MySQL : Open-Source, Relational Database Management System

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MySQL InnoDB 5.6.23 cannot start segmentation fault 11

I have a Linux Gentoo server which has OwnCloud application installed. It works for about 2 months with out any problems, and sudden this morning MySQL died. I have tried to restart mysql server and ...
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20 views

Counting per status group makes query very slow

I have an Intranet system developed that takes in orders and every order item has their own status, i.e. "Printed", "Labelled", "Filed", etc. This query will need to count how many items there are in ...
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2answers
138 views

MySQL - prevent OS cache for query

On high load production server I have many sql selects which are unique or re-use will be in hours. I use SQL_NO_CACHE but this queries are still cached with OS cache. Server have 64G ram and used ram ...
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2answers
2k views

Mysql Server Login and Permission Deny Error

I have a problem with MySQL server. After upgrading MySQL server from 5.3 to 5.4, I am not able to log-in using my MySQL root password (Yes, I am able to log-in without password!). Also not able to ...
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1answer
18 views

Are certain environment variables required for mysql login-path?

I created a bash script that backs up my database, db_backup.sh It basically just runs these commands: DB=/home/linuxuser/backups/backupfilename.sql.gz mysqldump --login-path=local db_name | gzip ...
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1answer
26 views

Migrate MySQL 3.23 Data

I have .FRM, .MYD and .MYI files from a MySQL (version 3.23 I think) database from back in the early 2000's. I managed to get the files into a Windows installation of 3.23 and then dump it, however I ...
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2answers
22 views

insert multiple depend on prev queries

I need to insert multiple records into a table. The number of records depend on the result of another query. For example:I want to insert booking detail depend on number of room customer choose. If ...
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1answer
38 views

Difference beetween mysql 5.5 and 5.6

I have a big performance problem beetwen my local mysql instance and the server. I have this request : DELETE a FROM a LEFT OUTER JOIN ( SELECT MAX(id) as id, `v_id`, `v_statut`, `c_controle`, ...
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30 views

MySQL: check max chracter length (ERROR 1118 (42000): Row size too large)

I'm trying to convert/copy MyISAM to InnoDB table and I'm getting the following error message: mysql> INSERT INTO test.innodb_table SELECT * FROM test.myisam_table ERROR 1118 (42000): Row size ...
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1answer
17 views

Mysql: binary log vs transaction log

In mysql with innodb, there are two types of logs: binary log and transaction log. I know transaction log is specific to innodb. But when comes to replication, backup and crash recover, what roles ...
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20 views

Optimization for aggregation and grouping with MySQL

I have an application that is pulling data on a daily basis from numerous APIs, storing it and then presenting it on the front end in various charts, tables, etc.. I'm having some issues avoiding ...
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1answer
439 views

Mysql closing immediately after new installation

I am using mysql as an backend for my webapp ,the software ran without any glitch but today it gave unexpectedly ERROR:2003 i tried many solution on the internet but none worked. so reinstalled the ...
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23 views

Avoid order by clause [on hold]

After migrating some code from Informix to MySQL, we saw that: On Informix when you issue a SELECT UNIQUE query, the result set that it returns its always sorted. However, on MySQL if you issue a ...
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1answer
45 views

Lock in mysql database

My schema 'test' has 3 tables: 'user', 'post' and 'revision'. CREATE TABLE IF NOT EXISTS `test`.`user` ( `iduser` INT UNSIGNED NOT NULL AUTO_INCREMENT, `name` VARCHAR(45) NOT NULL, PRIMARY KEY ...
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1answer
23 views

MySQL stored procedure user privilege

I have a query regarding user permission on a stored procedure. If a user that does not have permissions to create tables in a database, but it does have permissions to create and execute stored ...
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10 views

MySQL: Hierarchical query to get the direct and indirect child

I am just trying to modify the code as in MySQL: Tree-Hierarchical query to get values inside single quotes and seems like the system hangs. Not sure where I am going wrong.. Here is the code. BEGIN ...
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1answer
11 views

merge multiple fields of csv file while running mysqlimport command

I have a mysql table like this +----------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | ...
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1answer
25 views

Query calculating AVG per minute GROUP BY timestamp

I'm trying to query the average for each minute, so I can generate graph per 5, 15, 30 minutes. Here is my table, date stored in MySQL DateTime data type field. timestamp vif_2_rx ...
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phpmyadmin csv ms excel export with results different than phpmyadmin [on hold]

I'm trying to export a CSV file but the file is different than the results shown in phpMyAdmin interface. I think that it could be a phpmyadmin bug.
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1answer
19 views

Mysql: How does circular replication avoid infinite looping of a transaction

In case of circular replication A -> B -> C -> A. How come a transaction started on A will be ignored from being replicated from C to A at the end of one complete cycle ? I believe parent server-id ...
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1answer
40 views

Uber-wide tables: Time to switch to Mongo?

As a web developer, I've typically only worked with nice, normalized tables in SQL-based RDBMS, but I'm doing some data consolidation for a researcher who will be analyzing correlations between all ...
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1answer
16 views

Not all MySQL processes are killed when restarting

We have a MySQL 5.6 server running on Ubuntu 12.04 using the MySQL 5.6 PPA. The service comes up fine when rebooting the box, but whenever we restart the MySQL process via /etc/init.d/mysql restart, ...
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4answers
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MySQL Data directory move (WAMP)

I removed the old WAMPServer 2.0 and it left my old MySQL data directory and my.ini intact. I installed the new WAMPServer 2.2 and need to make my old databases active with the new WAMPServer MySQL. ...
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2answers
3k views

How to convert mysql database charset to utf-8

I have a vb forum with a huge amount of data I need a way to convert this forum database tables charset with thier data from latin1_swedish_ci to utf8-general-ci How to do this ?
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2answers
25 views

MySQL Error when importing CSV with empty fields

I have CSV file with exported table, that has rows with fields that do not contain values. Columns are separated using "," and if fields have no values they look like that: ,,,,,, I tried to load data ...
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611 views

How to allow remote connections to mysql from specific IPs only?

I have a fresh install of mysql server 5.2.6 on a 64 bit Ubuntu running on a remote server with static IP. Is there anyway to allow Mysql remote connections to be made from pre-approved IPs only? I ...
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1answer
6k views

how to fetch different data on compare rows of two tables

I have two tables in my database, one is user_app table in which user info are stored, table are as: +--------------+--------------+------+-----+-------------------+-----------------------------+ | ...
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1answer
224 views

Adding foreign keys constraint on databases used

We have a server with about 20 databases, all duplicates of the same original db, and we just noticed the original is missing all the foreign keys constraint for some unknown reason. So of course all ...
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7 views

MySQL ODBC Mirror/Failover

I am wondering if it is possible with the Windows MySQL ODBC driver to mirror the data writing on a local (Access) database or, at least, to write on the local database if the writing on the remote ...
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0answers
31 views

What happens when a mysql connection gets lost?

I hope this is a question for the dba board. Otherwise blame me and i'll switch to unix. imagine the following situation: you have a Mysql server S and two clients A and B. Both clients connect to S ...
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12 views

Foreign keys in MySQL Workbench

I am defining an EER model in MySQL Workbench. I have a library with multiple copies of each book and each book has its location in the library listed in the system. When I'm creating one-to-many ...
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1answer
40 views

Elegant Database Design

I'm trying to make "online Judge Environment"(like SPOJ). In which users have facility to see their past submissions for each question, their best code performance(like running time, if they succeed ...
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22 views

Exclude entries from SELECT COUNT

I'm new to MySQL and I have a problem with one task. I have a table like this: +------------+------------+-------------+ | code | name | location | ...
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12 views

Normalization and multivalued attributes

I am designing a relational database in mySQL - a library management system. I want to show examples of the data in 1NF, 2NF, 3NF, BCNF, etc. My example of 1NF looks something like this 'A relation ...
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1answer
14 views

Data normalization (from 0NF to 1NF)

I am designing a relational database in mySQL - a library management system. I want to show examples of the data in 1NF, 2NF, 3NF, BCNF, etc. My example of 1NF looks something like this "A relation ...
0
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1answer
154 views

insert row if table is empty, else update row (mysql)

i have 2 tables "table1" and "table2" both have TIMESTAMP cols for starttime and endtime. i want something like if (table2 is empty) insert into table2 (table2.starttime, table2.endtime) value ...
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problems with database replication mysql_config_editor

I would like to share with you the problem I have been having for almost a week. I am trying to create a replication between 2 servers. One is in hostgator and the other is a virual machine in Azure. ...
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9answers
64k views

What are the main differences between InnoDB and MyISAM?

What are the main differences between InnoDB and MyISAM?
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1answer
182 views

MySQL Entity Relationship Problem - 3-way join table?

This is a db relationship question. I have a scenario which I believe I have come up with a solution - however, I can't be sure it's a manageable one, or even correct. The scenario is as follows: ...
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2answers
293 views

Can anyone offer an opinion on handlersocket vs memcached performance in MySQL 5.6

I must say I was a little mis(un)-informed about the MySQL Memcached plugin which offers the same NoSQL like access to InnoDB tables as HandlerSocket, I had only had experience with entirely ...
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14 views

Mysql 5.0 and 5.6 INSERT_LAST_ID() difference

Migrating from MySQL 5.0 to 5.6 i noticed that the INSERT_LAST_ID() function behaves different when using inside a trigger. My simplified situation: Table A has the trigger: insert into table_B ...
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1answer
1k views

Improve MySQL Query Performance - Too many records

I am using MySQL RDMS for a contact management system. Now a days my database grew in size and contains more than 1 million records. Checking duplicate phone numbers became a big issue during ...
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Is there any option to import specific databases from all databases dump

Is there any option to import only required databases from a all database back up .
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3answers
75 views

get all dates in the current month

i have a query in MySQL which serves me very well by getting all the records within the current month; SELECT date_field,val FROM MY_TABLE WHERE date_field>=(CURDATE()-INTERVAL 1 MONTH); The ...
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2answers
208 views

Creating a MySQL db from an Informix database

There is an existing database that was created in Informix. I would like to export it and then import it into MySQL. I tried to export it using dbschema and it created the dbase.sql file and several ...
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2answers
1k views

Hyperthreading & MySQL InnoDB Thread Concurrency Performance

I have a dedicated DB Server with the following specs" Ubuntu 12.04 LTS Server Intel(R) Xeon(R) CPU X5670 @ 2.93GHz 12 Cores MySQL 5.5.29 64 GB RAM RAID10 We are currently doing Hyperthreading ...
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1answer
18 views

Can combine five mysql statements into just one statement?

Can I combine all the five statements into just one statement? update mytable set myfield1 = replace(myfield1, '…' ,'-') ; update mytable set myfield1 = replace(myfield1, '‖' ,'|') ; update mytable ...
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30 views

mysqldump Error 2013

I have a database installed, that I would like to backup in mysql. The problem is mysqldump fails on exporting the 'maia_mail' table # mysqldump -u root -p maia > maia.sql mysqldump: Error ...
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235 views

Update table from calculated temporary table

I have two tables, one containing a set of user ID's, vote direction (-1 or 1) and ID of the object they voted on (casted votes table). In the other table, the object id, upvotes, downvotes and ...
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14 views

how to boost range count query performace [on hold]

I have a table with single column in the table. The query fired will be two numbers and I have to return the count of range. But the query is running very slow. How to increase the performance of this ...