MySQL : Open-Source, Relational Database Management System

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What exactly do database passwords protect?

I would like to know what exactly I am password protecting on my server when I set a database password. I am unclear as to what people are referring to when saying to password protect a database. Are ...
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176 views

Where can I learn about MySQL master/slave, master/master, or clustering setups?

What are the best resources you've read or watched about setting up master/slave or clustering for database replication? I don't know much about this. I have a database that is getting rather large ...
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686 views

How do I remove duplicate entries in a given timeframe?

My table looks like this: +-----------+ | id | <- primary key | time | <- DateTime | row2 | <- varchar | row3 | | ... | +-----------+ I want to remove all ...
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1k views

MySQL ignoring some params from my.cnf

I have a virtual box with 2 installed instances of MySQL. First instance: - /etc/mysql/my.cnf - /var/lib/mysql - port = 3306 Second instance: - /etc/mysql2/my.cnf - /var/lib/mysql2 - port = 3307 ...
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6k views

MySQL Workbench, how to refresh EER diagram?

I'm using MySQL Workbench to design my MySQL database and model how entities would look like and how they would relate to each other. Now, sometimes I use Doctrine ORM. When using Doctrine ORM, I ...
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156 views

mysql: show which users have permissions to a DB

Is there a way to show all users that have permissions on a database? I'm looking for something like: > show_permissions_for_db <DB>; +----------+----------------------+ | User | ...
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2answers
3k views

MySQL - INSERT INTO … SELECT … UNION

I'm having an issue with a fairly complex query where I need to store the ids from one table (based on heavy criteria) into a narrow, alternate table for future reference, but I keep running into a ...
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246 views

Mysql slows down temporarily after large file copying

We have a MySQL 5.0 server on a Centos box. 32GB memory. We have only one harddrive, 374GB capacity, 50GB available. All our tables are MyISAM. When we copy a large file (2GB-3GB) within the hard ...
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1answer
128 views

Help Optimizing Query

For the following table structure in MySQL 5.1.49: CREATE TABLE `leads` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `institution_id` int(10) unsigned NOT NULL, `lender_id` int(10) unsigned ...
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266 views

Does this cause overhead ? Select name from User where user_name LIKE '%alex%'

I'm wondering if this statement can cause real overhead if many concurrent users send the same request to mySQL InnoDB storage engine. Let's say I have a table that has the user_name, and someone want ...
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1answer
447 views

For 768M RAM server is 617M allocation in my.cnf good or bad?

I have a write-intensive web app, and I bought a VDS with 768M RAM Is this my.cnf good for my purposes? I specified bulk_insert_buffer_size to 126M and some other parameters as below: ...
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206 views

Why are my results returned twice?

I've this query: SELECT DISTINCT `default_wall_posts_comments`.`c_id` as c_id, `default_wall_posts_comments`.`comments` as comments, UNIX_TIMESTAMP() - default_wall_posts_comments.date_created ...
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3k views

Shell Script / Tool to check the MySQL Replication Status? [duplicate]

Possible Duplicate: Monitoring replication on mysql I am running with MySQL Master/Slave Replication on Linux. Is there any tool/Shell script which monitors the Replication Status and send ...
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430 views

Where can I find a good tutorial or book for various MySQL performance guidelines? [closed]

Can anyone refer me a good book or a small tutorial for various use cases for database design on MySQL for high load test/high availability scenarios. It should include the following: What are ...
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2answers
762 views

Database Design - Employee Clocking In and Out System

I want to develop Employee Clocking In and Out System (website). I am concerned two things: If staff forgot to 'Clock Out' from yesterday and they have 'Clock In' today, it should flag to the ...
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2answers
262 views

How to recover previous values in Mysql Table?

I have MySQL Innodb table of 14M rows. There was a coloumn called is_disabled which had different values. By mistake I ran the query without the where clause: update url_queue set is_disabled=1 ...
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1answer
210 views

Randomly generated password for mysql admin over time?

I have this idea of making my database's Admin account secured by creating the following: Trigger is activated every hour in mysql this trigger activates a stored procedure Stored procedure ...
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673 views

Mysql master-master permission replication issue

I came to know it's safe to replicate mysql database to have the users and permissions replicated, from a post in ServerFault is-it-ok-to-replicate-mysql-db. I have setup master-master replication ...
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2answers
1k views

Join three tables

I have those three tables SELECT occuId as 'Occupation Id',occuDscr as 'Occupation Description' FROM occupation_field; +---------------+------------------------+ | Occupation Id | Occupation ...
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5answers
770 views

MySQL Replication monitoring [closed]

Im looking for a tool that could help me and my team monitor our MySQL Replication. I would love for a tool that could alert me if Seconds_Behind_Master passes a threshold Slave_SQL_running is ...
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2answers
776 views

MySQL UPDATE Performance Issue

I'm running out of ideas on a performance bottleneck I'm seeing on one of my projects. The table in question is pretty small, with only 5396 records. However, I'm seeing queries like this show up in ...
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1answer
357 views

Simple select statement not returning correct data

I am trying to return data, where I want the item name (items.name), vendor name (vendors.name), url of the price (prices.url), and the price (prices.price) from 3 different tables (items,vendors and ...
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2k views

MySQL: Trying to update to 5.5

I've followed this instructions, but after mysqld --skip-grant-tables --user=mysql, I'm getting this: 110913 20:29:18 [Warning] Can't create test file /var/lib/mysql/my-laptop.lower-test 110913 ...
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1answer
120 views

IF statement in ON clause

Can you help correct the syntax for this code? INNER JOIN Users u ON case when c.sender = ? then c.reciever = u.id else c.sender = u.id How do I do I put a CASE statement in a JOIN clause?
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How to backup live mysql database?

I have 12 GB MySQL InnoDB Database with around 800 queries per second. No sooner I start 'mysqldump' over it to make backup I start getting '503' on my website. How do I make backup of my live ...
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101 views

MongoDB Manual References vs DBREF

I've been researching MongoDB and trying to see if it would be a fit for my company's product catalog. I came across database references: http://docs.mongodb.org/manual/reference/database-references/ ...
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79 views

Does the order of a mysql multi-column MySQL index matter - if you're always using all columns in the query?

I'm aware that when you define a MySQL index that the order of the fields matters if the query is only using part of the index, as described here. But if your query is always going to use all columns ...
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110 views

Upgrading hardware for MySQL. If we get SSDs, are CPUs likely to become a bottleneck

We are upgrading hardware for a MySQL database server (DB is around 200GB). We're getting 4x Samsung 850 Pro SSDs and are planning to run them in a RAID10 configuration. Also, 128GB of RAM. The ...
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236 views

Very high load avg for MySQL database [closed]

I have a backend server which response to my clients app, it has more than 20k~25k hit per second and this make my server load average very high, I believe that my MySQL config is not appropriate. In ...
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1answer
77 views

MySql - unique key not working

I have the following table: CREATE TABLE `timeline_lists` ( `id` int(11) NOT NULL AUTO_INCREMENT, `user_id` int(11) NOT NULL, `list_type` int(11) NOT NULL, `s_object_id` int(11) NOT NULL ...
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2answers
178 views

Get only the oldest entry in a join

So I have a table bugs |bugid| title| the table is lacking a date column. But when creating a new entry, most likely always a new entry gets created in bugnotes as well saying "bug created" with the ...
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103 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 ...
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1k views

Checking if an Username is already in use

I am writing some scripts for my website, and I am currently focussing on checking if a username is already in use. I have tried writing a SELECT script where the datafield is selected and checks if ...
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2answers
140 views

mysqld constant CPU usage when absolutly nothing is connected and no queries

I'm using mysql on a windows development machine, and all was good for a long time. But today my PC was running slowly, and I noticed mysqld.exe is using between 25% and 40% CPU. I've tried ...
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3answers
286 views

Block user access to certain tables

DBMS allows the admin to grant table access to a user using something like: GRANT ALL ON mydb.mytbl1, mydb.mytbl2 TO 'someuser'@'somehost'; However, is it possible to grant all tables to a user and ...
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1answer
78 views

Why am I getting different results from a query vs. a view

The base problem I'm facing is that I need the latest record for each item. A little setup... MySQL 5.6.14. I need to create two views (because MySQL won't let me have a subquery in a view). My ...
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1answer
284 views

Which is better MAX function or ORDER BY column_name DESC with LIMIT 1

I have one scenario where I want to have max value on date column, eg. for table CREATE TABLE IF NOT EXISTS `sample_table` ( `id` TINYINT UNSIGNED NOTNULL, `name` VARCHAR(45) NOT NULL, ...
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136 views

Will redirecting queries to dev/null warm up indexes?

I'm trying to warm up the buffer pool. Will running a query and re-directing the output to /dev/null suffice? e.g. mysql -u username -p -e "select id from tbl where 1=1" > /tmp/results.txt Thanks
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52 views

Mysql Master Offline

In a unidirectional Master-Slave setup, should the slave be manually stopped in cases where the Master is offline due to Maintenance, Crash etc. ? Or should one just leave it so that it keeps trying ...
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168 views

Securing Your MySQL Server within your team?

Recently I have been having an issue with our internal team members changing the password of the root user. I noticed the following things: OLD_PASSWORD = 1 (So all passwords on our development ...
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3answers
624 views

Why does MySQL slow down in loading data?

We have a really large file (26GB) that we need to upload to MySQL. In order to do so we split it into nine 3GB files. What's confusing is that the first file took only 2 minutes to load, whereas the ...
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1answer
123 views

creating table result in errno 150

I'm trying to create the following schema, but I'm getting errors when I'm trying to create project and staffphone tables. Not sure what is it complaining about. mysql> CREATE TABLE staff( ...
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1answer
199 views

Best way to add a new column to a large table? (MySQL - MyISAM)

Here's more info on the table that needs to be altered: 15GB size MyISAM table with Index around 5GB Over 100 million rows MySQL 5.1 on RHEL 5 with 4GB RAM Currently live online What's the best ...
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1answer
406 views

what effect does changing the data type of an existing indexed field have on the index?

I have a few MySQL tables and I want to change the data type of some of the existing fields. The fields already have some single and multi-column indexes on them (all of which are type = "Normal"). I ...
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1answer
131 views

Understanding MySQL's 'explain'

I have following query with explain: mysql> explain select dd.data from dane dd join test1.tag1 t1 on dd.id = t1.id join test1.tag2 t2 on dd.id = t2.id join ...
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273 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 ...
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4k views

How to make MySQL table name case insensitive in Ubuntu?

I am using Ubuntu 13.10 and MySQL 5.6 and I know database name and table name are case sensitive in Ubuntu (and some other *nix environments) by default. Now, I want to make MySQL work as case ...
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178 views

MySQL server wont' start. Reason: Internal error

The very vague error message Reason: Internal error I've had this happen before, and it usually fixes itself after I restart my machine, but after the 4th time now it still is showing the error :( ...
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1answer
117 views

Join Query effects natural ordering [closed]

If we have 2 tables **user** +----+------+------+-----------+ | id | user | pass | gender_id | +----+------+------+-----------+ | 1 | lisa | good | 11 | | 2 | jack | pass | 10 | | 3 ...
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2k views

revoking mysql table level privileges

I have a mysql user account who has following Global privileges GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, PROCESS, REFERENCES, INDEX, ALTER, SHOW DATABASES, CREATE TEMPORARY TABLES, LOCK ...