InnoDB : MySQL's ACID-compliant Storage Engine

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mysql directory grow to 246G after one query, which failed due to table is full

I was trying to run the following statement with the hope to create a join of two existing tables. create table CRS_PAIR select concat_ws(',', a.TESTING_ID, b.TRAINING_ID, a.TESTING_C) as k, ...
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Why do MySQL threads often show “freeing items” status when the query cache is disabled?

When I run SHOW PROCESSLIST, there are often a large number of INSERT/UPDATE threads in the "freeing items" state. The MySQL manual suggests that at least part of the reason for a thread to be in ...
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0answers
108 views

Converting UUID's from CHAR(32) to BIN(16)

I have a few questions relating to UUID's, but before I go on, let me explain our schema a bit, first, we're on MySQL 5.5 (Percona's version to be exact)... In each applicable table, we use a two ...
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1answer
162 views

MySQL not releasing memory

MySQL seems to want to keep an entire table in cache (table size = ~20GB) after any large inserts or select statements are performed on it. Right now my innodb buffer pool is 20GB. Total RAM is 32GB. ...
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2answers
2k views

Is the overhead of frequent query cache invalidation ever worth it?

I'm currently working on a MySQL database where we are seeing a large number of invalidations from the query cache, primarily because of the high number of INSERT, DELETE and UPDATE statements that ...
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2answers
203 views

Are MySQL transactions under-utilised?

I have a vague understanding of transactions that it means you can help the server understand that a series of queries are related. Scenario : Suppose I have a series of queries which creates a user ...
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1answer
90 views

Innodb buffer pool and multiple joins

assume we have 1 Billion records and want to store them in One or Three tables by post_type. post_id -> primary key post_type -> ( page, group, user ) user_id -> index date -> ...
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2answers
88 views

Can CPU cores be separated for MySQL?

Is it possible to separate CPU cores in Mysql? I understand it is possible for Memory as we can tune it in innodb_buffer_pool_size or innodb_additional_mem_pool_size. How about CPU cores in ...
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0answers
120 views

RDS MYSQL instance rebooted and won't load INNODB table

So my production db in RDS apparently either crashed or was rebooted during a version update, and upon being restarted mysql couldn't load one of the innodb tables: as evidenced by the following error ...
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1answer
101 views

MySQL 5.1: Upgrade innodb plugin

My application is running on MySQL 5.1.58 community edition. As I studied on SO websites that After acquisition by Oracle, new InnoDB plugin has been released and MySQL 5.1 with InnoDB plugin is the ...
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2answers
1k views

Optimizing mysql queries running on 50 million rows

Is there any technique/advice in order to optimize the performance of the queries below? According to my needs, my average db size will be approximately 30mill. rows per day, so every second less, ...
2
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1answer
8k 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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The best MySQL Settings for 32GB RAM on a Dedicated Server

I am worrying about my memory usage as it is reaching more than 90% if I will not restart php-fpm. I have the following configuration on my MySQL: [client] port = 3306 socket = ...
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0answers
44 views

MariaDB : Larger innodb_buffer_pool_size causing SQL updates to be slower

Has anyone here encountered such scenario before where and update statement took longer time to run when innodb_buffer_pool_size is bigger. I've run a few tests using the same statements on around ...
0
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1answer
37 views

Immigrate to file-per-table mode in MySQL

I have 20 MySQL databases and in each there are about 20 tables. All the data is saved in a file called ibData1. Now I discovered about the file per table mode but if I change the value in the my.ini ...
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4answers
2k views

Prevent reset of auto_increment id in Innodb database after server restart

I recently read that because of how InnoDB recalculates the AUTO_INCREMENT value when the server restarts, any records on the high end of the ID list may have their IDs reused. Normally, this isn't a ...
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1answer
55 views

creating table result in errno 150

I'm trying to create the following schema, but I'm getting errors when I'm trying to create project and staffphone tables. Not sure what is it complaining about. mysql> CREATE TABLE staff( ...
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2answers
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Mysql used key changes between two consecutive EXPLAINs

I have a huge unmaintained innodb table (~1.5billion rows), I just started to try to query it. I write && instead of AND once; and surprise! it uses different key! EXPLAIN EXTENDED SELECT * ...
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1answer
70 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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1answer
582 views

How can Innodb ibdata1 file grows by 5X even with innodb_file_per_table set?

I have innodb_file_per_table set and just today my ibdata1 file jumped from 59M to 323M after I made several changes to an 800M table to reduce it to about 600M. That particular table's .ibd file was ...
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3answers
25k 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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1answer
40 views

Is the innodb_lazy_drop_table problem solved?

I'm researching database configuration for MySQL/MariaDB. I've been reading the configuration chapter in "High Performance MySQL". In there, it suggests that innodb_lazy_drop_table can be used to ...
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3answers
241 views

Verify mysqldump backup is corruption free

We've got a cron task backing up our Database using mysqldump - my main concern is corruption, short of manually importing and checking the backups each time whats the best way to check / verify a ...
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2answers
77 views

Recovering mysql innodb table from table.ibd backup file

Just practising DB disaster recovery. As per our back up policy, we do complete disk image back ups every half an hour (on our slave server). Now for a scenario, where some how a table has been ...
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2answers
68 views

Transaction basics. What is the result of 2 transactions running concurrently?

I have a rather basic question on transactions. Assume a table Account with a column amount. Now we have the following code: BEGIN $amount = SELECT amount FROM ACCOUNT WHERE id = 123; $amount = ...
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2answers
95 views

What variable(s) to look to maintain MySQL speed of scanning through all database tables while it starts?

We have few thousand small databases with total .ibd files of about 800000. We noticed that MySQL takes couple of minutes to stop but about two hours to start. For e.g. while MySQL is starting and ...
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2answers
831 views

Percona Xtradb Cluster : How to speed up insert?

I recently installed a 3 full master node cluster based on Percona Xtradb (very easy install). But now i need to make some tuning to increase INSERT/UPDATE requests. Actually, i made around 100 ...
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3answers
706 views

Backup / Export data from MySQL 5.5 attachments table keeps failing!

Can anyone please help! - I have a large table in a MySQL 5.5 database. It is a table which holds a mixture of blobs/binary data and just data rows with links to file paths. It has just over a million ...
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1answer
314 views

Why does auto increment jumps by more than the number of rows inserted?

I am very perturbed by this weird behaviour I am seeing in the auto_increment value recorded in the bidID of a Bids table after performing bulk insertion using a stored procedure: INSERT INTO Bids ...
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3answers
194 views

What does “InnoDB stores its tables and indexes in a tablespace” mean? [duplicate]

Was reading the mysql engine innoDB tutorial, I came across this sentence "InnoDB stores its tables and indexes in a tablespace" Can any body explain me this what does it means. Thank you :)
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0answers
89 views

MariaDB Galera Cluster

I have two mariadb servers in cluster that is working galera and xtradb. it is my primary server configuration: [mysqld] datadir=/var/lib/mysql query_cache_size=0 binlog_format=ROW ...
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1answer
62 views

Is there a table size above which SELECT performance degrades significantly?

In MySQL, does SELECT performance degrade significantly after a certain table size? I have a table with about 107 million rows and some queries seem stuck in "Sending data" for a long time. Of course, ...
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3answers
5k views

MySQL InnoDB crash post-mortem

MySQL crashed on me this morning. With the exception of the standard MySQL included databases everything I use is InnoDB. I attempted to restart the MySQL daemon but it failed twice. I then ...
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1answer
54 views

The most efficient method to obtain the total entries into a mysql table

I have a table that has a very high usage (insert/update/select) - one of the operations is to obtain a count of the number of rows. So far I've been using the classic select count(pk) from table but ...
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1answer
440 views

InnoDB - How to get top locked tables and rows which are locked

I was searching for a tool OR query which can give me top locked tables and which particular row is locked, Is it possible to get ?
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1answer
29 views

Check whether MySQL Innodb Rows are compressed

After setting the various variables to enable compression on the Innodb Barracuda tables, what query will you use to check that those tables are indeed compressed?
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345 views

MySQL InnoDB Sorting Issue

I was surprised to see MySQL's InnoDB showing an interesting behavior, which I cannot fully explain. According to the official MySQL InnoDB Documentation: "All indexes other than the clustered ...
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1answer
19 views

Mysql InnoDB exsited but can't show it

I have a InnoDB table A , While I type "show tables" , I can't see it. Even I type "drop table A" , it responses "table doesn't exist" . While I create a table B which refers from A , table B can ...
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1answer
155 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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1answer
5k views

What is causing Waiting for table level lock errors?

We got the database hanging twice already and trying to find a cause. show processlist Waiting for global read lock | INSERT INTO {myisam_table} ... In here the disk space was full so we thought ...
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1answer
685 views

Compressing Base64 Encoded Image in Database Field. Table Size too Large

Database Info Database Type - Percona MySQL. Table engine - InnoDB. I have a database table that is currently using 17GB at 400,000 rows. This size is mainly because I'm storing a 40kb base64 ...
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1answer
59 views

InnoDB to MyISAM Conversion Problem

I have a dedicated server based on CentOS 5 OS , mysql 5 and phpmyadmin I was trying to convert all database tables from InnoDB to MYISAM. I tried to do it by setting in /etc/my.cnf file the value ...
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3answers
24k views

Why does InnoDB store all databases in one file?

It was convenient that MyISAM used to store each table in a corresponding file. InnoDB has made advancements in many aspects, but I wonder why InnoDB stores all databases in one file (ibdata1 by ...
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2answers
434 views

Innodb table is taking randomly long time to execute the insert query and in show processlist showing as queryend/updating

Innodb table is taking randomly long time to execute the insert query and in show processlist showing as queryend/updating and it happens for the similar queries for the same table and the queries got ...
1
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1answer
108 views

Error while importing sql - Specified key was too long; max key length is 1000 bytes

I am trying to import an sql file which shows me the following error: Error SQL query: -- -------------------------------------------------------- -- -- Table structure for table `users` -- CREATE ...
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1answer
191 views

MyISAM with Innodb in the same Wordpress database reduce performace?

My new Wordpress database all the Wordpress created tables use InnoDB engine and plugin created table use MyISAM. But older site database all the tables use MyISAM table engine. I use MySQL ...
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1answer
104 views

row locking within ACID transaction innodb

I have a financial transaction that looks something like this (pseudo): begin select record for update update record(same record as selected) insert another record into another table ...
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1answer
36 views

mysql multiple database prioritize innodb buffer pool size

With a mysql instance and multiple databases within that instance is there a way to allocate which database you would like to assign priority to the buffer pool size?
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22 views

row locking with innodb [duplicate]

What is the most efficient way to lock a specific row for within a mysql transaction. I am currently using for update using select is there another method that im unaware of? if not are mysql locks ...
3
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1answer
14k views

How to Recover an InnoDB table whose files were moved around

So I have a test db server that was setup on a replication stream. Over the name an optimize came through that quickly filled up the space on the slaves datadir. Mysql dutifully was just waiting for ...