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

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Is it possible to force drop of mysql tables with FK?

For dropping a table in which a Foreign Key is used in other tables, it is necessary to drop all other tables having FK connection with the corresponding table. Is there a short way to drop a table, ...
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697 views

“Lost connection to MySQL server during query” error

I have MySQL 5.5.20 and this table: mysql> desc country; +----------------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | ...
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64 views

ORDER BY optimization issue

I have a query: SELECT user_details.id , user_details.first_name , user_details.last_name, user_accounts.name account_name, jtl0.account_id account_id, user_details.title , ...
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145 views

Do certain string patterns affect query performance on a VARCHAR column?

I am a beginner on MySQL Administration and performance problems. Now this is confusing me. I have a VARCHAR column identity, the string in it is consisted of a Class type and an id, like note:123, ...
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1k views

ERROR 13 (HY000) When Creating Database

I'm trying to create a database and when I type in CREATE DATABASE epik; I get the error ERROR 13 (HY000): Can't get stat of './epik' (Errcode: 13) I am running kubuntu 13.04 with mysql 5.5.31.
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22 views

Should store procedures be cached?

Should store procedures be cached in MySQL? If so, How long it is stay in cache? In my case, When I call one stored procedure first time, it is giving me results in 1 second, after that it gives me ...
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1answer
87 views

skip columns while using LOAD command mysql

I have a csv file having 5 columns and i want to load only one out of that, is there a way i can do it. I want to use LOAD statement of MySQL 5.5 Any pointers are welcomed, help would be much ...
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1answer
174 views

Unable to use mysql_upgrade:

I updated mysql recently and found problem related to privileges and backup. When I am using mysql_upgrade command it says- mysqlcheck: Got error: 1064: You have an error in your SQL syntax; check ...
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1answer
297 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
482 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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1answer
299 views

MySQL-5.5 InnoDB memory issue

Version in use is mysql-5.5.24. In the Enterprise version of MySQL innodb_buffer_pool space is released after a while, however this does not appear to be happening in the community version. I am ...
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461 views

Table corruption: How to perform Innodb Checksum checks in MySQL 5.5 for Windows?

Having a corrupted Mysql 5.5.31 (Windows) database, my question relates to the the top solution provided in How do you identify InnoDB table corruption? , more precisely to the following script that ...
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1k 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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3answers
226 views

Using MySQL InnoDB as an Archive

My site has a main MySQL InnoDB table that it does most of its work on. New rows get inserted at a rate of 1 million per week, and rows older than a week gets moved over to an archive table on a daily ...
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1answer
235 views

MySQL localhost vs Amazon RDS instance

I am seeing unexpected behavior with some MySQL performance. When I run a simple query SELECT 1; on my local host (MySQL 5.6.x) using workbench, it executes in 0.000s, but the same query run on ...
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1answer
136 views

INSTALL PLUGIN 'rpl_semi_sync_master' SONAME 'semisync_master.so' not working

I'm trying to install semi synchronous replication in my mysql 5.5 and trying to execute the below command: INSTALL PLUGIN 'rpl_semi_sync_master' SONAME 'semisync_master.so' but this command is ...
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2answers
239 views

How to avoid lagging when enabling log-slave-updates?

Master: 48GB RAM 16-core my.cnf: https://clbin.com/hlkUo Slave: 64GB RAM 24-core my.cnf: https://clbin.com/viLm0 Both are running 5.5.28. For the incremental backup purpose, I need to enable ...
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1answer
47 views

Identical subquery optimisation in an update

update activitybooking set `submitted`='1' where id='958' and (select SUM(pool1_count) from (select pool1_count from `activitybooking` where `abt`='12' and (id='958' or ...
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1answer
319 views

MySQL specific database configuration file

In MySQL's configuration file I've globally disabled autocommit as so. [mysqld] autocommit=0 I need to turn MySQL's autocommit on for a specific Ruby on Rails database though. It could be for the ...
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1answer
47 views

Optimizing Query

Can anyone help me tuning this query..... explain extended SELECT DISTINCT a.msisdn FROM `std_msc_opr_wise` a LEFT OUTER JOIN (SELECT msisdn FROM as_treat_pre_usage_30days GROUP BY ...
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1answer
158 views

Creating a partial unique constraint for MySQL

I have the same question as asked in a previous post: PostgreSQL multi-column unique constraint and NULL values. But the solution there is not applicable as I am using MySQL instead of PostgreSQL. My ...
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66 views

MySQL replication is not happening when piping sql into mysql client

Today I noticed a very strange issue where if I cat a SQL file and then pipe it to MySQL client, replication doesn't happen. These MySQL statements aren't also written to the binlog. But replication ...
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1answer
586 views

MySQL replication — issue with mysql.proc during replication from 5.0 to 5.5 host

We are replicating from a mysql 5.0.45 host to a 5.5.26 host over WAN. Every once in a while one of our databases does not accept a query and halts the replication. "'Column count of mysql.proc is ...
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1answer
43 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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1answer
668 views

MySQL General log not working on Mac OS X [duplicate]

I want to log all queries to the database running on my MacBook Pro (Mac OS X 10.8.1). I created a file /etc/my.cnf with the following content: [mysqld] general_log=1 ...
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2answers
447 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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1answer
146 views

Redo Logs Mysql Cluster

The mysql cluster has 4 directories namely D8 D9 D10 D11 for redo logfiles. But while inserting into table only one redo directory is used. I ran following command to get redo information "all dump ...
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3answers
8k views

mysql wont start after increasing innodb_buffer_pool_size and innodb_log_file_size

I am following this solution here http://stackoverflow.com/questions/3927690/howto-clean-a-mysql-innodb-storage-engine/4056261#comment14041132_4056261 and tried to increase my innodb_buffer_pool_size ...
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2answers
78 views

Error log - What does this mean and what can I do about it?

I have the following repeated errors in my error.log and I don't know what it means or what I should/can do about it: Access denied for user 'root'@'[some IP]' (using password: YES) There are ...
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1answer
189 views

MySQL Stress testing issues?

I had gone through MySQL High Performance book Chapter 2 for MySQL Bench marking and Profiling,I have some questions about benchmarking How can we test an existing database and queries against it ...
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1answer
556 views

when will Innodb support activation of triggers on cascade foreign key? [closed]

The Manual says: http://dev.mysql.com/doc/refman/5.6/en/innodb-restrictions.html Currently, cascaded foreign key actions do not activate triggers. Any Idea when will this be implemented. Is ...
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113 views

Error in alter table reorganize partition for MySQL Cluster

My cluster contains 48 million rows and cluster contains 4 storage nodes . After that I add online storage node and executed alter table 'customer_tbl' reorganize partition. Some parameters of ...
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3k views

MySQL slave stuck in “Reading event from the relay log”?

5.5.28-log MySQL Community Server (GPL) by Remi binlog-format=MIXED My problem is similar to this question. *************************** 2. row *************************** Id: 973415 User: ...
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1answer
100 views

Changing TEXT to VARCHAR

In a MySQL database (InnoDB) we have a table containing roughly 60.000.000 rows. One of the columns is of type text. Currently the longest entry has length 360 (found using SELECT MAX(LENGTH(value)) ...
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1answer
1k views

Should I disable triggers, timestamps in a slave in mysql?

We're using MySQL. We have a master that eventually will have 2 slaves. There are triggers in the db that execute when data changes in certain tables. I am wondering whether to disable the triggers in ...
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1answer
40 views

Reinsert data in new table with new IDs

I have the following two tables: buynsell CREATE TABLE `buynsell` ( `id` VARCHAR(20) NULL DEFAULT NULL, `msg` VARCHAR(255) NULL DEFAULT NULL, `date` VARCHAR(25) NULL DEFAULT NULL, ...
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366 views

Limit Access To mysql information_schema

In case of mysql attacks, many times user extracts information from information_schema. can i do something in mysql that can restricts user to xtracts information from information_schema while all ...
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1answer
103 views

Data usage increases initially when reorganize partition mysql cluster

In my MySQL cluster, the data usage of 4 data nodes is approximately 77%. I added a new data node online, and attempted to reorganize partition to redistribute data among all data nodes. But before ...
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1answer
50 views

How to create Mysql Replication on mysql 5.5 master-slave [duplicate]

Guyz please tell me how to replicate master-slave in mysql 5.5
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234 views

MySQL inserts/deletes slowing down after a while after Start/Reboot

The Setup here is: OS: Ubuntu 12.04 (1 Core and 1.75 GB of RAMO) MySQL Version: 5.5 There are about 8 to 9 tables in the database. On initially starting mysql the queries are fast at around 0.05 - ...
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1answer
184 views

MySQL not allowing text columns?

I'm using MySQL 5.5.27. I currently have a BLOB column, that I want to convert to text to allow fulltext searching. The ALTER TABLE command to create a text column is successful, but the ALTER TABLE ...
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1answer
166 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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1answer
379 views

How this simple Stored Procedure ended up in Deadlock

Thanks for all and this forum is really helpful. After few minutes of system running we get “Try restarting the transaction.” And its end up in deadlock. We use MySQL 5.5.28 and the Java code ...
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2answers
4k views

“Could NOT find Curses” error when installing MySQL from source

I am installing MySQL Server from the source distribution which I downloaded from: http://dev.mysql.com/downloads/mysql/#downloads. I have downloaded the file (mysql-5.5.19.tar.gz). I am using ...
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1answer
175 views

Unique index on 2 columns in mysql

I have one table in mysql named 'UserFriends' where I am updating my websites user's friends details. here is the schema of the table (UserFriends) id int, Userid int, friendid int, createdate ...
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2answers
174 views

Tinyint structure is confusing

I am confused to see this tinyint(3) structure. If tinyint can store only 1 byte then what is the purpose of giving the size in brackets? Is there something special with this parameter in MySQL?
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4answers
698 views

Stress Test to Saturate Memory for MySQL InnoDB

I'm investigating windows 32bit memory problems (the 2G limit) and am after a test which will max out MySQL's memory including InnoDB Buffer Pool, per connection memory and/or any other uses of ...
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84 views

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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1answer
5k views

How to get only month from MySQL date/time?

In my MySQL server, I have rows that have the date of my created content. Example: 2013-03-17 02:53:47 For now, I am using: $date = $fetch[thedaterownamegoeshere]; <?php echo $date; ?> But ...
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42 views

mysqlbinlog (mysql5.5) output errors out (char length)

wondering why an invalid insert (exceeds char length varchar(100)) breaks when piping mysqlbinlog output to RDS-- when pasted into a client and run separately-- it inserts, truncates, and warns ...