MyISAM is the non-transactional storage engine for MySQL. It provides high-speed storage and retrieval, as well as fulltext searching capabilities. In addition, it is the default storage engine type for versions of MySQL prior to 5.5.

learn more… | top users | synonyms

65
votes
8answers
39k views

What are the main differences between InnoDB and MyISAM?

What are the main differences between InnoDB and MyISAM?
3
votes
3answers
5k views

Best of MyISAM and InnoDB

Is it possible to make InnoDB to use indexes same as MyISAM instead of clustered index due to limitation of RAM while getting benefit of its concurrency performance?
17
votes
3answers
30k 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?
4
votes
2answers
6k 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, ...
5
votes
4answers
2k views

Benefits of table level locking

What are the benefits of table level locking which is used by the MyISAM storage engine? Row level locking has lots of benefits like concurrent updates and reads that do not lock the table. Edit Its ...
6
votes
2answers
2k views

Any gotchas at all with converting from MyISAM to InnoDB?

I'm ready to move from MyISAM to InnoDB but wanted to know if there was a full list of things to look for? For example, I haven't seen any list mention that running DISABLE KEYS on an InnoDB table ...
3
votes
1answer
1k views

Proper tuning for 30GB InnoDB table on server with 48GB RAM

I have a 30GB 15M rows InnoDB MySQL 5.5.15 table. It is running on a server with many other MyISAM tables (300GB db). The system has 48GB RAM. Besides the default configurations, I've changed the ...
6
votes
1answer
3k views

When to switch from MyISAM to InnoDB?

We have a MySQL 5.0 server running all tables as MyISAM. We have two slaves that, in the last month, we have upgraded to MySQL 5.5. Their tables are also still MyISAM. My original plan was to upgrade ...
3
votes
2answers
810 views

Quick MySQL Backup

I have a database which is grown to 3GB and it has 3 MyISAM tables. And I have 4GB RAM. What will be the best (quick) way to backup this database without any performance lack. Or mysqldump will work ...
2
votes
2answers
520 views

Which first: upgrade mysql version or convert storage engine?

I inherited a production mysql server at 5.0. It uses MyISAM exclusively. It is not a high volume database but it does have some large datasets. I am planning on: upgrading to 5.5 converting ...
5
votes
1answer
474 views

Should I use a storage engine other than MyISAM to optimise these tables or should I get better disks?

There's a production database I'm working on, whose 4 largest tables contain between 4 million and 10 million rows each and about 15 fields each, with indexes on different field types (numbers, ...
12
votes
3answers
3k 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 ...
4
votes
3answers
1k views

MySQL tables/databases into different disks

I am aware that there is a possibility to have a single database server with many tables/databases, and you can separate some of those tables/databases into separate disks. Lets say you have 5 ...
4
votes
2answers
473 views

Less RAM than Index_length MyISAM

I'm working on a database to store "time series" data (the value of X was Y at this time). The rows themselves are very small and static in size, with the primary key consisting of two smallint ...
3
votes
1answer
617 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 ...
3
votes
3answers
437 views

Dynamically changeable database

We have a database and some data is stored in a Trucrypt folder, my question is how can I include this trucrypt folder. The data type is MyISAM. I saw there is a symbolic link, but not really clear ...
10
votes
1answer
2k views

MySQL table with 100,000 records queried often

I have a single database of about 100 tables to store various kinds of information. The most important table is our order table which is used to store customers orders and is over 100000 records as ...
1
vote
2answers
4k views

Set up a MySQL slave using mysqldump to get the initial data

I have a master database which already has some data in it. The tables in the master database include both MyISAM and InnoDB engines. Now I want use mysqldump to dump the initial data of my slave ...
5
votes
2answers
645 views

Choosing MyISAM over InnoDB for these project requirements; and long term options

Sorry for the long post, but I had to give as much info as possible to make this very vague question more specific. My project's aim is to let users search a (huge) database of variety of products. ...
5
votes
1answer
622 views

Can I have an InnoDB master and MyISAM slaves with Full-Text for searching?

I'd like to use InnoDB on the master, for its transactional ability, but MyISAM on the slaves for the full-text search ability. Is this possible?
4
votes
3answers
1k views

InnoDB vs MyISAM with many indexes

I am not sure if there is a right or wrong answer to this question, as I suppose it severely depends on the situation, but for the sake of a mental exercise, I'll go ahead and ask it anyway: I have a ...
2
votes
1answer
1k views

importing myisam 5.0 database into a 5.5 innodb server

I have MySQL 5.0 and 5.5 servers (but not a 5.1 server). The 5.0 server is myisam only, the 5.5 default is innodb. I need to move a database from the 5.0 server to the 5.5 server. The database is ...
6
votes
2answers
2k views

Why does MyISAM support FULLTEXT Searching and InnoDB does not?

I know the basic differences between the MyISAM and InnoDB engines. In MySQL 5.6 beta, InnoDB will support fulltext search. But, I wonder why previous versions of InnobDB didn't support FTS? My guess ...
3
votes
1answer
102 views

What if I want to keep using MyISAM

In my current use of MyISAM the databases are extremely small and kept for a few weeks after which time they are deleted and completely rebuilt with a clean slate. The script uses MYISAM tables and ...
3
votes
2answers
1k views

How to copy a MySQL database which is a mixture of InnoDB and MyISAM to the same server?

Because mysqldump takes forever, we decided to just move around the files. Because the 2 databases are on the same server, a cp will be fast. The problem is, from research, MyISAM is okay with being ...
2
votes
2answers
2k views

Table compression in InnoDB?

I have read that table index compression happens just in MyISAM, but I came across an article in dev.mysql that said: InnoDB supports table and index compression! So now what is the pros of MyISAM? ...
2
votes
2answers
440 views

Any problem will all InnoDB and one MyISAM table?

I have a MySQL 5.5 DB with all InnoDB tables. For some reason, one of the developers decided to create a MyISAM table. It is a log table for user sessions. I don't see why we should mix in a MyISAM ...
5
votes
2answers
7k views

Why do MySQL tables crash? How do I prevent it?

I'm the Administrator of a Moodle site which had its Users table corrupted and it became unusable. Luckily, a simple REPAIR TABLE mdl_user made it work back again. The thing is that I don't know why ...
5
votes
1answer
648 views

Quick MySQL Backup (1 file per table)

I asked a relevant question few months back and got answer with wide variety of options for backup. But this time I have different scenario and I have got a database with 7 tables and 1 of them has ...
5
votes
2answers
8k 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 ...
2
votes
2answers
135 views

Are there implicit indexes in InnoDB like MyISAM?

If you have (id, a, b, c, d) table with primary key (id) and another key (a, b, c), in MyISAM that means that you also have the following implicit keys: (a) (a, b) (a, b, c, id) Is this valid for ...
2
votes
1answer
518 views

How does mysql deal with queries that touches myisam and innodb tables?

In our mysql database, we use both myisam and innodb tables, though there are more myisam tables. QUESTIONS If a query involves both myisam and innodb tables, will the query use table lock or row ...
1
vote
1answer
2k views

MySQL MyISAM Locking question

It was my understanding that MyISAM uses table locking during inserts and updates. To me that meant that read and write by other queries on that table is disallowed until the first insertion or update ...
12
votes
2answers
3k views

Rows missing after online conversion from MyISAM to InnoDB

We have a reasonably small database that we wanted to convert from MyISAM to InnoDB. Being database noobs, we just converted (using alter table) without even taking the site down. Now that the ...
1
vote
5answers
7k 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 ...
4
votes
2answers
3k views

Performance settings for MyISAM tables - keep everything in memory

I have a 8-core MySQL server with 32 GB of RAM, holding 40 MyISAM tables (total: ~4GB of data). Since the databases size is several times smaller than the available memory, how can I make full usage ...
4
votes
2answers
583 views

Preordering the table by a specified column

I have a table and I am always getting the data by ordering a column. In my case, I order by datenum. However, the selection is so slow because of the ordering. Is it possible to order the table ...
3
votes
1answer
2k views

MySQL high CPU usage (MyISAM table indexes)

I have a problem with an inherited MySQL database. From time to time mysqld uses up to 2300% CPU.. The only solution is to service mysql stop and run an myisamchk -r on a table. After the indexes have ...
4
votes
2answers
236 views

Using MyISAM for reading and InnoDB for writing data

I read many articles about comparisons of MyISAM and InnoDB from performance point of view and I decided to use MyISAM for reading data and InnoDB for writing data. I want to use two structure like ...
3
votes
1answer
2k views

Is Percona xtrabackup the right choice for my 500GB MySQL backup?

I have a MySQL db with 500GB, consisting mainly of Innodb tables, and one big (200GB) MyISAM table. My current backup strategy is copying the db files to an external harddrive. This causes a downtime ...
3
votes
2answers
626 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 ...
2
votes
2answers
2k 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 ...
1
vote
1answer
2k views

MySQL my.cnf Optimization

We are an email marketing company and we recently switched our setup to MySQL. We need to configure MySQL (my.cnf) for extreme performance. We have tried to configure my.cnf but heavy queries got ...
3
votes
2answers
526 views

Why innodb doesn't store geospatial data?

I am very curious. I have business tables. Now I think I will have to create a separate table, location table. That separate table should be myisam. But why would I do so? Why can't innodb store ...
2
votes
2answers
445 views

MyISAM table keeps crashing. What are my options?

My MYSQL table is very large (250GB, around 200M rows). Recently I've been putting it through a lot -- parallel processes that do a large number of reads. It has started locking and crashing with ...
2
votes
1answer
2k views

mysql table very large size although it doesn't have a lot of records

I have drupal website, one of the tables is cache_form. I have a cron to DELETE FROM cache_form where expire < UNIX_TIMESTAMP(NOW()); which works fine. The size of cache_form.myd is 4.9G ...
2
votes
1answer
1k views

MySQL Config for Large MyISAM tables

I have to do some updates on myisam tables which have around 20 M records. Our server has 24GB of ram and 2 quad core xeon with 24 MB of cache. I want to know how I can change the my.ini file so I get ...
1
vote
0answers
75 views

MySQL Partitioning Performance

I have a MyISAM table with billions of rows that is still causing me problems because the indexes, even after I shortened them as much as possible, do not fit in my 64GB of RAM. I am unable to index ...
1
vote
1answer
160 views

Issues converting MyISAM table to InnoDB (auto column issue)

I'm having issues trying to convert a table from MyISAM to InnoDB in MySQL 5.6. The following is the table dump: -- -- Table structure for table `companies` -- DROP TABLE IF EXISTS `companies`; ...
1
vote
2answers
331 views

MySQL: optimal configs / methods for ALTER of large MyISAM table to InnoDB (17gb+)

I have a large MySQL (5.1) MyISAM table (13gb table, 4GB indexes - 40mm+ records) I'm going to be converting this table to InnoDB in a production environment. The DB is on a cloud server with ...