InnoDB : MySQL's ACID-compliant Storage Engine

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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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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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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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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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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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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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mysql write lock

I dont add any manual locking or any transaction anything, just manual running queries from php script, and execute below two update queries at the same time update table_x set status = 'PROCESSING' ...
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612 views

DB disk space requirements comparision between MySQL versions

I have 2 labs where MySQL is installed. DataBases are created and deleted dynamically by certain internal processes. InnoDB is the Engine used. In one lab, MySQL version 5.0.77 is installed. The DB ...
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Yet another “ERROR 1005 can't create table” question

Well, I've been looking at the ERROR 1005 questions, but I haven't been able to see my error among the issues addressed by those questions. This code is generated by MySQL Workbench under Linux. Can ...
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132 views

Why does InnoDB allow a 772 byte unique constraint?

I've defined a unique constraint for two columns: A bigint and a VARCHAR(256) COLLATE utf8mb4_unicode_ci Then this error occured (which I'm already familiar with): Specified key was too long; max ...
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Big cpu caused by mysql

I have big cpu caused by mysql, 3 vcores, centos 6 64bits http://s3.postimg.org/z8l73e98z/mysql.png [mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock user=mysql symbolic-links=0 ...
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What if we skip the slave by counter 1 when it failed at event 1 of a transaction which has events 2 and 3

We have a master-slave replication which has all Innodb data. I ran 3 update statements under one transaction on master. ============= start transaction update T1 update T2 update T3 end ...
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troubleshoot high value for mysql innodb pages written per second

Our database is writting about 600 pages a second to its innodb buffer pools. Usually this value is about 10 pages/sec, so the server is experiencing a very high IO utilization, around 50%. Is there ...
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Using multiple cores for single MySQL queries on Debian

I am running a MySQL server for tests on a VM (VMWare) with Debian as guest OS. The guest has four emulated CPU cores, so I set thread_concurrency to four. I am doing expensive joins on large tables, ...
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290 views

Concurrency when simulating autoincrement with triggers on MySQL

I am updating an old application to implement virtual tenancy, which involves adding a tenant_id column to the primary key of every single table. The application uses auto-incrementing columns ...
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1answer
77 views

Acceptable to use Antelope and Barracuda simultaneously?

I've been doing some reading about the Antelope and Barracuda file formats for InnoDB. I recall at least one source mentioning that the two should not be used simultaneously. I can't think of a good ...
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Will a static MySQL database become bigger in file size over time, even without anyone writing to it?

I backed up a database a few weeks ago, then for comparison downloaded it again. It was about 10,000 kB larger. There should not be anyone writing to it, but there are lots of reads. Will a static ...
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What is InnoDB Buffer Usage and how to clear it?

In Mysql Workbench when I go in Server > Server Status there is a field called "InnoDB Buffer Usage" It is "95%" even if there is no query running. Why? It affects my performance in my new queries? ...
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InnoDB row metadata size (minimum row size)

I'm trying to decide whether to normalize a thing further, and need to know what the smallest a row in InnoDB can be (I've got MySQL 5.6). This is not exactly my case, but for simplicity, let's ...
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How to speed up mysql export and import

I need to perform a DB migration from Server A to Server B. Server A: MySQL version installed 5.0.6 Server B: MySQL version installed 5.6.20 OS: Both are running RedHat Linux 64bit. 16 ...
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#1025 - Error on rename of table errno: 150 : Table was deleted while tried to assign foreign key

When I tried to assign foreign key to a table named mydb.table1 it was deleted from my database, I could not understand the reason and tried to move on. For this tried to create same table with create ...
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Mysql backup strategies?

We have a innodb mysql database so we are lost with lots of different mysql backup strategies. Some talk about mysqldump some talk about third part tools. Some of the tables we also plan to run ...
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MySQL requires FORCE INDEX on huge table and simple SELECTs

We have an application which stores articles from different sources in a MySQL table and allows users to retrieve those articles ordered by date. Articles are always filtered by source, so for client ...
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185 views

What can I do about this MariaDB 10.0 error?

I have a serious error that crashes the mariadb service, and it won't start up again until I delete the database folder in the data directory of the database I was working on at the time. Here is the ...
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4answers
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If all tables are myisam, should I use myisam engine instead of default innodb?

I have read all of the innodb/myisam threads and they are confusing. Everyone says innodb but I am assuming that they are saying innodb engine with innodb tables.? The software I am using creates ...
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with MySQL, are multiple single column indexes faster than one multi-column index? [closed]

I have a performance related question, in MySQL, are multiple single column indexes faster than one multi-column index?
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How to optimize a slow query?

I work as an administrator and software developer for a company that provides services to the car selling business. In essence we develop the software that they use when selling cars and such. This ...
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317 views

Question About Large InnoDB Table with Deleted Rows

Our server has a DB that's over 600 GB - we are deleting older rows that are non-essential to contain the growth. We can't optimize the table due to possible downtown on the table but we are ...
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How “relatively safe” is the data which was salvaged from corrupted MySQL InnoDB database?

I encountered the corruption like the following. 150208 14:27:52 InnoDB: Error: page 443375 log sequence number 8941 870477908 InnoDB: is in the future! Current system log sequence number 5968 ...
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1answer
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SQL aggregate function performance in a table with many records that is well-indexed

My question is about 3 tables that stores data of a single entity, and there is a report generation feature that refers these tables and calculate COUNT and AVG information. There are three tables: ...
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InnoDB Deadlocks Involving Currency Transactions

We're dealing with InnoDB deadlocks that are affecting our virtual transaction system. LATEST DETECTED DEADLOCK 150210 20:51:03 *** (1) TRANSACTION: TRANSACTION 0 4240405649, ACTIVE 0 sec, process no ...
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How to check growth of database in mysql?

I want to know is there any method to check the growth of database on file EXAMPLES Database A contains all tables in INNODB storage engine Database B contains all tables in MyISAM storage engine ...
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DB Rolls Back And Loses Data

So we've come across an astounding issue here. At random moments, our DB is dropping the database and recreating the table with data from an earlier point in time. Unfortunately general query logs ...
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MYSQL: InnoDB inserts wont rollback transaction inside a stored procedure

I have this stored procedure: START TRANSACTION; code_gen_loop: WHILE @Codes > 0 DO IF MOD( @Codes, 10000 ) = 0 THEN EXECUTE qry_status_stmt2; EXECUTE qry_status_stmt3; ...
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135 views

How to Permanently solve MySQL error 2002 (HY000)

I have a problem on my cloud server with 2GB of RAM and 40GB Hard Disk that's hosting a Wordpress website that receives around 1000-2000 hits a day. My problem is that MySQL is always crashing and my ...
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242 views

Mysql might have too many indexes

I am using the php framework Laravel for my application, together with mysql 5.6, in order to have full-text search with innoBD. But I am not sure if I have too many indexes. My application allows ...
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Change Storage Engine on Referenced Tables

i need to change storage engine from 'InnoDB' to 'MyISAM' on some tables of different databases. So i made a script file to do so: #!/bin/bash DATABASES=$(mysql -u XXXXX -pXXXXX --skip-column-names ...
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MySQL information_schema doesn't update

I have a database, say abc, in mysql server. It has only one table named test. test uses innodb engine and I've set innodb_file_per_table to true. After I run the query delete from abc.test, I want ...
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DELETE seems to hang

The following command: DELETE FROM hours WHERE id IN (SELECT id FROM holdkey WHERE persons_id=60) seems to hang indefinitely. However, the corresponding SELECT * command completes in a fraction of ...
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Is a update-only-once-row table worth sharding?

I have a big MySQL 5.6 Inno DB table that contains user's request. A table row updates only once, shortly-after the initial insert! (The initial insert is to get the unique auto-incrementing ...
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How large should be mysql innodb_buffer_pool_size?

I have a busy database with solely InnoDB tables which is about 5GB in size. The database runs on a Debian server using SSD disks and I've set max connections = 800 which sometimes saturate and grind ...
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Is it a good idea to add a reserved field to a large MySQL table?

As you may know adding a new column to a MySQL table with millions of records is hard and in some cases impossible. Is it a good idea to add a text column to each table (say, meta) to save some ...
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Is possible to backup database online using rsync?

Some people tell me that the backup database on-the-fly using rsync is possible. I think it is possible but not safe because some log, buffer... is not flushed. Database is being recovered from the ...
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MySQL - Cannot add new Foreign Key [closed]

I'm using magento and it does some re-index for a product flat table structure. In this process a new table is created. The SQL for that table is something like: CREATE TABLE ...
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1answer
64 views

Is >58 hours to create an index normal? Should I cancel and try again?

I have an InnoDB table with ~43,964,557 rows containing 20.5 GiB of data (not counting existing indexes). mysql> show table status like 'backpack_items'; ...
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Why are tiny Innodb row updates causing so much disk IO?

This is a followup question to my earlier How can I determine which Innodb table is being written? Using the accepted answer from the above-referenced question I was able to determine which (two) of ...
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What does 'system lock' mean in mysql profiling a LOAD DATA INFILE statement?

2M rows inserted using LOAD DATA INFILE to innodb takes 7.5min, and profiling shows 99% of that time is in "System lock". Does this tell me anything useful? mysql> set profiling=1; ...
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54M InnoDB keeps shutting down unexpectedly [duplicate]

I have a mariadb server running several databases with very small load. From time to time, when I have 20+ users browsing one of the wordpress websites i have, the daemon just shuts down with the ...
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Do I need to reindex mysql table after bulk delete?

I have a table in MySQL with a lot of INSERT and SELECT at every second. And there is a bulk delete of some older data once in a day. Do I need to reindex the table after delete? I want to increase ...
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Error 1005: Can't create table can't find where the problem is

I have created a EER model using MySQL Workbench (latest release). Apparently all is fine but when I try to do a FORWARD ENGINEER I get the common Error 1005: Can't create table. As suggested in this ...