InnoDB : MySQL's ACID-compliant Storage Engine

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75 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 ...
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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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24 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 ...
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1answer
63 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 ...
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1answer
74 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 ...
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44 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. ...
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1answer
62 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 ...
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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 ...
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1answer
72 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 ...
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1answer
30 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 ...
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1answer
35 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, ...
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94 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 ...
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1answer
120 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 ...
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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 ...
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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 ...
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1answer
49 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
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1answer
48 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 ...
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53 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
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1answer
79 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 ...
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2answers
69 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 ...
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2answers
137 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 ...
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0answers
47 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 ...
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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 ...
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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 ...
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0answers
100 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 : ...
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1answer
44 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 ...
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10 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, ...
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1answer
106 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` ...
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43 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 ...
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2answers
65 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
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2answers
50 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] ...
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0answers
45 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 ...
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137 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 ...
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1answer
32 views

Why does mysql make delete offset?

I am implementing database(College project).So I come across innodb diagrams in github ...
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768 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) ...
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0answers
44 views

Our app lags “randomly” due to Disk I/O spikes?

Our database (InnobDb) is spiking at 99% I/O at random times. After the spike it goes down to about 2% until it spikes agian. There aren't any spesefic, huge queries running in these intervals that ...
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51 views

Optimizing a group by/where in/min() query in MySQL

Assume I have a table that looks like such (The actual column names of my real table would only make things harder to explain, so I have created a mimic that behaves similarly). id | cond1 | cond2 ...
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2answers
201 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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1answer
51 views

Mysql only using 10% of cache [duplicate]

I have a dedicated Mysql server that only uses 1.1 GB out of 16 GB ram (picture link 1). I belive this leads to my Disk I/O utilization beeing at 75% peaks (picture link1). How can i configure sql ...
2
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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 ...
1
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1answer
44 views

MySQL: Point in Time query using InnoDB log sequence number?

Is it possible to do a point in time query based on a log sequence number? For example, I would like to do something similar to Oracle's "as of" query select foo from bar as of scn 123923455; ...
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4answers
665 views

Mysql (percona-server 5.5) completely stalls during import (myloader)

While configuring our new servers (IBM X3650M4, 2x Intel Xeon E5-2620, 64G RAM, RAID 10 (4x 240G SSD)) we bumped into a strange problem. We're trying to import dumps (mydumper) from our (old) ...
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2answers
150 views

slow query on mysql innodb table with 2 million rows

I have a table with about 2 million rows (growing at about 1 million every 3 months) and am having trouble with slow queries. I've tried changing my query and indexes (ensuring left most order) to no ...
2
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1answer
129 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: ...
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1answer
296 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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1answer
59 views

Optimizing slow query

For a few days now, i'm trying to optimize this query. But still I haven't found the right solution in how to fix this. The contents table contains about 20 million records. As the connect table ...
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88 views

MySQL: equivalent of Oracle's SCN and “as of” queries?

Does MySQL have a similar concept to Oracle "SCN" (system change number)? Is there an equivalent way to do "as of" queries? e.g. select foo from bar as of SCN 104086584;
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1answer
22 views

MySQL InnoDB Error [duplicate]

I'm currently experiencing issues with my server MySQL databases as I keep receiving the following error: InnoDB: The log sequence in ibdata files is higher InnoDB: than the log sequence number in ...
3
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1answer
504 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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1answer
75 views

mysql innodb db full text search FTS_DOC_ID column

I am adding full text search to already existing mysql tables that have primary auto incrementing key of id integer. When I add the full text index I get a warning: /*!50604 ALTER TABLE ...