MySQL : Open-Source, Relational Database Management System

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Use Create Trigger to create New table using calculated values from common groupid column values

I have a TABLE_A in Database1 the contains rows with a common group id. I am wanting to use the CREATE TRIGGER function to generate a new TABLE_B in the same Database1 that contains calculated values ...
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1answer
1k views

MySQL Workbench Cannot start SSH tunnel manager

I don't know why this error is happening when I try to connect by MySQL Workbench. Cannot start SSH tunnel manager. I'm using slackware 14.1 and installed all dependencies. I already installed the ...
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1answer
150 views

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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1answer
19 views

Mysql slow query log always include “# Time:”

I am trying to parse the mysql slow log with logstash so it's important that the format is consistent. I have noticed that if statements execute at the same time, the line # Time: yymmdd is only ...
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1answer
92 views

Randomizing the Auto Increment in Mysql

We have a database, where we insert data into table whenever we receive an order from our services. We use auto_increment to generate the ID and assign the order with the same. This is usually same ...
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2answers
50 views

Schema review for system to advertise cars

Ok, so I am carrying out a rather simple task as part of a job requiretement. Here is the task in a nutshell: Design a form for creating ad for selling car Form has 2 have: 2 drop downs: Car make ...
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1answer
650 views

Proper procedure for migrating a MySQL database to another Debian machine?

I have one server running an older Debian version with MySQL 5.x and a newer Debian server, also running MySQL. I've created a backup of all databases on the first server like so: mysqldump -uuser ...
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11 views

creating deadlock for distributed database in mysql-(Testing purpose)

I need to create a deadlock for distributed database in MySQL for testing purpose with a simple sql query(without front end), can anyone good with MySQL query help me out in this with sample query. ...
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1answer
219 views

MySQL is using wrong index

This is my table: - user_id INT (foreign key on `user` with the reference `id`) - question_id INT (foreign key on `question` with the reference `id`) - option_id INT (foreign key on `option` with the ...
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3answers
450 views

Finding differences between a master and slave when pt-table-sync fails

I have a table that's showing some differences on a master and slave according to pt-table-checksum (PTC). I've found some verifying differences beyond that. Certain tables in the mix have composite ...
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2answers
4k views

How to force higher values of open_files_limit or table_open_cache?

I'm having a frustrating problem where setting my.cnf to values higher than I currently have them does not 'take'. This is MySQL 5.6.14 on MacOS X 10.8.3 I'm trying to address dropped connections ...
2
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1answer
600 views

How to normalize my db schema for a quiz application?

I am putting together a quiz application. (I'm calling each quiz a "challenge") I have a "challenge" table and a "challenge_question" table which is pretty straightforward. challenge table: id ...
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18 views

How to enable queries logs in MariaDB

I'm running mysql Ver 15.1 Distrib 5.5.42-MariaDB, for Linux (x86_64) using readline 5.1 in CentOS 6.6 server. I'm trying to get queries logging info and I'm doing by enabling log support at ...
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1answer
98 views

How to restore data after MySQL Upgrade?

I upgraded from MySQL 5.5 to 5.6 by uninstalling 5.5 and then installing MySQL 5.6. Now that MySQL 5.6 is running, none of my DBs or data is present/visible in MySQL Workbench. I also see that I ...
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96 views

custom product variant upload

I'm building a custom eCommerce solution for a client. I came up with this database design: +---------------+ +---------------+ | PRODUCTS |-----< SKUS | +---------------+ ...
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1answer
27 views

MySQL overhead of calling a Stored Procedure

Within Java, we access MySQL (v5.5.40) via JDBC -- a prepare statement, setting parameters then calling the stored procedure. It appears that every execute() has the overhead of 4 meta-calls (per ...
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1answer
748 views

Mysql Getting Access denied for user 'root'@'localhost' (using password: YES) constantly in log

I have MonYog running and it is monitoring my DB Server. It gives me constant alerts that the number of refused connections has exceeded the threshold etc. Looking in the LySQL.Log I can see constant ...
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1answer
69 views

Summing a column based on uniqueness of another column without using temporary table

I have a table like this: CREATE TABLE `files` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `name` varchar(255) NOT NULL, `hash` char(40) DEFAULT NULL, `size` bigint(20) unsigned DEFAULT '0', ...
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64 views

Selecting most recent date when dates are stored in another table

Working in a MySQL database, I have tables set up like this: Table song_instances has song_id (int), meeting_instance_id (int) The meeting_instances table has columns meeting_instance_id (int), ...
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1answer
278 views

How to repair all indexes in a MySQL database?

My database got corrupted, and now the php app is throwing this error: Invalid query: Can't find FULLTEXT index matching the column list The error is not very useful, since it doesn't say what ...
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2answers
5k views

How to sync two databases (alternative to mysql replication)?

Hello i have 2 mysql databases where most of the structure is constant except few tables (additions) in 2 dbs. I need to synchronize these 2 databases mainly common tables from one db to another. This ...
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1answer
244 views

MySql - is possible that performance issues are caused by dynamic SQL?

We have this MySQL SP, which uses dynamic SQL. It seems it does NOT perform well under load. It is possible that this SP becomes slow under load because it uses dynamic SQL? Can dynamic SQL cause ...
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1answer
73 views

Select only rows that equal x but not x and y?

I'm having quite the challenge with selecting hierarchical data in mysql although I feel the schema should be optimized for it since it's based on the wordpress database model. I've got 4 tables... ...
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1answer
1k views

MySQL : “FLUSH TABLES WITH READ LOCK” started automatically

I would like to understand how this happened. I was running a query that would take a long time, but should not lock up any table. However, my dbs were practically down - it seems like it was being ...
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2answers
1k views

Which one to use? InnoDB Replication or MySQL Cluster?

I am building a url shortener and I use InnoDB as the storage engine for link data. I will start with a single VPS containing both application instance and MySQL database instance on the same Virtual ...
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1answer
787 views

How to configure my.cnf for Mysql 5.1, which is using too much CPU?

I am new Database engineer. I am having trouble in my server which is using too much CPU on database query(simple count statement). I have googled about it, so i found out it depends on system ...
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1answer
30 views

Very weird Innodb Corruption Issue

I'll try to keep this to the point. System: OPenVZ VPS, debian 6, 512 MB RAM, 50 GB HDD (25GB free) I have a mysqldump dump file (3GB), that was created when the innodb database was working fine. ...
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5 views

MySQL log shows excessive meta queries on SP calls [duplicate]

We access MySQL via JDBC -- a prepare statement, parameters binding then invoking the actual stored procedure. It appears that every execute() has an associated "overhead" of 4 meta-calls (per MySQL ...
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10 views

how to design Multilevel and multiuser application database schema [closed]

I am developing an event management application with the user roles like super admin, admin and user. I want to design database in the way that only superadmin can login and create admins of ...
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2answers
14 views

Structure database(s) dealing with different time points

I have few data sets that give a score for a specific account at a specific point in time. So, account A might have a different score each quarter going back 5 years so. There aren't a ton of data ...
0
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1answer
200 views

How can i import 150GB database after deleting ibdata1,logfile in MYSQL?

I have 150GB database and my ibdata1 file size is 240GB so i want shrink the ibdata1 file so for that i have to export the DB and then drop the tables and then stop mysql, delete the ibdata1 file and ...
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3answers
1k views

Are there any tools to go from ERD to DB design and vice versa? [closed]

I'm learning DB design and looking for some tools, preferably open source software, that could help go from an ERD to a DATABASE and vice versa. For the record, the database i'm using is MySQL.
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9 views

Database Importing Collation

Migrating from DB2 found this error message: Error message: Incorrect string value: '\xF2\xAC\x9F\xB0or...' for column 'column_name' This is when trying to import an XML to MySQL. I should have a ...
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1answer
173 views

MySQL 5.6 replication causes 'waiting for table lock'

All of the sudden queries on slave server stopped with status "Waiting for table level lock" I restart mysql service and stop replications and locking does not show up anymore. Once I turn ...
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1answer
37 views

Is there a performance hit for querying two different databases?

I have two tables, A and B, which are located in different databases on the same MySQL server. I would like to create a derived table C from tables A and B, as an inner join between the two tables. ...
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11 views

Insert in PXC Cluster are not equally distributed

I have another query with regards to pxc cluster i have 4 nodes in pxc cluster all nodes have the same cnf file and one server as haproxy. Config File Detail [mysqld] datadir=/var/lib/mysql ...
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1answer
16 views

Mysql's internal mysql database in replication

I searched around but the word game seems to delude any valid result and could not find anything relevant. Mysql (the RDBMS) has an internal database named mysql, this database has information about ...
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2answers
17 views

How to deny connections to localhost and force to use FQDN instead

I have a server running Apache and MySQL. Connections to MySQL work fine when using localhost in the connection settings. Now I'd like to force our developers to use a FQDN instead of localhost. This ...
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1answer
29 views

Speed up procedure

I was wondering if this procedure can be executed faster. There are indexes on the joins and where's. Depeding on the size of product_id_CSV it takes approx. 2.5 sec. CREATE ...
2
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2answers
1k views

ERROR 1166 (42000) at line 65203: Incorrect column name ''

I have a big snapshot database size is about 44GB in mydata.sql. When I run it overnight, it show this error message: $ mysql -u root < mydata.sql ERROR 1166 (42000) at line 65203: Incorrect ...
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2answers
25 views

MySQL - SELECT on MyISAM Table on index - Does table size (rowcount) matter?

I was arguing with a coworker if SELECT * WHERE t BETWEEN ? AND ? on a MyIsam table where t is an index is significantly slower for huge tables. The hypothetically returned dataset is always the ...
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2answers
10 views

MariaDB/InnoDB: What to do on “Locks in Status-Log but no locked table found”

We migrated lately from MySQL to MariaDB. SELECT VERSION() 10.0.13-MariaDB-log When executing this: SHOW ENGINE INNODB STATUS I get (shortened): ... ---TRANSACTION 279257007, ACTIVE 23981 ...
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1answer
6 views

mysql dump import incredibly slow on my developer's machine

I have an SQL dump, it's pretty big (411 MB) and it took 10 minutes to import on server A, the same import on my workstation B has an estimate (pipeviewer) of 8 hours to import (it imported 31 MB in ...
0
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1answer
33 views

Storing small array of many possibilities

Let's say I need to store the text of a series of books, line per line in a database, and present them in a (CMS-based) website. I thought the correct setup would be: a 'library' table: containing ...
5
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2answers
723 views

Why are mysql password hashes internally saved with a star (asterisk)?

I was reading upon some mysql internals, when going through the mysql.user table in the my mysql shell, I get mysql> select * from mysql.user limit 1 \G *************************** 1. row ...
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168 views

Duplicate Relationships in Rails/MySQL Healthcare Application

Overview of the Application I am building a Ruby on Rails application to organize medications, using MySQL. The goal of this application is to provide dosage specific treatment recommendations, and ...
2
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1answer
2k views

Error Code: 1133. Can't find any matching row in the user table

Im reading O'Relly "Learning MySQL" and it says that you can create a user in MySQL by doing just this: mysql> GRANT ALL ON *.* TO 'jill'@'%.invyhome.com' IDENTIFIED BY 'the_password'; Query OK, 0 ...
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1answer
20 views

mysql prevent update other salve-master db while any record update in slave db

I have master and 3 slave (slave1,salve2,slave3) db in same host. So when I update any record in slave1 db its affected on all other master and salves db. My Question is: How to prevent update all ...
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1answer
530 views

MySQL server: Unable to connect with root because of skip-name-resolve option

We had our MySQL server on an old server. We decided to move all of the databases to our new server. Old MySQL Server engine 5.5.31 New MySQL Server engine 5.5.38 We created one general dump file ...
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1answer
12k views

How to transpose/convert rows as columns in mysql

I have table structures like below Subjects Table +----+------+------+--------+---------+ | id | C_Id | G_Id | status | subject | +----+------+------+--------+---------+ | 1 ...