InnoDB : MySQL's ACID-compliant Storage Engine

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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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3answers
2k views

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
131 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 ...
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1answer
36 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 ...
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4answers
63k 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 ...
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2answers
38 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
62 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
49 views

MySQL - Cannot add new Foreign Key

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
62 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
85 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 ...
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2answers
4k 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; ...
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7answers
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How can I optimize a mysqldump of a large database?

I have a symfony application with an InnoDB database that is ~2GB with 57 tables. The majority of the size of the database resides in a single table (~1.2GB). I am currently using mysqldump to ...
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2answers
12k views

InnoDB: Error: Table “mysql”.“innodb_table_stats” not found after upgrade to mysql 5.6

I upgraded to mysql 5.6 from 5.5, and now my logs are littered with such messages on startup I found a possible solution here, but it does not seem official. ...
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0answers
55 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
2k 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
733 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
2k 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 ...
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1answer
88 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
101 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
47 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
1k 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. ...
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0answers
29 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 ...
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1answer
678 views

Row size too large (> 8126)

I'm facing the following problem. Row size too large (> 8126). Changing some columns to TEXT or BLOB or using ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED may help. In current row format, ...
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2answers
178 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 ...
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34 views

How to synchronize locally two DB table in Master server in MySQL Server 5.6.19

I want to synchronize the locally two DB tables in Master Server. Suppose that first i have already table Employee in a Master Server. The Table Employee have already 20 fields records. Then i have ...
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826 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 ...
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2answers
773 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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56 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
151 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 , ...
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1answer
73 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 ...
3
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1answer
196 views

Migrate from innodb_file_per_table to off in MySQL

We have a large number (2,500+) of databases and users in MySQL 5.6 on a single virtualized server (4 cpus and 8GB of memory). All the tables are using InnoDB. The actual data size is not very large ...
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4answers
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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: ...
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1answer
31 views

Should I use additional id values as unique values that only applies in junction tables in MySQL?

I have created three tables called person, metadata_image and person_image. person table contains info about people. person_id person_name person_bio metadata_image table stores the images. image_id ...
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2answers
105 views

Flush/Clean MySql ib_logfile0 ib_logfile1

Is there a way to flush ib_logfile0 and ib_logfile1 without dumping the tables to a .sql file, deleting, then re-inserting? Somebody entered a couple plain text credit card numbers into the customer ...
0
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1answer
29 views

Will canceling InnoDB compression that's already in progress corrupt data?

I have a 155GB table that is in the process of being compressed. ALTER TABLE $table_name ROW_FORMAT=COMPRESSED KEY_BLOCK_SIZE=8; This compression has been running for a long time and is impeding my ...
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3answers
4k views

Can't create table, but table doesn't exist

I'm using these steps to create a table my_user, that already existed but somehow vanished from my database my_db: mysql> USE my_db; mysql> DROP TABLE my_user; mysql> ERROR 1051 (42S02): ...
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1answer
133 views

Dropping multiple KEYS of a table

Dropping multiple KEYS in a table is a preferred option or one by one is preferred? “DROP KEY A,DROP KEY B,DROP KEY C" For more 900 million records in the table. How does it work internally?
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sync 2 tables in a single database in mysql with no duplicacy [closed]

I have 2 tables in a single database of MySQL. The structures are like this: mysql> desc main_tbl; +-----------------+--------------+------+-----+-------------------+----------------+ | Field ...
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2answers
97 views

OOM in mysql-percona

Every 4th day I run in to OOM problem. [Sat Dec 27 12:20:21 2014] Out of memory: Kill process 3662 (mysqld) score 990 or sacrifice child [Sat Dec 27 12:20:21 2014] Killed process 3662 (mysqld) ...
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1answer
106 views

View last several innodb deadlocks

I see that I can view the latest deadlock in mysql/innodb, but is there a way to view past deadlocks? We have two deadlock issues, one being important and the other not. The less important deadlock ...
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2answers
271 views

Full text search results in a large amount of time spent in 'FULLTEXT initialization'

I'm currently trying to run some queries against a data dump of Stack Overflow's comments. Here's what the schema looks like: CREATE TABLE `socomments` ( `Id` int(11) NOT NULL, `PostId` int(11) ...
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1answer
35 views

Only InnoDB databases locking up

I'm trying to troubleshoot my MYSQL in a LAMP and have an interesting situation. At first I thought MYSQL itself was locking up, but it turns out to be ONLY innodb databases that are locking up. ...
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1answer
145 views

MySQL InnoDB Deadlock For 2 simple insert queries

I have a deadlock for this two insert queries: insert into PlayerClub (modifiedBy, timeCreated, currentClubId, endingLevelPosition, nextClubId, account_id) values (0, '2014-12-23 15:47:11.596', 180, ...
0
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1answer
62 views

what's a reliable way to determine the ideal innodb_thread_concurrency setting?

on an article from 2006 , here they suggest such formula. 2*(number of cpus + Number of Disks) has anyone tried their settings according to this formula ? or do you have any other formula ? our ...
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79 views

Minimizing database size (Many small tables)

Our database is interesting in that we have a large amount of tables that take up a correspondingly large amount of space, but when we do a MySQL dump of said database, it is surprisingly small. ...
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1answer
132 views

Pagination, check number of selected records

I am working on pagination for a complex join query and unfortunately I am not sure what's the best way to go... Right now I am thinking about the following solution. Imagine that SELECT id... is the ...
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1answer
10k views

MySQL: InnoDB keeps crashing - how to recover?

# free -m total used free shared buffers cached Mem: 48289 35288 13000 0 347 30399 -/+ buffers/cache: 4541 43747 ...
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772 views

When is it safe to disable InnoDB doublewrite buffering?

MySQL InnoDB allows us to disable doublewrite buffering by setting innodb_doublewrite = 0. Other databases doesn't seem to allow this setting to be tweaked. How could InnoDB still be able to maintain ...
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0answers
65 views

Slow Query Performance - Can't Debug

I have a MySQL query that I am trying to debug the performance issue but cannot. I know that the majority of the query is reading/processing rows (Sending Data state). However, in the explain output, ...
4
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1answer
3k views

Allocating 8GB memory to MySQL on a 64bit system

Specs - MySQL 5.0.x , Redhat 5.9 , Physical memory - 16GB I am trying to set innodb buffer pool size to 8GB (innodb_buffer_pool_size=8G). When i do, and start mysql, i get following error - ...