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

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Database and query optimizacion

I have a database containing three tables: tbl_database (main table is the primary), tbl_cmdatabase and tbl_blacklist. The three tables share the same structure but differ in the number of records ...
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3k 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 ...
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6k 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 ...
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574 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 ...
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7k views

Connect Error (2054) - mysql_old_password issue still not solved

i use php 5.4.3 and i want to connect to a MySQL DB remotely (php script resides on a different server than the db) with normal oop way: $mysqli = new mysqli(DB_HOST, DB_USER, DB_PASS, DB_NAME); ...
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71 views

Contains statement Query

I need to check the string with the column if the column contains that string or not. example:String 'how to make pizza' and the column if has 'pizza' i need to fetch that.. like SELECT * FROM ...
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380 views

mysql session logging tables

I've been building a session logging system for our sites. We get around ~15m hits a year and at the moment we're really only interested in stats about people who logon to our sites. Our table ...
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1k views

`show procedure status` doesn't list all of the procedures?

mysql-server-5.5.28-1.el5.remi I'm pulling my hair with this problem: only EMS SQL Manager can list all of my store procedures (1763). mysql client, mysql-workbench, Navicat, ... only see some of ...
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6k views

Some MySQL slave errors?

Master version: mysql-server-5.5.14-1.el5.remi Slave version: Percona-XtraDB-Cluster-server-5.5.24-23.6.340 Binlog format: ROW based I'm using PRM to setup HA for MySQL. Sometime, MySQL slave ...
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168 views

How we can enable index_condition_pushdown in MySQL..?

I have optimizer_switch variable as mysql> show variables like 'optimizer_switch'; +------------------+-------------------------------------------------------------------------------------------+ ...
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926 views

String comparison with integer is not working sometimes in MySQL 5.5

I have upgraded MySQL to version 5.5. Before upgrading when we used string comparison with integer, it was working. Code is "value = 1", here 'value' is declared as varchar(45) and its value can be ...
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3k views

Sudden MySQL error: Unable to connect to any of the MySQL Hosts

I am using MySQL Community Server 5.5.18 on Windows 7. My application was running absolutely fine without any troubles but since morning it is giving strange messages while opening reports. Reports ...
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6k views

Function returning “No data - zero rows fetched, selected, or processed” in MySQL 5.5

I have upgraded MySQL version to 5.5.16 After upgrading, some of the functions are giving warning as No data - zero rows fetched, selected, or processed. In those functions, cursors are there, but ...
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1answer
36 views

mysql replication and innodb_file_per_table

Is it possible for the master (5.1) to have innodb_file_per_table = 0 and for the slave (5.1 or 5.5) to have innodb_file_per_table = 1 ?
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24 views

MySQL: Incorrect binary log format - OFF.000

I have a Percona MySQL 5.5.30 as a master(Debian 6.0.7). I got a weird issue that all my binary logs started saving in format OFF.00* instead of the specified format in .cnf file. mysql> show ...
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42 views

Why is restoration from binary logs so slow?

We have a MySQL 5.5 server with binary logging enabled and a backup script that collects the binary logs and, once a day, generates a complete database dump with mysqldump. In testing database ...
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92 views

Mysql causing high load average with large amount of server resources left

I've have 2 servers running a application and the server that runs the mysql sgbd is with the load average around 3 times more than the webserver. I think that is something wrong because i have a lot ...
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53 views

Awful execution plans after migrating from MySQL 5.5.11 to MariaDB 5.5.41

We just migrated our web site database from a server running MySQL 5.5.11 to one running MariaDB 5.5.41. Everything is working mostly fine, except there's at least one query from our storefront that's ...
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53 views

phpMyAdmin and mysql not showing the same database

I have setup WAMP which I managed by using a tutorial and everything seems fine... I am logging into mysql as the root user with full privileges granted and I am able to create databases in mysql and ...
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26 views

Installed Percona-Toolkit, but no sign of xtrabackup

I've installed Percona-Toolkit on my Debian (Wheezy) test Server, using dpkg -i percona-toolkit.deb apt-get install --fix-missing -f dpkg -i percona-toolkit.deb However, there is no sign of ...
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2answers
47 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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64 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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1answer
79 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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274 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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177 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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165 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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1k 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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2k views

Hyperthreading & MySQL InnoDB Thread Concurrency Performance

I have a dedicated DB Server with the following specs" Ubuntu 12.04 LTS Server Intel(R) Xeon(R) CPU X5670 @ 2.93GHz 12 Cores MySQL 5.5.29 64 GB RAM RAID10 We are currently doing Hyperthreading ...
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153 views

about giving same column name in every table of database

I have a database with 5 tables. In every table there is a column for checking status. If i give the name to that column which is same in all the 5 tables; What will happen? Is it correct according ...
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1answer
332 views

How to take physical backup of MYSQL database

I am trying to find out some tool which can take physical backup of MYSQL database. Like mysqlbackup but it is not open source. There is mysqldump but i want to take physical backup. Can someone ...
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1answer
48 views

How to cache query for re-use in following UNION of queries?

I need to perform query, save the result and re-use it multiple times in one session (something like WITH in Oracle DB). This is the query I want to save: SELECT `event`.id, event.name FROM ...
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186 views

insert row if table is empty, else update row (mysql)

i have 2 tables "table1" and "table2" both have TIMESTAMP cols for starttime and endtime. i want something like if (table2 is empty) insert into table2 (table2.starttime, table2.endtime) value ...
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351 views

Identifying cause of high I/O

I'm trying to diagnose the bottleneck for high-write I/O activity on a percona master (with replication to a slave). The pattern of behaviour is roughly cyclic and regular: 60 mins of 75-90% ...
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256 views

Error 2003: Setting up MySQL Replication

Trying to setup MySQL Replication using this guide here : http://wpguru.co.uk/2013/05/how-to-setup-mysql-masterslave-replication-with-existing-data/ I was able to do this on two random VMs running the ...
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637 views

MySQL - grant all privileges on *.* brings back Access denied

GRANT ALL PRIVILEGES ON *.* TO 'username'@'localhost' IDENTIFIED BY 'somepassword'; Brings back error : ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES) If ...
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1answer
102 views

Different column for different conditions when joining

I am using MySQL database and in that two tables, relation is one to many. One table is product table, sample data: +----+----------+ | id | name | +----+----------+ | 1 | product1 | | 2 | ...
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286 views

mysql fulltext query is very slow

I have one table for User detail in MySql with about 500000 records in it. I have also created fulltext index on firstname, lastname field on this table. but when I am trying to search any single ...
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836 views

How to Reclaim Data Free in InnoDB Tables?

I came up with an idea on how to shrink ibdata1 in mysql database then i got this solution on stackoverflow STEP 01) MySQLDump all databases into a SQL text file (call it SQLData.sql) STEP 02) Drop ...
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853 views

Master-Master Replication Duplicate Key

I have set two servers master-master replication mysql , i manage to set successfully but the problem is the duplicate key i got MASTER 1 Configuration /etc/my.cnf [mysqld] server-id=1 bind-address ...
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63 views

How can I make multiple joins on the same table?

I have a table (signal) which contains references to two other tables (ee and eeav). I want to perform an SQL Query which combines the data from ee and eeav tables. The situation is as follows: The ...
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1answer
101 views

How to find the length of multiple column index in MySQL

Is there a way to find out what is the length in bytes for the unique index (NKU) key created through the following command: CREATE TABLE test_ ( testId bigint(20) NOT NULL, name varchar(75) ...
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1answer
31 views

Is there any value in adding an already indexed column to a composite index?

The title says it all. Does the query optimizer see composite indexes where each column is already indexed as redundant? Or, is it used when each of the composite index's columns are in the WHERE ...
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1answer
76 views

What's the complexity of renaming a column in MySql?

We want to rename a column in our MySql (version 5.5) database with something like this: ALTER TABLE t1 CHANGE a b INTEGER; Is this an O(N) (N=number of rows in the table) or an O(1) operation? I ...
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1answer
97 views

Immigrate to file-per-table mode in MySQL

I have 20 MySQL databases and in each there are about 20 tables. All the data is saved in a file called ibData1. Now I discovered about the file per table mode but if I change the value in the my.ini ...
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867 views

Generate INSERT statement from SELECT query

I have two databases, in first database I have a table called zoom_city and in the second database I have a table called courrier_city. The SQL for each is below: CREATE TABLE IF NOT EXISTS ...
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220 views

Mysqldump --flush-logs results in small backup files?

New to MySQL and just learning how to setup a daily full backup (binary logs enabled). My goal is to run a daily full backup of the databases/schemas and reset the binary log. I'm currently using an ...
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355 views

MySQL replication: slave not updated

This has been asked many times over but we really cannot get a simple Master-Slave Mysql (5.5.25) replication to work for our two dbs (FatTree and Torus). And no trace of error in the logs. The ...
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64 views

Poor query performance in MySQL

I have a 10 million record table in a MySQL 5.5 InnoDB. It's running in a 16GB RAM server with good CPU and fast HD. When I run the following query SELECT DISTINCT knowledge_id, ...
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517 views

What happens when we take a timediff between timestamp and datetime

Say I have following table in mysql (5.5+): CREATE TABLE IF NOT EXISTS `test` ( `id` int(11) NOT NULL, `x_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, ...
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2k views

How to use LOW_PRIORITY for heavy queries?

I have scheduled heavy UPDATE queries at administrator level, and since they are heavy UPDATEs with multiple JOINs, consume a huge amount of resources. I do not want them to stop end users from ...