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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How to generate data for News Feed efficiently like facebook , googleplus , twitter e.t.c?

I have created table as post ( post_id int(15) auto_increment primary key , user_id int(11) , post_text varchar(2000) , post_type int(1), ...
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329 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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202 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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226 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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819 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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353 views

MyISAM key buffer

Good evening, I want to know how can I use informations about MyISAM to calculate : size of buffer, size of buffer used, Write ratio, Read ratio, and MyISAM key cache hit rate and thank you.
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669 views

Optimizing disk space for MyISAM tables: what is the benefit of ALTER and ANALYZE if you already do OPTIMIZE?

Per this post, in order to optimize the storage of a MyISAM table, you need to: OPTIMIZE TABLE ; ALTER TABLE ENGINE=MyISAM ; ANALYZE TABLE ; It's obvious what OPTIMIZE does for disk space but what ...
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514 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 ...
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237 views

mysql freeze/crash on JOIN

here is query: SELECT nw.news_id, nw.title, nw.description, nw.url, nw.date, nw.image, nw.status, src.title as src_title, src.keyword as src_keyword, src.url as src_url, src.icon as ...
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141 views

How can I force myisamchk to modify the original data file in case of duplicate keys?

In the documentation for myisamchk, it says: --quick, -q Achieve a faster repair by modifying only the index file, not the data file. You can specify this option twice to force myisamchk to ...
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185 views

How to speed up this query

MySQL doesn't have nearest neighbor search so. So I try to come up with a "distance" that's reasonable so the number of returned query is around 20-200. That way innodb doesn't have to compute ...
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107 views

Why do we need myisam spatial extension anyway?

If just to determine whether a point is within a rectangle, What is wrong with this query? EXPLAIN SELECT DISTINCT TB.ID, TB.Latitude, TB.Longitude FROM TableBusiness AS TB WHERE ...
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93 views

Concurrency Issues when multiple users uses Portal (MySQL and PHP)

We have set up a portal using Yii Framework in Apache, PHP and MySQL. In the portal, there is a feature to export the data in dbf format, the extract takes around 7 minutes, but in those 7 minutes no ...
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4answers
518 views

Converting to MyISAM, `foreign_key_checks = 0` Not Working

At the end of a long series of compromises working in a system I didn't design, own, or maintain, I need to convert a number of MySQL InnoDB tables to MyISAM tables. However, when I attempt to alter ...
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2answers
64 views

Should I create a multi-column UNIQUE index?

I have created the following MySQL table, which stores which sections of our site a user visited (and the Count of visits): CREATE TABLE `Visits` ( `ID` int(10) unsigned NOT NULL AUTO_INCREMENT, ...
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2answers
60 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. ...
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1answer
2k views

Unable to select the records from specific partition in mysql?

I've created a table using the following query, CREATE TABLE employees ( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, fname VARCHAR(25) NOT NULL, lname VARCHAR(25) NOT NULL, store_id ...
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1answer
27 views

Query perfomance with multiple JOINs on MyISAM-based DB

I'm working with Enron Email Dataset in MySQL database. After I executed data import from dump-file into MyISAM-based DB, I got the set of tables without any connections between them via foreign keys. ...
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1answer
40 views

Mysql - MyISAM Default order

We are using Mysql V5.6. We have a MyISAM table. when we open the table, the records will be displayed in some order instead of primary key order. Even when selecting the records will not be retrieved ...
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365 views

Queries are taking long time to execute

I have large DB around 25 GBs and the most busy table is around 9.5 GBs, database is increasing @ 10% per month, I am using mysql with MyISAM engine. Problem started 3 days back, there is long list ...
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1answer
55 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 ...
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1answer
228 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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9k 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
258 views

Latin1 to UTF8 on large MySQL database, minimal downtime

Let me lay out the basic scenario for the problem I'm up against. I'm running MySQL 5.1 and have a single database with 2 large MyISAM tables (9M and 20M rows respectively). Each of these tables has ...
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2answers
347 views

Convert the table PROCESSLIST from InnoDB to MYISAM

I use MySQL. My database's name is "db", and I have a table called "Test". I want recover the last update, so I used this query: SELECT update_time FROM information_schema.tables WHERE ...
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321 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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1answer
121 views

myISAM data loss at DELETE / INSERT

I have a linked table id_group | id_user. Every time I add a one or more users to a group I DELETE all the links and INSERT the users again including the new one(s). This is how the framework of the ...
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2answers
1k views

How do I get spatial index feature if I mainly use innodb?

My current strategy is to create another table in myisam that contains those spacial information. Then if I want to find 20 closest business, I'll just use join. Is this a good idea?
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23 views

What does FTS_ file mean after converting from MyISAM to InnoDB?

I have convert some tables in database from MyISAM to InnoDB. After that, I see some modification on file system. The size of database is grown up, from 2.8GB to 4.8GB and there are many file with ...
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1answer
258 views

Why is my Mysql Query verry slow when selecting a text field

i have a problem with a left join. Tables are myisam. Tables CREATE TABLE `article` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `force_startpage` tinyint(1) DEFAULT '0', `title` varchar(255) ...
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1answer
112 views

How to transfer 70GB MySQL with no downtime?

I have a large amount (4000) of individual databases, 90% of which are small. They all include about 20 tables each, and in total, they use about 75GB of space. All tables are MyISAM. I want to ...
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286 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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1answer
708 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
40 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 ...
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1answer
65 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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2answers
74 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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2answers
128 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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1answer
152 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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1answer
330 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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1answer
76 views

MyISAM table is not working as expected in MySQL

mysql>show processlist; +-------+------+------------------------------+---------------------+---------+-------+-------+------------------+ | Id | User | Host | db ...
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2answers
221 views

MySQL database datafiles in windows SystemData directory

When I create a database and some tables in MySQL Server, it makes some data files in Windows SystemData directory in C:\ProgramData\MySQL\MySQL Server 5.5\data\mydb\. Each table has three files with ...
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1answer
283 views

Information about Disk Storage MySQL

I am trying to create an application for monitoring MySQL,in my application there's a part of monitor DISK STORAGE, so after more research I have not found how to calculate : used and free size of ...
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1answer
116 views

Two identical MySQL tables, one not using indexes

I have one MySQL Server (5.0.37) on a Linux Server that have many databases. Some of them (12) have each an identical table to log sensors data. Schema of one table CREATE TABLE `measuresHistory` ( ...
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1answer
487 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
382 views

MySQL: replicating to a different table engine type

According to the replication documentation from MySQL, it is possible to set up replication from InnoDB source tables to MyISAM destination tables. Unfortunately, the documentation has little to say ...
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618 views

Bypass MyISAM table lock

I have a big MyISAM table with a fulltext index for searching. Problem is that inserting data into that table results in a table lock and in the meantime no other sql query can perform any action ...
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2answers
1k 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
43 views

Which text-index I should create for xooops engine to achieve better search results?

In one of projects we use xoops engine to manage content. In mysql slow query log most of queries are following : SELECT p.uid,f.forum_id, p.topic_id, p.poster_name, p.post_time, f.forum_name, ...
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2k views

MySQL how to release memory used up by SELECT

I executed an INSERT IGNORE combined with SELECT from large table. The SELECT took up 16GB of memory and went into SWAP before I terminated it with CTRL+C. INSERT IGNORE INTO sid(sid) SELECT sid ...
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1answer
781 views

How to restore mysql from only myi files?

our server hdds has crashed and we didnt have a current backup so we sent our hdds to a data recovery company, they have been working on hdd's for over a week and they have finally managed to save ...