InnoDB : MySQL's ACID-compliant Storage Engine

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Why did the MySQL Storage Engine Change on Restore in one scenario?

In my production database life, there was one tragic incident when the MySQL engine type was accidentally changed from InnoDB to MyISAM on restoring a recent backup. The result was that all ...
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2answers
2k views

Different MySQL Datafile Sizes After Restoration

I'm quite new in database administration. The database architecture of my current company is master-slave replication. We are using MySQL version 5.0.86. Some weeks ago, we upgraded the company's ...
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3answers
5k views

ALTER TABLE on a large table with an indexed column

I have a large table with a VARCHAR(20) column, and I need to modify that to become a VARCHAR(50) column. Typically, performing an ALTER TABLE (adding a TINYINT) on this particular table takes about ...
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1answer
463 views

MySQL Replication: Insert generating VERY huge temporary tables

our replication slave is generating ~300GB temporary files while running relatively simple inserts. Our setup: Master: 5.0.45-0.sles10.x86_64, Slave: 5.0.85-win32, also tried with 5.1.57-win64, ...
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1answer
137 views

InnoDB foreign key and index duplication?

I'm have a part table like this: part_id INT manufacturer_id INT supplier_id INT part_number VARCHAR(50) part_description VARCHAR(120) with foreign ...
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2answers
3k views

Using MySQL triggers or transactions?

I want to ask your opinion in using MySQL triggers or transactions in a website. Actually I have a history payment table with - UserId | OperationId | Comment | Credits | Sign (debit or credit). So ...
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1answer
657 views

What are your use-cases for HandlerSocket?

There's a bit of hype around: HandlerSocket It seems like faster, nosql access to MySQL data is becoming more desirable. Percona Server is now shipping with HandlerSocket built in. My question is, ...
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2answers
3k views

Will these two queries result in a deadlock if executed in sequence?

This is almost certainly the cause of my other question, but I thought it was worth separating the two as I have a hypothesis based on the following log that I would love to have falsified or ...
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2answers
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Trouble deciphering a deadlock in an innodb status log

We are accessing MySQL from the Microsoft ADO.NET connector. Occasionally we are seeing the following deadlock in our innodb status and haven't been able to identify the cause of the problem. It ...
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2answers
11k views

MySQL 5.1 InnoDB Configuration / 24GB RAM - bi-xeon high load

i'm running a facebook app which currently has 300 - 600 concurrent users (and growing). To get the hardware ready for growing i changed my i7 / 12gb ram / 2x 80gb intel x25 ssd's (debian 5.0 / mysql ...
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1answer
432 views

Dealing with temp tables when I have not control over db variables

I have no control over things like tmp_table_size and max_heap_table_size, and so as our tables grow the time taken by queries requiring temp tables is growing geometrically. I am wondering if there ...
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2answers
639 views

Should I move to InnoDB during a planned migration?

I'm shortly migrating a Debian Lenny webserver to another host and Debian Squeeze. The standard MySQL installation even on Squeeze is 5.1 and therefore would default to MyISAM - I'm inclined to stick ...
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3answers
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What is the performance impact of using CHAR vs VARCHAR on a fixed-size field?

I have an indexed column that stores an MD5 hash. Thus, the column will always store a 32-character value. For whatever reason, this was created as a varchar rather than a char. Is it worth the ...
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3answers
607 views

Can I have create an InnoDB table without a PK? If so, would a secondary index be used as the clustered index?

Is it possible to create an InnoDB table without a Primary Key? Since InnoDB tables are structured as clustered index around the PK, what would be the structure of a table without PK? Would that ...
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4answers
922 views

Is tuning the innodb_buffer_pool_size important on Solaris ZFS?

We're running a moderate size (350GB) database with some fairly large tables (a few hundred million rows, 50GB) on a reasonably large server (2 x quad-core Xeons, 24GB RAM, 2.5" 10k disks in RAID10), ...
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1answer
5k views

Clarification on MySQL innodb_flush_method variable

Let me begin by admitting that I'm very ignorant of the inner workings of hard disks. So when I read over the manual for the variable innodb_flush_method, it confused me. Can I get an explanation in ...
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4answers
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How to improve InnoDB DELETE performance?

So I have this audit table (tracks actions on any table in my database): CREATE TABLE `track_table` ( `id` int(16) unsigned NOT NULL, `userID` smallint(16) unsigned NOT NULL, `tableName` ...
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1answer
2k views

COUNT(*) on InnoDB whenever phpMyAdmin loads

It's a known issue that innodb is slow in SELECT count(*) FROM Table Hence I avoided that. But I notice that whenever I login to phpmyadmin, it will automatically execute a count(*) for my innodb ...
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4answers
43k views

How to safely change MySQL innodb variable 'innodb_log_file_size'?

So I'm fairly new to tuning InnoDB. I'm slowly changing tables (where necessary) from MyIsam to InnoDB. I've got about 100MB in innodb, so I increased the innodb_buffer_pool_size variable to 128MB: ...
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1answer
495 views

Concurrent INSERTs in XtraDB (InnoDB)

I'm currently unable to insert rows concurrently in an XtraDB table on Percona Server 5.1.54. I had the same problem with a similar version of MySQL. My table definition is as follows. CREATE TABLE ...
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2answers
2k views

What's a good way to add a PRIMARY KEY to a large InnoDB table?

I have a table with around 30 million rows in MySQL 5.5 using the InnoDB storage engine. This table has a foreign key that links to another table with around 3 million rows. I want to add a primary ...
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1answer
2k views

Unexplained InnoDB timeouts

I've been seeing some very basic updates timing out lately and have not been able to determine the cause. An example: //# Query_time: 51 Lock_time: 0 Rows_sent: 0 Rows_examined: 0 UPDATE photos ...
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1answer
7k views

InnoDB create table error: “Row size too large”

We have some engineers that flatten a normalized db structure into a temporary table for the purposes of generating a report. The columns are specified as TEXT NOT NULL (I know "why are they doing ...
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5answers
12k views

Why do MySQL threads often show “freeing items” status when the query cache is disabled?

When I run SHOW PROCESSLIST, there are often a large number of INSERT/UPDATE threads in the "freeing items" state. The MySQL manual suggests that at least part of the reason for a thread to be in ...
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2answers
339 views

Will this Database design logic work and what should be used?

A few weeks ago I had a client of mine ask me about how complex it would be to develop a custom CRM application similar to the one being provided by highrisehq.com What he essentially wants to do is ...
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4answers
988 views

How do convert a 66,862,521 row table from MyISAM to InnoDB without going offline for several hours?

is it possible (and how) to convert a huge MyISAM table into InnoDB without taking the application offline. It requires to insert a couple of rows into that table every second but it is possible to ...
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3answers
4k views

Is it common practice to mix InnoDB and MyISAM tables on same server?

I've got a single database of about 4.5GB running on a server with 8GB RAM. The vast majority of the tables are MyIsam (about 4.3GB), but I'm soon going to be converting some of them to InnoDB. (It's ...
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5answers
24k views

How do you tune MySQL for a heavy InnoDB workload?

Assuming a production OLTP system with predominantly InnoDB tables What are the common symptoms of a mistuned/misconfigured system? What configuration parameters do you most commonly change from ...
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1answer
16k views

How can I change the default storage engine in phpmyadmin?

I use InnoDB almost exclusively in my applications. However, if I'm not careful when setting up the table, I forget to change it and phpmyadmin sticks me with MyISAM. Is there a way to change the ...
60
votes
6answers
46k views

How can I optimize a mysqldump of a large database?

I have a symfony application with an InnoDB database that is ~2GB with 57 tables. The majority of the size of the database resides in a single table (~1.2GB). I am currently using mysqldump to ...
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8answers
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What are the main differences between InnoDB and MyISAM?

What are the main differences between InnoDB and MyISAM?