
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1answer
23 views

Determining Homogeneity by Common Foreign Keys

I manage a MySQL database of ten or so tables. In higher code, I have a list of primary keys belonging to entries of some table A. These A entries have foreign keys to entries in another table B. The ...
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1answer
243 views

Partition by year and sub-partition by month mysql

I have a database with a date column having datatype as date. I am using mysql 5.6 The table is expected to have 10k rows each day. I want to create partition on the table on year range and then sub ...
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1answer
67 views

How to convert database mysql4 to mysql5

I have mysql dump file named booster.dump. It was export from 4.0.27-standard mysql server. Now I want to convert this database to mysql 5.1.73-cll. How can I do it. I search about this topic in ...
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1answer
151 views

MySQL max_connection value

Questions I got a 12 GB machine with apache & myqsl, i have may apache max_client set to 150 will this cause some bottlenecks with the 50 max_connection in mysql? What value should I set mysql ...
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1answer
23 views

mysql server cannot launch in windows 7

I have been using MySQL as a windows service successfully on my windows 7 machine for perhaps a year. It has always worked fine. Here are the steps which I think caused it to no longer launch: ...
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20 views

Conceptual model vs Logical model vs Physical model

I'm doing a work about database, and now I need to show three different images, one image with the conceptual model, other with logical model and other with physical model of a database. I'm looking ...
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1answer
28 views

WHERE attribute having two relation lines in the same SQL

I have a database designed with tree tables: checklist (id, name) tag (id, name) checklist_tag (checklist_id - FK, tag_id - FK) Running this SQL: SELECT cc.id as checklist_id, cc.name as ...
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1answer
6 views

pt-online-schema-change MySQL Error: This version of MySQL doesn't yet support 'multiple triggers with the same action time and event for one table'

I've attempted to alter table using pt-online-schema-change in our master-master replication environment (Percona used as a cluster). It seems, that an operation completed successfully, but inspecting ...
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2answers
171 views

database structure - complicated requirements

I have a project to build a website but it's complicated and I'm having trouble figuring out what the best way to build the database would be to handle these particular requirements. The site is for ...
0
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1answer
62 views

Need to get the first 15 rows from 200k rows of data fast [on hold]

I have 3 tables with a lot of data (each one has 100k rows). I used UNION to get data from that. It takes more than 5 seconds as wait time in server to load the first page. I need only 15 rows from ...
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0answers
1k views

mysql 5.6 GTID replication 'Got fatal error 1236 from master when reading data from binary log'

I Checked SHOW SLAVE STATUS error is "'Got fatal error 1236 from master when reading data from binary log: ''The slave is connecting using CHANGE MASTER TO MASTER_AUTO_POSITION = 1, but the master ...
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2answers
51 views

Database Design Help: MySql/PostgreSQL Single Database/Multiple Databases

We are planning to build a web based custom business analytics tool using PHP and MySQL/PostgreSQL. In our application, we are planning to upload customer’s data using a Excel sheet and these data ...
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1answer
22 views

In MySQL how do I grant a user access to a read replica only?

I have some users that I want to grant read only access to my database so I setup a replica server, but I don't want to grant them access to the master. I'd assume that this is a common use case, but ...
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1answer
14 views

Problem with MySQL Cluster in practice

I am researching MySQL cluster. For the purpose, I do a demo with 4 virtual machines. I have some problems in practice. Topology My topology contains four nodes Node 1: management node, ip address ...
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2answers
59 views

What is the best way to upgrade a MySQL version in a Linux Server

What is the best way to upgrade a MySQL version in a Linux Server I have database around 14 GB running with 8 -15 GB ram(diffrent deployments) .At present MySQL version is 5.5 and I’m planning to ...
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2answers
96 views

How to reduce mysql memory used

I'm using MySQL 5.1 and want to upgrade to latest version 5.6.17 (from Windows Installer) But when I installed, it used too much memory, about 420Mb although 5.1 vesion run only 8Mb memory. The setup ...
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1answer
212 views

Two different MYSQl instances on same machine?

I have MySQL 5.6 installed (Linux). /var/lib/mysql /etc/my.cnf I have a cold backup that I am recovering: /var/lib/mysql_backup /etc/mybackup.cnf In April I was able to get the backup started ...
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2answers
3k views

Why would SELECT * be magnitudes faster than SELECT foo?

Consider a table of values and hashes, like so: +------------+----------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | ...
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2answers
89 views

If an account has REQUIRE SUBJECT, does it still need a password?

I'm in the process of setting up SSL-secured replication between two servers. Each server has its own public/private keypair, and the CA cert is just the concatenation of the two public certs, like ...
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4answers
68 views

Index on 'GROUP BY' with functions

I have a log table. It logs visitor data (time of visit, browser, window size ...). I want to create reports. I use a query like this (MySQL): SELECT COUNT(*) as raw_views ... FROM logs WHERE ...
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1answer
64 views

re-enabling a table for mysql replication

We were able to setup mysql master-slave replication with the following version on both master/slave: mysqld Ver 5.5.28-29.1-log for Linux on x86_64 (Percona Server (GPL), Release 29.1) One day, ...
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1answer
172 views

ib_logfile0 and ib_logfile1 got deleted

After restoring from a percona-xtrabackup without a preparation step, ib_logfile0 and ib_logfile1 were not present in the restore data. Therefor during startup the following message is observed: ...
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1answer
34 views

Transfer all read request to Slave in Master-Slave MySQL

I have configured master slave on my system (MYSQL). Now, is there is any script or way available or possible to transfer all read request to SLAVE. So, let me make my question here more clear. I ...
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3answers
2k views

How long will a temporary MEMORY table persist if I don't drop it (MySQL)

I'm using a recursive stored procedure in MySQL to generate a temporary table called id_list, but I must use the results of that procedure in a follow up select query, so I can't DROP the temporary ...
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1answer
25 views

MySQL Syntax Error When Creating a Trigger

I am trying to create a trigger but I am getting a syntax error and I am not really sure why I am. CREATE TRIGGER Section_Insert AFTER INSERT ON Section -> FOR EACH ROW BEGIN -> INSERT ...
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2answers
65 views

mysqldump --single-transaction, yet update queries are waiting for the backup

If I use mysqldump --single-transaction, according to the docs it should do flush tables with read lock to get a consistent state and then start a transaction and no writers should be waiting. ...
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1answer
153 views

Restrict access to rows by usename

In my database i store data of different users (e.g. addresses or invoices) in the corresponding tables. I want to make sure that a logged in user only has access to it's own data in the tables (so ...
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1answer
46 views

Enforcing minimum cardinality in One To many design?

If we have the following One to Many database design. Team +------+-----------+ | t_id | team_name | +------+-----------+ | 100 | germany | +------+-----------+ FootballPlayers ...
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1answer
34 views

Why does adding a column to a MySQL table take incredibly long?

I am using MySQL version 5.6 and I have a database that is in total around 110 GB in size. One of the tables, "outputs" is 49 GB in size. I tried to add a simple BOOL column to the outputs table with ...