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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Why did the MySQL Storage Engine Change on Restore in one scenario?

In my production database life, there was one tragic incident when the MySQL engine type was accidentally changed from InnoDB to MyISAM on restoring a recent backup. The result was that all ...
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Disable Primary Key on MyISAM Table

I wanted to speed up a large insert bulk by disabling keys. So I ran the following command on a MyISAM table: alter table my_table disable keys; When I execute show index from answer_2011, I see a ...
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676 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?
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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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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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415 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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120 views

Issue with Storage Engine

Just got the below error in one of the slave. I just Googled it and changed the variable myisam_data_pointer_size from 4 to 6. Somehow, my ALTER TABLE was successful. Can you please let me know ...
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180 views

How to interpret explain sql?

SELECT DISTINCT TB.ID, TB.Latitude, TB.Longitude, 111151.293413 * SQRT( pow( - 6.185 - TB.Latitude, 2 ) + pow( 106.773 - TB.Longitude, 2 ) * 0.988392289802 ) AS Distance FROM `tablebusiness` AS TB ...
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34 views

How to define partition according to Date?

I am currently using MySQL 5.6. In my database, I have a log table called paramlog_ems. It has 2M rows I want like to partition this log table according to Date. Here is the table structure: ...
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62 views

How to optimize a table/db with 200 insert/sec

I'm facing a very hard problem. I have a mysql DB (MyISAM) with a main table (user) where I write a row for every new user (around 10 fields). Every INSERT triggers around 10 new INSERT in 10 ...
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If all tables are myisam, should I use myisam engine instead of default innodb?

I have read all of the innodb/myisam threads and they are confusing. Everyone says innodb but I am assuming that they are saying innodb engine with innodb tables.? The software I am using creates ...
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33 views

Tables with no rows not empty

I've got a couple of tables that get cleared out regularly by a cron job on a web server. However when these tables are completely empty it looks like there is still data in them. e.g. This database ...
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104 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 ...
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323 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 ...
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210 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 ) ...
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1k 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 ...
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915 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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214 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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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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2k 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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167 views

With MyISAM is there any index size savings when using INT vs BIGINT?

There is obviously a four byte per row space savings in a data column when using INT vs a BIGINT type. But I have been trying to figure out if there is also any space savings for myisam indexes on ...
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692 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 ...
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509 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 ...
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109 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) ...
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159 views

Optimizing table and choosing storage engine

Having the follow MyISAM table: +----------------------+-----------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | ...
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817 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 ...
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28 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 ...
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33 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' ...
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48 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 ...
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67 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 ...
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371 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 ...
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87 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). ...
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63 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 ...
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2k 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, ...
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246 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 ...
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322 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 ...
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2k 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 ...
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349 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 ...
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1k 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 ...
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345 views

MySQL select by primary key against 100M of records within 30ms

I have no expirience with MySQL and database performance tuning in general. Wondering whether it is possible to perform a large number of selects against 100 millions of records by primary key within ...
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158 views

MySQL command querying all MyISAM database

I would appreciate if anyone could help me of what's the proper command in MySQL to query all database for having "MyISAM" engine. I need to convert all DB & tables from MyISAM to InnoDB.
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861 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 ...
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108 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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383 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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452 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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89 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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5k 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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365 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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303 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 ...
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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 ...