InnoDB : MySQL's ACID-compliant Storage Engine

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2
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1answer
51 views

Why might a query not run until after I restart the MySQL server?

Why might MySQL not execute a query? Why might it freeze? It simply sits there and does nothing. Show processlist gives a result of "sending data" for as many hours as it takes for me to give up and ...
1
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1answer
76 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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0answers
21 views

MySQL 5.6.18 got signal 11

My MySQL Server 5.6.18 got signal 11 today very randomly. Has not happened before. This is the stack trace : stack_bottom = 7fdb9bcb1e0f thread_stack 0x40000 ...
3
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0answers
141 views

MySQL process stuck on “cleaning up”, locking table forever

It was suggested I post here as opposed to StackOverflow. I'm new to debugging mysql/innodb issues so here is the best I have: I'm trying to run an integration test so these results are near ...
0
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0answers
51 views

Individual inserts wait for several seconds for primary key lock (inno DB)

my application inserts about 2,000 records in a table per hour, at some time the database started to delay this inserts throwing a "lock time wait" exception, after some research I got this output ...
0
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0answers
27 views

Get records with specific group name from table A and see if any exist in table B, if it does then add matching records in Table B to group

Let me start off by saying I am not a DB admin or a DB pro, I work with SQL as a php developer but that's about it. So I hope I can explain this properly and I hope one of you DB guys/gals can help. ...
1
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0answers
68 views

How to resolve Innodb lock

I am trying to run a sitemap generator job for Magento and here is what I get as Innodb status after the query has failed to complete even after several hours. I do not know much about DBA stuff and ...
3
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2answers
34 views

import mysql schema data folder instead of from a dump

current state I have prod and dev mySQL databases. To create the dev database, I used the various schema backups generated from production and imported them like so: mysql -u my_user -p target_db ...
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0answers
31 views

cannot install_db after deleting /var/db/mysql

I am trying to reset mysql5.6-server back to its installation defaults and blowout/nuke all the databases to start off fresh and clean. [root@yoda:~] # rm -fr /var/db/mysql [root@yoda:~] # mkdir ...
2
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0answers
87 views

MySQL: Is the read committed isolation level safe with mixed binary log format?

When using the MIXED format with the READ COMMITTED isolation level, am I safe? The docs state (http://dev.mysql.com/doc/refman/5.5/en/set-transaction.html#isolevel_read-committed) If you use ...
3
votes
2answers
70 views

Should I normalise this database?

I have two database designs thought of for storing messages(instant messages) between users. It will be a group chat system. I have two table designs in mind. One is this: CREATE TABLE ...
7
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245 views

Avoid MySQL self-crashing on long semaphore waits [closed]

I run heavy queries on my InnoDB databases every night, and sometimes it causes long semaphore waits. More background in this question. What I have observed is that if the data is stored on an SSD, ...
3
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0answers
63 views

How does mysql(innoDB) handle same foreign key for join

I have a table called X and another called Y. There is a primary key on Y that is a foreign key on X. Now, my data is such that there will be many rows in X that will have the exact same foreign key ...
0
votes
1answer
44 views

Does innodb_data_reads include reads from the buffer pool?

We have set up some monitoring on many of our databases that serve many different applications. It seems that they all report back more writes than reads when in reality that is very unlikely. I ...
4
votes
2answers
151 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 ...
0
votes
1answer
93 views

RDS innodb_flush_log_at_trx_commit problem

I use Amazon RDS as mysql db backend for highload project and try to optimize insert performance for innodb tables. According to information from different sources - good candidate to speed up inserts ...
1
vote
1answer
72 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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0answers
26 views

Syntax error or access violation: 1286 Unknown storage engine 'InnoDB'

MySQL won't start after I changed the my.cnf file. After a lot of use on my site, MySQL crashes and I get this error: Syntax error or access violation: 1286 Unknown storage engine 'InnoDB' I ...
0
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1answer
64 views

mysql query taking differently long

I need some enlightenment on a MySQL query issue: I recently found out that a select query is taking differently long depending on how large ibdata1 is (at least that's how it seems to me). To be ...
4
votes
1answer
81 views

Should a table be split if only a particular column gets updates?

I have a table in my MySQL 5.7 database, which has 9 columns. One column is an AUTO INCREMENT PRIMARY KEY, where as the other 6 contain some data, which isn't going to be updated in a year. Now, the ...
1
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0answers
46 views

mysql innodb - strange data loss

I am running a mysql database on linux with several InnoDB tables. At some point, the ibdata1 file got quite big and I wanted to delete it. So I made a dump, deleted the file and restarted the server. ...
2
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1answer
63 views

Split Mysql Table internally

How to split the huge mysql table (size around 200GB) internally? Is there any mechanism other than partition? The table size is daily growing. Table created using innodb with indices. Thanks in ...
1
vote
1answer
76 views

Decrease Query Execution Time

I have been having issues with 2 queries with query execution times up to 250 seconds for each query. The tables joined have each less than 10,000 rows, with exception to 2 tables that have around 60k ...
2
votes
1answer
83 views

Cannot access MySQL database after moving files in data directory

I am using Xampp locally and I recently did a computer upgrade where I went from XP to Windows 7 and also got a new drive to install Windows on. I have all my old Xampp files in: G:\xampp I installed ...
1
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1answer
36 views

automatic innodb redo log archiving

We have an option to do recovery through bin-logs, but we thought recovery through bin-logs is not 99% consistent because there is no LSN(Log Sequence Number)/SCN (System Change Number) in bin-logs ...
0
votes
1answer
36 views

Prefix index length impact for VARCHAR?

I have a VARCHAR(255) primary field field in an InnoDB database table. I only store values of length 32 bytes in it (32 ASCII characters). My primary key has a prefix length of 767 bytes. Clearly, ...
0
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0answers
107 views

how to recover everything from ibdata in mysql

I lost all my databases files after my hard disk was broken, In a way or another I got ibdata files the size for the file is 4GB.After replacing log files and files and type innodb_force_recovery=6 in ...
1
vote
1answer
145 views

Why do innodb tables get corrupted so easily?

I'm upgrading a legacy system running MySQL 5.1 all the way to MariaDB 10. We're on a brand new Windows server, running XAMPP. I've done plenty of DB migrations in my time but this one has just been ...
0
votes
1answer
16 views

First Insert is skipped by the trigger

I am facing a very strange issue as i have implemented a trigger on tableA which does encrypt data and insert data to another tableB and update column to 4 digit. The issue is First insert is somehow ...
2
votes
2answers
32 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 ...
0
votes
1answer
50 views

How to ORDER a big table?

I have a simple but big table (tens of millions of rows). The performance is quite good except when I need to order the table by the column with format datetime. A simple SELECT query to fetch the ...
3
votes
1answer
57 views

How we can recover MySQL database (Innodb,myisam)

I have found some recovery tool innodb-recovery but it works only on linux machine, I would like to know how to recover innodb tables on windows. Transaction ID based recovery Cancel based, Change ...
0
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0answers
72 views

After recovering full backup with innobackupex, innodb system tablespace appears to be corrupt

I've a full backup of a database. From time to time, I recover those full backups on a recovery machine. This process has worked fine always, until today. The backup went OK, zero warnings, nor ...
2
votes
1answer
105 views

Query about MySQL Semaphores in Engine Status

During a recent problem / slow down with one of our slave databases I noticed that when I ran SHOW ENGINE INNODB STATUS. I am getting the following: ---------- SEMAPHORES ---------- OS WAIT ARRAY ...
3
votes
2answers
75 views

MySQL for Oracle DBA

I am a newbie to MySQL, but understand Oracle databases well. I need a quick help to understand the architectural differences. Currently I am working on a Windows platform. 1) In Oracle we have to ...
3
votes
2answers
165 views

Release MySQL Memory and Performance Tunning

I am new to the MySQL database. I have recently installed MySQL 5.7 and configured the my.ini file. Please find the below copy of the file. The server is a dedicated server for MySQL database and the ...
0
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0answers
55 views

Simple InnoDB update query locks transaction - why?

I have the following lines in my error log (often repeating after a recent code update): *** (1) TRANSACTION: TRANSACTION 2959776709, ACTIVE 0 sec starting index read mysql tables in use 1, locked ...
1
vote
1answer
27 views

Theory of indexes for query with joins

I found the following talk by Zardosht Kasheff enlightening: http://www.infoq.com/presentations/Index-SQL but it only covers the case of simple queries on a single table. Is there something similar ...
0
votes
1answer
50 views

Restored database copy larger than original

I've created a copy of a database for testing. It's on the same server as the original. However, tables are listed as being larger on the restored copy than on the original. My original database is ...
0
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0answers
116 views

“mysqld got signal 11” error

I have a MySQL 5.6.22 InnoDB database and just now, suddenly out of nowhere, when I try to start it up using /etc/init.d/mysqld start, I see this error in the error log and the server won't start up : ...
1
vote
1answer
48 views

How to make a unique datetime without seconds?

I need to build a table accepting one row for each minute. If I set the type of primary key to datetime, 60 records can be added for each minute. Is there any trick to design a table to keep ...
0
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0answers
11 views

Mtop - How to reset ID numbers?

Using Mtop for slow queries logging in our InnoDB. Since there is actually high database usage, the log IDs in front when using the mtop command are increasing rapidly and I would like to reset them, ...
1
vote
1answer
122 views

Slow MySQL InnoDB performance of table with 100 million rows

I have the database in this format. CREATE TABLE `dna` ( `p_id` bigint(20) NOT NULL AUTO_INCREMENT, `dna_bits` bit(32) NOT NULL, `user_id` int(11) NOT NULL, PRIMARY KEY (`p_id`), KEY `dna_bits` ...
0
votes
0answers
45 views

My DB restarts again and again

MySQL keeps restarting and logs keep giving this errors InnoDB: Database was not shutdown normally! InnoDB: Starting crash recovery. InnoDB: Reading tablespace information from the .ibd ...
2
votes
2answers
73 views

what is the difference between UPDATE … LIMIT and SELECT … FOR UPDATE?

I have read an article, there is one sentence about MySql: As one might expect, lock contention is an issue and we use several strategies to mitigate it including a separate table for each ...
2
votes
2answers
55 views

Mysql hand machine due to high load average and CPU

Mysql is used by only one application which only fire query periodically. When i restart server,It run smooth for period of time. and then crash the whole server. My my.cnf file [mysqld] ...
1
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0answers
46 views

Moving to innodb_file_per_table?

I have just noticed (unfortunately while trying to restore from backup), that on my production server there is a 35GB ibdata1 file! As I understand I can reduce its size by moving to ...
0
votes
0answers
153 views

How to find the total disk writes in MySQL

I'm trying to find the total number of disk writes in MySQL. I used the following command in the MySQL terminal. >SHOW GLOBAL STATUS; I got a list of different attributes status and few which ...
0
votes
1answer
32 views

Why does mysql make delete offset?

I am implementing database(College project).So I come across innodb diagrams in github ...
0
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0answers
893 views

MySQL 5.7 InnoDB is extremely slow on spatial data compared to MySQL 5.6

I have a table area which contains ~300,000 rows. It is defined as follows: CREATE TABLE `area` ( `area_id` bigint(20) NOT NULL AUTO_INCREMENT, `boundary` geometry NOT NULL, `name` varchar(255) ...