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.

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Will OPTIMIZE TABLE have any impact on my data?

I'm having issues with a database that is getting quite slow. The analyzer in phpMyAdmin recommends that I run OPTIMIZE TABLE on my tables. But before doing so, I would (of course) like to know if ...
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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 ...
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595 views

Converting Heap to MyISAM issue

At work we have a problem that has now occurred more then once. Problem is that query is in state of converting HEAP to MyISAM and it paralyzes our server( query in this state is not able to kill ...
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Whats row size in mysql?

i mean what does it mean ?, i have mysql db and table in myisam and it shows Space usage Type Usage Data 1.3 GiB Index 429.1 MiB Total 1.7 GiB Row Statistics Statements Value ...
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5k views

Configuring MySQL (my.cnf) for MyISAM and InnoDB

I want to convert some (not all) the MyISAM tables to InnoDB. Here is my current my.cnf: pastebin.com/FW8YXtLQ What would be the best configuration? (need to add InnoDB settings, byecause there are ...
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102 views

Configuration required for a big mysql database around 20GB

I need to host a single machine database (constraints), wherein the database size is roughly 20gb. Most of the tables are in MyISAM. Any way I can actually run it with decent speed ? Alternatives I ...
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1answer
655 views

Issue moving database between servers (cannot find .frm file even though it's there)

I used MAMP on my local machine to make a little site with a mysql database. I moved all the site files over the to server. Great. The name of my database is roster and it has one table called users. ...
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125 views

why/how does the number of matched columns influences the way of excecuting a query

Imagine the following situation: Table A uses MyISAM and contains 4 fields (text) with a combined FULLTEXT-index. FULLTEXT fulltext1 | fulltext2 | fulltext3 | fulltext4 Table B uses InnoDB and ...
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381 views

Can MySQL 5.1 read a MySQL 5.5 MyISAM file?

We're in the middle of an upgrade from mysql 5.1 to mysql 5.5. Our only remaining holdout is the master, at 5.1, while all the slaves are at 5.5. However, we have a stats process that runs on an ...
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1answer
4k views

Repairing Myisam Table when there was no additional Disk space & Table corrupted

I had a table which MyIsam as storage Engine contains million rows. There is a purging task and need to remove 35 days old data. i measured up the rows in following manner : mysql> select ...
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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 ...
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553 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 ...
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1answer
444 views

MySQL MyISAM Table Locking and Delayed Inserts for Webserver Access Logs

We will install a webserver that writes access logs to a MySQL table. Access logs of course will get really really big, so this will be a separate MySQL instance from the regular data and we will more ...
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4answers
98 views

If all tables are myisam, should I use myisam engine instead of default innodb?

I have read all of the innodb/myisam threads and they are confusing. Everyone says innodb but I am assuming that they are saying innodb engine with innodb tables.? The software I am using creates ...
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1answer
211 views

Will MyISAM prevent multiple users inserting data at the same time?

I am using a MyISAM database to store user data because I am using full text searching. I have looked in to options like Sphinx but cannot install this on my shared hosting plan which uses MySQL ...
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2answers
265 views

How to batch multiple insert statements for database dump with MySQL?

I have a MySQL database with some large tables. In particular, the largest table (by far) currently has ~11,000,000 rows. According to the a query I ran, the table clocks in at around 1.7GB, but it's ...
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1answer
189 views

MySQL repair deleted data - Any chance of recovery?

Well, this has been a long Saturday morning. MySQL was throwing an error when dumping backups. That error was... mysqldump: Error 1030: Got error 5 from storage engine when dumping table mytable at ...
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1answer
1k views

Space not reclaimed after dropping MyISAM table

I just dropped a rather large MyISAM table (~4 gb); it was 350k rows with about 11k of data per row. However, when I run df -h on my database server, I am still at 100% disk usage, so much so that I ...
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2answers
494 views

Why does MySQL fail to use an index effectively when LIMIT offset is large?

I do not understand when querying 5 rows from a table of 500,000 rows, the following query takes 0.00sec: SELECT id, username FROM Users FORCE INDEX (PRIMARY) ORDER BY id LIMIT 20,5; But querying ...
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1answer
102 views

How safe is it to widen a column in MySQL?

Apologies for the simple question but SQL isn't really my forte, and I want to be sure I don't shoot myself in the foot. A MySQL database I volunteered to help maintain has a table that looks like ...
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3answers
1k views

Converting live MyISAM table to InnoDB

I have a table that tracks web traffic. The table is constantly written and read from. Since table is pretty big in size I have to make sure the application will not "freeze" in the process of ...
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1answer
4k views

Merge multiple tables in a database

I have a MySQL database with table names like 1,2,3... upto 1000 Each tables have 2000 rows and has the same structure. This is how all my 2000 table's structure look like id,url,title,content id ...
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1answer
636 views

Is it safe to kill ANALYZE TABLE query on a MyISAM table?

I have a huge MyISAM table that is blocking my application. I frequently find ANALYZE TABLE queries running on that table. I guess that's because a join is being performed on the table or at least an ...
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1answer
484 views

Repair with 1 thread

Why would MySQL be using Repair with 1 thread to rebuild the indexes on a table (1 primary key, 2 billion rows) when I have myisam_repair_threads set to 4?
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234 views

Is the key_buffer_size applicable to myisam tmp tables?

I have a database about 750GB in size. It's all innodb. Larger analytical queries often need to group by several columns or use distinct so it's common that MySQL will have to create tmp tables. The ...
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1answer
314 views

High IO when switched to InnoDB

We have query that worked well in MyISAM. When we switched to InnoDB, the writes I/O raised up to 50 times. The query is type of INSERT ... ON DUPLICATE KEY UPDATE I don't know if the problem is ...
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4answers
2k views

Very small MySQL table keeps crashing

I have a MyISAM MySQL table that keeps crashing. The table has only 16 rows and is very rarely written to (maybe once a month). I have a medium-sized site that typically has about 500 pageviews per ...
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2answers
944 views

How can I check if the keys are enabled on a MyISAM table?

I have a script, which populates 4 tables. It goes like this: Disable the keys on all the tables Populate the tables Enabled the keys back. The problem is that windows decided to reboot the ...
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2answers
76 views

Optimal engine for small lookup tables in MySQL

I have following question: I am designing web application with several dozens of small lookup tables: These tables usualy contain three columns (ID, Name, Description) and a couple of rows (mostly ...
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2answers
49 views

MySQL - SELECT on MyISAM Table on index - Does table size (rowcount) matter?

I was arguing with a coworker if SELECT * WHERE t BETWEEN ? AND ? on a MyIsam table where t is an index is significantly slower for huge tables. The hypothetically returned dataset is always the ...
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1answer
69 views

Only InnoDB databases locking up

I'm trying to troubleshoot my MYSQL in a LAMP and have an interesting situation. At first I thought MYSQL itself was locking up, but it turns out to be ONLY innodb databases that are locking up. ...
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516 views

MySQL Error 1114 “table is full” Using MyISAM Engine

When executing the following query, we run into the error The table '/var/lib/mysql/temp/#sql_2d22_1' is full (actual table name varies). I've done a fair amount of research on this; most of the ...
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1answer
894 views

MySQL hangs in killed state

I have a strange situation where a mysql OPTIMIZE query will never end. After killinh it, it remains in the "killed" state. Scenario to reproduce: OS: CentOS 6.5 MySQL: 5.6 Engine: MyISAM (with at ...
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1answer
70 views

How to go about modeling the main object of relationship?

I'm using MySQL and MyISAM tables. I have a bunch of objects that I want to group together 1 object belongs to 1 and only 1 group 1 group can have many objects 1 group has 1 required main object ...
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1answer
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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 ...
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1answer
3k views

Unique insert performance: Primary Key vs Unique Index

I have a table of unique values (domains_unique), with collumn domain varchar(255), with more than 20 mil records. What's the fastest way to insert into the table, by keeping the domain unique ...
2
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1answer
413 views

MySQL table locks solution -> InnoDb / Partitions

I'm experiencing many table locks in a MyISAM MySQL table that is pretty big (Constx10xGB and 15M rows). It's mainly caused due many heavy inserts. My current thoughts to optimize: Changing to ...
2
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1answer
351 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 ...
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2answers
796 views

Need help in restore some rows into mySQL database frm myd myi

I am using one mySQL database for several sections of the website and one of the section is not working, when I go to the link of that section it gives the error "1146 Error @ Line 39: Table ...
2
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1answer
390 views

myisampack running really slow for large DBs

I was going through compressing a bunch of archival myisam tables using myisampack It was making decent progress until it got to the most recent tables. The overall database is a set of archives for ...
2
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1answer
88 views

Moving the binary location of MySQL for replication

Is it possible to move the contents of /var/lib/mysql when setting up replication instead of doing mysqldump > for export and mysql < for insert on the slave, because in our current setup it takes ...
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0answers
27 views

Tuning Issue / Temporary Tables

I've got a MySQL database (MyISAM) that handles a lot of read/writes and uses temporary tables quite frequently. Recently it's started having massive load spikes at peak load, and noticed that there ...
2
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1answer
320 views

Does MySQL guarantee atomic upgrade from read lock to write lock?

If a client session is currently holding a read lock (to allow concurrent reads while already preventing writes), and then acquires a write lock on the same table(s), does MySQL guarantee that the ...
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2k views

MySQL - high CPU usage (MyISAM tables)

We have a server running LAMP stack on CentOS release 5.6 (Final) MySQL is having high CPU usage constantly which causes server to lag as shown top - 13:50:47 up 80 days, 13:53, 1 user, load ...
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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 ...
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695 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 ...
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1answer
2k 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 ...
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63 views

Convert MyISAM to InnoDB

What are the considerations needed when converting myisam to innodb. I have a table around 80 GB with engine myisam. I would like to convert into innodb. What are the considerations needed to ...
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2answers
1k views

Why is MySQL not using the index with the higher cardinality?

I have an index called source with cardinality of 1122 and a second index called state with cardinality of 22. MySQL keeps using the state index when when query SELECT C1 FROM tbl WHERE source = 'x' ...
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342 views

MyISAM vs InnoDB for Forums [closed]

I want to design a forum script with MySql. Which database engine would have better performance? MyISAM or InnoDB ?