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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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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190 views

What's the optimal server configuration for fastest inserting in a MySql database in this scenario?

I have a MyISAM table partitioned by range with 90 partitions representing the last 90 days. I expect this table to receive somewhere between 500 million to 1 billion records before i start rotating ...
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72 views

MyISAM table is not working as expected in MySQL

mysql>show processlist; +-------+------+------------------------------+---------------------+---------+-------+-------+------------------+ | Id | User | Host | db ...
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MySQL 5.5 High CPU Usage

I have been working with a client with high traffic website(500k visitors and 600-800 active users at any given time). This uses wordpress and the DB is using MyISAM engine. The problem we had was ...
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Remove InnoDB files (ibdata1 and iblog files) after migration to MyISAM

I changed the only two InnoDB tables on a replication slave to MyISAM, so the slave now only has MyISAM tables. Can I now remove the ibdata1 file completely?
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128 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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167 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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90 views

InnoDB query duration inconsistent

I am running a series of UPDATE commands on a nearly empty InnoDB table, and around 1 out of every 20-30 queries will inexplicably take 10 times as long as the others. For example, the first 20 ...
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266 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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242 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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329 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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540 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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332 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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448 views

Getting Random Sample from large database MYSQL (No Auto Inc Field)

You were so helpful with my last question, I thought id throw another one at you thats stumping me. Basically I got a table, requirements from company was it was all supposed to be 1 table so I got ...
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295 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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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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109 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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280 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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3k 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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MySQL Hanging Completely when `ALTER TABLE… ENABLE KEYS`

I know very little about database administration but I have to deal with some very large tables on my site. This server has 64GB of RAM and Intel Core i7-3820 (4 x 3600 MHz). Most of everything it ...
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1answer
173 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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3k views

MySQL high CPU usage (MyISAM table indexes)

I have a problem with an inherited MySQL database. From time to time mysqld uses up to 2300% CPU.. The only solution is to service mysql stop and run an myisamchk -r on a table. After the indexes have ...
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261 views

Issues converting MyISAM table to InnoDB (auto column issue)

I'm having issues trying to convert a table from MyISAM to InnoDB in MySQL 5.6. The following is the table dump: -- -- Table structure for table `companies` -- DROP TABLE IF EXISTS `companies`; ...
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384 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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711 views

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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160 views

Start/Stop MySQL

I'm seeking help to understand what happens when the following command line is executed: root@prodn$ service mysqld stop Yes, it shuts down the MySQL server so access to it is no longer available ...
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230 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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2k views

High Mysql Load , over 700% CPU

I had high mysql load on server linux 64 bit , 24 G.B ram , Intel(R) Core(TM) i7 CPU 950 @ 3.07GHz , Alot of quiers in sending data mode Here is mysql status ...
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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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22 views

Myisam Mysql server crashed

I have a server with linux fedora 11 Operating System. Recently , I discovered that every morning mysql has been crashed, so I have to restart mysql service. Can any body help me?
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316 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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304 views

MySQL: OPTIMIZE after TRUNCATE?

Using MySQL (either InnoDB or MyISAM tables--I have both), if I TRUNCATE a table and then LOAD DATA INFILE, should I issue an OPTIMIZE TABLE call after the LOAD? It's unclear to me if this is a ...
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85 views

extra steps after changing storage engine and adding index

Someone told me to look into his website for quick optimization; I'm a programmer and i don't have much experience optimizing databases. I have a php/MySQL site uses the MyISAM storage engine. It ...
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3k views

MySQL my.cnf Optimization

We are an email marketing company and we recently switched our setup to MySQL. We need to configure MySQL (my.cnf) for extreme performance. We have tried to configure my.cnf but heavy queries got ...
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43 views

Reinsert data in new table with new IDs

I have the following two tables: buynsell CREATE TABLE `buynsell` ( `id` VARCHAR(20) NULL DEFAULT NULL, `msg` VARCHAR(255) NULL DEFAULT NULL, `date` VARCHAR(25) NULL DEFAULT NULL, ...
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752 views

mysql optimize table crash

When I try OPTIMIZE TABLE `table` (MyISAM) on a table which is about 300MB, then it is crashed and must be repaired. What could cause this problem? The same problem occurs on other tables over 300MB. ...
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Are there implicit indexes in InnoDB like MyISAM?

If you have (id, a, b, c, d) table with primary key (id) and another key (a, b, c), in MyISAM that means that you also have the following implicit keys: (a) (a, b) (a, b, c, id) Is this valid for ...
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1k views

Index before or after bulk load using load infile?

I have a database with over 1B rows and two columns that are indexed (in addition to the PK). Is it better to have the index pre-defined in the table before the load infile or better to index after ...
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172 views

Large queries on MyISAM tables crashing MySQL

I have a PHP website, which is using the third-party software ResourceSpace, that when I installed it, it used my default storage engine to create the tables, which at the time was MyISAM. Now that ...
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175 views

LOAD DATA INFILE on a MyISAM table blocks user read-queries, can we get around this?

I've got a large reference table, 100GB, in a MyISAM table, load it up from scratch goes well (4ish hours) using LOAD DATA INFILE. But we have 1GB each day we want to update in a batch process using ...
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235 views

Can I use mysql to serve 100's of millions of small image files?

I need to serve 300,000,000 small image files totaling 1.5TB. Trying to unpack these files to individual files on the file system is next to impossible (1 MByte/sec throughput rates to create the ...
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2answers
533 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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315 views

Why do MySQL MyISAM table indexes go out of date?

I have few MyISAM tables, where only the auto_increment primary key is up to date with the number of columns, but not other indexes. Any idea, why this happens?
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2k views

MySQL Table not repairing

Table info: Database name: user_motiva Table name: wp_options.frm wp_options.MYD wp_options.MYI wp_options.TMD when I do a mysqlcheck -r --all-databases it gets hung on that table even if you ...
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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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42 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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1k views

View dropped, now shows as table “in use”, can't drop

I have a view on a MySQL/MyISAM setup, then the underlying table had a column dropped, and made that view invalid. I tried dropping the view so I could recreate it, then MySQL said it was a table ...
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859 views

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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302 views

Does MySQL's MyISAM use cache before insert?

I want to test two different Disks, one of them is HDD and another is SSD I use exactly same information and app for both servers. They are exactly same, just one of them is SSD and another is HARD. ...
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2k 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 ...