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

1
vote
1answer
796 views

MySQL: To use MYISAM or INNODB engine? (plot twist enclosed)

We use INNODB for all of our tables, but I have one special table, a 100+ GB reference table (only read-queries against it). We are loading changes to this table in a nightly batch job using LOAD ...
1
vote
1answer
588 views

MYSQL MyISAM data recovery implementation

I am creating integration into eshop script, shop is using MyISAM tables and I need to implement something like transactions in InnoDB, what I actually need is full recovery of data after modifying or ...
1
vote
1answer
182 views

Select ``,* from table?

I'm trying to upgrade our database servers to MySQL 5.5. In doing so, I'd like to convert all of our tables to InnoDB to take advantage of several performance benefits. However, we use VARCHAR(50) ...
1
vote
1answer
173 views

Optimizing table and choosing storage engine

Having the follow MyISAM table: +----------------------+-----------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------...
1
vote
2answers
1k views

All columns of table should be indexed or not mysql database?

I am having one table with 4 columns. I that one is primary key and other three columns are references to columns of other tables. I am using join of these four tables for search filter. These joins ...
1
vote
1answer
781 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 ...
1
vote
1answer
36 views

Altering a large table to INNODB

I have a table of 4GB(18 Million Rows) in MYISAM Engine on one of my slave server, and I want to convert it to INNODB Engine, the server is replicating from a master. I tried to use the pt-online-...
1
vote
1answer
78 views

Innodb composite primary key with 4 columns vs MyIsam

I've created "MY TABLE" based on Innodb with composite primary key because I am storing many trees inside this table. The PK is for example (a,b,c,d). 1- Does Innodb store rows with same (a,b,c) near ...
1
vote
2answers
99 views

Optimize speed on 400GB MyISAM table

We have MariaDB server with single table with image url information. The table is about 400GB on disk and contains probably 400M rows. Table is partitioned in 1024 partitions. All queries are ...
1
vote
1answer
31 views

why MyISAM uses 3 files per table? [closed]

Why MyISAM uses 3 files per table? I know one of the file contains table definition, another contains primary key and all other indexes, third the data. What is unclear for me, what is the benefit ...
1
vote
1answer
550 views

MySQL: OPTIMIZE TABLE vs. myisamchk

I have a very large table (~50GB) and periodically rows are purged from it and I want to run OPTIMIZE TABLE to recover the space. But I do not have enough space to run it. If I do run it the server ...
1
vote
1answer
201 views

Cannot delete MySQL trigger. Appears in information_schema, but no .TRN file

I have a MySQL database with a few tables and triggers. A process was trying to drop one of the triggers and it failed with the following error: Malformed file type header in file 'trigger_name.TRN' ...
1
vote
1answer
442 views

Delete and Recreate Indexes in MySQL to reduce table size for copying the db to a new server?

I have to move a given database of 100gb from server a to server b and later this year to server c with a copy for testing to server d. So all servers are Unix (mostly Debian) with MySQL. The ...
1
vote
1answer
345 views

set global variable parameter?

My prod_server version is 5.1.47 and want to set the slow query log dynamically for certain period of time. I refered one site(http://toastergremlin.com/?p=276) there is mentioned below 5.1.6 we need ...
1
vote
1answer
496 views

MySQL backing up MyISAM tables by copying the physical files - and automating the process

I have 2 databases with MyISAM tables running on a Windows 2008 Server. These databases are about 20GB in size with a few tables with millions of rows. My question regards backing them up on a weekly ...
1
vote
1answer
163 views

MRG_MyISAM with myisampack tables blocking inserts

I'm using INSERT_METHOD=FIRST and compressing all tables that are members of the union but when I try to insert into the MRG_MyISAM table it tries to insert into the second one (instead of the first). ...
1
vote
1answer
76 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 ...
1
vote
1answer
3k 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, ...
1
vote
1answer
1k 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 ...
1
vote
1answer
299 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
1k 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
1answer
581 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
421 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 ...
1
vote
1answer
447 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 ...
1
vote
1answer
2k 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 ...
1
vote
1answer
1k views

Spatial Index on an InnoDB table

I have a database which is in InnoDB, because I wanted consistency (cascading delete). Now, I want to use spatial indexes for selecting rows ordered by geometric distance. However, spatial indexes ...
1
vote
1answer
121 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 ...
1
vote
1answer
636 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 ...
1
vote
1answer
98 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 ...
1
vote
1answer
8k 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 ...
1
vote
1answer
431 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?
1
vote
1answer
319 views

Set up replication and migrate to InnoDB with low downtime

Current situation is this: I have a large legacy DB using only MyISAM tables, the size of whole DB is 4GiB, one of the tables contains over 10 million rows, so it is pretty large. The database is ...
1
vote
2answers
4k views

MySQL not responding, Writing to net status

I just had to reboot MySQL to regain access to some of my website. It had under 300MB of RAM used. Another product was working fine though, accessing it's own tables which are InnoDB. Here's the show ...
1
vote
1answer
126 views

How can I reinitialize some MyISAM tables without restarting MySQL?

I'm using rsync to copy some measurement data from one PC to the server. Is it possible to load the new MyISAM tables without restarting the MySQL server?
1
vote
1answer
1k views

MySQL INSERTs waiting for UPDATEs (MyISAM)?

In show processlist;, MySQL 5.5, we see that INSERTs tend to wait for UPDATEs to complete before they can proceed. This is on MyISAM tables. We tried INSERT HIGH_PRIORITY and UPDATE LOW_PRIORITY. ...
1
vote
1answer
221 views

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 ...
1
vote
1answer
350 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 ...
1
vote
1answer
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? ...
1
vote
1answer
150 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, `...
1
vote
2answers
28 views

MySQL CREATE INDEX slowing down

My analytics table has 190M rows, about 150GB ins size. Storage engine is MyISAM with key-buffer-size=16G myisam_sort_buffer_size=2G myisam-max-sort-file-size=200G. Machine has 32GB memory. While ...
1
vote
0answers
27 views

Can MyISAM tables affect the backup recovery of innodb tables on Amazon RDS?

I have an Amazon RDS instance containing several databases. All the tables are innnodb except from one, that is MyISAM and currently cannot be converted to innodb. I know that the recovery of MyISAM ...
1
vote
0answers
62 views

Cardinality of an index in a MySQL table is equal to table's row size

I have just included an index to a MyISAM table and the cardinality appears to be 1 million something which is exactly the number of rows in the table. In fact it needed to be 315 because distinct ...
1
vote
0answers
60 views

Mysql slow copying to tmp table to indexing

I try to indexing table. The table size is about 60GB. But indexing query is hang on 'copying to tmp table' 18 hours. I found advice setting 'myisam_sort_buffer_size' myisam_sort_buffer_size : 128M ...
1
vote
0answers
59 views

Tuning MySQL MyISAM for large joined updates

I have a database with two tables that I would consider small. I need to update values on the larger of the two tables (1,100,000 rows, 75M MYD, 120M MYI) from the join of the two tables. The smaller ...
1
vote
0answers
48 views

Migrated servers… Innodb tables stayed innodb, but database is showns as MyISAM. Problem?

I moved servers. I exported DB on old, imported to new. Kept getting syntax error on import until I tried no compression. Weird, but it worked. I was skeptical so I compared the two carefully and ...
1
vote
2answers
1k views

Add UNIQUE index fails with duplicate entry error, but no duplicates found

Given table: CREATE TABLE mytable ( field_a CHAR(15) NOT NULL DEFAULT '', field_b MEDIUMINT UNSIGNED NOT NULL DEFAULT 0, field_c SMALLINT UNSIGNED NOT NULL DEFAULT 0, field_d SMALLINT ...
1
vote
1answer
146 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' ...
1
vote
1answer
89 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 ...
1
vote
1answer
178 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 ...
1
vote
0answers
281 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 ...