Database Administrators Stack Exchange
Database Administrators Stack Exchange

Questions tagged [mysql-5.5]

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

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

http://dev.mysql.com/doc/refman/5.5/en/

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Possible to make MySQL use more than one core?

I've been presented with some dedicated MySQL servers that never use more than a single core. I'm more developer than DBA for MySQL so need some help Setup The servers are quite hefty with an OLAP/DataWarehouse (DW) type load: Primary: 96GB RAM, 8…
gbn
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ALTER TABLE - Rename a column

This is driving me nuts! I want to rename a column from read-more to read_more in my blog table I tried all this: ALTER TABLE blog RENAME COLUMN read-more to read_more; ALTER TABLE blog CHANGE COLUMN 'read-more' 'read_more' VARCHAR(255) NOT…
Bojan
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Difference between On Delete Cascade & On Update Cascade in mysql

I have two tables in MySQL database- parent, child. I'm trying to add foreign key references to my child table based on the parent table. Is there any significant difference between ON UPDATE CASCADE and ON DELETE CASCADE My Parent Table CREATE…
Smokey
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MySQL Error Reading Communication Packets

In MySQL error logs, I see these quite few a warnings like these: 120611 16:12:30 [Warning] Aborted connection 2619503 to db: 'db_name' user: 'user_name' host: 'webapp_hostname' (Got an error reading communication packets) Haven't noticed any loss…
KM.
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Why does InnoDB store all databases in one file?

It was convenient that MyISAM used to store each table in a corresponding file. InnoDB has made advancements in many aspects, but I wonder why InnoDB stores all databases in one file (ibdata1 by default). I understand that InnoDB will map the…
Googlebot
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InnoDB: Error: Table "mysql"."innodb_table_stats" not found after upgrade to mysql 5.6

I upgraded to mysql 5.6 from 5.5, and now my logs are littered with such messages on startup I found a possible solution here, but it does not seem official. http://forums.mysql.com/read.php?22,578559,579891#msg-579891 2013-12-06 21:08:00…
giorgio79
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MySQL: How to create Column if not exists?

I am trying to create a Column for my table only if it does not exist. I have researched a lot but I could not find any solution yet. Is this really possible to conditionally create Column ?
zzzzz
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What is the difference between OPTIMIZE TABLE and ANALYZE TABLE table in MySQL

What is the difference between OPTIMIZE TABLE and ANALYZE TABLE table in MySQL? I have read the online documentation but not sure what the difference is.
Boolean
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intermittent MySQL crashes with error "Fatal error: cannot allocate memory for the buffer pool"

Added on edit, 2013-05-29: Because this is a long question and discussion, here's a short summary of the question and the solution. I had problems running MySQL and Apache on a small Linux server (1 GB of memory). Apache kept demanding more…
Teemu Leisti
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How to properly kill MySQL?

I have CentOS 64bit with CPanel installed and I use: service mysql stop It just keeps ticking periods and never seems like it stops. In the logs it just posts a lot of: 130303 17:42:38 [Warning] /usr/sbin/mysqld: Forcing close of thread In the…
Tiffany Walker
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innodb_file_format Barracuda

I have a couple questions for those more familiar. Most of my instances have been running Antelope despite having support for Barracuda. I was looking to play around with some compresses innodb tables. My understanding is this is only available…
atxdba
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Counting rows from a subquery

Simple: I would like to count the number of rows from the sub-query. Note that status is whether the host is online or not. Bad code SELECT COUNT(ip_address) FROM `ports` ( SELECT DISTINCT ip_address FROM `ports` WHERE status IS…
user90537
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MySQL InnoDB crash post-mortem

MySQL crashed on me this morning. With the exception of the standard MySQL included databases everything I use is InnoDB. I attempted to restart the MySQL daemon but it failed twice. I then restarted the entire server and MySQL started correctly…
Patrick
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MySQL transaction size - how big is too big?

I have an import process that runs every so often and I want it to be an 'all or nothing' kind of deal, aka: a transaction. There are many aspects, and the imports may yield anywhere between 100k-1mil+ records. This equates to a payload ranging from…
thinice
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Should a MySQL replication slave be set to read only?

I've got replication running on Percona Server 5.5 by following this guide and wondered if I should add read-only=1 to my slave's my.cnf to make it read only? The guide sets up replication for the mysql table so users are replicated but I am…
xref
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