InnoDB : MySQL's ACID-compliant Storage Engine

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Difference between On Delete Cascade & On Update Cascade in mysql

I have two tables in MySQL database- parent, child. I'm trying to add foreign key references to my child table based on the parent table. Is there any significant difference between ON UPDATE CASCADE ...
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0answers
42 views

Are these slow query and locks make database server get high load sys CPU two times in a week?

As title I mention, my database server sometime get high sys CPU. I do some troubleshooting I am possible. We built database using mariadb galera. We use two nodes(db1, db2) + one garbd. When db2 ...
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2answers
91 views

Mysql causing high load average with large amount of server resources left

I've have 2 servers running a application and the server that runs the mysql sgbd is with the load average around 3 times more than the webserver. I think that is something wrong because i have a lot ...
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1answer
344 views

MySQL select by primary key against 100M of records within 30ms

I have no expirience with MySQL and database performance tuning in general. Wondering whether it is possible to perform a large number of selects against 100 millions of records by primary key within ...
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1answer
328 views

Mysql HY000 the table table_name is full when adding new column

I can't add a new column innodb table which size's 16MB. when I try to add, mysql says HY000 the table table_name is full. I changed my tmp_table_size and heap_size but mysql still says same error. ...
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1answer
33k views

What is the best way to reduce the size of ibdata in mysql?

I have some Production servers whose ibdata files increases in size day by day. It has already consumed 290GB of space. The tables in the servers are mostly InnoDB and there are high read and write ...
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2answers
274 views

How to recover previous values in Mysql Table?

I have MySQL Innodb table of 14M rows. There was a column called is_disabled which had different values. By mistake I ran the query without the where clause: update url_queue set is_disabled=1 ...
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1answer
2k views

Getting duplicate primary key for auto increment column

I have a MySQL Innodb table with 'id' as auto increment primary key column. My Scripts are doing following operations: insert ignore into tablename set x='a', y='b' update ignore tablename set ...
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6answers
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Fastest way to check if InnoDB table has changed

My application is very database intensive. Currently, I'm running MySQL 5.5.19 and using MyISAM, but I'm in the process of migrating to InnoDB. The only problem left is checksum performance. My ...
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1answer
40 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 ...
6
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1answer
8k views

Error when dropping InnoDB database

I am trying to drop a database in mysql, but every time I get this error ERROR 2013 (HY000): Lost connection to MySQL server during query even logged in as root. Originally, I had a corrupted ...
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0answers
1k views

MariaDB MySQL server does not start

My MariaDB mysql server doesn't start with error 1067 This is the error log: 140222 0:43:44 InnoDB: The InnoDB memory heap is disabled 140222 0:43:44 InnoDB: Mutexes and rw_locks use ...
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1answer
90 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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1answer
45 views

Very weird Innodb Corruption Issue

I'll try to keep this to the point. System: OPenVZ VPS, debian 6, 512 MB RAM, 50 GB HDD (25GB free) I have a mysqldump dump file (3GB), that was created when the innodb database was working fine. ...
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2answers
51 views

MariaDB/InnoDB: What to do on “Locks in Status-Log but no locked table found”

We migrated lately from MySQL to MariaDB. SELECT VERSION() 10.0.13-MariaDB-log When executing this: SHOW ENGINE INNODB STATUS I get (shortened): ... ---TRANSACTION 279257007, ACTIVE 23981 ...
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1answer
64 views

Is it possible to restore a MySql database only using files from Data directory?

I have a mysql installed inside a windows virtual machine. The hard drive was crashed and the system is not able to restore all again. But I can have access to entire c: ROOT. So I went to ...
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1answer
42 views

Is it safe to disable InnoDB doublewrite buffering when setting Innodb_page_size = filesystem page size?

As I understand, doublewrite buffering is needed to avoid partial write, because Innodb_page_size default is 16K, while filesystem page size normallly is 4K; I wonder if I set "Innodb_page_size = ...
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2answers
78 views

Need to make MySQL's LOAD DATA LOCAL INFILE load large data faster

I need to load 4 million rows of data into a MySQL InnoDB table using LOAD DATA INFILE and would like to know if there are server configuration options I can tweak to get faster load. It took me 15 ...
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1answer
90 views

MySQL InnoDB 5.6.23 cannot start segmentation fault 11

I have a Linux Gentoo server which has OwnCloud application installed. It works for about 2 months with out any problems, and sudden this morning MySQL died. I have tried to restart mysql server and ...
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1answer
21 views

if set global transaction, how can I commit?

I found that MySQL can set a global transaction, but can I commit in another session? refer: http://dev.mysql.com/doc/refman/5.6/en/set-transaction.html
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1answer
68 views

MySQL: check max chracter length (ERROR 1118 (42000): Row size too large)

I'm trying to convert/copy MyISAM to InnoDB table and I'm getting the following error message: mysql> INSERT INTO test.innodb_table SELECT * FROM test.myisam_table ERROR 1118 (42000): Row size ...
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9answers
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What are the main differences between InnoDB and MyISAM?

What are the main differences between InnoDB and MyISAM?
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2answers
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Can anyone offer an opinion on handlersocket vs memcached performance in MySQL 5.6

I must say I was a little mis(un)-informed about the MySQL Memcached plugin which offers the same NoSQL like access to InnoDB tables as HandlerSocket, I had only had experience with entirely ...
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1answer
48 views

Query perfomance with multiple JOINs on MyISAM-based DB

I'm working with Enron Email Dataset in MySQL database. After I executed data import from the dump file into MyISAM-based DB, I got the set of tables without any connections between them via foreign ...
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1answer
74 views

Rolling update to all rows in innodb table (no rollback if aborted)

I have the following table, which stores the Social Security Death Master File database (~86M rows): CREATE TABLE `death_master_files` ( `id` int(11) NOT NULL AUTO_INCREMENT, `ssn_an` smallint(5) ...
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1answer
34 views

InnoDB index concurrent inserts

I have an InnoDB table with an index on it. I have a few million rows to insert, so I thought I might take advantage of the row-level locking and do it in parallel. I'm inserting in batches of 10000, ...
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2answers
88 views

Speeding Inserts of longtext or longblob columns

i'm currently migrating a DB2 database to MySQL, using SQL WORKBENCH Tool It basically does a select from DB2 and Insert to DB2. It works fine, but on the tables with longblob or longtext columns ...
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1answer
344 views

Server stuck in INTERNAL DDL LOG RECOVERY IN PROGRESS

Recently, one of my servers had a crash. I had alot of trouble but managed to restore everything. But, Now, the first background thread upon startup is locked on "INTERNAL DDL LOG RECOVERY IN ...
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2answers
2k views

COUNT(*) on InnoDB whenever phpMyAdmin loads

It's a known issue that innodb is slow in SELECT count(*) FROM Table Hence I avoided that. But I notice that whenever I login to phpmyadmin, it will automatically execute a count(*) for my innodb ...
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2answers
119 views

Inner Join and Right Join same query

I'm using MySQL and InnoDB, I have a table reserver with 2 columns : idReservation and idChambre I have a table reservation and a table chambre Now I want my query to return every "chambre.id" who is ...
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4answers
6k views

Mysql innoDB write operations are extremely slow

I'm having serious performance problems with MySQL and the InnoDB engine. Even the simplest table makes writing operations (creating the table, inserting, updating and deleting) horribly slow, as you ...
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1answer
51 views

MySQL query INSERT INTO … failed - The Table “x” is full

I apologize if my question is incomplete or noobish, I have extremely limited knowledge of SQL but the boss wants me to figure this one out. Environment: Webmin/Virtualmin | MySQL version 5.1.73 on ...
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2answers
124 views

MySQL - Changing from system tablespace to file per table

The MySQL database I am working on has the InnoDB tables and indexes stored in the system tablespace which is now > 20Gb. Some years ago I managed a MySQL database that made use of a file per table ...
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0answers
52 views

Cannot open table slave_master_info

I have a dabatase working on InnoDB engine Now it is damaged. I can´t open any table, it shows error 1146 Table 'database.tablefromdatabase' doesn't exist I tried innodb_force_recovery with all ...
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0answers
47 views

CPU jumps massively and stays high, under very light load

We had two separate RDS instances exhibit the same pattern today. This was both during low load times, one during the lowest load time for that server. They both started at almost the same time. No ...
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1answer
61 views

MYSQL any way to improve this query's performance?

MYSQL version 5.6.23 CENTOS 7 Hi, I have the following query that is coming from an application that I am hoping to make more efficient from the mysql side of things. I have an index built on ...
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1answer
39 views

InnoDB Table has backed up INSERT and UPDATE queries, high CPU

I am running an MySQL DB with all InnoDB tables. I often have many queries backed up for the same table when I run SHOW PROCESSLIST; Basically, I keep a table of every logged in customer and update ...
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1answer
40 views

What is the performance benefit when using a temporary table to update a regular table?

I'm trying to understand what the performance benefit between two different methods of updating multiple table rows. For the first method we have an explicit update statement for each line to be ...
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0answers
47 views

MySQL is pretty slow after 50-100k rows whats happen?

i have trying now a lots of time, and i try to find a way there make sense to find out of my problem, but this problem stil make a lot perfumes issues. i testing it of on a developer server ( 2 ...
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2answers
129 views

Large ibdata file in MySQL

I am having MySQL database with all my tables as InnoDB with file_per_table config on. But Still I m seeing huge ibdata file ( ~50GB). All tables are having .ibd file as well. This is a machine I have ...
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0answers
76 views

Why is MySQL not saving inserted data?

So I have the following insert statement that I run through MySQL Workbench: INSERT INTO PeakOnlineCount (time_stamp, LocationId, Count) values ('2015-03-26', 0, 1) If I run the following query: ...
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0answers
271 views

How to restore mysql database in XAMPP using backup of mysql folder?

I have a backup of the entire xampp/mysql folder. How can I use it to recover my old db on a fresh installation of XAMPP? Simply copying the old xampp/mysql folder to new xampp leads to mysql errors ...
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2answers
53 views

Slow database drop in mysql

Just installed a new 24 core server and it is noticeably slower when doing truncates and drops. Example: $ mysql -u root lmcdental_test2 Reading table information for completion of table and column ...
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1answer
24 views

I have a DB that is locking up from numerous updates to a table: Should I convert it from MyISAM to InnoDB?

FYI: I don't believe this is a duplicate question, I've looked and most are general questions with vague answers. See more specifics below: Currently a database I am in charge of locks up every once ...
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0answers
44 views

Percona Master-Master lag issues

I have 2 servers with master-master replication using Percona MySQL 5.6 and I am having replication lag in the second server: db-02, however db-01 never had a lag situation. What could be causing ...
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1answer
52 views

“Unknown table engine 'innodb'” error after changing my.cnf

I am getting "Unknown table engine 'innodb'" for some query after changing my my.cnf. I have reverted the old my.cnf and restarted mysql and now I can see innodb. Could you please help me figure out ...
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1answer
2k views

ibdata1 corrupted, recover from ib_logfile?

A failing hard drive have left me with a corrupted ibdata1 file. I know where the file starts but not where it ends. The hard drive recovery software claims the file is larger than the hard drive ...
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1answer
68 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? ...
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1answer
88 views

Complex query performance in MySQL InnoDB versus MyISAM

I am running on MariaDB 10.0.15 on a 4GB RAM cloud server with Local SSD disk for database. My model: users <n---n> right_holders <n---n> tracks ---n> raw_detections I have this ...
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2answers
196 views

ALTER primary key column from INT to BIGINT in production (MySQL 5.6.19a)

Some INNODB tables in our production database are about to hit the INT AUTO_INCREMENT limit of 2147483647 and we need to alter them to BIGINT otherwise writes will start failing. The tables are in a ...