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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0
votes
1answer
245 views

How can I rewrite the following removing the date_format function?

I have a table with a column when that is of type datetime. I am doing the following filter which can not use and index: AND DATE_FORMAT(t1.when, '%Y-%m-%d') <= LAST_DAY(now() - interval 1 month ) ...
1
vote
2answers
335 views

What's the best way to translate a website [closed]

I have a website in Django using MySQL, and I have more than 4.000 entries that I want to translate. What's the best way to do it? Create a new database for every language? Create other table for ...
1
vote
1answer
219 views

Impact of replication compression & encryption on performance, traffic?

What is the impact of MySQL compressed-slave-protocol on replication traffic? According to High performance MySQL it can lower the traffic to a third of the same replication without the compression. ...
3
votes
2answers
2k views

Fastest way to create local copy of live InnoDB MySQL database?

We have a MySQL database (InnoDB) on our live Ubuntu 12.04 server which has grown quite large (25gb+). Every month or so we need to copy this database to our development machines to work on locally. ...
4
votes
1answer
131 views

MySQL silly query plan

I'm using 5.6.15-56-log Percona Server. Here's my table(which has over 5M records) CREATE TABLE `promotion_codes` ( `id` int(11) NOT NULL AUTO_INCREMENT, `code` varchar(255) DEFAULT NULL, ...
2
votes
1answer
98 views

Formatting a float value

I am fetching data from MySQL using PHP. I know that most values stored in the database are float. Sometimes, the database outputs values like 3.9999E-5 and sometimes like 0.00104961904762 (14 ...
1
vote
2answers
261 views

MySQL Slave not updated

This might be a duplicate of questions on the same problem asked before. But all the suggestions to the previous questions do not seem to work in my case. I have set up Replication using SSH Tunnel. ...
0
votes
0answers
41 views

Why does MySQL randomly display my databases?

Using InnoDb for the tables, Zend installation that comes with MySQL on Windows. Basically what happens is that at each system startup (not MySQL) I get a random snapshot of my databases at some ...
1
vote
1answer
36 views

Duplicate Data from two column

i have a table which has only two column one is pid(Photo ID) and another one is tid(Tag ID) +-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | ...
2
votes
1answer
43 views

MySQL behaviour on connection failure

My MySQL database is hosted on a different machine from my application system, which issues queries to the MySQL database remotely. If for some reason the network connection between the two machines ...
2
votes
3answers
324 views

How to update cust_id from Customer table to order table Cust_id field while inserting customer name using trigger

I have two tables 1. Customer_details and 2. Order_details. 1.Customer_details table -->fields--> Cust_Id(Primary Key) and Customer_Name, 2.Order_details table --> fields-- Ord_Id(Primary ...
1
vote
1answer
154 views

Determining replication traffic

is there any way to determine from server statistics* running MySQL, how much traffic(bits per second) WOULD replication consume between 2 servers, without setting-up the actual replication between ...
1
vote
1answer
142 views

How does the transactions interact if you set a different isolation level per connection?

I read that I can have different isolation levels per connection and in the server. The default isolation level is REPEATABLE-READ. So if I have a transaction that issues a SERIALIZED to the client ...
0
votes
2answers
58 views

To replicate, or not to replicate

1.Intro Hello, I am running web application on 2 separate geographical locations(e.g. Europe, Hong Kong). Let's suppose Hong Kong server is an Amazon EC2 instance(paying for disk space, IO disk ...
0
votes
0answers
320 views

Auto Increment Column for Ordering

I have the following table and I just added the ord column because I need to ORDER BY ord all of my tasks selected for a user/group. I want them to always be returned in the order the user added the ...
1
vote
0answers
4k views

Table already exists error when trying to import sql file

I am trying to upload a backup sql file through phpMyAdmin. I create the empty db with the same db name as in my import file in phpMyAdmin then use the import function selected from within this empty ...
1
vote
1answer
1k views

MySQL: Filter results by joining a vertical table

Situation: I've got a table users and a table preferences along with some others. The table users is aligned horizontally (id, username,...) whereas the table preferences is aligned vertically ...
24
votes
4answers
64k views

How do I change the DEFINER of a VIEW in Mysql?

When I run mysqldump, I get an error: mysqldump: Got error: 1449: The user specified as a definer ('root'@'foobar') does not exist when using LOCK TABLES This makes sense because foobar is a legacy ...
1
vote
1answer
441 views

MySQL - Best long read query solution within a replication based system

I'm working on a project where work in a queue requires a database read against heterogeneous table schemas (InnoDB/MyISAM). The queries constructed during the "read" process can result in 10-15 ...
2
votes
2answers
4k views

How to Recover truncate table in MySQL?

I am getting the "wrong input table name" when use TRUNCATE as following: TRUNCATE `stats` The table should bans. How to recover stats table? I am using CentOS 6, and MySQL-Server.
0
votes
1answer
160 views

How does InnoDB store tables in ibdata file? [closed]

There are two tables and their default engine is InnoDB. I want know the following What's inside the ibdata file ? How does InnoDB store these two tables ?
6
votes
1answer
489 views

Can spatial index be a part of a multiple columns index?

This manual over here is extremely unclear and doesn't even provide some sample SQL statements: http://dev.mysql.com/doc/refman/5.6/en/column-indexes.html Another way to rephrase the question is the ...
-3
votes
1answer
161 views

How long will it take to import 28 millions rows in a MyISAM table? [closed]

Someone has idea how long time it will take to import? I hear something like 40k each minute? Thanks.
20
votes
2answers
27k views

MySQL: Create index If not exists

Is there a way to create an index in MySQL if it does not exist? MySQL does not support the obvious format: CREATE INDEX IF NOT EXISTS index_name ON table(column) ERROR 1064 (42000): You have an ...
3
votes
1answer
259 views

Is it possible to remove useless GRANTS in MySQL

I'm using pt-show-grants to create all my GRANTS on a new server but there's lots of old GRANTS that refer to tables that doesn't exist anymore so I get errors when I try to apply the SQL file on the ...
1
vote
1answer
2k views

MySQL master master replication, safe to delete rows on both masters?

We have a MySQL (v5.1.61) cluster with two masters (and two slaves). We have a table logs with a primary key column logID. This log table grows rather huge, and we'd like to delete data from it. So ...
0
votes
0answers
30 views

MySQL silly query plan [duplicate]

I'm using 5.6.15-56-log Percona Server. Here's my table(which has over 5M records) CREATE TABLE `promotion_codes` ( `id` int(11) NOT NULL AUTO_INCREMENT, `code` varchar(255) DEFAULT NULL, ...
0
votes
3answers
21k views

MySQL vs. Microsoft Access [closed]

I'm trying to aggregate about 500-1000 MS Excel files that deal with various small business issues (inventory, purchase orders, etc) and I'm currently trying to decide what kind of RDMS I should use. ...
0
votes
1answer
373 views

MySQL Server 5.6 only runs when making swapfile

I am new to MySQL server and I have setup a dedicated MySQL server. I am aiming to install MySQL server version 5.6 and since version 5.6 is not available on the Ubuntu repository I have to upgrade it ...
0
votes
0answers
72 views

MySQL 5.5 InnoDB migration using stored procedure is very slow in Linux/Windows 2008 Server

I am Migrating MYSQL data from one server to another server using my stored procedure. The target server is Linux//Windows Server 2008. The migration speed is extremely poor. It takes about 5-6 ...
1
vote
0answers
162 views

MySQL join query indexes

After recently discovering the MySQL feature to log queries that aren't using indexes, I've been chasing these down in a large app, looking for places to improve performance. There is at least one ...
0
votes
1answer
138 views

MySQL performance issues when saving Bitcoin data

I have set a cron job to a php script which periodically checks Bitcoin for new blocks, and if there are any, add the blocks and transactions to a database. After a few million records have been ...
1
vote
0answers
71 views

Move all InnoDB databases into one subdirectory (innodb_file_per_table is ON)

First of all, excuse my English. I want to run a MySQL 5.6 on ZFS volume, and need to move all InnoDB databases to one subdirectory (which in fact will be a different ZFS filesystem). For example, by ...
1
vote
2answers
412 views

Install MySQL on Ubuntu 12.0.4

This is my first time using Linux. I am trying to install MySQL 5.6.15 on an Ubuntu box. I download MySQL from their website and put it on a USB stick then plugged the stick into the box. How can I ...
0
votes
1answer
60 views

Optimize this query: SQL

I have this query in MySQL: SELECT p.idSentence, p.idPath, p.token, p.posTag, p.ner, p.isTV, r.relationType, t.tag FROM path p LEFT OUTER JOIN relation ...
0
votes
2answers
228 views

When do I need transactions /locks?

I know that transactions are meant to group several operations as one. But if for example in the same table one transaction does DELETE FROM table where state = 'done' and another does either SELECT ...
0
votes
0answers
209 views

Can I set a lower_case_table_names value for a specific database?

I'm running a MySQL 5.5 on Linux (Debian 7) with several databases. I need to import a database originally maintained in Windows MySQL using sqldump. My issue is that this database is used by a ...
0
votes
2answers
2k views

How can I execute multiple statements at once in MySQL Workbench?

I'm trying to execute multiple LOAD DATA INFILE statements at once using MySQL Workbench. However, they execute one at a time. Anyway of forcing them to run in parallel? Thanks for the help!
2
votes
0answers
39 views

Is it possible for unique key to break master-master replication in mysql?

I have a master-master mysql setup with 2 servers running the exact same application making writes to such a table: CREATE TABLE `metric` ( `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT, ...
0
votes
0answers
94 views

Why does the delete/update block each other in this case?

The following drives me crazy. I have: session1>begin; session2>begin; session2>update dummy set salary=1000 where id=11; session1>delete from dummy where id=1; id is the PK ...
1
vote
0answers
286 views

What do spikes in InnoDB lock structures indicate?

I co-maintain a high traffic site similar to StackExchange. It runs MySQL 5.1 (working on replacing it with MySQL 5.5 or MariaDB). All our tables are InnoDB. MySQL goes down a couple of times a day. ...
16
votes
3answers
8k views

Is it common practice to mix InnoDB and MyISAM tables on same server?

I've got a single database of about 4.5GB running on a server with 8GB RAM. The vast majority of the tables are MyIsam (about 4.3GB), but I'm soon going to be converting some of them to InnoDB. (It's ...
0
votes
0answers
149 views

Big Mysql table optimization

I have a table that I use to cache google translate API answers. Table structure is orig_string and group are indexes Now it has more that 1million rows with 35000 distinct values in group field. ...
1
vote
1answer
741 views

mariadb 5.5.36 with innodb plugin

I installed mariadb 5.5.36 on a win32 system. Everything runs fine except innodb requests are 2 x slower than an identical MySQL installation. So I want to switch back to original innodb plugin to ...
0
votes
1answer
590 views

Slow MySql server - even on a super fast server

I have just upgraded my 12 year old server to a really fast new one. It is a dedicated server, Dell R620 1 x Intel E5-2620 (2.0GHz, 6C) CPU 32GB RAM - 4 x 250GB SSD RAID 1, in short vastly faster in ...
0
votes
1answer
449 views

Time series data for ad platform

I am trying to figure out how to store time series data for an ad platform I am working on. Basically I want to know some strategies/solutions for storing billions of rows of data so that I can ...
1
vote
0answers
39 views

“dynamic set” in a MySQL table

I have a table where one column will have a few values many times (maybe 20 different values). Now I would like to use something like the set to improve performance and memory consumption. The problem ...
0
votes
1answer
6k views

Couldn't start MySQL

I looked in the other threads, but this did not resolve my problem. I am trying to start MySQL, but I am getting error as below D:\>cd mysql\mysql5.6.15\program\bin\mysqld --console The system ...
1
vote
1answer
185 views

MySQL update row cell with 0 value with value from closest row that does not have 0 value

I have a list of entries that has a time field where unix timestamp is stored. I recently discovered that some of the entries have that field value 0. I want to run an update that will update those ...
0
votes
1answer
292 views

mysql start and stop error

I install a mysql 4.1(Ok it's very old version) on debian. the service start and stop correctly but show this error. root@VM03:~# /etc/init.d/mysql start /etc/init.d/mysql: 63: /etc/init.d/mysql: ...