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

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How to turn Event Scheduler On permenantly in mysql

How do i turn on the event scheduler in mysql permanently. I'm using phpmyadmin and i have scheduled an event to copy records from one table to another everyday at a specific time, but the records are ...
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66 views

MySQL: How to write a recursive function to show menu tree?

I try to build a menu tree inside the SQL with this function: DROP FUNCTION IF EXISTS hello_world; DELIMITER $$ CREATE FUNCTION hello_world(_typeId INT, _typeText TEXT) RETURNS TEXT BEGIN ...
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14 views

MySQL 5.5 only use 1 thread and 30% cpu

i have a big issue, every day i need to update or insert like 3.3 milion rows, i have trying to do what ever i can but it still only run like 605 query/s i use VirtualBox so my setup are testing on 1, ...
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44 views

mySQL running on 100% CPU both on RDS and EC2

How do we troubleshoot an issue with Amazon wherein my database queries (PHP/MySQL) are eating 100% CPU most of the day? Traffic=200 connections average mySQL version = 5.5.40 The ...
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1answer
86 views

mysqldump doesn't restore database. why not?

Why doesn't my restore operation work? I created a dumpfile for a database using: mysqldump -u root -p databasename > /home/databasename_bkup.sql I then opened the dumfile and confirmed ...
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148 views

Table Design for Student Attendance hourly for each day

I have created a table (attendance_details) for storing every day attendance of Students in MySQL. Need to capture attendance for hourly (1-8hrs) every day. I have the student details in separate ...
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67 views

Is it a waste to set innodb_buffer_pool_instances greater than the # of CPUs?

I set the innodb_buffer_pool_size to 20GB on a server with 12 CPU cores. My full database is 11gb, however most of it is archived tables that are almost never used. The total queried data is around 3 ...
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42 views

Slow query while selecting a higher offset from millions of rows

I have sort of security log files containing millions of rows. On my current testing I imported the data for one month which is the sum of ~14,000,000 records. The table contains several set of fields ...
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20 views

Alternative to using subqueries

Anyone please help me to optimize this query SELECT COUNT(csd.search_id) AS searches,count(distinct cd.cust_phone) as unique_searches, (SELECT COUNT(csd.product_type) FROM ...
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216 views

Centos 5.11 mysql-server 5.0.95 upgrade to mysql55w-server

Here's my thought process on my upgrade: mysqldump --all-databases > backup.sql service mysqld stop yum remove mysql mysql-server yum install mysql55w mysql55w-server service mysqld start ...
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26 views

MySQL - Is it possible to assign permission to count the number of tables in a database without permissions on individual tables?

As part of a script I am trying to count the number of tables that exist in a particular MySql schema. Using my own user I am using the query SELECT COUNT(*) FROM information_schema.tables WHERE ...
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24 views

Does creating an empty table in MySql have any effect(downtime) on production?

Disclaimer: I am, in all probability, paranoid about pushing a patch on a production server. The patch alters the schema, by creating a new table (which is empty), and changes some stored procedures ...
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54 views

How to only display a variable in PHP inside a MySQL query when it has a content or when a condition is true?

How do I only display $mon or any variable when it has content? whenever i use this syntax and for example, monday must contain the number 1 and tuesday would contain number 2 and the other ones have ...
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2answers
46 views

Need to convert date to word using trigger

I have created a datetoword function in Mysql. Checked the function working fine. Now using this function need to convert the date from field1 (date-datetype) to field2 (Varchar-datatype) within the ...
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38 views

Different Auto-increment values Mysql schema Replication

I have 6 Slave set up (EC-2, linux) and a Master ; 2 schemas getting replicated. Version info: mysql Ver 14.14 Distrib 5.5.34, for Linux (x86_64) using readline 5.1 Once in few months in one of the ...
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1answer
45 views

Large query with subquery runs indefinitely after mysql update

We recently did a big server update, in the process migrating from mysql-5.0 to 5.5.40 Several of the queries, which had been running well on the old server, now grind everything to a screeching halt. ...
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1answer
59 views

Can MySQL log lock waits?

Is it possible to have MySQL log queries or transactions where lock waits occur? One can debug specific application errors generated from lock wait timeout errors from the DB but without the ability ...
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142 views

MySQL always writes simple temporary/memory tables to disk (both tmp_table_size and max_heap_table_size are set to 8GB)

I'm struggling with this issue and just can't figure out why this is happening. CREATE TABLE sitecache._test ENGINE=MEMORY SELECT * FROM website.gallery_likes WHERE 1=0; Every time I execute this ...
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31 views

Use join to aggregate data from various normalized tables

I have a database as follows: tbl_clients (Primary Key: client_id, Foreign Keys:place_id,district_id,zone_id,country_id) tbl_places (Primary Key: place_id) tbl_districts (Primary key: district_id) ...
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1answer
77 views

Add linked server from SQL-Server to MySQL: “Data source name not found” (Error:7303)

I'm trying to link my SQL-Server 2005 on Windows Server 2008 R2 with MySQL 5.5.40 on a different computer. I have followed this guide: ...
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1answer
37 views

Purge mysql log bins older than two weeks automatically

I have to manually write purge binary logs bin to "mysql-bin.somenumbers" ; Once in a while, I need to reduce the spaces that binlogs are taking on my web server. Is it possible to purge binary ...
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1answer
46 views

MySQL Data Files Missing?

We are upgrading our website and I was checking on the size of the new database compared to the old one and was really surprised to find that in the /var/lib/mysql/ directory, the only files there ...
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1answer
44 views

Mysql Master-Slave replication catchup and bin_logs

I have set up MYSql Replication using 2x 128gig ram 24 core cloud servers. we have a massive live database that cannot experience down time due to the high volume of data input. I have found while ...
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1answer
34 views

how to overcome these type of issues where null value inserted into primary key not null column in table

how to overcome these type of issues where null value inserted into primary key not null column in table
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103 views

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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77 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
85 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
71 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
150 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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70 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
43 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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587 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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102 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
132 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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2answers
165 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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1answer
55 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
83 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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317 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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46 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 ...
2
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1answer
126 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 ...
2
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3answers
173 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
99 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
111 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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34 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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46 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
2k 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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47 views

Hierarcy Query Mysql

I have a table like this... ========================================================================== UID || PARENT ID || SPONSOR ID ...
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24 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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31 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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63 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, ...