InnoDB : MySQL's ACID-compliant Storage Engine

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5
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2answers
270 views

How to optimize indexes on MySQL query with various sorts

I have an INNODB table levels: +--------------------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------------------+--------...
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1answer
33 views

ALTER TABLE engine from MyISAM to InnoDB: why does mysqldump --order-by-primary help me?

I found an interesting mysqldump option in MySQL 5.7 Reference Manual. In internet there are no further details and explanations. --order-by-primary Dump each table's rows sorted by its primary ...
4
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2answers
373 views

Is it a waste to set innodb_buffer_pool_instances greater than the # of CPUs?

I set the innodb_buffer_pool_size to 20GB on a server with 12 CPU cores. My full database is 11gb, however most of it is archived tables that are almost never used. The total queried data is around 3 ...
1
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1answer
62 views

Converting a composite primary key to composite unique, and adding an auto-incremented PK column

Background I have taken over responsibility for a table that, in the long run, will grow monolithic. The table is a very simple link table with 2 columns, call them col1 and col2, both being foreign ...
1
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1answer
82 views

howto read/interpret “show engine innodb mutex” output?

We use a 3 node Galera cluster with version 5.5.41-MariaDB-wsrep MariaDB [(none)]> show engine innodb mutex; +--------+---------------------------------+------------------+ | Type | Name ...
0
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2answers
139 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 ...
0
votes
1answer
34 views

Mysql repetition of column in Criteria

What happens when I repeat the same column in the criteria part but with different values . For example col1 ='val1' or col1 = 'val2' or col1 = 'val3' . Assume col1 is not indexed. Will mysql ...
1
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1answer
53 views

How to fix `The table '/tmp/mysql/#sql_xxxxx' is full`?

Ubuntu server 16.04, php7, nginx 1.10, mysql 5.7 in Hyper-V on Windows 10 host How to fix The table '/tmp/mysql/#sql_xxxxx' is full ? In mysql-error.log [ERROR] InnoDB: Tablespace ...
0
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2answers
203 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 ...
0
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1answer
41 views

MySQL disk scanning algorithm [closed]

How does MySQL (InnoDB engine) read data from disk? What scanning algorithm does it use? Since the rows are stored in data pages will it read the entire data page to get the resulting rows?
0
votes
1answer
114 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 ...
1
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1answer
300 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: ...
2
votes
2answers
868 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 ...
1
vote
0answers
31 views

Getting InnoDb internal Errors on every query run

I am having following errors in error.log at the run of each query due to which I am not able to use error.log properly. 2016-05-30 09:39:58 7f7c7e3cb700 InnoDB: Error: Column last_update in table "...
1
vote
2answers
2k views

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 ...
1
vote
1answer
64 views

Composite Primary keys and auto increment?

i'm developing SaaS app with multi-tenancy, and i've decide to use single DB (MySQL Innodb for now) for client's data. I chose to use composite primary keys like PK(client_id, id). I have 2 ways here,...
3
votes
1answer
847 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 ------------ ... ---...
6
votes
3answers
14k views

How do I get the current and next greater value in one select?

I have a InnoDB table 'idtimes' (MySQL 5.0.22-log) with columns `id` int(11) NOT NULL, `time` int(20) NOT NULL, [...] with a compound unique key UNIQUE KEY `id_time` (`id`,`time`) so there can ...
6
votes
2answers
16k views

MySQL: Error reading communication packets

I get this warning in mysql, [Warning] Aborted connection 21 to db: 'MyDB' user: 'MyUser' host: 'localhost' (Got an error reading communication packets) I have been through few topics in google ...
0
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0answers
20 views

What are the best settings of InnoDB for FULLTEXT queries?

This question has been asked before, but I was unable to find the right answer for my situation. We have a local server with Quad core and 32GB RAM dedicated for a single InnoDB database, which ...
0
votes
1answer
63 views

improving performance of concurrent inserts on innodb with randomized primary

I was looking at my design for primary keys which is based on my own incrementing BIGINT key generator. It is designed to generate batches of 50 numbers for use on that process, but mostly it ends up ...
1
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2answers
41 views

Insert and select the row autoincremented id

What I want to do is insert a row and than select its auto incremented id number, In a multhi-threaded enviroment. I know how to do it with a Stored Procedure. Will this line of code work: BEGIN ...
0
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1answer
28 views

How to use FULLTEXT in mysql innoDB?

Sorry, if my question is naive, but it has puzzled me, and cannot benchmark the performance. I want to use the newly introduced feature of innoDB for FULLTEXT index. I wonder what is the difference ...
1
vote
1answer
33 views

What happens to mysql information_schema after switching to innodb_file_per_table?

We're switching our mysql dev deb instance to innodb_file_per_table and moving the data dir onto another mounted drive so we can free up space on our dev box. We've backed all our dbs up and about to ...
0
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1answer
49 views

how to purge / shrink .idb tables

I know this has been asked many times but, what is the proper configuration to succesfully purge / shrink .idb tables? I have tried to use optimize table table_name but after the query the .idb ...
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0answers
60 views

MySQL is using swap memory while I have plenty of free RAM

I have a 6 GB buffer pool size for my database; however, mysqld process is moving to swap while there is plenty of RAM available. I think pool size and pages along with pool of reads and pool of read ...
1
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1answer
24 views

MySQL innodb_log_file_size change is not being recognized

I am trying to set the innodb_log_file_size option in a MySQL 14.14 (distrib. 5.6.30) installation on Ubuntu 15.10 to solve an issue (importing a database with large BLOB fields) however the log size ...
0
votes
1answer
58 views

mysql crashed, innodb fails to recover

On Mysql 5.0 on CentOS 5.11, mysqld service has crashed and fails to start. Adding innodb_force_recovery=3 in /etc/my.cnf, creates the following error, which repeats with all table names of database ...
2
votes
1answer
3k 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 ...
1
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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 ...
0
votes
1answer
384 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 ...
2
votes
2answers
697 views

InnoDB not enabled

I have a mysql database that when I run SHOW ENGINES; innodb does not show up as an engine. This seems strange as I have an identical server setup where innodb is enabled and in use. I have checked ...
0
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3answers
4k views

Migrate Jira to MySql - Unknown system variable 'storage_engine'

I'm migrating JIRA in Windows from HSQL to MySQL and I got stuck with the message Unknown system variable 'storage_engine'. Though I created a backup, installed MySQL and copied J connector to libs ...
1
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1answer
70 views

InnoDB files created even innodb_file_per_table is OFF in mysql-5.7

We have installed mysql 5.7 in ubuntu 16.04 and we got big surprise because databases are being stored individually in each folder even parameter innodb_file_per_table is 0. We decided to change ...
4
votes
2answers
442 views

ib_logfile opened with O_SYNC when innodb_flush_method=O_DSYNC

mysql will open and flush data/log files as below when innodb_flush_method=O_DSYNC Open log Flush log Open datafile Flush data O_SYNC NONE NONE fsync () ...
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1answer
171 views

MySql Innodb corruption recovery

I have a MySql database, just containing Innodb tables, that seems to have corrupted itself. It replicates to another server and it has corrupted that one too! The symptom is that I can restart the ...
0
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0answers
6 views

1K unused pages in each InnoDB buffer pool instance

I have configured a InnoDB buffer pool of 12 Gb, split into a dozen instances 1 Gb each. The buffer pool hit rate is 1000 / 1000, therefore so far it's looking good. Looking at the stats of the ...
0
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0answers
26 views

Completely reset innodb logs and files

So long story short, we've been dealing with a corrupt innodb installation on a MariaDB 10.0 server after a power outage, specifically a log in the future error. Rather than try and fake the log ...
0
votes
1answer
14 views

Monitor locks over long period of time

I am having some issues with one of my tables in a production server. I know there are many diffrent threads running on this table. I need to put some kind of monitoring tool to see how many locks ...
3
votes
2answers
11k views

How to use RESTRICT for Foreign Key in mysql?

In the database structure of CREATE TABLE Country ( name varchar(40) NOT NULL, PRIMARY KEY (name) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; CREATE TABLE City ( name varchar(40) NOT NULL, ...
5
votes
1answer
5k views

MySQL Index creation failing on table is full

UPDATE: tl;dr: The problem was MySQL uses the TMPDIR when creating indexes. And my TMPDIR was the one running out of disk space. Original Q: I'm trying to add an index to an InnoDB table, and ...
2
votes
1answer
65 views

Query with Indexes slower than without Indexes

I'm using MySQL 5.6 and my storage engine is InnoDB. I have a table with 1 million rows containing with the columns: ID (primary key) FirstName LastName foreign_key_id (foreign key, NOT NULL) ...
2
votes
2answers
183 views

Sudden MySQL freeze, with spike in dirty pages, but without obvious write queries

I'm systematically (1/2 times per day) experiencing a freeze in the DB server. Suddenly, all the COMMITs get stuck in 'init' state; they pile up (up to 20/30), an almost no other queries are executed ...
0
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1answer
104 views

Restore InnoDB from .frm files

My database crashed and my PC and I now only have the .frm and .ibd files left. Is there any way to restore my database?
8
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4answers
18k views

Making sense of INNODB buffer pool stats

After having read this page in the mysql documentation, I tried to make sense of our current InnoDB usage. Currently, we allocate 6GB of RAM for the buffer pool. Our database size is about the same. ...
39
votes
3answers
47k views

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 ...
0
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0answers
48 views

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 ...
1
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1answer
62 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 ...
2
votes
1answer
1k 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 ...
3
votes
0answers
56 views

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: ...