MySQL : Open-Source, Relational Database Management System

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Is there any difference between these two version of MySQL - 5.1.73-community-log Vs 5.1.73-community

I have installed MySQL 5.1.73 in Oracle LINUX 5 server. Just after RPM installation, I checked system variables and found that version is 5.1.73-community. When I copid ...
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Report Builder 3 error

Connecting to a report server running Win 2k8 R2 with SQL 2012. The dataset is coming from a linux box running MySQL. I can create a report in Report Builder fine. All the data pulls from MySQL ...
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Does MySQL guarantee atomic upgrade from read lock to write lock?

If a client session is currently holding a read lock (to allow concurrent reads while already preventing writes), and then acquires a write lock on the same table(s), does MySQL guarantee that the ...
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MySQL Workbench EER Diagram and ENUM data type

I am creating EER model diagram using MySQL Workbench (version : 5.2.47) The version for MySQL, I am using is 5.5.35-0ubuntu0.13.10.2. I have created a schema with 'Default Collation' set to 'utf8 - ...
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Sorting of results is slow some times but fast at other times

I have a mysql query that is joining a few tables and then uses order by field for sorting. It sometimes runs quite fast at other times it is slow. While it was slow i profiled the query to find that ...
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How to check if several tables exist in database, and how to show it in Mysql

I would like to check if several tables exist in a database, and return a easy to understand return, I know you can check if a single table exists by running show tables like "foo"; but is there ...
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28 views

How can I genereate a string from the returns of a SELECT query in Mysql?

I need to create a string from data that is extracted from an SQL query, and wish to accomplish it within the SQL Query. The return is something like +---------------+ | foo_ids | ...
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Mysql tar ball installation

I need to install two different versions of Mysql in one server OS RHEL6 and it will be separated by user called mysqlprod and mysqlpreprod. I need to separate their binaries, softwares,data ...
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MySql query keep running for a long time

Following query keep running for a long time and I'm using MySql 5.5.34 on XAMPP on Windows SELECT id_package, `pck`.`fk_sales_order`, `pck`.`fk_picklist`, count(pci.id_package_item) as items, ...
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24 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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5 views

How is the key length determine is an index?

Aside from explicitly setting the key length when creating an index, how does MySQL determine the appropriate key len shown when running "explain"? Thanks
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Is there any value in adding a pk column to an composite index? [duplicate]

I recently inherited a database with indexes that contain the table's primary key as part of some composite indexes. Given MySQL adds a hidden column representing the PK regardless of whether you ...
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1answer
16 views

Is there any value in adding an already indexed column to a composite index?

The title says it all. Does the query optimizer see composite indexes where each column is already indexed as redundant? Or, is it used when each of the composite index's columns are in the WHERE ...
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18 views

MySQL best practice DB recovery

I am trying to figure out what is the best practice is for Mysql recovery after a power failure. I need to find a way that if a server (which is running on a virtualbox VM) goes down when it goes ...
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1answer
12 views

Migrating MyISAM tables from 5.5 => 5.6

I was wondering if anyone had any pointers on migrating MyIASM tables from mysql 5.5 to 5.6, specifically using Percona builds, via an rsync? Is this safe? I know we need to do a full ...
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2answers
19 views

Does MySQL have a version of Change Data Capture?

We're in the process of phasing out an old system and migrating onto a new one. The last time that we phased out an old system, we ran both systems in parallel and integrated data between both until ...
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23 views

How to Identify the user who issued MySQL Shutdown command

We have had several situations when our production MySQL server suddenly became unavailable. The error log just shows "Normal shutdown" followed by the typical shutdown messages. How can I determine ...
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41 views

JOIN on variable number of columns

I have the two tables courses AND something_about_courses: courses course_code course_session course_type something_about_courses course_code course_session some_description To ensure that I ...
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1answer
21 views

InnoDB primary key efficiency

I've read a number of articles regarding efficiency of primary keys depending on the storage engine, and I am left confused. Given a simple many-to-many table with two fields, storeId and zoneId, ...
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1answer
12 views

How to structure renting and sale as type of purchase?

I'm currently planning a database which involves two different types of Products that can be bought outright, or rented for a weekly or monthly amount. I'm just trying to figure out how to structure ...
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39 views

Unclear deadlock condition messages in MySQL 5.6.17

I have recently upgraded from MySQL 5.6.10 to MySQL 5.6.17 in production server. In previous and in recent version i am getting deadlocks very frequently perhaps in every 5-10 minutes. I have online ...
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39 views

update and select is taking over 1.2 seconds to return [on hold]

I am trying to debug my MySQL server which takes up to 1.5 seconds to execute and return a simple update or select command. I have around 600k rows in this particular table and the db engine is ...
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I can't connect with the DB through the php file. [on hold]

i can't transmin from php file,to the localhost db created with phpMyAdmin. I doesn't giv mi any errors,but still,doesn't transmit the informations. The code is simple. from e form with post method, ...
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2answers
84 views

Why is this MySQL SELECT performing so slowly despite indexing?

I have a large MyISAM table A (500m entries) that connects two other tables B,C with a n:m relation. So my table A looks like this: CREATE TABLE `A` ( `id_b` int(10) DEFAULT NULL, `id_c` int(12) ...
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43 views

Do Inactive MySQL Databases Consume Memory?

I have inactive databases that are on the server just for archive purposes. I know I can do mysqldump for all of them, but I am not 100% sure they are inactive. When I started my system I didn't ...
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14 views

using the wordpress approach for storing taxonomies

multiple tables vs single table a user table will not need every social link in the database column, since every one will not enter all their social links and are used only on user profile ...
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1answer
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MySQL group concat not showing distinct values when joined to another table

I have one view that gives me comma separated values and want to use that data in another view. In the first view, I am using group_concat( distinct ...) and when I run that view by itself, I can see ...
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Why is this MySQL query performing slowly despite correct indexing? [duplicate]

I have a large MyISAM table A (500m entries) that connects two other tables B,C with a n:m relation. So my table A looks like this: CREATE TABLE `A` ( `id_b` int(10) DEFAULT NULL, `id_c` int(12) ...
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1answer
14 views

Report Builder cannot publish to report server

This is currently in a cloud lab environment. We're not allowed to join any AD domains. We have a linux server (RHEL 6) running MySQL 5.3 and a Windows SQL Server 2012 on Win 2k8 R2. Our laptop is ...
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1answer
29 views

Adding new tables — memory usage increases

I added more tables to my mysql server. 20% increase in tables that are all innodb. I have 200 + databases that use the same schema. Does adding more tables increase memory usage? I am using about ...
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33 views

High concurrency is even slower than low concurrency in mysql?

My application is supposed to handle high concurrency insert/update, now I have only one mysql instance setup for test. My application is full asynchronous, it should be able to handle 10,000 ...
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1answer
56 views

Query multiple rooms with different conditionals (Adults, Children)

I have a simple query where I select available x Rooms with x Adults + x Children per hotel that matches a date range, but I'm having a hard time trying to figure out how to query a list of rooms per ...
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1answer
27 views

MySQL: Converting Character set fails?

I'm in the progress of migrating my database from latin1 to utf8 character sets/collations. I wrote a simple script that loops through all of my tables and executes this statement: ALTER TABLE ...
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33 views

Mysql Insert taking too long. Table need optimzation

I have around 60 tables and a video table with over 600,000 rows. with 4 Btree and 2 FULLText Indexes and have around 30 Columns. Server Specs are high, over 30G of Ram, Intel Xeon Processor. Mysql ...
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38 views

How can I store least used table files to a slower drive?

Is it possible to separate the least used and most frequently used data files on to separate disks when using InnoDB?
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31 views

How to find the rows from a table which has exactly two 'n' s in the employee name?

I want to find all the employees whose names have exactly two n's in their name. How can this be done?
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12 views

PHPMy Admin Exporting Importing with Foreign Key Constraints

I have a major issue here, How do I export a MySQL Database from PHPMyAdmin whilst retaining all the table relationships(foreign key constraints) - I have noticed performing a quick export does not ...
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15 views

How do you hide tool tips in MySQL Workbench?

Is there a way to hide the tool tips that popup when you hover over objects? Especially when you hover over tables, I do not want to see the breakdown of what objects are in that table.
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1answer
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Can this architecture supports 350 concurrent access?

This question is more about server capacity issue. I have a linux server with Apache 2.24 installed (12G Ram, 32 cores CPU, Red Hat 64Bit). Install 11 instances of Wordpress, all 3.8.1, with WP ...
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34 views

Mysql 5.5 InnoDB growing CPU - Going crazy

Good morning, I'm currently facing a problem where CPU usage keeps going up until the server crash. I've tried multiple best practices proposed in this forum and on Percona, reinstalled the server ...
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1answer
14 views

How to decipher the transaction message in innodb status log.

I have several transactions that seem have stalled. Looking at the innodb status log, I found several messages similar to the following: ---TRANSACTION 69DBBB, ACTIVE 947 sec starting index read, ...
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MySQL - Out of memory: Kill process 3046 (mysqld)

We run a MySQL (v5.6.17) dump backup every 4 hours, and today noticed: Apr 19 20:09:30 mysql1 kernel: Out of memory: Kill process 3046 (mysqld) score 970 or sacrifice child Apr 19 20:09:30 mysql1 ...
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1answer
25 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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1answer
22 views

Need help tuning my.cnf file

I need help tuning mysql. Currently it is using a lot of CPU. I dont find any query that last longer than 3 seconds in SHOW PROCESSLIST and there are only around 20-25 running most of the time. Still ...
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1answer
38 views

Mysql join two tables and limit by first input?

i am only starting to play with MySQL and i seem to have been stumped by one problem. I have one table containing a number of fields including a primary id field. I have a second table containing ...
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1answer
48 views

Optimizing indexes

I just began optimizing my schemas with indexes (pretty late I guess). I never dealt with huge dataset but I'll be soon coping with about 1 to 5 millions rows. Here is the schema I'm using right now ...
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Does having many databases affect MySQL performance?

I have huge unused databases in MySQL. Do they affect my MySQL engine performance even if they are unused? Do they consume memory on their own? Thanks
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Can I estimate the row count of a large mysql table using the disk space?

Sysadmin here (not a developer by trade), so go easy please ;) I have a mysql table, on a linux server that uses innodb_file_per_table. When I try to do select count(foo) from table; It doesn't ...
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How to store temp tables in memory during table “optimize”?

When optimizing tables, SHOW PROCESSLIST lists it as "copying to tmp table". I'm trying to ensure the copy takes place in memory to speed up the process. I've tried adjusting the tmp_table_size to ...
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MySQL ran out of space, now won't start

So the partition MySQL was mounted on ran out of space. As a quick fix, I decided to move mysql's data directory to /home/minecraft/mysql/. I then changed the datadir in the config to the correcy ...