InnoDB : MySQL's ACID-compliant Storage Engine

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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 ...
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3answers
5k views

innodb_buffer_pool_size not changed

I use MySQL 5.5.23-1~dotdeb.0 (Debian) and here is the relevant part of my.cnf default-storage-engine = innodb innodb_buffer_pool_size = 3G innodb_log_file_size = 256M innodb_thread_concurrency = 8 ...
5
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2answers
4k views

Frequently slow queries while in the 'Update' state

I have two tables that I update very frequently, one with a direct UPDATE .. and another INSERT .. ON DUPLICATE KEY UPDATE ... Normally these queries are instant but at times will take 0.1s to 1+ ...
4
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1answer
4k views

MySQL Innodb corruption

I recently inherited a Drupal site that has an Innodb corruption. MySQL will run for sometime--usually about 24-hours but will eventually need to be manually restarted(see log output below). I have ...
2
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1answer
835 views

innodb_flush settings on Amazon RDS

Setting innodb_flush_log_at_trx_commit = 2 improves my application performance considerably on my local development environment. The response time and number of requests per second on a 40 concurrent ...
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2answers
1k views

Investigate peak in MySQL throughput

Recently one of our servers has ran out of memory and crashed. After reviewing the munin graphs, it appears that the only metric (other than memory usage) that peaked just before the crash was the ...
1
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1answer
2k views

Why do my ON UPDATE/ON DELETE rules disappear?

I'm trying to connect a couple of Mysql tables with foreign keys and ON UPDATE/DELETE rules. My rules are working on all tables except the last one (OrderContains). Why aren't my rules working? I am ...
1
vote
1answer
698 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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2answers
2k views

mysql 5.5 corrupt - missing temporary table

One of our mysql instances crashed and failed to start: 120422 10:04:13 InnoDB: Error: trying to open a table, but could not InnoDB: open the tablespace file './databasename/#sql-29f6_45.ibd'! ...
9
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3answers
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MySQL: how to restore table stored in a .frm and a .ibd file?

I have previously saved a copy of /var/lib/mysql/ddms directory ("ddms" is the schema name). Now I installed a new MySQL on a freshly installed Ubuntu 10.04.3 LTS by running apt-get install ...
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2answers
15k views

MySql - Clean ibdata1

I have a database that its entire size is ~44GB, out of it ibdata1 is ~35GB that doesnt make sense, the size of the data shouldnt be more then 10GB. i use the following query to get an esstimation of ...
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4answers
3k views

Prevent reset of auto_increment id in Innodb database after server restart

I recently read that because of how InnoDB recalculates the AUTO_INCREMENT value when the server restarts, any records on the high end of the ID list may have their IDs reused. Normally, this isn't a ...
4
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2answers
2k views

What happens when InnoDB hits its tablespace autoextend max?

The latest version of High Performance MySQL (3rd ed.) recommends that one: ...place an upper limit on the tablespace's size to keep it from growing very large, because once it grows, it doesn't ...
12
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1answer
17k views

Mysql Innodb: InnoDB: ERROR: the age of the last checkpoint is InnoDB: which exceeds the log group capacity

I really need some mysql expertize. I am a newbi to mysql and I am seeing some server crash of my db in the past 1 week. I am using mysql 5.1.36 on Ubuntu. This is a dedicated mysql server with Dual ...
4
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5answers
12k views

Mysql: Insert performance INNODB vs MYISAM

I am inserting into a simple small table with 5 attributes and 1000 rows. I observed when the engine is INNODB, each insert is taking 0.03 - 0.05 seconds. I changed the engine to MYISAM, then the ...
6
votes
2answers
21k views

How do you remove fragmentation from InnoDB tables?

I have a Database having number of tables. I want to delete some records from the tables say the no of records are more than 20K or 50K. The All the Tables are InnoDB. And file_per_table is off. ...
2
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2answers
2k views

How to sync two MySQL high load tables with 10M rows?

I have two identical MySQL innodb table with 10M rows each. One is used at backend while other at application end. Thus, either of them loaded. I need to synchronize them in a way which is fast and ...
1
vote
1answer
202 views

Unit testing with InnoDB transactions

So, I'm running some unit tests against some InnoDB tables in MySQL. Each unit test is wrapped in a transaction: setUp: SET autocommit = 0; SET SESSION TRANSACTION ISOLATION LEVEL SERIALIZABLE; ...
2
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2answers
1k views

Is there any performance difference among MariaDB (xtradb plugin) and XtraDB Server for InnoDB?

Title says it all. However i have to enter at least 30 characters.
9
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4answers
10k views

Why using innodb_file_per_table?

There are many articles exaggerating (IMHO of course) the need for innodb_file_per_table. I understand that with innodb_file_per_table, there should be a better control over the individual tables; ...
2
votes
3answers
1k views

InnoDB UPDATE slow need a better option

I'm using MySQL 5.5 with a table in InnoDB running: deleteme tinyint NOT NULL DEFAULT 0;` UPDATE `import` SET `deleteme` = 1; -- Set the delete field LOAD DATA LOW_PRIORITY LOCAL INFILE ...
2
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3answers
2k views

Is it normal to use many Triggers?

I have many so-called summary columns throughout my database to count number of rows in other tables. For example, counting the number of comments by a user (a column in the user table). Currently, I ...
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vote
1answer
830 views

How does innodb_stats_on_metadata relate to query execution plan stability?

The MySQL documentation for innodb_stats_on_metadata says "It can also improve the stability of execution plans for queries that involve InnoDB tables." That is a little vague. What is an example ...
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4answers
4k views

Should I use the Infobright database or is there a better aggregation solution?

We are a MySQL front-end shop and have a system currently logging event data in a highly structured format. Think apache traffic log. We need to be able to aggregate counts of this data (cube) vis a ...
4
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2answers
375 views

Foreign key constraints with MySQL/InnoDB

I am try to do some performance testing with varchar foreign keys vs int foreign keys and was wondering how foreign key constraints effect performance of MySQL. I assume that they effect ...
10
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3answers
10k views

Is innodb_file_per_table advisable?

We have an application where just one of the table will be growing into million of lines but the rest will just below a million. So what is the advice should we go with innodb_file_per_table or leave ...
11
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4answers
11k views

Mysql int vs varchar as primary key (InnoDB Storage Engine?

I am build a web application (project management system) and I have been wondering about this when it come to performance. I have an Issues table an inside it there are 12 foreign keys linking to ...
5
votes
3answers
15k views

InnoDB row locking - how to implement

I've been looking around now, reading the mysql site and I still can't see exactly how it works. I want to select and row lock the result for writing, write the change and release the lock. ...
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1answer
700 views

InnoDB - How to get top locked tables and rows which are locked

I was searching for a tool OR query which can give me top locked tables and which particular row is locked, Is it possible to get ?
5
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1answer
1k views

Does the order of columns has a significant effect on INSERT?

Do we experience a noticeable difference in performance for these two queries? INSERT INTO table (col1, col2, col3, col4, col5) ... and INSERT INTO table (col5, col3, col1, col2, col4) ... Do we ...
3
votes
1answer
4k views

When are InnoDB table index statistics updated?

In a vanilla build of MySQL 5.5.20, when are InnoDB table index statistics updated? What events trigger such updates? I've seen comments suggesting that the following might trigger it: table is ...
9
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2answers
6k views

Percona vs MySQL

What is Percona? How does it differ from MySQL? When should we consider switching (or upgrading) from stock MySQL to Percona? To add some specifics in our situation we almost exclusively use ...
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1answer
5k views

How to use ON DUPLICATE KEY for UPDATE

Consider a table of CREATE TABLE test ( id int(11) unsigned NOT NULL AUTO_INCREMENT, external_id int(11), number smallint(5), value varchar(255), UNIQUE INDEX (external_id, number), PRIMARY KEY(id) ...
3
votes
1answer
212 views

Is UNIQUE(), INDEX() different from UNIQUE INDEX()?

Is there any different how mysql treats UNIQUE (column1, column2), INDEX (column1) and UNIQUE INDEX (column1, column2) and UNIQUE (column1, column2) In the latter, I think mysql will ...
26
votes
3answers
34k views

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 ...
6
votes
2answers
1k views

Why does MySQL choose this execution plan?

I have two queries, select some_other_column from `table` order by primary_index_column asc limit 4000000, 10; and select some_other_column from `table` order by secondary_index_column asc ...
6
votes
2answers
3k views

Is one-to-one relationship normalized?

Consider we have a large set of statistical data for a record; e.g. 20-30 INT columns. Is it better to keep the entire set in one table as they all belong to a record OR creating a another table ...
2
votes
1answer
2k views

Sort buffers and tables on disk, MySQL/InnoDB

I have the following type of query frequently running: # Time: 120322 13:03:29 # User@Host: root[root] @ localhost [127.0.0.1] # Query_time: 17.039286 Lock_time: 0.000141 Rows_sent: 24 ...
3
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1answer
1k views

Are many NULL columns harmful in mysql InnoDB?

As I explored the clustered B-tree index system of InnoDB, I think that the presence of many NULL (or small) columns has no significant effect on InnoDB performance. Does the presence of excess ...
1
vote
1answer
2k views

How to recover the innodb when mysql data dir moved from one system to another system?

I have transfer the mysql data dir from one linux box to another box. When i start the mysql server. I can find that the innodb based DB are corrupted. So, may i know how to recover the corrupted ...
4
votes
2answers
2k views

“freeing items” taking forever on inserts, updates and deletes

Recently I migrated all my MySQL database tables from MyISAM engine to InnoDB. I'm using the DotCloud MySQL service as my server (http://docs.dotcloud.com/services/mysql/). After the migration, ...
5
votes
2answers
10k views

Using multiple cores for single MySQL queries on Debian

I am running a MySQL server for tests on a VM (VMWare) with Debian as guest OS. The guest has four emulated CPU cores, so I set thread_concurrency to four. I am doing expensive joins on large tables, ...
0
votes
1answer
954 views

Problem with Error: InnoDB: page … log sequence … number is in the future!

i know this question was asked before, but i am at a point where i am really stuck and do not know how to continue with this problem and i would really like to know, what causes this error to come up. ...
1
vote
1answer
5k views

How to set a specific directory location for individual MySQL database?

Is it possible to set each database in MySQL to use a separate datadir? I'm running a userdir development (sandbox) server and would like to put the MySQL data files for the database(s) for that user ...
3
votes
1answer
145 views

What are some key configuration settings for using an InnoDb table for session storage?

I want to start clustering my PHP app servers but don't want to go for a sticky-sessions load balancing setup at this point. However, I want sessions that are persisted to disk and implement proper ...
5
votes
4answers
2k views

MySQL subquery slows down drastically, but they work fine independently

Query 1: select distinct email from mybigtable where account_id=345 takes 0.1s Query 2: Select count(*) as total from mybigtable where account_id=123 and email IN (<include all from above ...
2
votes
1answer
1k views

ACID-compliance of MySQL master-master replication?

I've created two MySQL 5.1 servers, replicating off each other (log-bin) in a low latency environment (different AZs within an EC2 region). All tables that are being replicated are using the InnoDB ...
7
votes
3answers
7k views

InnoDB table SELECT returns ERROR 2006 (HY000): MySQL server has gone away (after power outage)

This server is a virtual machine running CentOS 6.0, MySQL 5.5.21 There is a database named devSystem. There are InnoDB tables within. Running the following commands causes error ERROR 2006 ...
4
votes
1answer
4k views

How can I find who holds the lock based on the hex-dumped?

I've been reading the Diagnosing MySQL InnoDB Locks article. Karl E. Jørgensen writes on 2008 so I'm consfusing it is in effect. I would like to supply a snippet of the SHOW ENGINE INNODB STATUS: ...
2
votes
1answer
2k views

Why can't I get a lock on an InnoDB table?

I have problem with lock table command: LOCK TABLE v3_cam_date WRITE; the command always running with state: "Waiting for table metadata lock". Try to find out which thread was hold the lock on ...