MySQL version 5.5 - please also tag with mysql for search purposes.

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How to drop a column named 'column'? [closed]

I need to delete a column named "column" form a table but the standard: mysql> ALTER TABLE table_name DROP COLUMN 'column'; returns: ERROR 1064 (42000): You have an error in your SQL syntax; ...
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7k views

Mysql 5.5: Optimizing all tables with mysqlcheck - is it useful to run the -check option along with -optimize?

I plan on running 'mysqlcheck --optimize --all-databases' to clear up some fragmentation. Would it be useful to run -check with this option or does the -optimize already take care of that? I am only ...
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How to properly change “innodb_buffer_pool_size” value for mysql?

I have following environment: # cat /etc/redhat-release CentOS Linux release 7.2.1511 (Core) # rpm -qa | grep ^mysql-community- mysql-community-common-5.5.48-2.el7.x86_64 mysql-community-libs-5.5....
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41 views

Why does this SQL work on one version of MySql-Server but not another?

I'm trying to run the following very simple SQL command on two different MySQL databases: CREATE TABLE mytable ( created DATETIME(6) NOT NULL, updated DATETIME(6) NOT NULL, my_id ...
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33 views

Is it safe to “FLUSH STATUS” in mysql?

We have deployed REDIS to hold some frequent query result to reduce number of connections made on Database server. We need to find out Max_used_connection after deploying REDIS. So we plan to reset ...
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786 views

MariaDB/InnoDB: Temp file write failure

When attempting to alter a table to enable compression by modifying the KEY_BLOCK_SIZE I received the error: ERROR 1296 (HY000): Got error 64 'Temp file write failure' from InnoDB The command ...
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257 views

Fixing MyISAM database without losing data

My old server was crashed but I was able to recover the databases from MySQL through testdrive. I'm trying to dump a database using mysqldump but it gives error for certain tables are crashed and ...
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425 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 "...
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397 views

Filtering the results of a SELECT query to avoid certain words in the value of a column?

I have a table called videos with a column named title and there is a set of words (around 50 words as of now but the number of words may increase) which is the knowledge base for filtering the ...
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36 views

Why does mysql treat “<” like it was “<=”?

I've tried the following command: SELECT * FROM `mi_schedule` WHERE `day`<=(DATE_ADD(NOW(),INTERVAL 7 DAY)) AND `day`>=NOW() Got 8 rows. Then I changed the <= to <, and nothing changed, ...
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MySQL Community Edition Capacity

I am using MySQL Community Edition on Amazon RDS service. It is a very large database, 2/3 tables has about 10 millions records and 4-5 tables has 7-8 millions records. Questions How much capacity ...
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Will MySQL redirect a read request to the master after a certain time? [closed]

I can't find what variable controls this or any information about the time limit. Thanks!
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496 views

How to create two same name databases in two different MySQL users?

I am using MySQL 5.5 running on Ubuntu 12.04. I have created two different users as 'root' and 'abc' and I want to create 'Items' database in this both user accounts but I want this two databases ...
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265 views

mysql forbidden database names

I was wondering whether there were a list of forbidden (reserved) database names in mysql. For instance, mysql is obviously one. But is there a determinated list? I don't want to cover 99% in my ...
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813 views

How to update a table by count from another table?

I have two tables as CREATE TABLE country_statistics ( id int(11) NOT NULL AUTO_INCREMENT us int(11), uk int(11), ca int(11), PRIMARY KEY(id) ) ENGINE=InnoDB DEFAULT CREATE TABLE entries ( id int(11)...
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84 views

MySQL Partitioning: why it's not taking appropriate partition

DROP TABLE temp; CREATE TABLE `temp` ( `CallID` bigint(8) unsigned NOT NULL, `InfoID` bigint(8) unsigned NOT NULL, `CallStartTime` datetime NOT NULL, `...
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472 views

Help my database isn't performing fast enough! 100M Merge with 6M need < 1 hour!

I have a server right now receiving more raw data files in 1 hour then I can upsert (insert -> merge) in an hour. I have a table with 100M (rounded up) rows. Table is currently MyISAM. The table has ...
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4k views

Error “#1118 - row size too large” on the first row of the table only

I ran into a problem using a mySQL database. I have some columns as type text but when I try to enter data into the first row I get the error code "#1118 - Row size too large. The maximum row size for ...
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45 views

Misunderstanding statement in MySQL documentation

I can't understand this statement in Optimizing Data Size: Declare columns with identical information in different tables with identical data types, to speed up joins based on the corresponding ...
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3k views

Steps to upgrade MySQL from version 5.0 to version 5.5

I have been developing under MySQL v5.0 for a while now and need to upgrade to v5.5 to be in step with the hosted production server. After having searched for precise steps to do this migration, I am ...
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461 views

MySQL Slave Lagging Almost Daily -Ver 5.5.17 ( Master & Slave )

I am observing this lag in a continuous manner. Investigating in the bin log events, i found the following information. Slave executing the relay Logs slowly. 1. Changing the Innodb File Format ...
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67 views

What would be the first things you do to find out about an MYSQL environment you are taking over?

I am new to DBA role, and wanted to know if there was any commands (or free software) that come with Mysql 5.5 (master/slave/slave) replication to quickly get familiar with the database, and also ...
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2k views

What exactly is SOLR? [closed]

It seems like a magical technology that can Do spatial search do full text search The problem is, It doesn't say where does it store all the data. Does it have it's own proprietary database If it ...
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57 views

2 Very similar queries return different number of result (one is null)

I want to find businesses near a point that contain a word that start with sea lat=-6.185068&long=106.773121&keyword=sea&distance=5000&startfrom=0&howmany=20&prominent=5 ...
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232 views

Which is the best tool to monitor replication on MySQL 5.5.20? [closed]

I have just installed and setup replication for 3 MySQL 5.5.20 server( 1 Master/ 2 slaves). I intend to add more slaves to the equation. Which is the best software tool to monitor the replication ...
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91 views

Practices to keep SQL Server databases easy to port to MySQL?

We've developing an ASP.NET Web application that is to be designed for MS SQL Server 2008. I'd like to minimize my future dB admin's headaches should there be a need to migrating over to MySQL. With ...
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46 views

Upgrading to MySQL 5.5 from 5.0 looks broken

I was using SLES SP3, and had earlier MySQL 5.0.67. I upgraded it to 5.5.48 (available with the CD) after upgrading my OS to SP4. I edited the /etc/my.cnf file, and replaced skip-locking to skip-...
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65 views

MySQL dies at same time by night [closed]

my MySQL Database dies every night at around 11p.m. and I have absolutly no idea whats the problem. Maybe you can help me: The error.log says: 160412 11:37:13 [Warning] IP address '123.158.49.205' ...
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44 views

What is the difference between CREATE INDEX and ALTER TABLE ADD INDEX? [duplicate]

I have searched the web but I have failed to find a conclusive answer for this question. Is there any difference between CREATE INDEX and ALTER TABLE ADD INDEX? Are there any problems that may ...
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47 views

Select rows with most recent date for the given date

I have a table to manage the stock which looks like below product batch qty date Grape BAT0 42 10/3/2016 Apple BAT1 12 11/3/2016 Banana BAT2 15 11/3/2016 Orange ...
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121 views

sql_safe_updates set to ON by default

This is fresh mysql install from Debian apt. mysql> \s -------------- mysql Ver 14.14 Distrib 5.5.47, for debian-linux-gnu (x86_64) using readline 6.3 .. Server version: 5.5.47-0+deb8u1-...
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28 views

Optimising a query with two aggregate fields

I have a table in a MySQL 5.5 database with around 7 million records, with fields typeId, regionId, scanTime, scanId and a query that returns around 239,000 results. For every combination of typeId ...
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27 views

selecting duplicate values with a condition from a mysql table

I have the following table in mysql: Key DI CI FD FA NM Valid_from Valid_to 0 1224468 123 2012-06-30 3 6 2013-01-23 9999-12-31 1 1234567 123 2013-12-31 3 ...
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276 views

MySQL starts using > 90% of CPU, “Copying to tmp table on disk” and “converting HEAP to MyISAM”

I have a server where MySQL is periodically taking up 11 of the 12 CPU cores. Once this starts it doesn't end until I restart MySQL. At least, I haven't let it run like this for more than a half hour ...
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223 views

MySQL Trigger On UPDATE “Unknown Column” Error

I want to log a table when its updating a row which is column "insertDate" or "updateDate" value is before than 3 month. I wrote this trigger: DELIMITER /// CREATE TRIGGER `trig_before_up_dad_records`...
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75 views

Copying MySQL schema, some tables not getting recognized!

From the 'data' folder of my colleague I copied the entire 'MyDatabase' folder and pasted that in my own 'data' folder.Now, some tables are getting recognized while others are not.**All the tables are ...
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35 views

What could cause a record to appear in the MySQL binary log but not the original table?

I have a web application (CiviCRM) that has the option to enable binary logging, which I've done. We use this software to record donations, including automatic recurring donations. Our payment ...
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99 views

mysqlbinlog: unknown variable ssl_key or ssl_cert or ssl_ca

I am trying to recover binlog from a remote server using mysqlbinlog client program, however it appears that mysqlbinlog doesn't recognize the SSL options that's required to establish SSL connect to ...
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1answer
2k views

Use of log_bin_trust_function_creators in MySQL

What is the use of log_bin_trust_function_creators? Also, Is the value of the parameter dynamic? Will it change if I restart my MySQL service?
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83 views

Backup a huge database 200gb+

i have a mysql database where i need to take a backup of the log database. the problem is the log database i over 200gb and contains over 280 millions of rows, i need right now to remove a kind of ...
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100 views

Working with variables in stored proc

I want to create a meta table on the fly using a stored pdocedure and passing a table prefix as "in" parameter and then build the final table name somehow. My code looks like this: SET @table_ = ...
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377 views

InnoDB Index Doesn't Fit in Memory

I am using InnoDB tables in my database and total index_size is 250 GB and my data size is 500 GB. Server has 128 GB RAM, and innodb_buffer_pool_size is set to 64 GB. Data size is increasing every day ...
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280 views

'USE db_name' takes too long to change when login remotely

I gave SELECT privilege to a user on a particular database, Now whenever I try to connect remotely $ mysql -h ip-of-remote -u username -p with that user credentials and try to change the database ...
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209 views

How to most efficiently store possible combinations of categories?

I have a table of categories (currently with 14 rows, not likely to change). A need to cache combinations of categories emerged, so I'm creating a table of allowed combinations (only few hundreds of ...
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21 views

Import lots of mysqldumps with missing CREATE DATABASE

I have a bunch of mysqldumps of my old server with one database each. Unfortunately we forgot to add CREATE DATABASE ... in all those dumps. How can I import those files in one batch?
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125 views

Error: Incorrect usage of UNION and ORDER BY

I have this query: SELECT DISTINCT CONCAT (MONTH(`Date`),'-',YEAR(`Date`)) from wp_result_plugin WHERE Bet=2 AND month(`Date`) = EXTRACT(month FROM (NOW())) ORDER BY MONTH(`Date`) ASC UNION ...
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318 views

mysql database under symlinked directory: ERROR 1018 (HY000): Can't read dir of './<dbname>/' (errno: 13)

I'm using mysql 5.5 on an ubuntu linux server. I need to move a database from its current location (under /var/lib/mysql) to a disk with more space, so I attempted to move the directory and create a ...
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23 views

Can combine five mysql statements into just one statement?

Can I combine all the five statements into just one statement? update mytable set myfield1 = replace(myfield1, '…' ,'-') ; update mytable set myfield1 = replace(myfield1, '‖' ,'|') ; update mytable ...
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46 views

Unable to get the latest value added to Mysql table based on posted time

SELECT * FROM discussion_comments GROUP BY disc_id ORDER BY posted_date DESC I have table example like given below: CREATE TABLE example ( id int(11), cname varchar(11), posted_date date, ...
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1k 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 ...