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

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MySQL Load Avg High — CPU bound or IO Bound or Memory Issues

We are using MySQL 5.5 and the database is approximately 10TB. The load avg is constantly high during day time. Following are the configurations and a snap shot of a 'top' command. I wanted ...
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2answers
79 views

Mysql 5.5.25 must be restarted to connect

We have MySQL v5.5.25 running on Windows Server 2008 R2. Occasionally people are unable to connect, and the only way we have found to fix this is to restart the mysql service. This happens every 2-3 ...
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259 views

What is the ideal connection pool size for RDS MYSQL?

I have a tomcat server hosting REST APIs. It is connected to a MySQL (RDS Instance) server on the backend. A majority of the operations are write operations (Around 75%). I'm using the Tomcat's ...
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2answers
413 views

Warning before issuing delete/update command in mysql/oracle , then executes

Is there any utility , function either in mysql /oracle that if i issue some delete/update command wrongly , a message must prompt at command_line* (if possible in ubuntu) asking whether "you sure to ...
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1answer
180 views

Data Analysis with MongoDB or MySQL

I have a need for processing some data in order to come up with some statistic. This is the scenario: Each user can answer several questions from the question list. They pick their answers from a ...
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1answer
483 views

Datetime Difference in MySQL when format is Varchar

I have two columns in a table: STOP and START, of type varchar. I want to have the difference between both columns, and I'm using : SELECT DATEDIFF(stop, start) AS difference from T1; It is ...
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1answer
191 views

Update the host field in Grant privileges in mysql

I have an existing table and I want to update host part in privileges using Grant command mysql> show grants -> ; ...
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1answer
39 views

Migrating database with views trough phpMyAdmin causes error in second host

I'm trying to migrate a database which contains some views and I'm doing trough phpMyAdmin export feature. MySQL version on servers are: Server to migrate: Server version: 5.5.34-0ubuntu0.12.04.1 ...
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30 views

Accessing Database from Slave server

I have an application running in one server eg: My Server's Ip is 192.168.10.10, and I have the MySQL database server in the same machine. The application connects database server as localhost. ...
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102 views

Query Execution Plan for MySQL

In Microsoft SQL Server you can see Execution Plans for queries to see how a query is executed, what joins take the most time and see any missing indexs now i want to do the same for MySQL scripts ...
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334 views

mysql doesnt have write access in data dir?

I am running a MySQL on my Windows 7 64 bit development machine at work and I can't seem to get around a database corruption issue. In my unit tests it is telling me that the storage engine (which is ...
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1answer
49 views

Join on with modified ON

I am trying to create table with summary of few other tables. All solutions i came up with are very slow and clearly not optimal. Initially I tried with multitude of subquerries but that was very ...
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1answer
119 views

Whether or not to create separate tables

I am working on a project, where I need to store the information related to A and B, the A and B both have identical columns.There might be thousands of As and Bs. Should I use "type" column to ...
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2answers
85 views

Mysql Command required for getting values from my.cnf

I am new to MySQL DBA, i have a doubt, Is there any command for finding my.cnf configuration file variables and its respective value which is mention in my.cnf file in mysql prompt itself. like we ...
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117 views

Importing large .sql file stops before even midway and starts deleting

Okay so i'm trying to import my minecraft servers .sql file into database and after first 1GB of importing data it stops without error and starts deleting what already has been imported any ideas? ...
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28 views

Merge rows with common field value in MySQL [duplicate]

I have a table which was imported from MS-SQL, it has about 1.9 million rows. After importing I realized that a lot of the rows are duplicates and there are no primary key constraints. The rules to ...
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1answer
366 views

Strange Locking issues while playing back logs via percona playback

Problem while replaying logs I am in the process of benchmarking a new DB node (specs at the end) and have run across some strange behavior: As described here i: Created a dump (innobackupex ftw) ...
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2answers
306 views

How can we check for data integrity when we upgrade from MySQL 4.1 to MySQL 5.5?

By data integrity, I mean: Schema integrity Data (record level) integrity Checksum was an option, but since the storage format for some data types in MySQL 5.5 has been changed, it won't be ...
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21 views

mySql Event gets expired on closing of the command prompt

As I am quite new to server side, I tried to create a event using CREATE EVENT enetname ON SCHEDULE AT '2013-06-13 18:00:00'+INTERVAL 30 SECOND DO update tablname set status= 'Expired' where ...
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1answer
193 views

What's the practice to generate long user id like those on Facebook?

Now I am about to launch a site and I have trouble coming up with a way to create long user id(e.g. 4000002). Do I set id to auto-increment(Starts at 0) and then add something(e.g. 4000000) to this ...
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65 views

Replicate database without Internet connection

I'm working on a company where I have a central DB and several agency databases. See the diagram at here. All the databases are identical, just the data can change and in some cases. I've no internet ...
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2answers
481 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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23 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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72 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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2answers
735 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
232 views

Mysql query is very slow

I am developing a website like any other social networking site using mysql. I wish it give people suggestion to my users, and I have implemented this functionality in my application, but It is ...
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1answer
43 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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1answer
312 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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0answers
48 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 ...
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1answer
32 views

Why isn't my includeThreadNamesAsStatementComment JDBC parameter working?

The JDBC API lists a includeThreadNamesAsStatementComment parameter that seems to indicate it will prefix all queries with the Java thread ID. I thought this would be useful in tying back DB activity ...
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0answers
56 views

How to properly kill MySQL? [duplicate]

I have CentOS 64bit with CPanel installed and I use service mysql stop However, it keeps doing ..... for minutes and it never stops. It used to be instant. Any idea why it does that and how to fix? ...
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2answers
571 views

How to restore mysql dump file? [closed]

We have created a dump file (.sql) using the command mysqldump in mysql5.5. Now we want to restore the same. We are using the command :- -u[username] -p[pwd] [dbname] < [.sql file] But we are not ...
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1answer
359 views

Unable to take backup of mysql database using Xtrabackup

I am trying to take mysql backup without any downtime but unable to take the backup using Xtrabackup . Actual Database is almost about 40+ GB in size. I am trying to first satisfy myself. Hence, I ...
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149 views

Please help configure my Mysql for 12GB 4cores server

I use a dedicated server with 12GB memory and 4 core CPU with Ubuntu 12.04 LTS (x64). This not just a database server. MySQL appears to be restarting frequently, I think I can tune the config to ...
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2answers
2k views

MySQL 5.5 Fail start Fedora 16

I installed mysql and mysql-server from the repos (MySQL version 5.5). Then tried to start it, but got an error. [root@server]# service mysqld start Redirecting to /bin/systemctl start ...
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0answers
507 views

MySQL import file with no column delimiter

Is there a way to use the mysqlimport command on a file that has no column delimiters? I would like to import the ctl file used with the sqlloader for Oracle
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0answers
73 views

memc_delete called from a MySQL trigger loop fails randomly

I'm calling memc_delete from a MySQL trigger's code. The call is inside a loop. Logging the results, I see that memc_delete sometimes returns 1 (ok, memcached entry deleted) and sometimes returns 0 ...
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0answers
176 views

Are there any caveats to install mysql 5.5 in CentOS 5?

I need to install mysql 5.5 in cent OS 5. As Cent OS 5 is a little bit old is there any odd behavior when you want to install mysql 5.5 on Cent OS 5?
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2answers
40 views

Mysql replication with c

I have huge database on MySql and It's become more and more huge. So, Now I am facing performance issues with my database. Some of tables has millions of records in it. like my login detail table ...
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1answer
1k views

Restoring a single database from mysql enterprise full backup

I am having command to restore all databases from full dump taken by enterprise full backup .Can anyone help me how to restore single database from full dump .
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1answer
54 views

Optimizing a union query

SELECT id FROM user WHERE id IN ( 2,3,4,7,9,21,23,45,324,12,43,254 ) UNION SELECT DISTINCT user_id FROM workgroup_users WHERE workgroup_id IN ( 1,345,34,654,213,123,5,2,3,4 ) I know we should not ...
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votes
1answer
50 views

How do I create a trigger that cascades new rows into another table?

I am having a table name link with two columns link1 and link2 and another table name hide with four columns hide1, link1,link2 and hide2. If i insert data into link table the data should insert into ...
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1answer
74 views

Btree index and Bit Map Index [duplicate]

Please clarify the difference between BitMap Index and Btree index. I am using mysql version 5.5.37-0ubuntu0.12.04.1. I can able to create Btree index but unable to create the same, Please find the ...
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1answer
53 views

Query to retrieve data based on several where conditions ( Not off Topic , Answer provided below is right ) [closed]

Database : Mysql 5.5 i have a table T1 containing 4 columns : No. , Height , start_time , end_time In column height i have 3 distinct values only : Small Medium High Now i ...
-1
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1answer
854 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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1answer
49 views

Is there any limit for MySQL database rows

I'm creating a database website which has a lot of data (Username,name,address,posts etc). Is there any limit to store database rows? (I have a table with more than 100,000 rows) How to host this ...
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1answer
263 views

mysql server is not starting [closed]

mysql server is not starting after modifying configurations key_buffer = 16M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 query_cache_size = 16M after ...
-1
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1answer
263 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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1answer
13 views

What should I do if i forget password in MySQL?

I am using MySQL5.5. I trying to login in mysql from terminal by using "sudo -u root -p" But i could not remember password. How can i fix this problem?
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1answer
192 views

Restrict access to rows by usename

In my database i store data of different users (e.g. addresses or invoices) in the corresponding tables. I want to make sure that a logged in user only has access to it's own data in the tables (so ...