InnoDB : MySQL's ACID-compliant Storage Engine

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Is it normal to use many Triggers?

I have many so-called summary columns throughout my database to count number of rows in other tables. For example, counting the number of comments by a user (a column in the user table). Currently, I ...
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2answers
3k views

How to optimize MySQL for large BLOB updates

I have a table that holds large BLOBs (up to 10M), and is updated frequently. The problem is that UPDATE statements can take up to 1 second to execute, and due to app design this blocks UI. I need to ...
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3answers
986 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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3answers
405 views

MySQL instance stalling “doing SYNC index”

Problem An instance of MySQL 5.6.20 running (mostly just) a database with InnoDB tables is exhibiting occasional stalls for all update operations for the duration of 1-4 minutes with all INSERT, ...
11
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1answer
7k views

MySQL transaction size - how big is too big?

I have an import process that runs every so often and I want it to be an 'all or nothing' kind of deal, aka: a transaction. There are many aspects, and the imports may yield anywhere between ...
5
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1answer
1k views

Possibilities to speed up InnoDB INSERTs and UPDATEs

My website retains user sessions in an innodb table. This usually works well, but a few hundred times a day, the INSERT and particularly the UPDATE statements run slower. I'm monitoring when, and it ...
5
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1answer
5k views

How can I find who holds the lock based on the hex-dumped?

I've been reading the Diagnosing MySQL InnoDB Locks article. Karl E. Jørgensen writes on 2008 so I'm consfusing it is in effect. I would like to supply a snippet of the SHOW ENGINE INNODB STATUS: ...
5
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1answer
3k views

Find out MySQL index size for a concrete index

In MySQL, for InnoDB engine, how do I find out the size of one of the indexes I have in the same table ? I know I can select the index_length from information_schema.tables, but this gives the total ...
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4answers
3k views

Incomplete mysqldump

I'm trying to run mysqldump to create a database snapshot, and I'm finding it will randomly stop midway, without reporting any error. My database is relatively small (about 100MB) and is using InnoDB. ...
5
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1answer
483 views

Dealing with temp tables when I have not control over db variables

I have no control over things like tmp_table_size and max_heap_table_size, and so as our tables grow the time taken by queries requiring temp tables is growing geometrically. I am wondering if there ...
4
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1answer
78 views

Does MySQL exectution plan depend on available indexes?

Does MySQL choose an execution plan for a given query taking into account what indexes are available, or does it first choose an execution plan and then uses indexes if they are available? ...
4
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2answers
6k views

MySQL performance impact of increasing innodb_buffer_pool_size

I have two databases one of size 170 MB and second one is of 15 MB, both having INNODB tables and innodb_buffer_pool_size is set to 8 MB. My queries are responding well now i.e under mili seconds. ...
4
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1answer
4k views

Why does that query cause lock wait timeouts?

From time to time, I find a lot of these errors in my PHP error log: MYSQL.1213: Deadlock found when trying to get lock; try restarting transactionSQL The problem persists for about 2 or 3 minutes. ...
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4answers
11k views

How to increase fast backup and restore of 500GB database using mysqldump?

There is a database A size of 500GB. Tables in database A contains both MyISAM and INNODB tables. MyISAM tables are master tables and Innodb tables are main transaction tables. Backup and restore ...
4
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1answer
4k views

Is Percona xtrabackup the right choice for my 500GB MySQL backup?

I have a MySQL db with 500GB, consisting mainly of Innodb tables, and one big (200GB) MyISAM table. My current backup strategy is copying the db files to an external harddrive. This causes a downtime ...
4
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3answers
678 views

Is Oracle DB immune to the InnoDB deadlocks found in MySQL?

It seems odd to me that MySQL would not handle this internally: "Deadlock found when trying to get lock; try restarting transaction" Does Oracle DB work around this issue? After all, Oracle owns ...
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2answers
458 views

How to speed up mysql export and import

I need to perform a DB migration from Server A to Server B. Server A: MySQL version installed 5.0.6 Server B: MySQL version installed 5.6.20 OS: Both are running RedHat Linux 64bit. 16 ...
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1answer
4k views

Recover the disk space after deleting rows from table

I deleted millions of rows from one of the table with innodb engine. I know that I need to run optimize table to recover the space. But running that will cause lock on the table, which will affect the ...
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2answers
8k views

Finding and fixing InnoDB index corruption

I encountered a new issue yesterday with one of my MySQL 5.5 slave DBs that runs on EC2 in AWS. The DB was created from a snapshot of another slave. The data is correct, but for at least one table a ...
3
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2answers
1k views

How to split a string to and get info from another table in mysql

I have a system to assign score for each sentence stored in a column: TABLE 1: word_scores word score this 3 is 4 a 5 test 1 another 0 sentence 8 TABLE 2: ...
3
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1answer
938 views

InnoDB “corruption”

I use: 5.1.63-0ubuntu0.11.10.1 Apache/2.2.20 (Ubuntu) MySQL client version: 5.1.63 The system is continuously displaying the following error during reading data from a MySQL database: ...
3
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1answer
3k views

Slow insert performance in mysql innodb table for solr indexing

I have a Slave server (MySQL 5.5) having innodb tables. This server is being used for SOLR indexing. Few procedures used to fill 12 million data into 9 tables. The insertion speed is too slow. ...
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2answers
690 views

Should I move to InnoDB during a planned migration?

I'm shortly migrating a Debian Lenny webserver to another host and Debian Squeeze. The standard MySQL installation even on Squeeze is 5.1 and therefore would default to MyISAM - I'm inclined to stick ...
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2answers
543 views

How to monitor InnoDB Disk I/O using Server Status Variables?

This question is extension of my previous question "How to monitor InnoDB Disk I/O Required for MySQL? " As mention in my previous question i want to count total number of disk i/o per query, but ...
2
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1answer
1k views

How can I make a select statement get blocked?

Hello I am trying to intentionally make a SQL select statement get blocked by another simple SQL delete or update statement, for the purpose of learning. I prefer only InnoDB tables. To prepare the ...
2
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1answer
503 views

Drupal 7 Uses InnoDB, so do I need other configs?

If I'm optimizing a database that will be delivering multiple Drupal 7 websites, all using InnoDB, do I need to worry about [myisamchk] & [isamchk] sections, or can I just worry about the stuff ...
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2answers
3k views

MySQL / InnoDB: Does daily optimization improve performance?

Would performing daily optimizations of tables increase performance for MySQL and InnoDB? I have never did this before, but I have seen this module for Drupal http://drupal.org/project/db_maintenance, ...
2
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1answer
2k views

MySQL 5.5 Runs Out of Memory, Drops All Connections When Creating Many Databases

I'm running into a problem when I create a large number of databases consecutively on an Amazon RDS db.m1.large instance. The MySQL Engine Version is 5.5.23. At some point, the RDS instance drops all ...
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3answers
3k 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
1k views

Can putting mysql DB into memory or having the innodb_buffer_pool_size match the size of DB increase performance?

We have a mysql database that has roughly 80 gigabytes (GB) of data using inno_db engine. We are looking to increase performance on the database (we looked at the slow log and gone through and ...
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2answers
3k views

ibdata1 grows exponentially when innodb_file_per_table is configured

I Have installed a MySQL Cluster with InnoDB (innodb_file_per_table enabled subsequently), but since I switched to innodb_file_per_table, the file ibdata1 grows (2GB at month). Is My my.cnf file is ...
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2answers
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How to analyse innodb status on deadlock in insert Query?

I have a dead lock which i have posted here. I managed to get the innodb status from my server. Here is the Innodb status. OS WAIT ARRAY INFO: reservation count 247864, signal count 247470 Mutex ...
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2answers
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Similar function NOWAIT in MySQL

Select for update nowait doesn't work in MySQL 5x (innodb). Is there any function like NOWAIT in MySQL?
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1answer
123 views

Too much IO to MySQL InnoDB log files

I am using MySQL version: 5.5.38 I have dedicated HDD to InnoDB log files using innodb-log-group-home-dir option. atopsar -d 30 shows big load (>50%) to this HDD The thing is that I have only 75 ...
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1answer
319 views

Information about Disk Storage MySQL

I am trying to create an application for monitoring MySQL,in my application there's a part of monitor DISK STORAGE, so after more research I have not found how to calculate : used and free size of ...
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1answer
4k views

Deleting MySQL table with pending transactions

Is there a way to delete an InnoDB table or database with pending transactions in MySQL (preferably on file system level)? What happened: I use MySQL 5.5.28 and ran LOAD DATA INFILE… to import a ...
4
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1answer
8k views

MySQL: Row size too large (> 8126)

Here's the issue. I have a table which has 300 columns in it, each up to 255 bytes (there IS a business justification for this). When I try it create it using VARCHAR(255), I go past the limit for ...
4
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2answers
3k views

Partitioning and freeing disk space

I am running MySql innodb with innodb_file_per_table. As a daily script, I would like to create a new partition for a set of tables, as well as delete yesterday's partitions. What command would need ...
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4answers
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Is tuning the innodb_buffer_pool_size important on Solaris ZFS?

We're running a moderate size (350GB) database with some fairly large tables (a few hundred million rows, 50GB) on a reasonably large server (2 x quad-core Xeons, 24GB RAM, 2.5" 10k disks in RAID10), ...
3
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2answers
235 views

Copying datadir directory enough for backing up a database with InnoDB tables?

I have an innodb table with 80 million rows and it's extremely slow with mysqldump so I'm thinking of copying the datadir directory for a backup / transfer. I used to copy database with only MyISAM ...
3
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1answer
2k 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 ...
3
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1answer
448 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 ...
3
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0answers
1k views

Query getting periodically stuck in 'copying to tmp table' state, never completes

I am running Wordpress on a dedicated server with a MySQL backend. I have a query that usually takes <1 second to execute, but periodically, this query will get stuck in a 'copying to tmp table' ...
3
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1answer
1k views

Speeding up a NOT IN subquery

Good evening, I'm currently up to try to improve the performance of some of my queries. As far as I know, statements like "IN" or "NOT IN" are even faster with a large amount of values if a subquery ...
3
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1answer
8k views

MySQL: Error reading communication packets

I get this warning in mysql, [Warning] Aborted connection 21 to db: 'MyDB' user: 'MyUser' host: 'localhost' (Got an error reading communication packets) I have been through few topics in google ...
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3answers
4k views

InnoDB insertion faster

I'm a graduate school student researching OLAP with Mondrian OLAP. So I want to insert data into InnoDB (MySQL 5.5) faster at the initial loading. In this environment, the only user is me, so I think ...
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2answers
841 views

MySQL insists on trying to use InnoDB even when told not to, please help

We're trying out MySQL 5.5, and have installed it on one of our slave servers as a test run. Our main server is 5.0, and we have zero optimization here for InnoDB, so I want everything to just be ...
3
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1answer
602 views

why is mysql still writing data two hours after all transactions have stopped

I have a mysql server used mostly as data warehouse. It loads about 4-5GB of data per day (actual database size, not the size of the source data). Lately, I noticed something peculiar. After I ...
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3answers
6k views

innodb_buffer_pool_size not changed

I use MySQL 5.5.23-1~dotdeb.0 (Debian) and here is the relevant part of my.cnf default-storage-engine = innodb innodb_buffer_pool_size = 3G innodb_log_file_size = 256M innodb_thread_concurrency = 8 ...
2
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2answers
236 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 ...