Questions tagged [innodb]

InnoDB : MySQL's ACID-compliant Storage Engine

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6
votes
3answers
30k views

How to repair, or drop/create a corrupted table in mysql?

Situation: I have a MySQL database with 104 tables, running locally on XAMPP on windows 7. All the tables have InnoDB engine. XAMPP MySQL is running as windows service. As front end I have PHP (...
4
votes
1answer
3k views

Can SHOW TABLE STATUS query performance on MySQL be improved ? - Amazon RDS

I have a fairly large database on the Amazon Relational Database Service (RDS) running on MySQL 5.1.57. There are 900+ tables, so that running the "SHOW TABLE STATUS" query can take up to 30 seconds. ...
4
votes
1answer
6k views

How to check growth of database in mysql?

I want to know is there any method to check the growth of database on file EXAMPLES Database A contains all tables in INNODB storage engine Database B contains all tables in MyISAM storage engine ...
11
votes
5answers
18k views

Incomplete mysqldump

I'm trying to run mysqldump to create a database snapshot, and I'm finding it will randomly stop midway, without reporting any error. My database is relatively small (about 100MB) and is using InnoDB. ...
8
votes
1answer
6k views

Is Percona xtrabackup the right choice for my 500GB MySQL backup?

I have a MySQL db with 500GB, consisting mainly of Innodb tables, and one big (200GB) MyISAM table. My current backup strategy is copying the db files to an external harddrive. This causes a downtime ...
6
votes
2answers
3k views

In what cases are BLOB and TEXT stored in-line on InnoDB?

I've googled this and can't find it, you can see Rick James mention it here. ... BLOB and TEXT are not always stored separately The answer on What is the difference between MySQL VARCHAR and TEXT ...
5
votes
1answer
11k views

MySQL Innodb corruption

I recently inherited a Drupal site that has an Innodb corruption. MySQL will run for sometime--usually about 24-hours but will eventually need to be manually restarted(see log output below). I have ...
4
votes
2answers
3k views

Two updates cause a deadlock

I have a mysql queue with the following sheme: CREATE TABLE IF NOT EXISTS `media` ( `mid` int(11) NOT NULL AUTO_INCREMENT, `order_type` int(11) NOT NULL, `media_id` varchar(50) COLLATE ...
3
votes
3answers
5k views

Is it normal to use many Triggers?

I have many so-called summary columns throughout my database to count number of rows in other tables. For example, counting the number of comments by a user (a column in the user table). Currently, I ...
2
votes
2answers
11k views

How to optimize MySQL for large BLOB updates

I have a table that holds large BLOBs (up to 10M), and is updated frequently. The problem is that UPDATE statements can take up to 1 second to execute, and due to app design this blocks UI. I need to ...
2
votes
1answer
4k views

MariaDB XtraDB Performance Tuning

I believe that innodb has a single read thread. However, with MariaDB you can set multiple read threads. I'm unsure what the recommended value would be. Questions Does anyone have any experience ...
1
vote
1answer
3k views

I have delete database from mysql but storage is not freed

I have deleted multiple databases (schema) from mysql on amazon RDS but the storage is not freed, is there anything else I should do to free up the storage? I have a mysql database that the total ...
11
votes
3answers
47k views

mysqldump --single-transaction, yet update queries are waiting for the backup

If I use mysqldump --single-transaction, according to the docs it should do flush tables with read lock to get a consistent state and then start a transaction and no writers should be waiting. ...
11
votes
4answers
36k views

How to increase fast backup and restore of 500GB database using mysqldump?

There is a database A size of 500GB. Tables in database A contains both MyISAM and INNODB tables. MyISAM tables are master tables and Innodb tables are main transaction tables. Backup and restore ...
11
votes
4answers
12k views

Full text search results in a large amount of time spent in 'FULLTEXT initialization'

I'm currently trying to run some queries against a data dump of Stack Overflow's comments. Here's what the schema looks like: CREATE TABLE `socomments` ( `Id` int(11) NOT NULL, `PostId` int(11) ...
9
votes
1answer
33k views

What is InnoDB Buffer Usage and how to clear it?

In Mysql Workbench when I go in Server > Server Status there is a field called "InnoDB Buffer Usage" It is "95%" even if there is no query running. Why? It affects my performance in my new queries? ...
7
votes
2answers
12k views

How can I find who holds the lock based on the hex-dumped?

I've been reading the Diagnosing MySQL InnoDB Locks article. Karl E. Jørgensen writes on 2008 so I'm consfusing it is in effect. I would like to supply a snippet of the SHOW ENGINE INNODB STATUS: ---...
7
votes
1answer
8k views

Why does that query cause lock wait timeouts?

From time to time, I find a lot of these errors in my PHP error log: MYSQL.1213: Deadlock found when trying to get lock; try restarting transactionSQL The problem persists for about 2 or 3 minutes. ...
7
votes
2answers
67k views

Row size too large (> 8126)

I'm facing the following problem. Row size too large (> 8126). Changing some columns to TEXT or BLOB or using ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED may help. In current row format, ...
5
votes
2answers
9k views

Deleting Entries from Table not reducing my DB file

Iam usind INNODB Engine with innodb_table_per_file , so every table has it's own .ibd file instead of ibdata1 file. When i Entered 512 Record in my users table its size get increased to 200kb from 96 ...
5
votes
4answers
2k views

Which columns should be indexed when all may be used in different search queries?

Background I'm working on a website for a movie theather chain currently located in four different cities (might expand in the future). They use the same, single-database website for all cities, ...
5
votes
1answer
1k views

InnoDB primary key efficiency

I've read a number of articles regarding efficiency of primary keys depending on the storage engine, and I am left confused. Given a simple many-to-many table with two fields, storeId and zoneId, ...
4
votes
1answer
10k views

Revoke write privileges vs setting database to readonly

I am planning to do a database migration to a new server. During the transition stage, I do not want Apache user to be able to write anything to the database. I have two options. Revoke write ...
4
votes
4answers
14k views

Is it better to use AUTOCOMMIT = 0

Is it better to use (for perfomance tuning) AUTOCOMMIT = 0 before bulk inserts of data in MySQL, if the insert query looks like INSERT INTO SomeTable (column1, column2) VALUES (val1,val2),(val3,val4)...
3
votes
2answers
14k views

High MySQL “InnoDB Writes Per Second” - Can't see the queries?

On our live MySQL 5.5 database server, we use MySQL Workbench for running manual queries, checking running queries to see what's going on, etc. I noticed today that on the "Server Status" tab there's ...
3
votes
3answers
13k views

How to decide whether to enable MySQL query cache using InnoDB

How should the decision to enable / disable the MySQL query cache be made, on a server that uses just InnoDB tables. Say for example, if the cache is enabled, then how should the output of: SHOW ...
3
votes
1answer
6k views

Delete data from huge InnoDB table from MySQL Master and Slaves

We have some huge tables in MySQL database, We have already archived/deleted data older than 2012 in 2013, Now we need to archive/delete data older than 2013 means we need to archive data for year ...
3
votes
2answers
7k views

MySql InnoDB tables are missing after restarting

I had a MySql database with a few InnoDB tables. After restarting the server, and starting MySql Server again, I connected to the MySql Server using MySql Workbench, and couldn't see the database at ...
3
votes
2answers
6k views

MySQL auto increment column increases after insertion error occurs

I was doing some insertion tests in my database and I realized that when the INSERT statement fails, due error 1452, causes the auto_increment value increase by 1. Even though, there wasn't any row ...
3
votes
2answers
9k views

How can I defragment tables in MySQL?

I have a database named COUNTY. COUNTY has a fragmented table GEO. I executed OPTIMIZE TABLE GEO against the GEO table, but this returned the error "Table does not support optimize, doing ...
3
votes
2answers
2k views

MySQL stores BLOB in innodb buffer pool (innodb_buffer_pool_size)?

I have several databases all in INNODB, 50GB are BLOB columns, only 700MB are not BLOB data. Tools as mysqltuner ask me to set innodb_buffer_pool_size = 51GB. Does MySQL store the BLOB in RAM? If yes,...
2
votes
1answer
3k views

UPDATE does not use INDEX, but SELECT does

I'm actually struggling understanding the problem here. I read everywhere saying that UPDATE benefits from indexes on the WHERE clause. However, this query, UPDATE `documents` SET `read`="1" WHERE `...
2
votes
1answer
4k views

MySQL 5.5 Runs Out of Memory, Drops All Connections When Creating Many Databases

I'm running into a problem when I create a large number of databases consecutively on an Amazon RDS db.m1.large instance. The MySQL Engine Version is 5.5.23. At some point, the RDS instance drops all ...
2
votes
1answer
7k views

InnoDB Buffer Pool Hit Rate

As given at http://cherry.world.edoors.com/COBFKUqnUdBY one can obtain buffer hit ratio by following sql query: SELECT round ((P2.variable_value / P1.variable_value),4), P2.variable_value, P1....
2
votes
3answers
3k views

MySQL InnoDB Sorting Issue

I was surprised to see MySQL's InnoDB showing an interesting behavior, which I cannot fully explain. According to the official MySQL InnoDB Documentation: "All indexes other than the clustered ...
1
vote
1answer
2k views

Can putting mysql DB into memory or having the innodb_buffer_pool_size match the size of DB increase performance?

We have a mysql database that has roughly 80 gigabytes (GB) of data using inno_db engine. We are looking to increase performance on the database (we looked at the slow log and gone through and ...
10
votes
1answer
3k views

recover a single mysql database on a busy master-slave replicated system

Looking for a strategy or tool to deal with recovering a single database to a point-in-time in a busy replicated system. I have 12 databases running on 2 MySQL 5.0.77 servers in master-slave ...
10
votes
2answers
9k views

Deleting MySQL table with pending transactions

Is there a way to delete an InnoDB table or database with pending transactions in MySQL (preferably on file system level)? What happened: I use MySQL 5.5.28 and ran LOAD DATA INFILE… to import a ...
9
votes
2answers
6k views

Amazon RDS I/O requests - 1 query = 1 billable I/O?

I have an InnoDB database that I'd like to migrate onto Amazon RDS. My current implementation, hosted on my own server, shows roughly 8M queries per month. The RDS site say that I/O Rate $0.10 ...
7
votes
1answer
609 views

Dealing with temp tables when I have not control over db variables

I have no control over things like tmp_table_size and max_heap_table_size, and so as our tables grow the time taken by queries requiring temp tables is growing geometrically. I am wondering if there ...
7
votes
1answer
13k views

Corrupt InnoDB: Start mysqld only innodb_force_recovery=6

I am working with version 10.0.19-MariaDB-1~trusty-log and I'm only able to restart mysqld with innodb_force_recovery=6 and I don't know why. The output of the /usr/sbin/mysqld is the following: ...
7
votes
1answer
10k views

What is log sequence number ? How it is used in MySQL?

Can anybody give an example or scenario of log sequence number(LSN) used in MySQL
7
votes
1answer
5k views

Find out MySQL index size for a concrete index

In MySQL, for InnoDB engine, how do I find out the size of one of the indexes I have in the same table ? I know I can select the index_length from information_schema.tables, but this gives the total ...
6
votes
2answers
3k views

Do I need to index a key that I partition by?

I have an InnoDB table of customers, partitioned by KEY, with each partition being one US state. I have an index on phone number, and the performance is great. We also need to SELECT by last name in ...
5
votes
1answer
4k views

InnoDB “corruption”

I use: 5.1.63-0ubuntu0.11.10.1 Apache/2.2.20 (Ubuntu) MySQL client version: 5.1.63 The system is continuously displaying the following error during reading data from a MySQL database: InnoDB: ...
5
votes
2answers
19k views

How to set a specific directory location for individual MySQL database?

Is it possible to set each database in MySQL to use a separate datadir? I'm running a userdir development (sandbox) server and would like to put the MySQL data files for the database(s) for that user ...
5
votes
1answer
5k views

Mysql/innodb deadlock on simple delete query

Mysql/innodb 8.0.16, read committed transactions, several statements in transaction raise deadlock on deletion of non intercepting rows. Trying to understand what is happening: -----------------------...
5
votes
1answer
3k views

Possibilities to speed up InnoDB INSERTs and UPDATEs

My website retains user sessions in an innodb table. This usually works well, but a few hundred times a day, the INSERT and particularly the UPDATE statements run slower. I'm monitoring when, and it ...
5
votes
3answers
1k views

Is Oracle DB immune to the InnoDB deadlocks found in MySQL?

It seems odd to me that MySQL would not handle this internally: "Deadlock found when trying to get lock; try restarting transaction" Does Oracle DB work around this issue? After all, Oracle owns ...
5
votes
1answer
2k views

Does MySQL exectution plan depend on available indexes?

Does MySQL choose an execution plan for a given query taking into account what indexes are available, or does it first choose an execution plan and then uses indexes if they are available? Motivation:...

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