MySQL 5.5 brought many performance enhancements and expanded the feature set of the popular open-source RDBMS.

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Why does this ALTER TABLE ADD FOREIGN KEY query create two foreign key constraints

I am attempting to add a foreign key constraint to existing tables via an ALTER TABLE statement: CREATE TABLE `blog` ( `blogid` int(11) NOT NULL AUTO_INCREMENT, `deptid` int(11) NOT NULL DEFAULT ...
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68 views

MySQL Dynamic columns duplicate value workaround

As the title suggests i have the following code which transposes certain row values into field names, however the problem im having is that the values "closed" & "reopened" may appear in several ...
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1answer
84 views

Why are tiny Innodb row updates causing so much disk IO?

This is a followup question to my earlier How can I determine which Innodb table is being written? Using the accepted answer from the above-referenced question I was able to determine which (two) of ...
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1answer
68 views

How can I determine which Innodb table is being written?

I am running Mysql 5.5. I have about 100 Innodb tables spread over 10 DB's (mostly wordpress sites) and I am recently seeing a lot more disk IO than I have been, without any increase in traffic. The ...
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2answers
147 views

Find total duration of each consecutive series of rows

MySQL Version The code will run in MySQL 5.5 Background I have a table like the following one CREATE TABLE t ( id INT NOT NULL AUTO_INCREMENT , patient_id INT NOT NULL , bed_id INT NOT NULL , ...
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62 views

How to use a subquery that returns multiple rows?

I am getting Error 1242 : Subquery returns more than 1 row. Basically, I have to do this : select data from my database based on a time criterion (between 2 dates) and then apply a filter on the ...
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1answer
42 views

Unique constraint for new values only

I have a large table with a column that contains duplicates. I want to add a unique constraint on this column for future entries only (not the old data). Is this possible?
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544 views

Combine and display multiple row data with same column data in MySQL

I have a menu, from where every item ordered is stored in a row. For a single order, there can be multiple rows.What I want is that when I display it, for same order_number ( number) all rows data is ...
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1answer
70 views

MySQL Workbench - “deploying” schema into a real database

a noob here, finding my way around. So, how can I "transfer, deploy or whatever the right term is" the database tables, fields, etc. that I have created with Workbench into a real database? The dB I ...
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2answers
119 views

Is there a (non-binary) MySQL collation that doesn't treat different mathematical symbols as the same character?

I've run into a real headache with MySQL's collations and non-BMP characters (ones with Unicode codepoints above U+FFFF). Basically, given a table and data like: CREATE TABLE `math` ( `id` int(11) ...
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1answer
115 views

DELIMITER issue in MySQL 5.6

Drop procedure if EXISTS rotatepjp; DELIMITER // CREATE PROCEDURE rotatepjp() BEGIN DECLARE u_id, settingval, pjp_userid, pjp_beatid, u_frequency INT; DECLARE u_pjpstartdate, pjp_fordate, ...
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43 views

import text file getting command is not allowed with this MySQL version

here is my table CREATE TABLE cities ( country CHAR(2), city_ascii VARCHAR(100), city VARCHAR(255), region CHAR(2), population INT UNSIGNED, ...
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1answer
70 views

Is it possble to replicate MySQL server on Azure virtual machines

I have two Windows Server 2012 R2 virtual machines on Azure. I need to replicate the database on each of the windows servers. I have followed this link but I am not getting the connection between the ...
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0answers
268 views

Server version (5.5.40-MariaDB) does not match with the version of the server (10.0.15-MariaDB) with which this program was built/distributed

I just upgrade MariaDB (Mysql) 5.5.40 to MariaDB 10.0.15 by following this step by step. I have failed to enable the mysql and also mysql_upgrade with the following errors mysql_upgrade -u root -p ...
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0answers
45 views

Access Denied to users after upgrading mysql to 5.5.40

I recently upgraded mysql from 5.1.0 to 5.5.40 but suddenly some users seem to have lost the previlages. All the projects are live and those with issues are showing database connection error. How can ...
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1answer
91 views

MySQL - Get Minimum Value, Data From Multiple Tables

Good evening all, first post on the DBA forums. I am having real issues working out how to accomplish a seemingly simple task within MySQL as a model for PHP code later on. I am not exactly a MySQL ...
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3answers
127 views

mysql replication master 5.5 slave 5.1 error on create database

I have a replication system where my master has a mysql 5.5 version while the slave is mysql 5.1. I know that this is not supported because the slave version should be greater than the master, but we ...
2
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1answer
68 views

View last several innodb deadlocks

I see that I can view the latest deadlock in mysql/innodb, but is there a way to view past deadlocks? We have two deadlock issues, one being important and the other not. The less important deadlock ...
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1answer
89 views

When try to do Mysqldump Backup from console then getting such as error [closed]

mysqldump: Got error: 2003: Can't connect to MySQL server on 'localhost' (10061) when trying to connect when i am tring to do MySQLDump backup from console then getting such as above error. I am ...
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0answers
30 views

MySQL JDBC Driver puts transaction in read only. Why?

Using the MySQL JDBC connector with a MySQL 5.6.22 data source defaults the transaction mode to read only. Anyone know why?
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1answer
43 views

Finding out the exact size of the database after inserting records?

I have this query: SELECT table_schema "db.name" , Round(Sum(data_length + index_length) / 1024 / 1024, 1) "DB Size in MB" FROM information_schema.tables GROUP BY table_schema; Does this ...
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1answer
1k views

MYSQL query to find records between two date range

I am working in a web application using PHP and MySQL. I have two tables Employee employee_id email_id 3 tl1@jasmine.com 4 agent1@jasmine.com 5 ...
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1answer
46 views

Hierarcy Query Mysql

I have a table like this... ========================================================================== UID || PARENT ID || SPONSOR ID ...
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18 views

Can MySQL Index Merge an Composite index with a single column index?

I am tuning a query and currently have an index as following : Index 1 : (col1, col2) An example query would be : SELECT * FROM t1 WHERE col1 = '1' AND col3 = '2'; I have created an index on ...
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27 views

Mysql Master - Master Replication

i have established a master A and master B replication between two servers.Both are getting replicated.But it is limited with only one database. My questions 1.How to create a new database in ...
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55 views

Slow Query Performance - Can't Debug

I have a MySQL query that I am trying to debug the performance issue but cannot. I know that the majority of the query is reading/processing rows (Sending Data state). However, in the explain output, ...
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26 views

Oddness with MySQL with InnoDB - CPU capped at 50%

I have MySQL 5.5.22 with InnoDB, running on multiple c3.8xlarge EC2 instances. Which is to say, the VMs are set up with 32 CPUs & 59 GB RAM There are no CPU controls in MySQL, right? Then why ...
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1answer
34 views

Queries that ran, and the number of times they ran

I want to profile a running web application in dev on a mysql 5.5 database. The web application uses hibernate and I am able to see that a rather large number of queries are run against the database. ...
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23 views

unable to add data source on idashboard admin

I am in the process of adding data source on iDashboard , Data Source section. So, for that I downloaded the driver from here which is mysql-connector-java-5.0.8-bin-jar and currently trying to enter ...
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2answers
108 views

One to many join, Sum from both table

I have two tables: orders and ordersdetail...(partial table) orders- id(primary key), amount, date( index) orderdeails- id(primary key), skunitid, quantity, order_id Each order has multiple order ...
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1answer
61 views

MySQL Latest Deadlock Explanation

Can someone explain this deadlock to me? It seems as if there are 2 inserts happening within milliseconds of each other with the same Primary Key. I'm not sure how this can cause a deadlock. At most a ...
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1answer
51 views

SQL INSERT and UPDATE queries run far to slow

I have two queries that run far too slow and I have no idea why. Both tables contain about 500000 rows. Each call needs ~20 minutes and the they have a really high CPU usage (~90% on Mac). I have ...
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1answer
716 views

Why mysqldump is returning with error 1143: Couldn't execute 'show table status like

I ran the following command to create a mysqldump mysqldump -ubackup -psomething --single-transaction --quick somedatabase | gzip > 4_19.gz I got following error after 60% (estimating checking ...
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1answer
269 views

Many mysql queries stuck at sending data

I am using opencart and I can se many queries blocking the mysql server. All queries are the same except the p.manufacturer_id. Attached there is the query and the explain of the query. The query is ...
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4answers
110 views

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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316 views

How to solve MySql Slave Error 1452 Foreign key constraint fails?

I am site administrator. We use to have a mysql 5.5.40 master(db01) - slave(db02) setup. One day our master server (db01) got down due to hardware failure. So we switched our site to slave (db02) ...
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2answers
114 views

Why wouldnt Mysql use index on the Primary query in a nested query

I have two tables: search_criteria and pricing. There is an index on search_id column in search_criteria table and on pricing_id column in pricing table. But running this nested query does not use ...
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189 views

How do I recover from MySQL InnoDB table/index corruption?

While trying to upgrade a database (in place) I got the following error. The server starts up and everything seems to be fine, except that the table mentioned in the message is no longer accessible. ...
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19 views

Trying to create a trigger to fill two columns (MySQL)

I am trying to create a trigger to update columns on a table when a new record is added to another table. This is the code I am using CREATE TRIGGER `hire` AFTER INSERT ON `hire` FOR EACH ROW BEGIN ...
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1answer
76 views

Adding a primary key to an existing table in mysql is taking time

22 hours ago I started a script that executes an alter table to add a primary key to a table which has 225 millions of records. MSISDN is the only column. In showproceslist its process status is ...
2
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1answer
131 views

How much space is needed to reclaim space from a table in INNODB

I inherited a MySQL InnoDB table that has approximately 200 GB worth of data, as well as several unneeded indices that amount to approximately 500 GB. I've archived approximately 75 percent of the ...
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3answers
240 views

Bulk Delete for Large Table in MySQL

I have a Notification table contains about 100 million rows host in Amazon RDS with 1000 IOPS, and I want to delete those rows older than one month. If I do DELETE FROM NOTIFICATION WHERE CreatedAt ...
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2answers
150 views

How to batch multiple insert statements for database dump with MySQL?

I have a MySQL database with some large tables. In particular, the largest table (by far) currently has ~11,000,000 rows. According to the a query I ran, the table clocks in at around 1.7GB, but it's ...
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25 views

Daemon Waiting for activation in mysql event

When I do, SHOW PROCESSLIST; on mysql, for my event, I see the following result: Q1 )Why does it shows Waiting for next activation all the time? Q2) At times my scheduler turns off which causes my ...
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81 views

Configuration help my.cnf Mysql

Is the following my.cnf file OK for a dedicated server with 56GB of RAM (on ubuntu server and 8 processors)? I'm running just one website on the server and there is a high demand on my cpu from ...
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1answer
25 views

Failing to get multiple values using join

I have below scenario: create table t1 (id int, title varchar(20), description varchar(20)); create table t2 (id int, info1 varchar(20), info2 varchar(20)); create table t3 (id1 int ...
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300 views

Lost Connection to mysql server at 'reading authorization packet', system error 0"

OK, this has been bugging me all afternoon now, I have a new MySQL Database '5.5.40-0+wheezy1-log' running on Debian Linux. It is to all extents and purposes a clean install. I have created two ...
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480 views

Following mysqltuner suggestions: query_cache_size and join_buffer_size

So I am following the suggestions of mysqltuner, and so far I've had great results, the server is performing well (dedicated VPS running a large Magento eCommerce store) There is only two issues left ...
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73 views

MySQL Crash due to “InnoDB Assertion” after Query

Current setup: Ubuntu 12.04 LTS MySQL 5.5.31 Current Use: Slave - Only ETL queries 64 GB RAM Intel(R) Xeon(R) CPU X5670 @ 2.93GHz - 12 Cores - Hyperthreaded (24 Logical) MySQL Main Settings: ...
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39 views

Last synchronization time between master and slave (replication)

During replication process where a Master is connected with slave. Some times connection between these two goes down. Any options to get the details of the last synchronization time?