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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What is the SQL command to get 20 closest points from some center location

There are 1.6 million rows. Must not compute distance for all rows. Spatial index is available This is the table structure. The name of the table is businessauxiliary. So yes I used MyIsam, added ...
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291 views

extremely slow MyISAM slave updates

I have 2 slaves and one is working as expected. The other slave is extermely slow while executing the "update" statements. The insert and deletes are fast. I used "check table tbl_name" to see if any ...
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3k views

Write lock during mysqldump even using --lock-tables=false

When I try to dump an online database using --lock-tables=false, others cannot update the table. Are there any methods to solve this? As I am using MyISAM, does --single-transaction for InnoDB help? ...
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3k 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 ...
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729 views

How to Prevent an Ever-Growing index file (MyISAM engine) From Causing Disk Fragmentation in Windows (NTFS partition)?

We have a keep-growing table which using MYISAM storage engine. Almost every half year, this table will crash, and need to be repaired. I checked the defragment result reported by windows ...
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143 views

MyISAM table row size is bigger than the sum of all the columns size?

I have a table: CREATE TABLE `playlist` ( `pid` int(11) unsigned NOT NULL, `mid` bigint(21) unsigned NOT NULL, `status` tinyint(1) NOT NULL, `add_time` int(11) unsigned NOT NULL, ...
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63 views

How to speed up query containing concat() in WHERE clause?

In my company we use a commercial software running with mysql 5.5 (MyISAM) that often executes a query of this form: SELECT table1.attrib1 FROM table2, table1 WHERE table2.status = 'Active' ...
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51 views

Why MySQL SELECT performance depends on table size? [closed]

I've got two identical tables with the following structure: CREATE TABLE words ( id bigint(20) NOT NULL, `text` int(11) NOT NULL, w1 int(11) NOT NULL, w2 int(11) NOT NULL, w3 int(11) NOT ...
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31 views

MySQL, can't find MYD files on OS X, MAMP

Try as I may I can't find the data files for my MAMP installation! FRM files are here: /Applications/MAMP/db/mysql/database_name/ but, there are no corresponding MYD or MYI files anywhere. The ...
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47 views

how to cache a subset for cascading select queries in mysql

Here is another database problem I stumbled upon. I have a date-range partitioned MyIsam look-up table with 200M records and ~150 columns. On this Table I need to perform cascading SELECT-Statements ...
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82 views

Suddenly high CPU usage

I've read a lot about MySQL optimisation and I already optimised MySQL about a year ago. Reason for that was a high system load average. I tuned many queries and edited the my.cnf file. Since then ...
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107 views

Invision Power Board 3.4.6 - mysql locks during query with pending updates

about 2 weeks ago, we started experiencing random lockups and slowdowns on our forums. We've been running this site for around 6 years minimum with no issues. the site and db are on dedicated vms. The ...
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50 views

MySQL column type to boost performance

I'll have a table where: userid (link to user's id in users table) foldername (a varchar, max. 260 char) entry (varchar, max. 1024) data (varchar, max. 20kb) Single user will have several ...
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1answer
3k views

Strange MySQL replication error 1146 (Table doesn't exist)

I'm getting a very weird MySQL replication error No. 1146 for a REPLACE INTO query on a slave host replicating all tables in all databases from a master, and I'm having a bit of a hard time ...
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127 views

“Unexpected EOF” during SELECT on huge MyISAM table

When executing a SELECT query that uses filesort on a huge table (2 billion rows) the execution stops after ~30mins with the following error message: ERROR 9 (HY000) at line 1: Unexpected EOF found ...
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91 views

How do i increase the total MyISAM indexes?

I have just made a check for my server with mysqltuner. -------- Storage Engine Statistics ------------------------------------------- [--] Status: +Archive -BDB +Federated +InnoDB -ISAM -NDBCluster ...
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81 views

Fastest engine for Mass Updates (only updates done on table)

I have a table of 2 columns and 60 million rows. I want to update the table by incrementing one field by 1 on various different rows (This is the only type of operation that will ever be done on the ...
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77 views

Indexed query fails to return rows in large (15 billion rows) MyISAM (MySQL) table

I have a very large table (15 billion rows) with a structure like this: CREATE TABLE `textlines` ( `PGUID` binary(16) DEFAULT NULL, `StatID` int(11) DEFAULT NULL, `Time` datetime(3) DEFAULT ...
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2k views

mysqlcheck --repair a specific table?

I logged in my server via SSH and committed a "repair table xxx" query on a MyISAM table with 34 million rows and 69GB of data. Unfortunately the SSH connection was lost. When I logged back in I found ...
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113 views

Question on MySQL insert race condition

I'm using MySQL 5.1, PHP 5.3 and the table is MyISAM. Here's the DTD of this very fake table: CREATE TABLE `temp1` ( `value` varchar(10) DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 This ...
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242 views

Options to include with mysqldump when taking backup of hybrid databases

I'm planning on taking backups of all MySQL databases on a remote production server. The combined database size is around 2 GB. Most of the tables are InnoDB ~1.8 GB and the rest are MyISAM. Now I've ...
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171 views

Mysql sequential numbering based on MAX of another column

I've a table lp_pictures which have these fields: [id | plate_uid] [1 | aaa] [1 | aaa] [1 | aaa] [1 | bbb] [1 | bbb] [1 | bbb] and i need to UPDATE the field id to becomes: [id | plate_uid] ...
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506 views

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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442 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 ...
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536 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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276 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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1k 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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437 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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960 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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2answers
615 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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284 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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159 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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191 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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115 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
1k 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
94 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
64 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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2answers
31 views

Fixing MyISAM database without losing data

My old server was crashed but I was able to recover the databases from MySQL through testdrive. I'm trying to dump a database using mysqldump but it gives error for certain tables are crashed and ...
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1answer
41 views

Query databases that have MYISAM tables that do not have only fulltext index tables

I am trying to query from the information_schema where the database (table_schema) has MYISAM tables but does not have only fulltext index tables. The statistics tables is very poorly designed for ...
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1answer
48 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 the dump file into MyISAM-based DB, I got the set of tables without any connections between them via foreign ...
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1answer
77 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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541 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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61 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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328 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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326 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
382 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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2answers
374 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
126 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 ...