All versions of MySQL (not Microsoft SQL Server). Please also add a version-specific tag like mysql-5.7 if that is relevant to the question.

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3
votes
2answers
921 views

Are there benefits to using more than 4 CPUs for MySQL?

We are running MySQL 5.5 on linux under VMWare, running on 2 CPUs. We are planning on increasing this to 4, but we have un-used CPUs available, and I'm wondering if there is any benefit to increasing ...
2
votes
1answer
320 views

How to do the complex nested select SQL?

I have two tables, table1 is as following, id is primary key, table2_id is foreign key id date aid table2_id message 1 2014-03-19 16:21:02 121 1 login from xxxx 2 2014-03-...
2
votes
1answer
572 views

Optimize Percona MySQL InnoDB 3.2TB database

(Before you will call me an idiot or start laughing, please remember it's a real deal on my side and I cannot cancel this assignment as it is a part of a bigger project) I have a database server that ...
0
votes
2answers
977 views

What is the best choice for MySQL high availability (zero downtime)? [closed]

As I know there are many solutions for MySQL HA, but most of them are congenitally not zero downtime solution, like MHA, AWS RDS... That said, if zero downtime is "must have", the only choice is ...
0
votes
1answer
342 views

MongoDB Storage Architecture (MySQL innodb_file_per_table equivalent to MongoDB)

I am new to MongoDB.I looked inside dbpath I found users.0 - 16.8MB users.1 - 33.6MB users.ns - 16.8MB Further when I dig deeper I found, The .0, .1 files are datafiles. Each datafile is ...
1
vote
1answer
5k views

Too Many database connections on Amazon RDS

We are having problems with users running queries/views in Drupal that occasionally cause our site to freeze. The freeze occurs because the query causes the number of database connections to go up to ...
0
votes
2answers
388 views

How do I extract row/column elements from multiple tables with same schema in single query

My question is as follows: Given that I have three tables with exactly the same column names and exactly the same keys for the "name" column e.g. Table r name | A | B | C ----------------- elem1| 12|...
2
votes
2answers
3k views

How to monitor InnoDB Disk I/O Required for MySQL?

I am doing an estimate on how much i/o[disk read write] on Mysql 5.6 [innodb storage engine], for getting idea how to calculate total number of disk read write i have searched a lot on SO on DA and ...
1
vote
2answers
2k views

SQL - query multiplying records returned - Cartesian Product

I am using the following query which is returning a huge number of multiplied records - i.e. a cartesian product: SELECT * FROM specimen, topography_index, morphology, functions WHERE SUBSTRING(...
2
votes
1answer
285 views

Need scalable database solution for very big automated data entry database

I've been working on MySQL database in simple web applications for a long time and i now have a project which should maintain about 1,000 up to 10,000 query per minute (it is some logging database ...
0
votes
1answer
405 views

MySQL: How to clean MySQL from RHEL5?

I have installed MySQL 5.1.73 community edition through RPM. It was working fine. I uninstalled this version by using yum remove mysql-server command. I wanted to upgrade MySQL from 5.1.73 to 5.6.19 ...
0
votes
1answer
34 views

Omitting [INTO] in the INSERT … SELECT statement

Does the INTO keyword only makes the query more readable, or does it bring another benefits as well? The queries beneath both seem to run equivalently . insert ignore tbl (type, details) values ('1', ...
0
votes
1answer
53 views

Cannot start MySQL Cluster Management Service

Could not determine which nodeid to use for this node. Specify it with --ndb-nodeid= on command line. This is what EventViewer is saying
0
votes
0answers
31 views

Disable procedures for data load in MySql using Innodb engine

I have a database with an integrated ledger for a multi-unit company. As we bring new units into the database we load their existing ledger data into ours. Unfortunately the existing procedures on the ...
1
vote
0answers
155 views

Question on MySQL insert race condition

I'm using MySQL 5.1, PHP 5.3 and the table is MyISAM. Here's the DTD of this very fake table: CREATE TABLE `temp1` ( `value` varchar(10) DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 This ...
1
vote
1answer
338 views

How to make MySQL join one-to-many with lowest value?

I have following database structure Domain has many URL which has many positions which belongs to phrase which belongs to user which belongs to subscription. In subscriptions table I have period ...
-2
votes
1answer
648 views

Can I install MySql and Oracle 10g both Databases in same machine? [closed]

I have MySql Installed in my windows 7 machine and PHP on IIS. Now i need Oracle 10g anyway.I'm having king of dilemma to install Oracle 10g. If i can do so please suggest necessary steps and ...
1
vote
1answer
163 views

MRG_MyISAM with myisampack tables blocking inserts

I'm using INSERT_METHOD=FIRST and compressing all tables that are members of the union but when I try to insert into the MRG_MyISAM table it tries to insert into the second one (instead of the first). ...
1
vote
1answer
7k views

Good configuration for 2gb (my.cnf) [duplicate]

I'm little newbie in configuring mysql and i seek a good configuration for mysql i have one site in ajax with many query and very slowly with VPS Iam in kimsufi 2gb i run only mysql in vps not apache ...
0
votes
0answers
35 views

Optimization mysql very slowly [duplicate]

Hello I have a server in kimsufi 2gb RAM and 500gb storage but the query with php mysql is very slowly I have change innodb buffer pool size to 500M but i have error too many connections, i add max ...
1
vote
1answer
109 views

InnoDB issue after power outage a few weeks ago - no backup

A few weeks ago we had a power outage on one of our web servers that hosts several websites, we didn't think it affected anything and everything came back up as normal as far as we were aware. I have ...
2
votes
2answers
371 views

Why is this simple join taking so long?

I'm trying to run some reporting queries on a MySQL database, and I'm running into serious performance issues for some reason. One table, page_views, is extremely large (~70 million records), so some ...
1
vote
0answers
254 views

Query takes over 200ms [closed]

So, im using symfony2 with doctrine running in local with WAMP. I have to select from my database : latest shop comments with shop & user informations latest liked shops with shop and user ...
1
vote
0answers
59 views

Multiple selects ordering desc from single table

I'm trying to do multiple selects to give multiple ordered columns. I'm struggling to get the below mysql query to achieve the output I want. SQLfiddle: http://www.sqlfiddle.com/#!2/a1002/3 ...
-1
votes
1answer
39 views

Server down after PDO connection

I don't know is this off-topic for this site but I have site that run on PHP and MySQL. And I want to change my MySQL connection to PDO. This is my connection file that I include in every file at the ...
0
votes
0answers
34 views

Creating a table for indexing another table

We have a table with 350m rows and 12 columns, and around 1m rows adding everyday. We have crappy hardware and we cannot add an index on one of the 12 columns that we really really need to. (severe ...
2
votes
2answers
297 views

Whats row size in mysql?

i mean what does it mean ?, i have mysql db and table in myisam and it shows Space usage Type Usage Data 1.3 GiB Index 429.1 MiB Total 1.7 GiB Row Statistics Statements Value ...
4
votes
1answer
6k views

MySQL Innodb corruption

I recently inherited a Drupal site that has an Innodb corruption. MySQL will run for sometime--usually about 24-hours but will eventually need to be manually restarted(see log output below). I have ...
0
votes
1answer
36 views

Mysql functions for web apps

I have few questions about using functions in a MySQL database for plugins and extensions of web apps like Magento or Wordpress. Mostly this is for a few extensions I want to do for Magento. The ...
1
vote
1answer
444 views

Safely changing innodb_buffer_pool_size on MySQL replication master?

We have a MySQL server which is a replication master. We need to change the innodb_buffer_pool_size and innodb_flush_method to (hopefully) improve performance as the database has grown. What is the "...
0
votes
1answer
208 views

How to install TokuDB on MAMP

I'm by no means a DB admin. Just a hobbyist actually, and more of a programmer than a database person. I have MAMP 3.05, PHP 5.5.10, Mac OSX 10.9.3. I have a big suite of PHP applications and a ...
0
votes
1answer
43 views

Optimizing a query so MySQL will use the indexes for the joins

Some context: migrating some data from a 3rd party cloud MongoDB platform service into MySQL. Wrote a query but it's very slow. Here's the query: SELECT Table1.*, (long list of fields for each ...
6
votes
1answer
8k views

Product Attribute List Design Pattern

I am working on updating our website's product database. It’s built in MySQL but this is more of a general database design pattern question. I’m planning on switching to a Supertype/Subtype pattern. ...
2
votes
1answer
2k views

MySQL replication working fine, but still shows “Waiting for master to send event” at 280000 seconds

To repeat the title: MySQL replication working fine, but mytop still shows a thread "Waiting for master to send event". It has been like this for a few days, and is now at 280000 seconds. But ...
0
votes
1answer
55 views

What kind of data type to use for numbering in the Harmonized System?

The harmonized system uses a numbering that shows the hierarchy between different items. Similar to bookkeeping ledger numbers. Here is an example: 01 LIVE ANIMALS 0103 swine, live 010310 Purebred ...
4
votes
1answer
1k views

Is it possible for a MySQL database to have duplicate tables with the same name?

As in the question title - is it possible for a MySQL database to have duplicate tables with the same name? Is there a directive that can be used for a database to allow this? Normally, when trying ...
6
votes
2answers
3k views

MySQL hogging memory

An installation of MySQL 5.6.10 on a virtualized Ubuntu 12.04 is exhibiting massive memory hogging. The mysqld process claims the entire available memory within a couple of hours of uptime and forces ...
1
vote
1answer
3k views

Show processlist / Max concurrent connections seem to max out at 131

When I put my database under a load test (basically just a basic write and basic read from our app), and run show processlist; in the middle of it, there is always 131 rows in the set and that's it. I'...
1
vote
2answers
78 views

mysqld is not producing binary log

I'm trying to understand why mysqld is not writing binary log anymore... [root@ip-10-179-155-214 mysql]# grep ^log-bin /etc/my.cnf log-bin=mysql-bin [root@ip-10-179-155-214 mysql]# ll mysql-bin.* -rw-...
1
vote
1answer
689 views

Dedicated mysql server slow response [closed]

I have server in Kimsufi with 2gb RAM but my server is very slow , with simple hosting in ovh it responds quickly ... With pingdom.com test i have for server: 10 sec and simple hosting: 2sec is ...
0
votes
0answers
123 views

Store both a city and its region?

I store various events (such as a search on the site) into a table (in fact I have two tables: one for the event and other (linking to the first) with characteristics of the event). Each city belongs ...
0
votes
1answer
189 views

Optimization for 100 GB Real-time info table

I have a table of device information feed which is filled by data from remote device units. There will be like 1000 units each sending an update per minute which will be stored as a row in that table....
21
votes
3answers
19k views

What are reasons *not* to use the MEMORY storage engine in MySQL?

I recently discovered that MySQL has a "memory" engine that I wasn't aware of (most of my database work is for hobby projects so I learn what I need as I go). It seems like this option should give me ...
-1
votes
1answer
38 views

60M+ InnoDB table simple query performance HELP

I know it is a repeated question but really need help here. What can I do to improve the performance of this query? Considering that I have no freedom to change system variables/configs :( Thanks in ...
1
vote
1answer
724 views

When tables are locked does MySQL queue queries?

I have a small production website, but it's live 24/7. When running the Optimize, Analyze or Repair commands, MySQL locks the table it is working on. QUESTIONS How would this effect users trying ...
0
votes
1answer
3k views

Plugin 'FEDERATED' is disabled

Im trying to start Mysql using easyPHP : the response is an alert window to a log file. The main error is <-- Plugin 'FEDERATED' is disabled -->. Through my research on internet i found that the ...
7
votes
3answers
2k views

Two tables with same name in MySQL

I got this weird issue today when I dropped a temporary table. I dropped the temporary table and desc the table just to verify. But, the table was not dropped. After some searching I found that: ...
6
votes
1answer
2k views

Benefits of Barracuda and Compression

I've been reading about MySQL's file formats Antelope and Barracuda a while ago, and I wonder if I could benefit with having Barracuda and Compression. My server is currently using Antelope, as it is ...
0
votes
0answers
54 views

Is there a MySQL setup for my use case?

I have multiple nodes that are mostly independent of each other, meaning 99% of traffic is reads to data contained inside themselves, plus some writes that need to be instantly available for the node ...
5
votes
1answer
1k views

ROW_FORMAT - COMPRESSED vs COMPACT vs DYNAMIC

In MySQL InnoDB, what is the difference between COMPRESSED, COMPACT and DYNAMIC for ROW_FORMAT? What are the benefits between each other?