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
1answer
6k views

mysql works, mysqldump doesn't

I have mysql 5.5 on my ubuntu 12.04 server. This command: mysql -u root -p works perfectly, but this gives me error: mysqldump -u root -p mydb_name > a.sql mysqldump: Got error: 2002: Can't ...
2
votes
0answers
836 views

How do I safely import MySQL data in a directory to a running MariaDB server?

We're integrating another office into ours. That includes some of their data. I have a new installed MariaDB 5.5 server. The data dir = /home/data/MariaDB. I've done a new/fresh install into that ...
3
votes
2answers
2k views

Problem with order by in MySQL subquery

I'm running a query that runs in about 2 seconds when the subquery does not include the order by date_sold clause. However, when I add the order by clause, the query runs forever. I'm confused, since ...
1
vote
2answers
410 views

multi master replication [duplicate]

Let us say I have a master(m) slave(s) replication. Now, in the scheme of things, I introduce another database/schema(foo) not associated with the master in any way and I want this schema to be ...
3
votes
1answer
200 views

Most efficient ordering post database design

I have posts table that is has post_order column. I store order of each post in it. when I change the order of a row from 25 to 15, I should update all the row from 15 to end. It's good for few rows, ...
-3
votes
1answer
2k views

How to merge two rows in a table? [closed]

I have a table called Person with columns Col1, Col2, Col3, etc. In Col1 I have two values: ABC and XYZ. What I want is to replicate all the values from the other columns (Co2, Col3, etc.) for the ...
0
votes
1answer
559 views

Need to find the number of employee who are not in all department

i have a table T1 which has two columns empname , department every emp must be in 37 department , but there are some employee who are in less than 37 department . I need to find the names of emp who ...
1
vote
1answer
1k views

Large table delete in mysql

I want to delete a table with 10,000,000 records. Due to some restrictions I can't do truncate on that table (I don't have the DROP privilege), I can think of two options: DELETE QUICK To set some ...
0
votes
1answer
159 views

Foreign key in MySQL

I am learning about database, I need to know something about the foreign key in MySQL. Consider the following two tables. UserGroupType. UserGroup. UserGroupType: UserGroup: In this table ...
1
vote
0answers
229 views

Mysql key_buffer_size already 16GB but some fulltext searches are still slow

I have a query w/ full text search which takes 5 - 10 secs. key_buffer_size is already 16GB. Table has 15 million records and has a compound fulltext index on fields: categories and company. Table ...
1
vote
1answer
3k views

Which is faster among MySQL Community Server, Percona and MariaDB [closed]

I have a small setup of MySQL Community Server version 5.6 running on KVM based VPS. 4 CPU cores are available and total memory is limited to 1GB. I use MyISAM tables mainly for Wordpress and few ...
3
votes
1answer
5k views

Create Table If Not Exists Hanging

I am still new to using databases, but currently I am using a mysql database and attempting to make my bash script unbreakable because it might be used in several different environments (dev, qa, etc)....
1
vote
0answers
114 views

Is it possible to keep track of changes to tables structure?

Is it somehow possible to keep track of changes made to the STRUCTURE (not the data) made to tables? I mean, i don't want to know when rows are inserted/updated/deleted, what i want is to know when ...
1
vote
1answer
111 views

Unable to generate a MySQL query

I have a table in a MySQL database as below: ID Timestamp State 1 2013-07-10 09:00:00 Good 1 2013-07-10 09:10:00 Good 1 2013-07-10 09:20:00 Good 1 2013-07-10 09:30:00 Bad 1 2013-...
2
votes
1answer
1k views

MySQL replication between datacenters

I am trying to figure out the best MySQL replication topology, but I am not sure the best way to lay it out. datacenter A | datacenter B ____ | ____ | | | | | | AA | |...
2
votes
1answer
520 views

Inserting filtered data from one table to another

I need to find the number of employees who are not in all departments. I have one more table T2 in which same department column is present. Now I want to insert only those values of department which ...
0
votes
0answers
700 views

Trouble converting MySql Database to SQL Server

I have an mysql database that contains 38 tables. I used "SQL Server Migration Assistant for Mysql" tool to convert this database to SQL server Database. I successfully converted 37 tables. Only one ...
5
votes
5answers
10k views

MySQL said “InnoDB: Initializing buffer pool, size = 128.0M”, does it mean it is using 128MB RAM?

I am just using a very few InnoDB tables (e.g. less than 1MB), but during MySQL startup, it said InnoDB: Initializing buffer pool, size = 128.0M Does it mean even I am using in such a small size, ...
0
votes
1answer
493 views

MAMP PRO not showing all MAMP database

I was earlier using MAMP and Now switched to MAMP PRO. I used to use MAMP mysql as root default user and having lots off database as that user. If i start MAMP and go to terminal with mysql command ...
-1
votes
1answer
600 views

How to create a mysqldump file automatically from SQL server database on a daily basis

I want to create a mysqldump file from a SQL Server database, I know its possible using MYSQL workBench, what i want is to make it completely automate. So the script runs on a daily or weekly basis ...
-1
votes
1answer
63 views

What could I possibly be doing wrong with this update statement

UPDATE pcdbak SET pcdbak.Title = pcd.Title FROM pcd, pcdbak WHERE pcdbak.eCommNum = pcd.eCommNum This was the error message: [Err] 1064 - You have an error in your ...
2
votes
2answers
2k views

Changing the mysql.proc table directly after upgrade

Our host upgraded our mysql install without us knowing from roughly 5.1 to 5.5. This caused a problem because the table definition of mysql.proc is different as discussed here: http://bugs.mysql....
1
vote
0answers
920 views

Mysql raising intermittent “system error: 32” errors on connect

I'm running mysql 5.6.12 on OSX 10.8 and getting an error like this one constantly: ERROR 2013 (HY000): Lost connection to MySQL server at 'sending authentication information', system error: 32 ...
2
votes
0answers
932 views

The nature of the relationship between two tables in MySQL

Good day. I'm designing a database for a research project where we're predicting whether or not young female athletes will rupture their ACL(s) based on the nature of a test jump recorded with a ...
-1
votes
1answer
386 views

MySQL 5.6 Delayed Replication - cancel delay questions

I'm using the MySQL 5.6 Master/Slave replication, with Delay set for 2 hours. My questions are : Q1. What is the proper way to cancel the Delay at the slave - i.e. "roll forward" all the changes ...
0
votes
0answers
361 views

Efficient, up-to-date way to import an Oracle database into MySql

Here's the situation: I need to automatically merge data from an Oracle and a MySql server into a single, new MySql server. The merging will happen daily, and the resulting server will be hosted on a ...
0
votes
1answer
1k views

Why would mysql “show global status” query be taking 15 minutes?

I'm reviewing the slow log, and on one of my slaves the average time for SHOW GLOBAL STATUS is 914s. Any idea how to determine the cause of this?
1
vote
1answer
701 views

Can I force mysql server to resolve the external ip to localhost?

I'm finally succeeded with ssh tunneling. My point is to open the mysql server to local users only (user@localhost etc.) while providing a remote control to my customers through ssh tunneling. The ...
2
votes
1answer
1k views

Would adding indexes to my foreign keys improve performance on this MySQL query?

Consider the following query: SELECT `locations`.`id` AS `location_id`, `locations`.`address`, `locations`.`lat`, `locations`.`lng`, `tickets`.`status_id`, `customers`.`name`, `tickets`....
1
vote
1answer
539 views

Mysqlbinlog statement reading

I am trying to perform a point in time on a specific database using a snapshot and mysql's transaction logs. I am using the following to pull statements from the time of the snapshot to the time of ...
0
votes
2answers
4k views

Difference between two recordsets

I'm looking to calculate the difference between two record sets in MySQL. Say I have the following table: colname type attrbutes id uInt PK date date PK count uInt With this data: id ...
0
votes
1answer
1k views

Modify MySQL foreign key related column without dropping foreign key relation

I need to modify a foreign key related column. When I tried to alter it I got "Error on rename of 'x' to 'y' (errno: 150)" error. So I googled and found foreign key relation is the 'villain'. I ...
20
votes
7answers
44k views

Get the rank of a user in a score table

I have a very simple MySQL table where I save highscores. It looks like that: Id Name Score So far so good. The question is: How do I get what's a users rank? For example, I have a users ...
3
votes
1answer
7k views

mysql ibdata1 corrupt

I do not know whether this is a mysql(version 5.6.11) bug, the case is as following. today when i update mysql conf and kill -9 and restart mysqld, i find that it can't restart anymore. after having a ...
0
votes
1answer
83 views

Indexes and Optimizations for Logging System

I'm designing tables for a new log system and am having trouble figuring out what indexes I'll need (I'm a developer, not a DBA), and am also open to any suggestions/criticisms/etc. for making the ...
2
votes
1answer
317 views

mysql binlog file size stop growing

I made a master(A)-slave(B)-slave(C) mode MySQL instances for backup. But today when I see whether the mode works fine, I find A and B are OK. That is B can get binlog from A, but B does not write ...
0
votes
1answer
144 views

Database design in MySQL

I am designing a database for an web application, in this system there are multiple users. Consider, Public (Buyer). Merchant. Tele Marketing Executive(TME). Marketing Executive(ME). Lead Generator.....
2
votes
1answer
232 views

Changed root password from '<blank>' to '<password>'. Now cannot connect to databases in Cloud SQL prompt

I changed the root password using Google APIs SQL Prompt from blank to using: UPDATE mysql.user SET password = PASSWORD('<password>') WHERE user = 'root'; It has been documented here that ...
1
vote
2answers
4k views

MYSQL matching one column to another in a different table via a FULLTEXT index

I current have two different tables. The first table has a list of titles and IDs associated to these titles, the second table is a list of random heading. What I would like to know is if there is a ...
0
votes
1answer
174 views

MySQL Migration from Slave to Master

I recently had a problem with our server. It required us to install a new hard drive, cpanel, and setup the old hard drive as a slave. How can I migrate the mysql database from the slave drive to the ...
0
votes
2answers
180 views

Storing complex userdata

Assume a tool where one can create an useraccount, then store 'fields' for that account. Each field can contain zero or more 'sub-fields' and each of those can contain zero or more strings. I wonder ...
2
votes
2answers
1k views

any documentation on tpcc-mysql benchmark tool

Where can I find tpcc-mysql documentation? I google it but I can't find any documentation about it.
1
vote
2answers
430 views

Security: writing to a file from MySQL CLI

I was testing writes to a file from MySQL CLI (locally & remotely) and I wonder what settings are preventing writes for remote users, basically I would like to make sure that it's set on all ...
1
vote
2answers
699 views

MySQL+Web-App Performance Issues using different servers

We are having a performance issue with our MySQL servers that does not make any sense. I have read countless articles from many people (mostly Percona) and have made my.cnf tweaks. We have even manage ...
2
votes
2answers
3k views

How do I use MySQL Workbench to edit an existing, in-production database?

This is basically a repost of this question, which didn't give a satisfactory answer. I'm finishing up the design of a database using an EER diagram. I now want to forward engineer and import the ...
0
votes
0answers
290 views

setup mysql row-based-replication without downtime?

Is it possible to use setup rbr on a mysql server (current version happens to be 5.5.31) to a slave without incurring downtime? (and if "yes", how?) My thought is first to configure the master and ...
2
votes
3answers
2k views

index mysql concatenated columns

I have a table for author names with two fields, first_name & last_name, both varchar(55), both nullable (for crazy business logic reasons) although in reality last_name is unlikely to ever be ...
1
vote
2answers
2k views

/usr/sbin/mysqld was deleted and replaced by another mysqld with different inode

This happened on three of our mysql server running on RHEL. While checking for open and deleted files, I found that mysqld in use is deleted (as seen in lsof) and was replaced by a similar mysqld (in /...
2
votes
1answer
281 views

Is the key_buffer_size applicable to myisam tmp tables?

I have a database about 750GB in size. It's all innodb. Larger analytical queries often need to group by several columns or use distinct so it's common that MySQL will have to create tmp tables. The ...
4
votes
1answer
2k views

Update one table from another table while sorting that table based on one column

This is the problem I'm trying to figure out in MySQL. We have an old table contains some forms submitted by our users. Somehow, the previous decision was each time a user comes to this survey, a new ...