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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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 ...
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MariaDB/Galera Cluster with 3 nodes - Change ENGINE from MyISAM to InnoDB without crash

We have tables with MyISAM. The are out of sync, the number of records is different on each cluster node > select table_schema, table_name from tables where ENGINE = 'MyISAM' and table_schema != ...
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24 views

MYISAM can't create table: Row size too large

We are having database in MySQL 5.1, we have taken the DB backup from MySQL 5.1 and trying to restore in MySQL 5.6. We are getting below error: ERROR 1118 (42000) at line 603: Row size too large. ...
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44 views

Index on integer and string fields

A table has about 300M records. Each has an unique ID that starts with 13 to 14 digits (with the first digit on the left being either 1 or 2), and is optionally followed by a string of up to 7 ASCII ...
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21 views

How can I restore a MySQL dump faster on Windows?

I am restoring some InnoDB and MyISAM .sql files that are on the order of GBs (ranging from 1 GB to ~ 10GBs) and they are taking a day or longer to restore. The command I am using currently is: use ...
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81 views

MySQL query takes over a minute to complete

I am trying to pull calls associated with website visits from our huge database... I have got SQL that works, pulls correct results it just takes over minute to complete... Here is the SQL SELECT ...
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26 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 ...
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23 views

Fulltext searching on shared hosting - 2000 Entires with around 500 words each

I'm fairly new to db administration and would appreciate some help. I want to host a site which requires full text search on around 2000 items, each with around 500 words each. I need this to be ...
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1answer
66 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 ...
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119 views

Integrate MySql Full Text searches in CMS

I'm developing my own CMS and using MySql v5.5 DB to save the content items records. Due to a technical limitations, I can't upgrade my database to a newer version that support Full-Text searches on ...
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1answer
68 views

Small database size but very slow performance. What can I do?

We have this opencart installation with a database size of roughly 120 MB, 90MB of which is MyISAM and other is InnoDB. Most of the queries like : SELECT DISTINCT *, a.*, vd.seo, p.image, ...
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31 views

MySQL Database Archive

We have 300 databases in our environment mixed of MyISAM and Innodb(innodb_file_per_table has been enabled) tables.Using MySQL 5.5.19 version. I we are planning archive inactive database.Is there any ...
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8 views

MySQL editable reports from multiple identical tables

Let's say I have two sets of four identical tables for my sales that are generated by our apparatus. The first set represents each sales made in a region. Sales_Canada_Est, Sales_Canada_West, ...
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1answer
51 views

Mysql is shutting down in every 5 minutes

My MySQL 5.6 is shutting down about in every 3-5 minutes. I only can use it after restart. I don't know what happened; everything was OK 2 days ago. What do you suggest to me? Here is my ERR file ...
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69 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 ...
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46 views

MySQL Command to Mass Change Specific DB from MyISAM to InnoDB and vice versa?

I have an mu WordPress database and I want to change it from MyISAM to InnoDB to test its performance. Which MySQL command/commands will do it for all of the tables instead of doing manually one by ...
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1answer
27 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 ...
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1answer
84 views

How do I insert tens of thousands of rows without locking?

I have a server that receives data from thousands of locations all over the world. Periodically, that server connects to my DB server and inserts records, one row at a time in rapid succession. There ...
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1answer
41 views

Global Read Lock for Snapshot of MySQL Data

I have a database that is entirely comprised of MyISAM tables(yes, I did not create it). I need to create a slave and start replication so we could point read-only queries there. Here is my idea: ...
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82 views

Is it possible to block a specific query, or return a static result?

Before you yell at me for doing it wrong, I know I'm doing it wrong. I'm using WHMCS (source code is not available), and we have a quarter of a million invoices. One particular query, which runs on ...
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1answer
118 views

Fulltext Search Doesn't Match a Hashtag

We maintain a table that looks like this to perform search queries on our forums database. I'll draw your attention to the FULLTEXT columns: CREATE TABLE `forums_posts_search` ( `post_id` ...
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2answers
45 views

What storage engine do I need - Mysql?

I have designed a database and came to the point of actually deciding which storage engine is better for my case. I estimate that during the first few years I would have around 100,000 - 500,000 ...
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3answers
182 views

Convert MyISAM to InnoDB

What are the considerations needed when converting myisam to innodb. I have a table around 80 GB with engine myisam. I would like to convert into innodb. What are the considerations needed to ...
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54 views

Got an error reading communication packets

Facing error in MySQL Log which is "Got an error reading communication packets" for multiple IP's. Current MySQL version is 5.0.67 running in Linux Things looked into so far are as follows ...
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56 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 ...
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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 ...
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58 views

Database Tuning Issues

I'm not a DBA so looking for some advice on tuning a MySQL (MyISAM) database. I've found that during peak hours we are getting pretty severe load spikes which are slowing down the web front-end. I've ...
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2answers
576 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 ...
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27 views

Tuning Issue / Temporary Tables

I've got a MySQL database (MyISAM) that handles a lot of read/writes and uses temporary tables quite frequently. Recently it's started having massive load spikes at peak load, and noticed that there ...
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1answer
209 views

Configuration required for a big mysql database around 20GB

I need to host a single machine database (constraints), wherein the database size is roughly 20gb. Most of the tables are in MyISAM. Any way I can actually run it with decent speed ? Alternatives I ...
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1answer
283 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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173 views

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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1answer
138 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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101 views

MySQL - high CPU usage (MyISAm tables) in LAMP

I have a LMAP stack running on Centos 6.6. Here is the detail which may help. # cat /etc/redhat-release CentOS release 6.6 (Final) MySql version # rpm -qa | grep -i mysql ...
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8 views

Database storage engine and performance [duplicate]

What will be the performance issue when I change my database storage type from MyISAM to InnoDB?
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1answer
182 views

How important is InnoDB versus MyISAM? [duplicate]

Does it really matter if the default storage engine is InnoDB? My default storage engine is MyISAM
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402 views

Are TEXT fields stored separately from the row in MySQL-ISAM?

We have a "notes" table and some of the queries are getting very slow even though we're not searching on the note contents. We're wondering if moving the note content into a separate table would speed ...
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148 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
100 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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56 views

Got an error from unknown thread, /pb2/build/sb_0-13157587-1410170252.03/rpm/BUILD/mysql-5.5.40/mysql-5.5.40/storage/myisam/mi_write.c:226

I am using mysql 5.5.40-log and my default storage engine is Innodb, I found this error in my error log "[ERROR] Got an error from unknown thread, ...
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2answers
163 views

Optimal engine for small lookup tables in MySQL

I have following question: I am designing web application with several dozens of small lookup tables: These tables usualy contain three columns (ID, Name, Description) and a couple of rows (mostly ...
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1answer
52 views

Confused over table_open_cache

I've been reading about the table_open_cache and I'm slightly confused about how big it should be, I've seen conflicting advice. My DB is running on MyISAM and has 199 tables. I ran into an issue ...
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1answer
215 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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127 views

How to backup huge Mysql db containing both InnoDB & MyISAM tables in Aws RDS?

I am running a Mysql RDS with 150GB+ data. The DB size is growing very fast(But normal considering the application's nature) Till now we were having only InnoDB storage engine, so we were using the ...
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2answers
143 views

Best configuration for MySQL? InnoDB and MyISAM

I read that InnoDB is supposed to be better at writing into MySQL than MyISAM, however, I'm trying it out, by running 3000 MySQL queries(Inserting rows, 8 Columns + id)... but results haven't turned ...
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78 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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70 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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1answer
115 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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1answer
76 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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2answers
58 views

MySQL - SELECT on MyISAM Table on index - Does table size (rowcount) matter?

I was arguing with a coworker if SELECT * WHERE t BETWEEN ? AND ? on a MyIsam table where t is an index is significantly slower for huge tables. The hypothetically returned dataset is always the ...