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
votes
1answer
9k views

MySQL: Create multiple tables with one query

Can you list multiple table names in a MySQL CREATE TABLE query? CREATE TABLE table1, table2, table3 LIKE table_template; If so, can you do it with the IF NOT EXISTS clause? CREATE TABLE IF NOT ...
5
votes
4answers
9k views

Handling a big table in mysql

I have a really big table (approx. > 100.000.000 rows and a size of > 50GB) and it's getting a big performance kill right now. Beneath the primary key (id) it uses a fulltext key on a varchar(500) ...
17
votes
5answers
52k views

How to properly kill MySQL?

I have CentOS 64bit with CPanel installed and I use service mysql stop However, it keeps doing ..... for minutes and it never stops. It used to be instant. Any idea why it does that and how to fix? ...
0
votes
0answers
56 views

How to properly kill MySQL? [duplicate]

I have CentOS 64bit with CPanel installed and I use service mysql stop However, it keeps doing ..... for minutes and it never stops. It used to be instant. Any idea why it does that and how to fix? ...
0
votes
1answer
2k views

MySQL Fulltext match with forward slashes

I'm trying to run a fulltext match against a product database, where the product names have forward slashes in them. These are staple sizes, so it's quite important that they get matched. However, ...
1
vote
3answers
5k views

MySQL Table not repairing

Table info: Database name: user_motiva Table name: wp_options.frm wp_options.MYD wp_options.MYI wp_options.TMD when I do a mysqlcheck -r --all-databases it gets hung on that table even if you ...
1
vote
1answer
9k views

Error 1044 Access denied to user

This is driving me crazy. When I try to create a few tables from my Workbench model I get this error 1044. I've been trying to find a solution but nothing works for me. Curiously when I run ...
7
votes
1answer
7k views

Slow Queries Not Logging

I am attempting to enable slow query logging on our server in order to identify any queries that could use optimization. Sounds simple enough, however my file is not being written to. I get no errors ...
2
votes
1answer
967 views

SQL Uniqueness Across Multiple Tables

I have two SQL tables: Users and clients. Every row in the users table has a set of clients in the clients table, linked by the users table id field and the clients table user_id field. The users ...
1
vote
1answer
248 views

Sleep Processes are Running Longer Than Allowed

From time to time my mysql server will run into a "too many connections" error. I believe part of the problem is large amount of sleep processes that are running, some over 1000 seconds. When ...
1
vote
2answers
283 views

Multiple database servers for performance vs failover

If I have two database servers, and I am looking for maximum performance vs high-availability, what configuration would be best? Assuming the architecture is two load-balanced web/app servers in ...
0
votes
1answer
68 views

Two dichotomy views of a table, and means to express this as a stored procudure?

There is a table events. Some relatively complex logic determines for each event whether it is archived. Then I need two more views: All archived events and all not archived events. How to express ...
2
votes
2answers
5k views

MySQL Replication without stopping master

I am currently setting up a replication for my database one of the ways i am thinking of synchronizing the master and slave without write locking the master, is by first taking a log position then ...
1
vote
1answer
5k views

mysqld_safe version different than mysqld?

Is it a problem that mysqld socket has a different version than the mysqld server? I noticed this in my mysqld log during startup 120420 19:30:06 mysqld_safe Starting mysqld daemon with databases ...
6
votes
1answer
13k views

Error when dropping InnoDB database

I am trying to drop a database in mysql, but every time I get this error ERROR 2013 (HY000): Lost connection to MySQL server during query even logged in as root. Originally, I had a corrupted ...
3
votes
2answers
2k views

moving to AWS RDS (InnoDB vs MyISAM

I am in the process of moving my servers from stand alone hosting to AWS using RDS (MySQL) for database usage. One of the first things RDS states is that in order to use their backup, and snapshot ...
1
vote
1answer
4k views

How to copy MySQL Database from Linux to Windows?

I would like to copy a MySQL database form Linux to Windows, from a little research I found this url http://www.cyberciti.biz/tips/howto-copy-mysql-database-remote-server.html where the author says we ...
6
votes
2answers
4k views

A database in MySQL is a schema in Oracle : I do not understand this statement

Please help me understand this statement: A database in MySQL is a schema in Oracle. I have just started to use Oracle and I find it different from other RDBMS softwares I have used like MSSQL, ...
4
votes
1answer
6k views

Enable MySQL to use more than 1 core (multicore) [duplicate]

I am running a very intensive MySQL query and noticed that only 1 core is being used to 100% while the other cores are idle. The system is running Ubuntu 12.04 and MySQL 5.5.28 Is there a way to ...
0
votes
3answers
4k views

How to avoid deadlock while updating 2 rows in MySQL

This is a interview problem: There is a perl program that updates the database, and it could run in different processes. One process may execute a transaction like: update row A -> update ...
0
votes
1answer
301 views

how to avoid deadlock while updating 2 rows in mysql [duplicate]

This is a interview problem. There is a perl program that updates the database, and it could run in different processes. One process may execute a transaction like: update row A -> update row B -> ...
0
votes
1answer
810 views

Unable to restore dump file in mysql5.5 [duplicate]

I'm trying to restore a mysql5.5 dump file using mysql command prompt using the command given below: mysql> -u <username> -p <password> <dbname> < <dumpfile> But it is ...
2
votes
2answers
2k views

mysqldump: flush-privileges option

I'd like to get some clarification about the --flush-privileges option for mysqldump. Here's the description of the option from the MySQL docs: --flush-privileges Send a FLUSH PRIVILEGES ...
1
vote
1answer
91 views

How does MySQL determine the 'index first key' and 'index last key' with indexes?

In other words, how does MySQL find the result range with indexes on the first step when it's executing a select query?
3
votes
1answer
116 views

Process sessions foreach minute

I have a table that stores sessions. The columns are: ID, Start (Timestamp) and Stop (Timestamp, can be NULL). It's for online radio. A listener connects to the stream, and a row is created. Once ...
1
vote
2answers
75 views

MySQL design problem

I have nearly no experience in database design, so forgive me if I'm asking something super nooby and ridiculous :) I have an item I need to create. This item will be constructed from 3-4 types of ...
19
votes
2answers
21k views

Possible INDEX on a VARCHAR field in MySql

I am working in a MySql database, with a table like this: +--------------+ | table_name | +--------------+ | myField | +--------------+ ...and I need to make a lot of queries like this (with ...
2
votes
1answer
1k views

How to improve INSERT speed in large table that has unique constraint

I have a simple MyISAM table: explain entities; +------------+-------------+------+-----+-------------------+----------------+ | Field | Type | Null | Key | Default | Extra ...
0
votes
1answer
141 views

Implementation of stack in MySQL

I had an abstract idea of implementing a stack in MySQL. Tried a lot of Google work but couldn't reach to any logical conclusion. The Stack must be a collection of tables with the stack top pointing ...
1
vote
2answers
63 views

Need logic to collate data

I have a table in the below structure. phone bigint answer_time datetime I should group all phone numbers, and its total number of attempts and mention its no:of time answered and no:of time not ...
1
vote
2answers
59 views

Separated databases, separeted datas

We have a global project. We will have some servers all continents. We separate the datas because it is not necessary that they be in one place together. BUT! We need unique IDs (MySQL, InnoDB). I ...
1
vote
0answers
187 views

Replication issue - CREATE SELECT alternative?

I've an MySQL 5.1 slave for our BI team. They need to make some CREATE SELECT with big select queries (several million lines). As CREATE SELECT is a DDL, if the replication attempts to update some ...
1
vote
1answer
377 views

INSTALL PLUGIN 'rpl_semi_sync_master' SONAME 'semisync_master.so' not working

I'm trying to install semi synchronous replication in my mysql 5.5 and trying to execute the below command: INSTALL PLUGIN 'rpl_semi_sync_master' SONAME 'semisync_master.so' but this command is ...
0
votes
2answers
1k views

How to take a database dump for selective set of values in few tables?

create table foo (id, val1, user_id,...) create table bar (id, foo_id, val2, ...) create table baz (id, bar_id, val3, ...) select * from foo where user_id = 1; select * from bar where id in (select ...
1
vote
2answers
3k views

Unable to change engine to MyISAM in MySQL

I have installed MySQL 5.6.10 on Mac OS X 10.6.5. My issue is that MySQL is using InnoDB as its default engine. I have checked following engines are supported in MySQL: show engines\G ************...
5
votes
2answers
2k views

How much data is needed to show MySQL Cluster's performance scaling vs. InnoDB

I am evaluating MySQL Cluster as a possible replacement for an InnoDB schema. So far, I have tested it with 10s of MB of data, and found MySQL Cluster slower than InnoDB; however, I have been told ...
3
votes
1answer
1k views

MySQL specific database configuration file

In MySQL's configuration file I've globally disabled autocommit as so. [mysqld] autocommit=0 I need to turn MySQL's autocommit on for a specific Ruby on Rails database though. It could be for the ...
1
vote
1answer
555 views

mysql query - how to delete duplicates based on highest int?

I'm running a reverse auction website and I need to delete the duplicate bids and keep only the highest amount . lastPriceBid_rounded is the "amount". The duplicate is defined by the userId. +-------...
0
votes
1answer
44 views

Which text-index I should create for xooops engine to achieve better search results?

In one of projects we use xoops engine to manage content. In mysql slow query log most of queries are following : SELECT p.uid,f.forum_id, p.topic_id, p.poster_name, p.post_time, f.forum_name, p....
0
votes
1answer
694 views

Making a message system

I have created a messaging system with MySQL structure is as follows `message_id` int(11) NOT NULL AUTO_INCREMENT, `message_from` int(11) NOT NULL, `message_to` int(11) NOT NULL, ...
1
vote
1answer
100 views

MySQL Replication using SSL

I am in the process of replicating my database so i can have a master slave configuration, one of the issues i have is with security i am basically generating my server/client keys and certificates ...
2
votes
0answers
93 views

How can one improve the performance of a query that selects on a low cardinality column in MySQL?

I have a "State" column that has a low cardinality (three possible value), on which most of my queries perform an equality selection (WHERE col = 'blah') AFAIK you need something like a bitmap index ...
1
vote
1answer
1k views

mysql restart won't kill child processes on CentOS

I have a mysql database running on a CentOS server. I have noticed that, when left to run for several weeks without restarting the service, then when I need to do a restart (/etc/init.d/mysqld restart)...
1
vote
1answer
2k views

View dropped, now shows as table “in use”, can't drop

I have a view on a MySQL/MyISAM setup, then the underlying table had a column dropped, and made that view invalid. I tried dropping the view so I could recreate it, then MySQL said it was a table (...
2
votes
1answer
770 views

Is it okay to have different lower_case_table_names value on master and slave?

I have a OSX MySQL master with lower_case_table_names set to 2. I have just setup a Linux MySQL slave with lower_case_table_names=1. I haven't started replication on the slave, but everything looks ...
3
votes
1answer
1k views

Why is InnoDB auto_increment column skipping over large blocks of unused values?

We have an active and important InnoDB table with about 8M rows. We just noticed that for several months, the primary key value (a BIGINT) has been jumping by hundreds at a time. I turned on query ...
1
vote
1answer
143 views

Is there a tuning parameter for MySQL that allows you to set an on-disk gap between non-sequential primary keys?

I understand that one of the primary issues with using a non-sequential primary key is that every disk/memory write that does not come after the last known key causes a re-write of everything from the ...
1
vote
2answers
2k views

How to get non repeat results

I've two tables default_tb_persona and default_tb_envio, this are the DDL for those tables: CREATE TABLE `default_tb_envio` ( `codigo` varchar(7) NOT NULL, `fecha` date NOT NULL, `id_modalidad` ...
1
vote
2answers
580 views

managing a growing database in the long run (10 years from now)

I'm close to finishing-up a WEB app (PHP + mysql website portal), which will start slowly, as in uploading few pictures and inserting few rows in main database table, but soon, and over few years, I ...
1
vote
1answer
620 views

Group By days interval (aging type)

I would lIke to have Mysql group by days interval for example group by every 20 days from current day, like 1 - 20, 21 - 40, 41 - 60 and son on up to lets 120 days. The user can choose the days ...