InnoDB : MySQL's ACID-compliant Storage Engine

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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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31 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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23 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
29 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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6 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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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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1answer
31 views

Mysqli prepare error: Unknown storage engine 'InnoDB'

I'm getting this error on my XenForo installation. Server logs show out of memory because of too many php processes opened up which cause mysqld to shutdown. The WordPress installation associated with ...
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47 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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18 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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58 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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1answer
28 views

Lowering MySQL Memory Usage without Restart

We are using Percona Server 5.5.35-rel33.0-611.precise with InnoDB in our production server. Recently Mysql memory went high and it did't drop from there. We are afraid whether it would result in OOM ...
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1answer
44 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 ...
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115 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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18 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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1answer
56 views

MYSQL: How to improve performance of inserting over 1M rows to a table with over 100M indexed rows

I have this mysql table: CREATE TABLE `codes` ( `code` bigint(11) unsigned NOT NULL, `allocation` int(11) NOT NULL DEFAULT '0', `used` tinyint(1) NOT NULL DEFAULT '0', PRIMARY KEY (`code`), ...
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1answer
24 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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22 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 ...
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1answer
28 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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1answer
49 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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1answer
49 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 ...
2
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1answer
33 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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45 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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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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48 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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64 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
28 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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60 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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1answer
49 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, ...
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1answer
50 views

#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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2answers
61 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
51 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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2answers
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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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23 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, ...
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1answer
24 views

trying to understand table size

Can somebody help explain the "data_length" of the table? Why is it so big in my example below of a table with just one column and one row? mysql> create table `network_type` ( `id` int(11) NOT ...
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7 views

Percona XtraDB and innodb_flush_log_at_trx_commit=2

I'm running Percona XtraDB on a three nodes cluster. Each one has this piece of configuration: innodb_flush_log_at_trx_commit=2 sync_binlog=0 I perfectly know that this is not the safest ...
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53 views

Can I lose data if I use InnoDB? [closed]

During a power failure, is it possible to lose data if I use InnoDB? I remember reading such things.
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15 views

ERROR 2013 (HY000) When long string data managed

This is my first question on this community, I'll explain the situation: I have a server with PHP and Mysql on it, on that server I have a wordpress blog. Lately i've been receiving a lot of spam ...
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63 views

25.000+ rows - MySQL SELECT consecutive numbers performance issue

I have tried to be as explicit as I could. Below you have the query explained in details What I want to obtain? - I want to SELECT start_number and end_number from a set of consecutive numbers from ...
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1answer
21 views

MySQL InnoDB restoration from hardware failure

One of my server went down due to old hardware failure on a old Dell server that's over 10 years old. I was able to recover the files and got it to a local machine. I want to restore a MySQL instance ...
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1answer
244 views

SELECT INTO OUTFILE vs INSERT INTO … SELECT

During my cursory research I have not been able to find a definitive answer on the benefits that SELECT INTO OUTFILE provides over INSERT INTO ... SELECT. Upon reading the docs related to INSERT INTO ...
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1answer
59 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
47 views

What's the approach to figure out reason for mysql crash?

The database I'm using crashes a lot recently. And I can't find a decent way to dig into the issue. I looked into mysql error log, but don't know how to start. I know there was a "load data infile" ...
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1answer
43 views

MySQL/Percona Server is taking long and I'd prefer to skip all this waiting even if it means data loss

Originally posted to https://www.facebook.com/groups/GNUAndLinux/permalink/10155020539805019/ but no replies received. I run Percona Server 5.6.21-70.0-688 x64 on Ubuntu Server 12.04 LTS x64, 64GB ...
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3answers
66 views

Drop Tables with Bigger size

We have a mysql database with a size of 2 TB, in which we have for to five big tables ranging from 110GB to 350GB. When we try to drop these tables the mysql goes to the defunct mode and hangs in that ...
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4answers
90 views

How to backup live mysql database?

I have 12 GB MySQL InnoDB Database with around 800 queries per second. No sooner I start 'mysqldump' over it to make backup I start getting '503' on my website. How do I make backup of my live ...
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63 views

Blob datatype issue with log file

I am getting continuously below error message in mysqld.log [ERROR] InnoDB: The total blob data length (10152274) is greater than 10% of the redo log file size (3072). Please increase ...
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1answer
52 views

InnoDB & Isolation Levels - Aren't repeatable reads a bad thing?

I was reading about InnoDB's isolation levels and it makes sense for the most part, but what I don't get is why are unrepeatable reads a bad thing? Shouldn't it be the other way around? For examples: ...
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1answer
230 views

InnoDB inserts 100 times slower than SQL Server inserts

I have a simple table with two columns: id (autonumber) and name (char(255). When I use C# to insert 100 records in a loop it takes about 30 milliseconds per insert. This is way too slow. So I ...
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20 views

MySQL what is the order of the table lock for this query?

An example query looks like this: INSERT INTO Adventure (sword, fighter, quest) SELECT Swords.id, Fighters.id, Quests.id FROM swords Swords, fighters Fighters, quests Quests WHERE Swords._id = ...
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86 views

How do I recover from MySQL InnoDB table/index corruption?

While trying to upgrade a database (in place) I got the following error. The server starts up and everything seems to be fine, except that the table mentioned in the message is no longer accessible. ...