InnoDB : MySQL's ACID-compliant Storage Engine

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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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Why does InnoDB store all databases in one file?

It was convenient that MyISAM used to store each table in a corresponding file. InnoDB has made advancements in many aspects, but I wonder why InnoDB stores all databases in one file (ibdata1 by ...
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1k views

Restore InnoDB to different machine

It was pointed to me from serverfault that the following question would be a better fit here so this is basically my original question from there. I currently have backups that were taken with ...
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2answers
766 views

tmp_table_size with mostly InnoDB tables

I use MySQL version 5.6.25-0ubuntu0.15.04.1 on 64-bit Ubuntu 15.04. I have 2GB RAM and the disk is SSD (so, in my mind, writing to disk isn't that costly). I currently have databases for just two ...
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InnoDB: why “non-locking” SELECT still gets locked?

This issue can be related to my first question: InnoDB: very slow random updates, hanging in “updating” state But i think it needs to be clarified in a separate thread. The Problem: a simple read ...
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1answer
35 views

Is the SQL syntax for InnoDB gauranteed to be the same between MySQL, MariaDB and Percona?

I develop an application that uses MySQL and explicitly uses InnoDB table engine. In a few cases we have clients using this application with MariaDB or Percona. I understand that MariaDB and Percona ...
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483 views

inno_db_buffer_pool_size and key efficiency

I have the following metrics from mysql workbench After I have set innodb-buffer-pool-size to 6G, according to this answer's query on how to determine the recommended size. While the used buffer ...
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2answers
114 views

How does InnoDB access disk?

I know that block(multiple disk sectors) is the basic unit of data transfer for the virtual file system so, if NTFS uses 4 KB cluster size for files how does InnoDB access disk if it uses 8 KB page ...
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1answer
968 views

using Aria vs InnoDB vs MyISAM

I was wondering (if anyone knows) if Aria database is crash safe . I had some tables with MyISAM which were getting corrupted very often and switch them to InnoDB . However innodb is a bit slower and ...
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197 views

Too much IO to MySQL InnoDB log files

I am using MySQL version: 5.5.38 I have dedicated HDD to InnoDB log files using innodb-log-group-home-dir option. atopsar -d 30 shows big load (>50%) to this HDD The thing is that I have only 75 ...
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1answer
261 views

Select only rows that equal x but not x and y?

I'm having quite the challenge with selecting hierarchical data in MySQL although I feel the schema should be optimized for it since it's based on the WordPress database model. I've got 4 tables: ...
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MySQL queries waiting for other queries to finish

We have 30-40 different projects in Python and PHP that update, insert and select more than 1 million rows of data in MySQL DB every day. Currently we use InnoDB Engine for our tables. The problem: ...
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InnoDB: very slow random updates, hanging in “updating” state

I've been fighting my problem for the whole last week, studying stackexchange threads with similar issues in the first place. The main problem is that after switching from MyISAM to InnoDB ...
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1answer
58 views

MySQL - NOT IN … vs LEFT JOIN

I am trying to understand in terms of performance which approach is better: Query 1: SELECT * FROM table1 WHERE col1 NOT IN(SELECT col1 FROM table2) Query 2: SELECT * FROM table1 LEFT JOIN table2 ...
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1answer
46 views

MySQL INSERT … SELECT Performance

I know that this query will lock table2: UPDATE table1... SELECT .. FROM table2 How about this query ? INSERT INTO table1... SELECT .. FROM table2 Does this query also create a lock on table2?
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1answer
105 views

Missing statement information from 'LATEST DETECTED DEADLOCK' InnoDB status output

I'm learning how to interpret the LATEST DETECTED DEADLOCK section in the output of SHOW ENGINE INNODB STATUS, and had a question about the output. Some sample output of SHOW ENGINE INNODB STATUS ...
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1answer
509 views

What does “cleaning up” mean in MySQL InnoDB transaction status and how to prevent it?

In our database (MySQL 5.6.22 on RDS) we have a lot of transactions (~500) in a state "cleaning up" under the load: > SHOW ENGINE innodb STATUS; ... ------------ TRANSACTIONS ------------ ... ...
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2answers
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Which one to use? InnoDB Replication or MySQL Cluster?

I am building a url shortener and I use InnoDB as the storage engine for link data. I will start with a single VPS containing both application instance and MySQL database instance on the same Virtual ...
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13 views

How can I disable xb_doublewrite?

Getting error while service restart. [ERROR] InnoDB: A parallel doublewrite file /test/mysql/xb_doublewrite found on startup.
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3answers
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What does having the primary key as the last column in a composite secondary index in an InnoDB table do?

Say I have a 1-to-N relationship (person_id, pet_id). I have a table where pet_id is the primary key. I understand that an InnoDB secondary index is essentially a B-tree where the values are the ...
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1answer
38 views

Migrate from innodb_file_per_table to off in MySQL ALTER TABLE removing ibd files

Trying to migrate individual tablespaces back into the shared ibdata tablespace. MariaDB version 10.0.16 SET innodb_file_per_table to off in MySQL, restated mysql and new tables are in fact going ...
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2answers
366 views

Migrate from innodb_file_per_table to off in MySQL

We have a large number (2,500+) of databases and users in MySQL 5.6 on a single virtualized server (4 cpus and 8GB of memory). All the tables are using InnoDB. The actual data size is not very large ...
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1answer
40 views

MySQL InnoDB constraint does not work

I stumble upon strange behavior with innoDB constraint, and cannot find cause of it. I have tables with data. Below listed their structures: CREATE TABLE `contents` ( `id` int(10) unsigned NOT ...
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47 views

How I can reduce disk IO in MySQL 5.6.26?

I was using MySQL version 5.1.52 for my application but recently I have updated it to 5.6.26, but now I am facing very high disk IO. Following are system configuration: OS : Linux 2.6.39.4 RAM : ...
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Mysql Deadlock on update query on same row

My server is experiencing occasional deadlocks on two update queries on same row both using index (primary key). The conflicting queries are: UPDATE auth_user SET rep_score=185 WHERE ...
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Server memory consumption not changed after innodb buffer size change

I observed a strange thing while applying the innodb_buffer_pool_size on mysql. I applied the innodb_buffer_pool_size=20G (75% of my physical RAM size) and as per logs and innodb status the mysql is ...
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1answer
2k views

MySQL InnoDB page_cleaner settings might not be optimal

Seeing this note in mysqld.log: [Note] InnoDB: page_cleaner: 1000ms intended loop took 15888ms. The settings might not be optimal. (flushed=200 and evicted=0, during the time.) There seems to be ...
2
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1answer
282 views

InnoDB internals - checkpoint, LSN, dirty pages

I'm looking into InnoDB internals regarding buffer pool, checkpoint and dirtypage. However there isn't enough information to answer my question. When I run show global status, I can get ...
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1answer
36 views

How to delete rows from the mid of the table without any where condition?

I have a table testing with two columns id: auto_increment name: varchar(20) I fired a query select * from testing limit 1, 2 which gave me 2nd and 3rd record. Now, I want to delete these records ...
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1answer
411 views

MySQL Entity Relationship Problem - 3-way join table?

This is a db relationship question. I have a scenario which I believe I have come up with a solution - however, I can't be sure it's a manageable one, or even correct. The scenario is as follows: ...
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1answer
110 views

InnoDB compression: memory usage

InnoDB offers table compression for Barracuda-type tables and the recommendation seems to be to "adjust" buffer_pool_size. The documentation is rather vague about the definite impact of compression on ...
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1answer
19 views

In [Percona] MySQL, is the Adaptive Hash Index included in the Total memory allocated count?

I'm debugging a memory problem with MySQL 5.6 (I'm using the Percona distribution), but I can't figure out, searching around the web, if the Adaptive Hash Index amount is part of the Total memory ...
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1answer
450 views

Storing history of full/partial tables

I'm building a web-application with Django and MySQL (InnoDB) and am currently pondering over how to manage historical changes on various tables. I wonder if it's efficient to store a lot of rows ...
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2answers
74 views

Better understand table indexing best practices

I'm not completely sure when would I start indexing my tables, when there are some criterias that I should consider: The tables are not that big, I think (1000 - 10,000 rows). The searches are made ...
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1answer
148 views

Fastest engine for Mass Updates (only updates done on table)

I have a table of 2 columns and 60 million rows. I want to update the table by incrementing one field by 1 on various different rows (This is the only type of operation that will ever be done on the ...
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2answers
109 views

Does MySQL Workbench lock database during migration process?

I am doing a migration of my database from one server (RDS) to another (localhost) via the MySQL workbench tool. I want to know if during this process my database will be locked for write and read ...
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2answers
188 views

How can delete an orphaned temporary table on Mysql Innodb?

I was issuing an Alter table statement and suddenly the server crashed, Now i can not run any alter table to that table because it shows me the error 1050 and it says that a table named #sql1504d ...
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1answer
21 views

Partition Wise Joins in Mysql

Is it possible to create or simulate a partition-wise join in Mysql/Innodb?? Here is a good description of partition-wise joins.... ...
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1answer
203 views

innodb , mysql Indexes difference when adding index

When I am altering one of my MySQL table to add an index I am getting below error in error log. Table a/b contains 4 indexes inside InnoDB, which is different from the number of indexes 3 defined ...
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2answers
33 views

InnoDB file per tablespace

I am using following syntax to create an InnoDB table: create table InnoDB_Test(a INT) DATA DIRECTORY='/var/log/storage/MySQL' INDEX DIRECTORY='/var/log/storage/MySQL' engine=InnoDB;` I want to ...
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1answer
312 views

MySQL: Merge Same Database on Several Location into Single Location

I have registration form, which exactly same for several location. Each of them has REG column, which this field is unique for each row. Basically each data input have different REG number for it, ...
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1answer
849 views

Cannot Start mySQL Daemon with Error “mysqld from pid file … ended”

I cannot get MySQL to run. It was working just fine hours ago, but upon starting, repeatedly ends without telling me very much. Here are my logs [myusername@location ~/mysql]$ ./bin/mysqld_safe ...
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1answer
299 views

Mysql Tuning for a small server

I have a small Cloud Server running under Ubuntu 2 core, 2GB ram and 2GB swap, with Plesk Panel, Apache, Nginx as reverse proxy and Mysql 5.5. I have about 18 domains hosted here and each domain has ...
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2answers
202 views

Trick for AUTO_INCREMENT on composite keys in InnoDB

In contrast to the MySQL MyISAM-Engine, the InnoDB-Engine can not handle when one column of a composite primary key is declared as AUTO_INCREMENT. For example consider the following table: CREATE ...
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49 views

Very Very Veeery slow insert queries

I am writing here because I`ve already spent days reading tutorials, other topics in here, and trying different configurations. The project : Fashion website with ~200k products which should be ...
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1answer
2k views

MySQL SELECT query hangs - Opening Tables INNODB

On my server I have 6 MySQL databases. They all power Wordpress websites. For some reason, 2 of these databases are not accessible. To my knowledge they use INNODB, but I can't confirm it as even ...
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1answer
233 views

What's the approach to figure out reason for mysql crash?

The database I'm using crashes a lot recently. And I can't find a decent way to dig into the issue. I looked into mysql error log, but don't know how to start. I know there was a "load data infile" ...
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1answer
50 views

MySQL - Deleting old data; Select with index taking time

I am a bit confused about 2 queries. First query I am running on a 50m rows table by index on a timestamp row with a limit, I would expect the query to be immediate regardless of the size of the ...
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1answer
143 views

Write-lock a whole table during transaction

I need to perform a delicate operation to my table in which I will solely insert, delete and select upon all of my rows and no God may interfere with the table during this operation: the table will be ...
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1answer
327 views

Large long-running reporting queries are causing very slow new mysql connections

Usually, mysql's connecton time is in the 0.001 second range. However, when I run a large reporting query (that spans multiple tables with aggregates), I get tons of warnings saying that new mysql ...