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

2
votes
0answers
20 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 ...
1
vote
1answer
13 views

Migrating MyISAM tables from 5.5 => 5.6

I was wondering if anyone had any pointers on migrating MyIASM tables from mysql 5.5 to 5.6, specifically using Percona builds, via an rsync? Is this safe? I know we need to do a full ...
2
votes
1answer
33 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 ...
1
vote
2answers
76 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' ...
1
vote
2answers
70 views

Why does MySQL slow down in loading data?

We have a really large file (26GB) that we need to upload to MySQL. In order to do so we split it into nine 3GB files. What's confusing is that the first file took only 2 minutes to load, whereas the ...
0
votes
0answers
22 views

using Aria vs InnoDB vs MyISAM

I was wondering (if anyone knows) if Aria database is crash safe . I had some tables with MyISAM which were getting corrupted very often and switch them to InnoDB . However innodb is a bit slower and ...
1
vote
1answer
101 views

MySQL - Best long read query solution within a replication based system

I'm working on a project where work in a queue requires a database read against heterogeneous table schemas (InnoDB/MyISAM). The queries constructed during the "read" process can result in 10-15 ...
0
votes
1answer
18 views

MyISAM recover updated row

The row (with type MEDIUMTEXT) has been accidentally updated with empty value. I can see previous data in MYD file of a table, but I can't get them neither from mysqldump or any mysql client. If I ...
0
votes
2answers
35 views

MySQL query optimization for legacy application

I'm working with a legacy application that started out with little data years ago (developed by a third party custom for this client), and now we're seeing MySQL load skyrocket on this query alone. ...
0
votes
1answer
39 views

Fetching User Recent Status

I am running mysql with MyISAM storage engine to store user status(user updates data). To load user recent updates data i am using this query: $limit = 20; $uid = 3; SELECT * FROM userstatus WHERE ...
0
votes
0answers
33 views

Quick MySQL Backup (1 file per table) - v2

Improving bash shell script written by RolandoMySQLDBA. Continuing the following thread: Quick MySQL Backup (1 file per table) I tried to adapt your script, but after the first rsync was done, I get ...
3
votes
2answers
167 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 ...
1
vote
0answers
113 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 ...
1
vote
1answer
61 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, ...
0
votes
1answer
55 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 ...
0
votes
2answers
61 views

How to determine the optimal sort_buffer_size?

I read from a sample configuration file which says the following: # Sort buffer is used to perform sorts for some ORDER BY and GROUP BY # queries. If sorted data does not fit into the sort buffer, a ...
1
vote
1answer
28 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 ...
1
vote
1answer
40 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 ...
0
votes
0answers
61 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 ...
2
votes
2answers
83 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 ...
0
votes
1answer
46 views

Is searching an alternate index on a partitioned myISAM table concurrent or serial?

I have a myISAM table with 30 partitions. The primary key is a SHA1 hash value, which is also used in the partition selection function. I also have an alternate key - an autoincrement integer. Since ...
1
vote
1answer
58 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 ...
0
votes
1answer
87 views

INSERT take too much time

I have in my MySQL DB a few tables Most of the time, I'm only doing INSERT in my db. I have up to 4 connections to the DB, each one inserting into a different table. There cannot be two connections ...
1
vote
2answers
70 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?
0
votes
1answer
44 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 ...
7
votes
2answers
247 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 ...
5
votes
1answer
305 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. ...
3
votes
1answer
59 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 ...
0
votes
1answer
55 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 ...
1
vote
2answers
81 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 ...
0
votes
0answers
20 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? ...
0
votes
0answers
35 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 ...
2
votes
1answer
49 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 ...
1
vote
0answers
80 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 ...
0
votes
1answer
130 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: ...
0
votes
0answers
65 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 ...
0
votes
1answer
36 views

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 ...
1
vote
1answer
74 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 ) ...
0
votes
1answer
48 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 ...
0
votes
2answers
40 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 ...
1
vote
2answers
163 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 ...
0
votes
2answers
68 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 ...
0
votes
1answer
224 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 ...
0
votes
0answers
36 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 ...
1
vote
1answer
273 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 ...
0
votes
3answers
194 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 ...
0
votes
1answer
71 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 ...
0
votes
1answer
73 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 ...
0
votes
1answer
109 views

Debugging error report percona 5.6

I'm running percona 5.6 on a new centos 6.4 server. Things seem to work OK. I personally only really use InnoDB tables for my databases, but only the standard 'mysql' table is in MyISAM format. I ...
0
votes
0answers
154 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 ...