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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2
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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
690 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
190 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?
0
votes
1answer
4k views

Innodb: Operating System Error number 5 in MySQL

I am trying to retrieve the data from MySQL ibd file but facing following error. 140601 17:00:45 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated ...
-1
votes
1answer
213 views

how to link category, stock , purchase and sales tables in a erp

i have a database design like the following: i have a table for storing camera details and then different tables for stock, purchase_stock, purchase_order, delivery_challan and sales_invoice. The ...
1
vote
1answer
686 views

Personal and Global messaging database design

I am trying to implement a database design system that will be sending messages to a person(thus 1 to 1) or many persons (1 to many). table --users |u_id | Name | | ...
1
vote
1answer
688 views

How to store multiple values in a column in database?

I'm trying to make three tables in phpMyAdmin. The main columns here are named Campaign, Program and Asset. Under Campaign, there are different kinds of Programs. And under each Program, there are ...
0
votes
0answers
186 views

Performance: Interleaving several statement handles in MySQL

Does interleaving several statement handles slow the system down? Example (Perl): $sth1->execute(...); $sth2->execute(...); $sth1->execute(...); $sth2->execute(...); (interleaved) vs $...
8
votes
3answers
14k views

MySQL replication - slave is continuously lagging behind master

I am using MySQL-5.1.50 with a Master-slave replication setup. Most of the time the slave is lagging behind the master. When I run show processlist;, there is no query that's taking a long time. ...
0
votes
2answers
2k views

MySQL Slaves lag behind master

I have one master and four slaves. Sometimes all my slaves lag behind the master. I have implemented the heartbeat for monitoring replication lag. Now I am trying to find why the slaves are lagging ...
0
votes
1answer
37 views

SHOW INNODB STATUS averages calculated

I am reading to all tutorials/books that when running SHOW ENGINE INNODB STATUS the Per second averages calculated from the last X sec, the X should be 20 to 30 seconds. I have never manage to exceed ...
0
votes
1answer
279 views

Two MySQL requests at the same time - Performance issue [closed]

I have a MySQL server with many innodb tables. I have a background script that does A LOT a delete/insert with one request : it deletes many millions of rows from table 2, then insert many millions of ...
1
vote
1answer
54 views

Understanding how relationship sides works

So, I have this relations on my tables (see image) and I need to understand some things. I'll enumerate what I understand and what I need from yours is to say if I'm right or not and in case I'm not ...
1
vote
2answers
325 views

Any way to force “garbage collection” in TokuDB?

Playing around with TokuDB I'm finding even after "optimize table" for things such as changing row compression or other DDLs it takes a non deterministic amount of time for freed space to be reflected ...
0
votes
1answer
102 views

Sync MySQL 4.0 table to MySQL 5.6 server every few minutes

I am tasked with getting a copy of a table on a MySQL 4.0 server synced to a completely different database on a MySQL 5.6 server every few minutes for the purposes of having that table available ...
3
votes
1answer
486 views

How to upgrade MySQL (5.5) production DB to 5.6 with minimal downtime

Our existing Database size around 200GB. We want to use consistent, parallel backups methods. For testing, I migrated my Development DB from 5.5 to 5.6 by running mysqldump with option --single-...
0
votes
0answers
20 views

Installing database

I have created database in my system using mysql.I tried to use in one of my friend's system.How can install the database in other system?
0
votes
2answers
91 views

SELECT query with referenced subqueries

How does one reference the currently-grouped by field in a subquery? Consider a table with the following data: Client Status Size 1 A 500 1 B 1500 2 ...
5
votes
2answers
1k views

Choosing MyISAM over InnoDB for these project requirements; and long term options

Sorry for the long post, but I had to give as much info as possible to make this very vague question more specific. My project's aim is to let users search a (huge) database of variety of products. ...
0
votes
2answers
271 views

MySQL: Moving Database from Windows to Linux

I have a Windows based dedicated server have below configuration: Windows edition: Windows Server 2008 R2 Standard Service Pack 1 Processor: Intel(R) Xeon(R) CPU X5460 @3.16GHZ 3.16 GHZ (2 Processors)...
8
votes
1answer
6k views

Qcache_free_memory not full yet I get alot of Qcache_lowmem_prunes

I just started dabbling with the query cache for our CMS. Can anyone tell me (or at least give a good guess) why I get a lot of Qcache_lowmem_prunes when more than half of Qcache_free_memory is free? ...
1
vote
0answers
734 views

Optimization Tips For MYSQL Tuner/Primer

So I have a site that has a crap ton of traffic. I see a decent amount of latency when the site has over 1,000 active visitors on it. I have new relic installed and it seems Im only using 10% of the ...
0
votes
1answer
33 views

Will my query pick up where it stopped due to connection timeout?

I am doing a rather large query that hits MySQL connection timeout. I know how to change the timeout parameter, but I'm also query from a laptop that can't be left running for long. The database ...
-1
votes
1answer
176 views

Remove all duplicate data in mysql

I want remove all duplicate data from my table. anyone help me. my table : biblio one one two three three four five i want to get result like this biblio two four five
1
vote
2answers
819 views

How can I repair a TokuDB table?

I have a TokuDB table that works fine for most queries, but segfaults on others. I did a CHECK TABLE which indicated that the table had errors. However, TokuDB doesn't support REPAIR TABLE. How can I ...
2
votes
1answer
4k views

“Limit 1000,25” vs “limit 25 Offset 1000”

Recently I've found out that MySQL has a offset feature. I've been trying to find documentation about the results of offset, or the difference in between offset and the limit variant, but I can't seem ...
0
votes
1answer
280 views

How to transfer 70GB MySQL with no downtime?

I have a large amount (4000) of individual databases, 90% of which are small. They all include about 20 tables each, and in total, they use about 75GB of space. All tables are MyISAM. I want to ...
0
votes
1answer
10 views

Get devices with not driver assigned

I have this related tables: And I need to get those devices with no driver assigned, in other words the device returned on this query shouldn't be on driver_has_device table since it'll not have ...
1
vote
1answer
1k views

Mysql error : Slave SQL Could not execute …on table

Im running a percona cluster of 3 nodes. Yesterday I needed to throw some more memory in them, so I had to power down all nodes Now I booted up and then my 3rd Node, Gave me this error : 140701 23:...
0
votes
1answer
415 views

serial numbers for products

Let's say I'm selling 3 products. I have a products table with id and name (so that table would have 3 entries). I want each product to have a serial number, each independent from one another, but I ...
8
votes
4answers
6k views

One slave, multiple masters MySql

Is it possible to set-up MySql Replication to have one slave listening to two different masters?
1
vote
1answer
30 views

Combining Tables in MySQL

I have two tables, which are very similar, in MySQL. I want to combine them into a single table with new column names. Some of the column names in Table1 or Table2 may not be used in the new ...
1
vote
0answers
64 views

Architecture for a MySQL MDBS

My coworker and I are tasked with redesigning our current Access databases in a MySQL environment. Between the two of us, this wont be a problem but we need to connect to other external databases that ...
0
votes
1answer
353 views

Audit DML operations on MySQL Tables

We have several MySQL 5.0 databases. We've been having security problems, like records being modified without authorization. We need to implement some kind of audit on DML operations identifying ...
1
vote
1answer
244 views

How to create trigger with NOT FOR REPLICATION

I tried adding "NOT FOR REPLICATION " in many parts in the below code but ended up in the below code. I searched a lot for an example where I can see how its done with a trigger. Can any one show me ...
1
vote
1answer
367 views

MySQL Cursor Batching Process

I have a cursor in MySQL and what I want to do is rather than having an enormous cursor loop that can be up to 4000+ users in size, do it smaller batches so that the MySQL engine doesn't suffer. I ...