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

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How to use OR in query with priority?

In a simple query like SELECT * FROM table WHERE id='x' OR id='y' How to give a priority to get only one of the WHERE clauses? I mean getting rows with id='x'. Only if there is no row, get row ...
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1answer
5k views

Upgrading MySQL 5.1 to 5.5 on Centos 6 without removing dependencies

I'm trying to upgrade MySQL 5.1 to 5.5 using yum/rpm combo (yum to remove MySQL 5.1 and rpm to install MySQL 5.5). Most instructions I've found suggest to do first: yum remove mysql mysql-server ...
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1answer
128 views

Need to Rewrite/optimize Slow Query

I have a query with following explain plan EXPLAIN SELECT COUNT(applicant.id) as applicantCount, application.name,applicant.application_id,application.id FROM applicant LEFT JOIN application ...
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1answer
10k views

BEFORE INSERT trigger in MySQL

I am new to MySQL and I'm having problems creating a BEFORE INSERT trigger. I get an unexpected END error. I have a table named verlof_aanvragen with a column datum (and 6 more columns). What I ...
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1answer
3k views

Dealing with empty strings while loading a table from a CSV

I am trying to load a CSV file into a table. The CSV file contains some empty strings for example: 1,2,,4 I want to load the empty field as null. One way I know is to use \N i.e: 1,2,\N,4 but it ...
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2answers
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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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2answers
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mysql 5.5 corrupt - missing temporary table

One of our mysql instances crashed and failed to start: 120422 10:04:13 InnoDB: Error: trying to open a table, but could not InnoDB: open the tablespace file './databasename/#sql-29f6_45.ibd'! ...
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2answers
592 views

Any problem will all InnoDB and one MyISAM table?

I have a MySQL 5.5 DB with all InnoDB tables. For some reason, one of the developers decided to create a MyISAM table. It is a log table for user sessions. I don't see why we should mix in a MyISAM ...
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1answer
56 views

why my MySQL binary log file size is so small?

I have a lot of small binary log files , each of them just only 126 Bytes -rw-rw----. 1 mysql mysql 126 Jan 6 16:13 mysql-bin.000001 -rw-rw----. 1 mysql mysql 126 Jan 6 16:16 mysql-bin.000002 ...
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1answer
59 views

Joining two fast subqueries is very slow

DB: MySQL 5.5.20 (WampServer) OS: Win 7 HDD: Western Digital 3TB Caviar Green, 3.5", IntelliPower, 64MB, Sata3 (WD30EZRX) Memory: 8GB my.ini: http://pastie.org/private/s7l9aadyi0qhfl5bcrnnqq I've ...
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1answer
106 views

Query about MySQL Semaphores in Engine Status

During a recent problem / slow down with one of our slave databases I noticed that when I ran SHOW ENGINE INNODB STATUS. I am getting the following: ---------- SEMAPHORES ---------- OS WAIT ARRAY ...
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1answer
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Set sql_mode “blank” after upgrading to MySQL 5.6

After upgrading MySQL from 5.5 to 5.6, some our app face to problem and need set sql_mode to blank to solve this issue. I added sql_mode = '' to my.cnf but there was no effect on the mysql setting. ...
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1answer
154 views

Mysql can't start?

Mysql can't start, here is the log : 150708 06:28:36 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql 150708 6:28:36 [Warning] Using unique option prefix key_buffer instead of ...
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1answer
184 views

Is there an easy way to update a mysqldump file from version 9.11 to 10.11? [closed]

We have a client that has had their servers for soo long, they were still running MySQL 4.0.24. Now that they are refreshing their servers, we took a mysqldump of their current database to put into ...
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1answer
155 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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1answer
478 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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2answers
689 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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2answers
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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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1answer
2k views

Auto_increment value needs to be set as S1

Hi I need to set auto increment for a table as S1. I tried by altering the table and also by creating by new table I am aware how to set auto_increment but when i try to set auto increment as S1 i am ...
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2answers
884 views

How to monitor InnoDB Disk I/O using Server Status Variables?

This question is extension of my previous question "How to monitor InnoDB Disk I/O Required for MySQL? " As mention in my previous question i want to count total number of disk i/o per query, but ...
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819 views

MySQL user without SUPER privilege

This may be a simple question and may not be the right place to ask but I couldn't find any useful information from Google. Here is my question. When creating users in mysql using grant all ...
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1answer
53 views

Will composite indexes or unique indexes help with query performance?

I need help with identifying indexes to increase performance of the following query. I'm currently using v5.5 with InnoDB. I cannot modify the query. However, I can add indexes as needed. The ...
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1answer
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Space not reclaimed after dropping MyISAM table

I just dropped a rather large MyISAM table (~4 gb); it was 350k rows with about 11k of data per row. However, when I run df -h on my database server, I am still at 100% disk usage, so much so that I ...
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2answers
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Mysql used key changes between two consecutive EXPLAINs

I have a huge unmaintained innodb table (~1.5billion rows), I just started to try to query it. I write && instead of AND once; and surprise! it uses different key! EXPLAIN EXTENDED SELECT * ...
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Converting live MyISAM table to InnoDB

I have a table that tracks web traffic. The table is constantly written and read from. Since table is pretty big in size I have to make sure the application will not "freeze" in the process of ...
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1answer
115 views

Unknown column error with an index

I created a simple index associated with a timestamp column CREATE TABLE `data` ( `id` INT(11) UNSIGNED NOT NULL, `ticker` VARCHAR(16) NOT NULL COLLATE 'utf8_unicode_ci', `comment` TEXT ...
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2answers
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MySQL Synchronous Replication on Ubuntu 12.04 with DRBD

I have been looking around for some easy and open-source ways to handle database synchronous replication. DRDB on a Linux server seems to be one of the fastest and easiest methods to handle database ...
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2answers
700 views

Errors while creating multiple mysql-5.5 instances

I have installed 3rd mysql instance on my testing server. 2 instances already running without any issues. When I installed 3rd instance by mysql-5.5.30 zip source, it installed successfully but when ...
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1answer
563 views

datetime vs timestamp in mysql 5.5

What is the difference between datetime and timestamp in MySQL with respect to data being inserted from different timezones? Does anyone have any clues on this? I have a situation where I am trying ...
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1answer
508 views

select count(*) in mysql 5.5 innodb— rewrite advice?

I need advice on how to rewrite a select count(*) query for innodb tables mysql 5.5. in new environment its very slow... select count(*) from mails3 join questions using (question_id) where ...
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1answer
750 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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1answer
532 views

How can I disable utf8mb4 entirely on MySQL 5.5?

I know you're not supposed to do this, but I have a MySQL 5.5 master and a MySQL 5.1 replication slave. That's supposed to be okay, unless I do something stupid like use utf8mb4 that isn't supported ...
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3answers
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Automatic MySQL Replication Fail-over Strategy

I want to know that if replication is down due to some reason as if master is down then what strategy should be followed so that the replication is up instantly without manually intervening the ...
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1answer
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Issue with connecting to the mysql database

We have an outstanding issue with VCC in chicago, there is an issue connecting to the mysql database If an agent does a refresh of the monitor they will be logged out. This is the error we ...
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1answer
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Does mysqld wait for init-script code to complete before opening the instance?

I'm trying to automate the execution of an application code at MySQL startup. The init-file server option seems handy and I need to know if mysqld waits for all the code in the init-file to complete ...
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1answer
548 views

Restriction on self referencing on insert in MYSQL?

How to restrict insert on adding self referencing rows in a recursive relation table (a table contains foreign key points itself). mysql> SELECT * FROM Employee; ...
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1answer
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Extract some columns data from one table and insert into multiple tables

I have a table with 16,000 records and need to get out some columns and then insert values in multiples tables. For example, suppose I have the following tables tbl_1: id, name, lastname tbl_2: id, ...
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1answer
741 views

“set-variable = innodb_thread_concurrency=4” or “innodb_thread_concurrency=4”

Based on this question, the asker wrote: set-variable = innodb_buffer_pool_size=2M set-variable = innodb_additional_mem_pool_size=500K set-variable = innodb_log_buffer_size=500K set-variable = ...
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1answer
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MySQL Workbench ERROR 1064

I have a problem with my database. I have created the model and now I want to sync it with my database on my WAMP Server (local) but it keeps giving me an error. I searched for the cause of the ...
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3answers
1k views

InnoDB UPDATE slow need a better option

I'm using MySQL 5.5 with a table in InnoDB running: deleteme tinyint NOT NULL DEFAULT 0;` UPDATE `import` SET `deleteme` = 1; -- Set the delete field LOAD DATA LOW_PRIORITY LOCAL INFILE ...
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1answer
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InnoDB - How to get top locked tables and rows which are locked

I was searching for a tool OR query which can give me top locked tables and which particular row is locked, Is it possible to get ?
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1answer
442 views

Referring to super parent or as a separate entity?

I have this person table as super parent, id firstname lastname email telephone ... ... and user table as a child id person_id (FK) password username screenname ... ... They must be 1:1 ...
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1answer
324 views

mysql emits BINLOG rows even though binlog_­format=­STATEMENT

We have MySQL 5.5 installed, we have the binlog_format=STATEMENT (the default) According to the MySQL Documentation, the binary log should contain SQL statements only, but we still see BINLOG rows in ...
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1answer
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Is there a PPA for MySQL 5.5 for ubuntu 10.10 and 11.10?

I want to install MySQL server 5.5 on ubuntu 10.10 and 11.10 servers but have not yet found a problem free PPA or installation method as of yet. Has anyone managed to do this with the said versions of ...
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1answer
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How to upgrade MySQL to a New version..?

I have installed mysql using the package management system.I am using ubuntu machine. After that i have very well configured the server for InnoDB and other server related parameters. I am using the ...
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1answer
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Fixing MySQL errors recorded in error logs

Below is the extract of the most common lines of error being recorded in error logs on my PC: 110905 16:16:54 [Note] Plugin 'FEDERATED' is disabled. 110905 16:16:54 InnoDB: The InnoDB memory heap is ...
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How do you properly remove “REQUIRE SSL” from a single user?

I successfully granted REQUIRE SSL to a single user by doing... mysql -u"${targetMySqlUser}" -p"${targetMySqlPass}" -e "GRANT USAGE ON dbname.* TO 'dbusername'@'%' REQUIRE SSL;" but im failing on ...
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2answers
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MySQL Database Archive

We have 300 databases in our environment mixed of MyISAM and Innodb(innodb_file_per_table has been enabled) tables.Using MySQL 5.5.19 version. I we are planning archive inactive database.Is there any ...
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1answer
2k views

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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1answer
589 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 ...