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

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3
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2answers
557 views

How to split a string to and get info from another table in mysql

I have a system to assign score for each sentence stored in a column: TABLE 1: word_scores word score this 3 is 4 a 5 test 1 another 0 sentence 8 TABLE 2: ...
3
votes
1answer
363 views

How to Update same table on deletion in MYSQL?

In my Database I have a table: Employee with recursive association, an employee can be boss of other employee. Following is query I used to create table: CREATE TABLE IF NOT EXISTS `Employee` ...
3
votes
1answer
1k views

What does the base64 BINLOG statements in mysqlbinlog output mean?

I have looked over the mysqlbinlog command as a candidate for rollback method from MySQL 5.5 to MySQL 5.0. When I ran the command on one of the bin-log files in the MySQL 5.5 server, I've noticed ...
2
votes
2answers
92 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 ...
2
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2answers
3k views

MySQL 5.5 High CPU Usage

I have been working with a client with high traffic website(500k visitors and 600-800 active users at any given time). This uses wordpress and the DB is using MyISAM engine. The problem we had was ...
2
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1answer
277 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; ...
2
votes
1answer
1k views

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 ...
1
vote
2answers
5k views

MySQL using too much CPU

I'm studying to be a DBA right now because I have a massive live database that is very sensitive that I manage. Here's the current system stats of my dedicated database server: CentOS 5.9 24gb Ram 8 ...
1
vote
1answer
1k views

MySQL 5.5 - determining correct write[read]_io_threads on high-end system?

Specifically dual-CPU 32 core - 128RAM - RAID 10 SSD . Ubuntu 64 server. Heavy Innodb load at times - ~ 2000+ queries per sec. Heavy read and write. Currently we are running on the default ...
1
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2answers
161 views

Is there a way to get slow-query-log-like profiling information on a single query?

Specifically, I'm looking for this information: # Query_time: 0.011922 Lock_time: 0.000088 Rows_sent: 107 Rows_examined: 663 Rows_affected: 0 Rows_read: 107 # Bytes_sent: 4152 Tmp_tables: 3 ...
5
votes
2answers
213 views

Is there a reason/benefit I am not aware of for this kind setup?

I now manage a MySQL database that was designed and created by another. I am confused about a certain setup that the original developer created.. He did not use auto increments for table IDs. ...
4
votes
2answers
2k views

Large files in wamp\bin\mysql\mysql5.5.24\data directory

I have discovered these files located in the wamp\bin\mysql\mysql5.5.24\data folder on my Windows 2008 server. They are consuming about 22 GB on a 40 GB drive. I am using a LMS called moodle, that ...
3
votes
3answers
2k views

InnoDB insertion faster

I'm a graduate school student researching OLAP with Mondrian OLAP. So I want to insert data into InnoDB (MySQL 5.5) faster at the initial loading. In this environment, the only user is me, so I think ...
3
votes
3answers
1k views

MySQL optimization - year column grouping - using temporary table, filesort

I have a transactions table which is having 600,000 records, I need to list the count for the dashboard on financial year basis. The table used is MyISAM. I tried adding index for the transaction date ...
3
votes
2answers
1k views

MySQL replication to slave having VPN connection to Master

I am setting up an environment in which the Master and Slave are on different networks at different physical locations (both run on MySQL 5.5.20). I have set up a VPN connection from slave's network ...
2
votes
2answers
739 views

How to GROUP_CONCAT between given rows?

I have a table as id diary 1 breakfast 2 walk 3 start 4 office works 5 office projects 6 end 7 taxi 8 start 9 preparing for meeting 10 doing the meeting 11 end 12 night I want ...
2
votes
2answers
116 views

How to see what was executed in the database via binlogs for specific date?

I am trying figure out how to "query" binlogs to see what was exectued in the database for a specific date. For example, if I execute mysqlbinlog binlog then the thing just runs forever and it is had ...
1
vote
2answers
39 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 ...
1
vote
1answer
58 views

Slow queries InnoDB occasionaly

I have the next table: CREATE TABLE `sessions` ( `session_id` char(32) COLLATE utf8_unicode_ci NOT NULL, `session_expires` int(11) NOT NULL DEFAULT '0', `session_data` varchar(10000) COLLATE ...
1
vote
1answer
22 views

Is there any value in adding an already indexed column to a composite index?

The title says it all. Does the query optimizer see composite indexes where each column is already indexed as redundant? Or, is it used when each of the composite index's columns are in the WHERE ...
1
vote
3answers
259 views

What happens when we take a timediff between timestamp and datetime

Say I have following table in mysql (5.5+): CREATE TABLE IF NOT EXISTS `test` ( `id` int(11) NOT NULL, `x_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, ...
1
vote
2answers
98 views

Is column order reliable in UPDATE?

Can we reply on the order of columns in an UPDATE? SET @x = 0 UPDATE table1 SET col1=IF(col1 IS NULL, NULL, @x:=@x+col1), col2=IF(col2 IS NULL, NULL, @x:=@x+col2), col3=IF(col3 IS NULL, NULL, @x:=0) ...
1
vote
1answer
830 views

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, ...
1
vote
1answer
249 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 ...
1
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2answers
144 views

Breaking Semisynchronous Replication in MySQL 5.5

I've set up Semisynchronous Replication between two MySQL 5.5 servers running on Windows 7. My application is running and updating the database of the master server and same is being updated in the ...
1
vote
2answers
5k views

MySQL Installation error: Unable to update security settings

I tried to configure MySQL server 5.5 on Windows and this is what I get mysql-server-5.5-winx64:56 - Attempting to update security settings. mysql-server-5.5-winx64:100 - Unable to update security ...
1
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3answers
3k views

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 ...
1
vote
1answer
4k views

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 ...
1
vote
1answer
120 views

Several values from different tables

I'm totally lost here and not know how to get this to work and hope any can help me here. I have several tables: default_users, default_profiles, default_status, default_comment and latest ...
1
vote
1answer
867 views

I am getting an error while trying to download binary for mysql 5.5.11

I am trying to upgrade MySQL 5.1 to 5.5.11 on Ubuntu 10.10. Everytime I try the wget command I get this error: wget ...
0
votes
2answers
37 views

MySQL query performance question

I have a MySQL database where I would like to return results based on multiple rows. id | key | value | selector --------------------------------------------------------- 1 | username ...
0
votes
2answers
69 views

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 ...
0
votes
2answers
89 views

Buffer pool above 90% utilized causes MySQL to crash

Without getting deep into the architecture and setup, is it common behavior for MySQL to act in this manner? EDIT I'm using Rolando's script to identify how full the innodb_buffer_pool is. SELECT ...
0
votes
1answer
59 views

Few Insert queries rollbacked due to system crash

Well, this problem occured to me first time. Yesterday, one of our mysql system server crashed and when it restarted last few inserts were completely rollbacked. I am sure that they were proper ...
0
votes
3answers
499 views

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 ...
0
votes
1answer
242 views

Export just rows modified in last month (date defined by user)

I'm asking if it's possible in MySQL to export just rows modified in a period of time for example in the past month, if it is possible, how?
0
votes
1answer
86 views

How we take dump with batch of records option?

we have 30 GB database.we want to take backup of this database. here the question is we want to take the backup batch of every 10k records. How we can take batch of records backup using mysqldump
0
votes
1answer
2k views

In place upgrade from MySQL 5.5 to 5.6.11 removes all users from user table

On Windows, I upgraded from 5.1 to 5.5 no problem. Copied my 5.1 data folder into my 5.5 instance Started mysqld skipping grants Ran mysql_upgrade All good, but going from 5.5 to 5.6: Copied ...
0
votes
2answers
531 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 ...
0
votes
3answers
253 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 ...
0
votes
2answers
460 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 ...
0
votes
1answer
4k views

Connect Error (2054) - mysql_old_password issue still not solved

i use php 5.4.3 and i want to connect to a MySQL DB remotely (php script resides on a different server than the db) with normal oop way: $mysqli = new mysqli(DB_HOST, DB_USER, DB_PASS, DB_NAME); ...
0
votes
1answer
619 views

consequences of using “innodb_flush_method = O_DIRECT” without having a battery backed write cache? or on a KVM guest?

Mysql 5.5.29 Innodb- 128GB Ram - 32 cores - Raid 10 SSD. Our server which is a dedicated KVM guest on a 'baremetal' is hosting our heavy read-write DB server. Everything is file-per-table. ...
-3
votes
1answer
65 views

Need help on query optimization in MySQL

Below is the query, I need to optimize it. It is using subquery, I need to re-write it using join how to do this SELECT Client_ID FROM SQL_AuditPro.clients c WHERE (SELECT ...