MySQL : Open-Source, Relational Database Management System

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MySQL General error: 126 Incorrect key file for table '/tmp/#sql_27e6_0.MYI'; try to repair it'

I have a table in MySQL with ~2,000,000 rows. When I try to select all records, it exhausts the system's memory and I get an error about memory exhaustion back. When I try to use the MySQL LIMIT and ...
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15 views

MySQL not using optimum composite key [closed]

I have a table which I've added a couple of composite keys to: CREATE INDEX idx_foo on my_table(col_one, col_two, col_three); CREATE INDEX idx_bar on my_table(col_one, col_four, col_three); Why, ...
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36 views

Maximum possible memory usage: 23.6G (785% of installed RAM)

I have a virtualized 32bits Server for Mysql (RAM : 115 Go). I am trying to optimize with mysqltuner and I get this : >> MySQLTuner 1.1.1 - Major Hayden <major@mhtx.net> >> Bug ...
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1answer
554 views

Why would the size of MySQL MyISAM table indexes (aka MYI file) not match after mysqldump import?

I've been archiving some MySQL (version 5.0.96) MyISAM tables locally and deleting from my server after checking the data. Every time the process has been pretty similar and comes off mostly without a ...
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1answer
460 views

MySQL server: Unable to connect with root because of skip-name-resolve option

We had our MySQL server on an old server. We decided to move all of the databases to our new server. Old MySQL Server engine 5.5.31 New MySQL Server engine 5.5.38 We created one general dump file ...
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15k views

Fastest way to check if InnoDB table has changed

My application is very database intensive. Currently, I'm running MySQL 5.5.19 and using MyISAM, but I'm in the process of migrating to InnoDB. The only problem left is checksum performance. My ...
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1answer
20 views

Are there any risks in running 'flush hosts'?

Due to an error in my code I got my PC blocked from an active production DB (too many connection errors). The error calls for me to use 'flush hosts' in order to reset the host cache. Are there any ...
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2answers
136 views

#1093 - You can't specify target table 'R' for update in FROM clause

As an attempt to answer Difference data between adjacent rows UPDATE Visits R SET Duration = TIMEDIFF( ( SELECT ReqTime FROM Visits N WHERE N.ID > R.ID AND N.Session=R.Session ORDER BY ID ...
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1answer
18 views

Restore of db's on local locks me out of accessing other sites

Running my local dev websites on my Mac locally and when I am restoring a database via terminal, which the restore is running I cannot access anything that uses mysql, I get a broken pipe notice. Is ...
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2answers
37 views

User, host, and privileges

In a MySQL 5.6 database I found one user 'foo'@'10.0.0.2' with ALL PRIVILEGES. I also discovered an user 'foo'@'10.0.0.3' granted only USAGE privileges. Does this second user definition make sense? ...
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Restore from mysqlbackup not showing tables

I have searched but can't find an answer to this question. I tried following the directions of creating a new slave from MySQL using mysqlbackup. The backup seemed to go fine, and I had a fresh ...
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1answer
70 views

Most efficient way to set up a database handling millions of links? [on hold]

I'm looking at making a site that will potentially have up to a million users, and each user will have hundreds/thousands of links connected to a set of sites, as well as other info. I'm using mysql ...
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1answer
142 views

NDB Cluster seems to ignore foreign_key_checks=OFF

According to MySQL documentation on the local foreign_key_checks variable Beginning with MySQL Cluster NDB 7.3.2, setting this variable has the same effect on NDB tables as it does for InnoDB ...
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2answers
5k views

MySQL shutdown unexpectedly

2013-09-09 10:21:44 5776 [Note] Plugin 'FEDERATED' is disabled. 2013-09-09 10:21:44 1624 InnoDB: Warning: Using innodb_additional_mem_pool_size is DEPRECATED. This option may be removed in future ...
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3answers
4k views

What is the best way to recover from a mysql replication fail?

Today, the replication between our master mysql db server and the two replication servers dropped. I have a procedure here which was written a long time ago and i'm not sure it's the fastest method to ...
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2answers
4k views

How to force higher values of open_files_limit or table_open_cache?

I'm having a frustrating problem where setting my.cnf to values higher than I currently have them does not 'take'. This is MySQL 5.6.14 on MacOS X 10.8.3 I'm trying to address dropped connections ...
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1answer
15 views

Replication Issue - Changing the replication-do-db filter

I have a server that someone has setup which are acting as a master on both database. Since they have been configured as both master on the same database, changes one on end has caused all sorts of ...
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1answer
157 views

Query multiple rooms with different conditionals (Adults, Children)

I have a simple query where I select available x Rooms with x Adults + x Children per hotel that matches a date range, but I'm having a hard time trying to figure out how to query a list of rooms per ...
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3answers
208 views

How to solve multidimensional data relationship

I'm having a problem, that I could solve programmatically, but for my personal (test) project I'm trying to see if I can fix it in the relational model. Imagine a complex fashion product Pants with ...
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1answer
719 views

Slow insert with MySQL full-text index

I use a full-text index in a MySQL table, and each insert into this table takes about 3 seconds. It seems that MySQL rebuilds (a part) of the full text index after each insert/update. Is this right? ...
2
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1answer
555 views

How to normalize my db schema for a quiz application?

I am putting together a quiz application. (I'm calling each quiz a "challenge") I have a "challenge" table and a "challenge_question" table which is pretty straightforward. challenge table: id ...
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1answer
40 views

Alias of Subquery not working

I have been trying to get an order by to work correctly with an aggregate function. i.e. order by (bp + points) I also try adding these as a total amount from the following query however. If I try ...
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1answer
1k views

MySQL SELECT query hangs - Opening Tables INNODB

On my server I have 6 MySQL databases. They all power Wordpress websites. For some reason, 2 of these databases are not accessible. To my knowledge they use INNODB, but I can't confirm it as even ...
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2answers
24 views

Slow database drop in mysql

Just installed a new 24 core server and it is noticeably slower when doing truncates and drops. Example: $ mysql -u root lmcdental_test2 Reading table information for completion of table and column ...
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ERROR 1166 (42000) at line 65203: Incorrect column name ''

I have a big snapshot database size is about 44GB in mydata.sql. When I run it overnight, it show this error message: $ mysql -u root < mydata.sql ERROR 1166 (42000) at line 65203: Incorrect ...
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I have a DB that is locking up from numerous updates to a table: Should I convert it from MyISAM to InnoDB?

FYI: I don't believe this is a duplicate question, I've looked and most are general questions with vague answers. See more specifics below: Currently a database I am in charge of locks up every once ...
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14 views

Does MySQL Backup Restore affect Master-Master Replication

Hello I got some problems with a MySQL shemas and it seems that the schemas got deleted for an unknown reason. I try to find in the binlog for more information of this but I didn't find the way to see ...
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1answer
3k views

MySQL: Lock wait timeout exceeded

I have a developer that has been trying to alter a large table (~60M rows). Via LiquidBase/JDBC they're running ALTER TABLE foo DROP FOREIGN KEY fk_foo_1; Today while it was running I checked in ...
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17 views

MySQL Replication 2003 error connecting (servers behind monowalls)

I'm trying to get MySQL replication, Master-Slave, configuration working. On my slave when I do a SHOW SLAVE STATUS\G; I get a 2003 error: Last_IO_Errno: 2003 Last_IO_Error: error connecting to ...
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38 views

Percona Master-Master lag issues

I have 2 servers with master-master replication using Percona MySQL 5.6 and I am having replication lag in the second server: db-02, however db-01 never had a lag situation. What could be causing ...
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200 views

pt-table-checksum - Verify MySQL replication integrity

export/import: $ mysqldump -h6dhdbm01 -p clee2 users > 6dhdbm01-clee2.users.sql Enter password: $ echo $? 0 $ mysql clee2 < 6dhdbm01-clee2.users.sql $ echo $? 0 $ pt-table-checksum: $ ...
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1answer
412 views

Alter mysql database engine doesn't work from cluster to other

I got into this issue when I tried to alter my database table engine to InnoDB from ndbcluster, It did not work. But When I changed engine from InnoDB to ndbcluster it worked. It did not throw any ...
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1answer
38 views

CONCURRENT SELECT's SLOW … LOCK IN SHARE MODE

My Table has 25 Million rows total and 6 million rows satisfying below where clause. Select 1: select max(stamp) from Table where type = "string" LOCK IN SHARE MODE ; 6000+ seconds Select 2: ...
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How should I store image, text type files in mysql?

I came across some answers mentioning the "disasters" of storing files outside database and saving the path inside database. I've also noticed dozens of answers about storing images- which suggest to ...
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Clustering MySQL with InnoDB engine

I have a MySQL single server setup with all tables using the InnoDB engine (because I need support for foreign keys). As response times are getting longer, I now believe I need to create a cluster of ...
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23 views

How to get mysql view definitions?

Show create view viewName does not display correctly formatted text. How can I get the correctly-formatted SQL? For example, I created a view like create view v1 as select * from mysql.uer, but it ...
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1answer
2k views

How to perform a while loop on the query result

I created a trigger AFTER an UPDATE of a column in a MySQL database. When the trigger detects a certain value, it should perform some actions. This is what I have at the moment and is working fine. ...
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1answer
24 views

“Unknown table engine 'innodb'” error after changing my.cnf

I am getting "Unknown table engine 'innodb'" for some query after changing my my.cnf. I have reverted the old my.cnf and restarted mysql and now I can see innodb. Could you please help me figure out ...
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1answer
3k views

Mysql got signal 11 error

6 [Note] InnoDB: Check that you do not already have another mysqld process using the same InnoDB data or log files. 2014-09-26 12:51:53 14166 [ERROR] InnoDB: Unable to lock ./ibdata1, error: 11 ...
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1answer
13 views

Will 'sleeping' connections open files other than the socket in MySQL?

Recently, in our MySQL replication setup, the replication slave crashed due to 'too many open files' error. We brought it backup, but trying to figure out what caused the unexpected hike in the number ...
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2answers
351 views

Restore InnoDB to different machine

It was pointed to me from serverfault that the following question would be a better fit here so this is basically my original question from there. I currently have backups that were taken with ...
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Innobackupex - Safe and recommended value for lock-wait-timeout?

I am using xtrabackup tool as a backup, can someone please suggest what is the recommended value for lock-wait-timeout option for innodba? Is it similar to InnoDB Lock wait timeout ?
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3answers
2k views

How to join two result sets from same table with different conditions on same column?

select * from unit_of_measure; +--------+-----------+--------+------------+--------------+-----------------+-------------+---------------+------------------+ | uom_id | uom_name | symbol | created_by ...
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2answers
3k views

How to disable starting MySQL service on Windows7 startup?

When I turn on my desktop (Windows 7 SP1), I often find 2 or 3 GB of memory is already occupied by MySQL processes. I don't care about how much memory a database requires, if it actually runs some ...
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149 views

MySQL replication using a lot of IO

I'm having big troubles on a database pool I've setup recently. There is a master, and 4 slaves replicating one DB. All using MyISAM engine. Thing is, during the replication period (when the slave ...
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1answer
20 views

Export all MySQL users

I need export all of a MySQL database users (including permissions) for a migration. There is over 5,000 users, what is the best way to do this? Should I just dump the mysql.user table?
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506 views

add column without metadata lock in mysql 5.6

I am using MySQL Server version: 5.6.15 Homebrew. I need to add new null column. alter table requires no metadata lock. In order to avoid this MySQL 5.6 introduced algorithm=inplace. Here is the ...
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153 views

SQL SELECT - adding field to SELECT with JOIN is changing the results

I have a SQL sentence with JOIN, running on mysql 5.5.16: SELECT DISTINCT (ot.orders_id), ot.value FROM orders_status_history osh INNER JOIN orders_total ot ON ( osh.orders_id = ot.orders_id ) WHERE ...
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268 views

How to repair all indexes in a MySQL database?

My database got corrupted, and now the php app is throwing this error: Invalid query: Can't find FULLTEXT index matching the column list The error is not very useful, since it doesn't say what ...
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3answers
412 views

Mysql - How to Optimize Retrieval Time in a Table

I have query like this! which has 200 million Records in a single table.. I am using BTree Indexes in my table... mysql> select COUNT(DISTINCT id) from [tablename] where [columname] >=3; ...