InnoDB : MySQL's ACID-compliant Storage Engine

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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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1answer
267 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
76 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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1answer
53 views

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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1answer
2k views

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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2answers
90 views

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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2answers
1k views

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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1answer
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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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3answers
5k views

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 ...
4
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1answer
11k views

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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1answer
176 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 ...
2
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4answers
244 views

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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4answers
887 views

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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1answer
76 views

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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2answers
298 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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0answers
10 views

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 ...
2
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1answer
292 views

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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0answers
81 views

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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1answer
2k views

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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0answers
29 views

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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0answers
389 views

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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2answers
130 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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2answers
234 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 ...
0
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1answer
90 views

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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3answers
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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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2answers
473 views

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 ...
0
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1answer
75 views

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 ...
63
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4answers
115k views

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 ...
0
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2answers
46 views

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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2answers
646 views

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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0answers
99 views

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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1answer
91 views

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 ...
3
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2answers
9k views

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; ...
0
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0answers
173 views

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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3answers
9k views

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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1answer
1k views

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 ...
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3answers
5k views

How to decide whether to enable MySQL query cache using InnoDB

How should the decision to enable / disable the MySQL query cache be made, on a server that uses just InnoDB tables. Say for example, if the cache is enabled, then how should the output of: SHOW ...
0
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1answer
245 views

Dropped connections, corrupted schema … is MySQL sick?

Lot's of problems and I wonder if it's all tracable to some root cause. I'm trying to load a simple schema related to product marketing. The symptoms are: Not being able to forward engineer said ...
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1answer
560 views

Cannot add a column to an InnoDB table in Mariadb

I have this InnoDB table with less than 10 rows in mysql 5.5.40-MariaDB on Linux (x86_64). +-----------------+--------------+------+-----+-------------------+----------------+ | Field | ...
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1answer
120 views

MySQL Data Files Missing?

We are upgrading our website and I was checking on the size of the new database compared to the old one and was really surprised to find that in the /var/lib/mysql/ directory, the only files there ...
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2answers
13k views

MySQL any way to import a huge (32 GB) sql dump faster?

I have this huge 32 GB sql dump that I need to import into MySQL. I haven't had to import such a huge sql dump before. I did the usual: mysql -uroot dbname < dbname.sql It is taking too long. ...
0
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0answers
33 views

Would we see a performance increase by moving one table to another physical drive?

We have a database of about 600MiB. One table is particularly large and occupies about 70% of that space. We quite often have to query this table - sometimes as far back as a few years, so we can't ...
2
votes
2answers
652 views

How to batch multiple insert statements for database dump with MySQL?

I have a MySQL database with some large tables. In particular, the largest table (by far) currently has ~11,000,000 rows. According to the a query I ran, the table clocks in at around 1.7GB, but it's ...
0
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2answers
1k views

How to run a cold backup with Linux/tar without shutting down MySQL slave?

I run the following before tar-ing up the data directory: STOP SLAVE; FLUSH TABLES WITH READ LOCK; FLUSH LOGS; However, tar will sometimes complain that the ibdata* and ib_logfiles* files are ...
8
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2answers
3k views

ROLLBACK doesn't work after INSERT INTO newly created destination table

I am working on PHP-script which imports CSV file (customers.csv) into MySQL table (customers). Before inserting contents of CSV-file into the mysql table I am first backing up the original customers ...
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0answers
162 views

MySQL InnoDB Configuration with 60Gb of Memory

I'm running a large MySQL Database, in the range of 30Gb in size. The MySQL 5.5 server is running on a dedicated server with 60GB of RAM, with no other processes installed apart from monitoring tools, ...
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2answers
251 views

Find total duration of each consecutive series of rows

MySQL Version The code will run in MySQL 5.5 Background I have a table like the following one CREATE TABLE t ( id INT NOT NULL AUTO_INCREMENT , patient_id INT NOT NULL , bed_id INT NOT NULL , ...
2
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1answer
153 views

How can I determine which Innodb table is being written?

I am running Mysql 5.5. I have about 100 Innodb tables spread over 10 DB's (mostly wordpress sites) and I am recently seeing a lot more disk IO than I have been, without any increase in traffic. The ...
66
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4answers
93k views

How to safely change MySQL innodb variable 'innodb_log_file_size'?

So I'm fairly new to tuning InnoDB. I'm slowly changing tables (where necessary) from MyIsam to InnoDB. I've got about 100MB in innodb, so I increased the innodb_buffer_pool_size variable to 128MB: ...