InnoDB : MySQL's ACID-compliant Storage Engine

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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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71 views

MySQL Create Table with Partition Slow on server machine

Following create table statement with Partition runs in 10 Second on My Development Machine windows 7, i5 , 8GBRam, single disk runs in 16 Second on Virtual Machine windows server 2012 , xeon 2GHz ...
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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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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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113 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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1answer
38 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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2answers
49 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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79 views

Invision Power Board 3.4.6 - mysql locks during query with pending updates

about 2 weeks ago, we started experiencing random lockups and slowdowns on our forums. We've been running this site for around 6 years minimum with no issues. the site and db are on dedicated vms. The ...
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6answers
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DELETE command not completing on 30,000,000 row table

I have inherited a database and am looking to clean and speed it up. I have a table that contains 30,000,000 rows, many of which are junk data made by an error by our programmer. Before I add any new, ...
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2answers
50 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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39 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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36 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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45 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
331 views

UPDATE waits for lock too long after SELECT in MySQL (Innodb)

I have PHP function Pics::getPicture (yii2 ORM) which selects one row from table and then updates one field from this row. The table structure contains only id (PK), path (VARCHAR(500)) and seen ...
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1answer
71 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
74 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
42 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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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
245 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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17 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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2answers
636 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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1answer
74 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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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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46 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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1answer
83 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
73 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
66 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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146 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
31 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
130 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
29 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
70 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
88 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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79 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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1answer
65 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
87 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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2answers
36 views

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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1answer
94 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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2answers
185 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
32 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
61 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
99 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
216 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
75 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
121 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
474 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
54 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
26 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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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 ...