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3
votes
2answers
2k views

Cannot update certain rows in innodb tables

I found the following on http://dev.mysql.com/doc/refman/5.1/en/innodb-deadlock-detection.html When InnoDB performs a complete rollback of a transaction, all locks set by the transaction are ...
1
vote
1answer
326 views

pt-table-checksum from remote server

I am using pt-table-checksum for the first time and have some questions that I can't seem to resolve by reading the documentation on Percona's website. Per the documentation, pt-table-checksum ...
7
votes
2answers
11k views

How to use Unique key via combinations of table fields?

Take a look at the following sqlfiddle: http://sqlfiddle.com/#!2/dacb5/1 CREATE TABLE contacts ( id int auto_increment primary key, name varchar(20), network_id int, ...
1
vote
1answer
257 views

Getting slaves of a master-master setup stopped in sync

I have a master-master setup where each master has it's own slave. They layout might be illustrated as: M1 <===> M2 | | \/ \/ S1 S2 That is both S1 and M2 slave ...
6
votes
1answer
7k views

Do you still use MyISAM or prefer Aria storage engine?

If Aria storage engine (previously called Maria) is the "new" MyISAM, which supports transaction and automatic crash recovery: Why still use MyISAM ? Should changing storage engine from MyISAM to ...
1
vote
1answer
608 views

What language and data structures does MYSQL uses as backend?

I am just curious to know what data structures and languages does MYSQL exactly use as back end language? and what does the file format .MYD , .MYI and .frm stand for and how does MYSQL use them? ...
2
votes
3answers
520 views

MySQL Cluster Installation

I am very new to mysql-cluster.I downloaded the binaries and was trying to configure it on my local machine. Can anybody suggest how to install it on single machine with the 1 management node,2 data ...
1
vote
2answers
8k views

Script to show mysql health status?

Kev suggested this question ( http://stackoverflow.com/questions/10524981/php-script-to-show-mysql-health-status ) is better fitted here. I know phpMyAdmin can shows the lists of mysql vars and ...
1
vote
2answers
325 views

Why are my results returned twice?

I've this query: SELECT DISTINCT `default_wall_posts_comments`.`c_id` as c_id, `default_wall_posts_comments`.`comments` as comments, UNIX_TIMESTAMP() - default_wall_posts_comments.date_created ...
2
votes
1answer
95 views

MySQL replication constantly checking tables

I recently moved one of our slave databases to a new server, the database is purely used for offsite replication/backup and doesn't handle any of the live traffic. Since moving, the new server seems ...
1
vote
1answer
1k views

Triggers vs Views in MySQL

We are in the process of denormalizing a large amount of data for performance reasons. Basically a Query that would normally JOIN over 10 tables is replaced with a Query that has no JOINs, yet all the ...
10
votes
2answers
20k views

Why is MySQL is creating so many temporary tables on disk?

Can any configuration mistake lead to creating too many temp tables by mysql..mysql tuner shows Current max_heap_table_size = 200 M Current tmp_table_size = 200 M Of 17158 temp tables, 30% were ...
0
votes
1answer
445 views

ENABLE KEYS on a large table is crashing mysql

I am trying to copy our data over to a new server, and at the same time, testing our backup-and-restore processes. I have a 2.6GB file created by SELECT INTO OUTFILE, containing 19 million rows. I've ...
1
vote
1answer
281 views

Database for efficient retrieval of data from large data set

I am designing a new system that will be dealing with large data set. This system is expected to have over 10 million records. A user of the system needs to check for the availability of the name he ...
1
vote
2answers
6k views

Shell Script / Tool to check the MySQL Replication Status? [duplicate]

Possible Duplicate: Monitoring replication on mysql I am running with MySQL Master/Slave Replication on Linux. Is there any tool/Shell script which monitors the Replication Status and send ...
2
votes
1answer
198 views

SELECT for values in a table

I have this table structure: id1 id2 1 2 1 3 2 1 2 4 id1 and id2 are not unique as you can see in the values. I need to retrieve those values that exists in the two columns ...
2
votes
1answer
9k views

How to properly stop MySQL server on Mac OS X?

I installed MySQL Community Server following instructions at http://dev.mysql.com/doc/refman/5.0/en/macosx-installation.html with the Startup Item and the MySQL Preference Pane. I can stop the ...
1
vote
2answers
7k views

In MySQL, how to manually edit values of a BLOB column in few tuples?

In MySQL, how to manually edit values of a BLOB column in few tuples? For convenience of manual curation of database like this, should the column be created as BLOB or TEXT, or something else at the ...
2
votes
1answer
2k views

Transaction Lock Timeouts When Updating a Row

I'm trying to determine the cause of an InnoDB transaction lock timeout. This one is very strange in that it appears to be a deadlock error instead - nonetheless, here's the output of my slow log ...
1
vote
2answers
6k views

Error while importing a “.sql” file in database

I am trying to import a .sql file in to my local database. whenever i type the command to import the file, I get an error ERROR at line 1: Unknown command '\S'. This is the first line of the sql file ...
1
vote
4answers
583 views

cross self join to get more rows - better solution?

I have a table employees: +----------------+------------------+ | Field | Type | +----------------+------------------+ | id | int(10) unsigned | | persons_id | ...
1
vote
1answer
358 views

MySQL lost records in a master slave scheme

We have developed a web application that uses two MySQL servers set up with replication (master-slave scheme). The application was to be used for a couple of days only, when ~ 50-60 users would enter ...
4
votes
2answers
4k views

Setting Circular Replication in mysql

I have 3 MySQL servers say A,B,C. What I want to do is that I want to make all of them master as well as slave.If there is update on any of the MySQL Servers it should be replicated to all of the ...
3
votes
1answer
2k views

MySQL Server Performance

I have a few questions regarding MySQL server running under Windows Server 2008 R2: How do I check the number of allowed connections? How do I turn on query logging to see performance of queries ...
4
votes
1answer
4k views

What is the use of ibdata1 file in mysql?

I have application which has the backend db as Mysql(InnoDb engine), and currently my client wants to decrease the size of the ibdata file to some fixed size. I found the three below solutions. ...
5
votes
1answer
1k views

MySQL EXPLAIN doesn't show 'use index' for FULLTEXT

I have a basic table : create table fullTextTest ( id INT(11) NOT NULL, superText CHAR(255) NOT NULL, superLongText TEXT NOT NULL, primary key (`id`), FULLTEXT KEY `superText` ...
2
votes
2answers
5k views

Monitoring replication on mysql

I have managed to setup master and slave replication. It is working fine. What are the possibilities that it might go down? Is there any alerting tool to monitor that? Another thing: Can I run a ...
3
votes
2answers
2k views

Which is better for long term database scalability: adding columns or having key/value store

For application, which has few (5-10) settings at the moment but will have a lot more (up to 100) in the future which would be better approach: to add new columns to settings table every time new ...
1
vote
2answers
4k views

Recover a MySQL InnoDB from ibdata1 that won't repair using innodb_force_recovery

We have a MySQL database that we have manage to grab the raw files from a server with a fatal hardware failure. However, this failure seems to have occurred when the DB server was running. As a ...
1
vote
1answer
577 views

PostgreSQL vs MySQL benchmarks when a 2nd level cache is included

Has anyone been able to find any benchmarks comparing PostgreSQL and MySQL performance when they are used by a system through Hibernate (or another comparable ORM) and the 2nd level cache (backed by ...
40
votes
4answers
72k views

Which is faster, InnoDB or MyISAM?

How can MyISAM be "faster" than InnoDB if MyISAM needs to do disk reads for the data? InnoDB uses the buffer pool for indexes and data, and MyISAM just for the index?
6
votes
2answers
2k views

Amazon RDS I/O requests - 1 query = 1 billable I/O?

I have an InnoDB database that I'd like to migrate onto Amazon RDS. My current implementation, hosted on my own server, shows roughly 8M queries per month. The RDS site say that I/O Rate $0.10 ...
2
votes
1answer
236 views

Why does OS login not exist in the user table, but I can still login to MySQL?

mysql> select user, password, host from user; +------+----------+---------------------------------------------+ | user | password | host | ...
1
vote
1answer
112 views

Assignment of Thread IDs?

I'm in the process of decommissioning an old mysql server. Of course there's a few things left connecting to it periodically people had since forgotten about. I turned on general query logging to ...
0
votes
1answer
341 views

Can't connect to MySQL Cluster Storage (data) nodes [duplicate]

Possible Duplicate: Can't connect to MySQL Cluster Storage (data) nodes I've deployed a MySQL Cluster with a few nodes, and I want to access the storage nodes directly from another ...
1
vote
1answer
2k views

Keeping 2 tables in sync

I need to write a trigger that will keep one table synced with 2 other tables. I have table_a, table_b and table_c on slave. The master has only table_a and whenever this table is updated on master, ...
2
votes
0answers
103 views

Can't connect to MySQL Cluster Storage (data) nodes

I've deployed a MySQL Cluster with a few nodes, and I want to access the storage nodes directly from another machine using NDBAPI. When I tried to connect from the same host it worked, but when I try ...
2
votes
1answer
391 views

FLUSH TABLES stays in the processlist even after execution

Here is my code from Stored Procedures in Mysql FLUSH TABLES; TRUNCATE TABLE tbl_cdrload; TRUNCATE TABLE tbl_cdrdetails_temp; Then i execute a query to load a file in to database as below LOAD ...
5
votes
1answer
2k views

Which mysql storage engine to choose?

I'm confused about which mysql engine should I choose (lets talk about the most used : MyISAM and InnoDB). The theories say: Both work with BTree indexes, but MyISAM can work with FULLTEXT index ...
90
votes
7answers
55k views

How can I monitor the progress of an import of a large .sql file?

I am importing a 7 GB foobar.sql to restore a table in a local database. $ mysql -h localhost -u root 'my_data' < foobar.sql $ mysql --version /usr/local/mysql/bin/mysql Ver 14.12 Distrib ...
1
vote
1answer
820 views

Finding Duplicates in LEFT JOIN

Here is my table structure: create table table_a (emp_name varchar(100), dept_name varchar(100)); insert into table_a values ('amar', 'finance'); insert into table_a values ('akbar', ...
5
votes
1answer
5k views

I want to know about the IOPS (I/O Per Second) and How it influences the DB CRUD operation

I want to get a dedicated server for my Database (MySQL) which runs InnoDB Engine. There is this option in InnoDB capacity that you can define the IOPS in it. Let's say that I have a SATA 72K-RPM HDD ...
3
votes
1answer
8k views

Problem with View When Restoring a MySQL Backup

I have a database (InnoDB) with some tables, views and routines... Periodically I do a backup using the command line: mysqldump -u user -ppassword --routines db_name > backup.sql But I have a ...
1
vote
2answers
3k views

Restore data from remote server using “.sql” file

I have a ".SQL" file which contains data at a remote server. I could download that file to my local machine and import data in my local DB, but because of network issues, and the size of ".sql" file ...
3
votes
2answers
7k views

what is bigger than a longblob?

the longblob is the biggest data type of Mysql. If I want to save something bigger than 4gb (longblob) how can I do?. I'm talking about Mysql v-5.+
2
votes
2answers
184 views

Is this Dedicated Server good enough to Run MySQL on Linux Ubuntu?

I have a web application that runs simple logic. Most of the SQL procedures that I have only do simple selects, some simple join table and some simple inserts. I want to get a dedicated server for My ...
1
vote
1answer
751 views

MySQL: Try to Port a Trigger from SQL Server

Here, there's a sample of a trigger with "INSTEAD OF UPDATE" clause: CREATE TRIGGER [dbo].[Test_PTA_Table_Update_trg] -- ALTER TRIGGER [dbo].[Test_PTA_Table_Update_trg] ON [dbo].[Test_PTA_Table] ...
8
votes
2answers
3k views

BigInt or Varchar for a large number I won't ever sort / calculate on

I need to store users' Facebook IDs in a column in my DB. The ID always consists of only digits, and can be as large as a number in excess of 500 million. Considering that I won't ever need to do ...
3
votes
3answers
5k views

How do I create a user-defined aggregate function?

I need an aggregate function that MySQL doesn't provide. I would like it to be in MySQL's flavor of SQL (that is, not in C). How do I do this? What I'm stuck on is creating an aggregate function -- ...
0
votes
1answer
8k views

PHPMyAdmin incredibly slow [closed]

Does anyone else's phpmyadmin take an incredibly long time to load? like 68 seconds after i click a table it finally gets there...! its also very slow when i click the "add data from text file into ...