InnoDB : MySQL's ACID-compliant Storage Engine

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3answers
4k views

How to repair, or drop/create a corrupted table in mysql?

Situation: I have a MySQL database with 104 tables, running locally on XAMPP on windows 7. All the tables have InnoDB engine. XAMPP MySQL is running as windows service. As front end I have PHP ...
2
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2answers
185 views

Is there a rule of thumb regarding the size and number of a buffer pool instances?

I know the consensus seems to be approximately 75% of ram should be dedicated to the buffer pool. But, I'm more interested in the optimal number of buffer pool instances. What are some things to ...
0
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1answer
83 views

Restore InnoDB from .frm files

My database crashed and my PC and I now only have the .frm and .ibd files left. Is there any way to restore my database?
0
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1answer
749 views

Delete Query takes a long time

I have a innodb table that counts circa 1 billion entries. I started a delete operation (with a small where condition on an indexed column) that should delete a lot entries, leaving circa 100 million. ...
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1answer
132 views

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, ...
2
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1answer
1k 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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1answer
231 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 -> ...
0
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1answer
166 views

Slow queries with many self joins in variable-column database

I'm creating a table structure which needs to handle a variable number of columns. To handle that case the table structure is a listing of cells with a column and row number. To view the table a ...
4
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0answers
274 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 ...
0
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2answers
253 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 ...
0
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1answer
49 views

what is the best configuration for innodb_flush_log_at_trx_commit?

There are 3 different configuration is available for innodb_flush_log_at_trx_commit innodb_flush_log_at_trx_commit = 0 innodb_flush_log_at_trx_commit = 1 innodb_flush_log_at_trx_commit = 2 Which ...
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1answer
280 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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0answers
154 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 ...
1
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1answer
93 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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1answer
154 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
38 views

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 * ...
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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1answer
403 views

mariadb 5.5.36 with innodb plugin

I installed mariadb 5.5.36 on a win32 system. Everything runs fine except innodb requests are 2 x slower than an identical MySQL installation. So I want to switch back to original innodb plugin to ...
3
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5answers
730 views

MySQL runs out of memory when importing innodb database

I have a small VPS with 512MB RAM and no swap (can't have any). I am importing a 1.5GB innodb database with mysql -u -p < database.sql Before the operation can finish it says : Lost connection ...
3
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1answer
164 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 ...
0
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2answers
331 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 ...
2
votes
3answers
1k 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 ...
2
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2answers
126 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 = ...
0
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1answer
166 views

Why is setting open_files_limit making MySQL slow?

We noticed that adding open_files_limit in /etc/my.cnf is making server slow. Reference : What variable(s) to look to maintain MySQL speed of scanning through all database tables while it starts?
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1answer
717 views

ib_logfile0 and ib_logfile1 got deleted

After restoring from a percona-xtrabackup without a preparation step, ib_logfile0 and ib_logfile1 were not present in the restore data. Therefor during startup the following message is observed: ...
3
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1answer
1k 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
471 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
182 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 ...
0
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1answer
96 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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2answers
209 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 ...
0
votes
1answer
121 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 ...
0
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1answer
953 views

how to recover .ibd and .frm files in mysql

so i am developing java application with mysql 5.6.13, few days before i purchased new laptop, from previous laptop i forgot to create dump of application instead i copied folder of my database(.ibd ...
0
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1answer
43 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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1answer
726 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
24 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
443 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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1answer
1k 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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0answers
1k views

MariaDB MySQL server does not start

My MariaDB mysql server doesn't start with error 1067 This is the error log: 140222 0:43:44 InnoDB: The InnoDB memory heap is disabled 140222 0:43:44 InnoDB: Mutexes and rw_locks use ...
1
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1answer
354 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 ...
2
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1answer
410 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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0answers
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 ...
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1answer
69 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?
2
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1answer
358 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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2answers
445 views

MySQL High Availability for InnoDB

I am looking for MySQL High Availability with huge transactions. I prefer to go with InnoDB Engine. I prefer to use MySQL Master - Slave Replication. However, this option provides us Manual fail over ...
1
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1answer
282 views

MySQL, temporary on disk table on primary key retrieval?

MySQL 5.5.24, Windows 7 64-bit. I've InnoDB table with primary key defined on three columns: CREATE TABLE `common_descriptions` ( `object_id` mediumint(8) unsigned NOT NULL DEFAULT '0', ...
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0answers
51 views

Does union all have an enforced ordering

I know that a union does a de-duplication so can jumble the results, but I can't find a definitive answer for union all Example query select id from ( select id from table where id = 1 union all ...
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1answer
331 views

Abnormally high MySQL writes and larger than normal Binary Log files. How can I determine what caused this?

We have a MySQL master database which replicates to a MySQL slave. We were experiencing issues where MySQL was showing a high number of writes (but not an increased number of queries being ran) for a ...
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1answer
243 views

What is a storage need for MySQL index on Varchar(100) in InnoDB?

I have a InnoDB table, which has EMail column (VARCHAR(100)), now I will run script which will hash some of that email addresses. I am wondering, if there is a difference in data storage (for example ...
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1answer
1k views

InnoDB: very bad performance on INSERT/UPDATE

Lately I have really big problems with INSERTs and UPDATEs. On my website 80% of all queries are SELECTs but in query slow log there are only INSERTs and UPDATEs. My dedicated server has 32GB RAM, ...
0
votes
1answer
277 views

I have delete database from mysql but storage is not freed

I have deleted multiple databases (schema) from mysql on amazon RDS but the storage is not freed, is there anything else I should do to free up the storage? I have a mysql database that the total ...