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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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 ...
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435 views

Does a MyISAM table locks if I copy it while MySQL is running? (READ DISCLAIMER)

DISCLAIMER: I'm very aware this is not supposed to be done, but time consistency between tables aren't a concert here and Im trying whatever pops in my mind right now to have alternatives for ...
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473 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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94 views

When and how would MyISAM concurrent insert = always be a problem?

I wish to set concurrent_insert to always on a MyISAM log table, so that inserts wouldn't have to wait for selects to perform when there are some holes in the table. We're talking about 10-20 inserts ...
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280 views

mysqldump: Does --lock-tables=false work with MyISAM tables?

So, I have to check and come with a backup solution for a very busy mysql server (with tables over 5 GB). Due to resources constraints, they choose to set all tables with the MyISAM engine. Currently, ...
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92 views

Best way to add a new column to a large table? (MySQL - MyISAM)

Here's more info on the table that needs to be altered: 15GB size MyISAM table with Index around 5GB Over 100 million rows MySQL 5.1 on RHEL 5 with 4GB RAM Currently live online What's the best ...
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5k views

What is causing Waiting for table level lock errors?

We got the database hanging twice already and trying to find a cause. show processlist Waiting for global read lock | INSERT INTO {myisam_table} ... In here the disk space was full so we thought ...
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1answer
59 views

InnoDB to MyISAM Conversion Problem

I have a dedicated server based on CentOS 5 OS , mysql 5 and phpmyadmin I was trying to convert all database tables from InnoDB to MYISAM. I tried to do it by setting in /etc/my.cnf file the value ...
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158 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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143 views

How to recover a crashed MyISAM table which myisamchk couldn't recover?

We take db backup by stopping the database and then issuing a tar -zcf on the mysql data directory. When we restore the data directory on another machine and try to start the slave, the mysql error ...
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190 views

MyISAM with Innodb in the same Wordpress database reduce performace?

My new Wordpress database all the Wordpress created tables use InnoDB engine and plugin created table use MyISAM. But older site database all the tables use MyISAM table engine. I use MySQL ...
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651 views

How to check growth of database in mysql?

I want to know is there any method to check the growth of database on file EXAMPLES Database A contains all tables in INNODB storage engine Database B contains all tables in MyISAM storage engine ...
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213 views

MySQL views and table locking (5.1 MyISAM)

I have a large (160 million rows, 50GB) table in MySQL 5.1 using MyISAM. If I were to construct a view defined by a fairly complicated query, would a SELECT on the view lock the underlying table?
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1answer
53 views

Backup live MySQL database

I have a single MySQL database Server version: 5.5.35-cll MySQL Community Server (GPL) ENGINE is MyISAM I use 'mysqldump' to backup and restore the database. Size of the dumpfile is 3GB+ Once a ...
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2answers
350 views

How to drop empty tables

Is it possible to drop all empty tables from my huge database (mysql)? I'm looking for a sql command to automatically remove all those empty tables. Currently, I have 305 tables in my dataset, and ...
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1answer
989 views

MySQL 5.1 to 5.6: massive performance hit

Okay, this is possibly three questions. I want to move my existing MySQL 5.1 database using MyISAM to 5.6 using InnoDB for what I think are a host of obvious -- and possibly even good -- reasons. ...
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1answer
111 views

Tuning key_reads in MySQL

We are trying to tune our MySQL database (Myisam, 5.1.73) which is getting busy. We investigated Key_reads: $ mysqladmin ext -ri10 | grep Key_reads During a normal load we have the following ...
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88 views

Should we explicitly lock MyISAM tables or is it implicit…?

Does MyISAM tables automatically lock a table for each select or insert statement .... I mean if I query the database as select * from tablename then does the MySQL engine first lock it for read ...
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116 views

Upgrading mysql myisam 5.1 to mysql 5.6: force innodb on restore?

I inherited a DB using myisam on mysql 5.1 because of the need for fulltext search. I now read that fulltext search is available on mysql 5.6 innodb. Doing this would solve a lot of problems, as long ...
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2answers
276 views

Help my database isn't performing fast enough! 100M Merge with 6M need < 1 hour!

I have a server right now receiving more raw data files in 1 hour then I can upsert (insert -> merge) in an hour. I have a table with 100M (rounded up) rows. Table is currently MyISAM. The table has ...
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3answers
375 views

MySQL Tables Require Daily Repairs - Server, Table or HD?

I've been experiencing a weird issue with one of MySQL DBs. Every day, sometimes 2-3 times per day, I'll need to repair the tables. The MySQL DB has 25 tables with 5.6m rows in total. The bigger ones ...
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152 views

Why does MySQL + Windows Server = crashed tables periodically?

Windows Server 2008 R2 x64 MySQL Server 5.6.14 x64 Is anyone else having an issue in where some tables are marked as crashed on a Microsoft Windows server? We have a couple of Windows servers (not by ...
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24 views

How to change a table's data directory

I tried to modify with ALTER TABLE, and as I found from the official documentation: ALTER TABLE ignores the DATA DIRECTORY and INDEX DIRECTORY table options. What other options do I have? ...
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71 views

.myd and .myi versus .frm and .ibd

I'm new to MySQL.I have trouble finding the .frm files and .ibd files in Windows 8 Explorer.They seem hidden and I have to find them using 'Find' and 'Open File Location', not sure how to make these ...
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1answer
608 views

mysql: find column data size on disk

I have fairly large MyISAM table with longtext field in it Table size is somewhat 16GB. I need to know if clearing this column in old records helps to keep table small I can retrieve table wise ...
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2answers
982 views

Unable to change engine to MyISAM in MySQL

I have installed MySQL 5.6.10 on Mac OS X 10.6.5. My issue is that MySQL is using InnoDB as its default engine. I have checked following engines are supported in MySQL: show engines\G ...
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1answer
59 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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1answer
251 views

MySQL MyISAM index causes query to match no rows; indexes disabled, rows match

I created a table and index as described in this SE post, but when I query the table for a particular ID, no matches are found. When I disable the index, matches are found. Commands ran: CREATE ...
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111 views

Missing rows in MyISAM tables with 10-20 billion records

I've got 2 tables with 10-20 billion records each. Currently these are in MyISAM (MySQL). They only require to be built and indexed once, after this only SELECT is used. They are currently ...
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312 views

My database keeps crashing on startup how can i repair it without it running?

I've got some problems with my database. I hope somebody can help me out. Problem: The database keeps crashing on startup. In my log i see a couple off these errors: [ERROR] /usr/libexec/mysqld: ...
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1answer
55 views

Few Insert queries rollbacked due to system crash

Well, this problem occured to me first time. Yesterday, one of our mysql system server crashed and when it restarted last few inserts were completely rollbacked. I am sure that they were proper ...
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85 views

What are the steps to change tables engines from MyISAM to InnoDB?

I have a Datebase with 10MB size . The Tables' engines were MyISAM (table-lock level). So I deiced to change them to InnoDB (row-lock level). I used the sql query for each table : ALTER TABLE t ...
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is it possible to set engine for database (not the tables)?

There are about 250 tables in my database and they all have InnoDB engine. I imported them into a server. They were imported and were displayed in the tree structure of phpmyadmin (under the ...
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1answer
98 views

Need to optimize simple SELECT query for InnoDB table with 2million rows

I'd like to make this query the fastest possible, since it's called really often. SELECT login_events.id FROM login_events WHERE ( DATE(created_at) >= DATE(CURRENT_DATE) AND person_id = 1 ) ...
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2answers
53 views

MySQL using swap during conversion to InnoDB

I'm trying to convert some MyISAM tables in my database to InnoDB (MySQL 5.1). The server has quite a bit of memory (96G), and the tables that are giving me problems can be on the order of 50 millions ...
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347 views

Setting default CHARSET and DB Engine

I recently updated my server's database system from MySQL to MariaDB. After update, everything works well. But, when I went to phpMyAdmin, the default charset and types are changed: At the end of ...
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1answer
128 views

Mysql Performance tuning for myisam tables.

Folks I have a 4-core MySQL server with 4 GB of RAM, holding 19 MyISAM tables (total: ~164GB of data) and 32 innodb tables ( 5mb ) and we use it to process CDR files( basically call detail records ...
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1answer
383 views

how to set bulk_insert_buffer_size in mysql?

I want to set bulk_insert_buffer_size variable for insert. I searched from other pages too, all they are saying about my.cnf. But there is no my.cnf in my system. I checked my.ini and there is no such ...
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42 views

How to get rid of the table lock in MySQL

I have a database for my website the website have a betting game(using insert and update queries) and the other pages of the website are using (select, insert and update queries). When a user make a ...
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1answer
465 views

Timeout on ALTER TABLE table ENGINE=InnoDB - is table still converted?

I'm converting tables in an old MYISAM database to InnoDB to increase robustness in case of power loss etc. I'm using Mysql 5.5.x Before doing the production system, I am doing a trial run on a copy ...
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3answers
424 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
127 views

Backing up MySQL w/MyISAM on Amazon RDS

So, for various good reasons, we're maintaining a mySQL database using a MyISAM engine on Amazon RDS. I've just taken over this application, and I'm concerned we're not getting good backups, since ...
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311 views

MySQL Read Speed and Partitioning on Separate Drives

Introduction Simple project but for an heavy read load -90% reads- over a table(~20Milion Rows ever-growing where I have to boost performance and ensure response low time for read queries) that was ...
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1answer
317 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
2k views

Consistent logical backup of databases that use MyISAM and InnoDB engines

I have a question regarding the logical backup of MySQL databases that use both MyISAM and InnoDB. The mysqldump utility supports these two options: --single-transaction - Creates a consistent ...
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179 views

Improve Speed of MySQL Database Import

I'm importing around 44 GB (14 million rows) of information into an InnoDB MySQL database, and I'd like to do so in a reasonable timeframe. Since I'm doing this on a personal computer, I only have 8 ...
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1answer
184 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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57 views

Performance setting for MyISAM tables - my.cnf file

I have a 4-core MySQL server with 4 GB of RAM, holding 19 MyISAM tables (total: ~164GB of data) and 32 innodb tables ( 5mb ) . QUESTIONS Since the databases size is smaller than the available ...
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1answer
119 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 ...
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1answer
56 views

MySQL command querying all MyISAM database

I would appreciate if anyone could help me of what's the proper command in MySQL to query all database for having "MyISAM" engine. I need to convert all DB & tables from MyISAM to InnoDB.