InnoDB : MySQL's ACID-compliant Storage Engine

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2
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2answers
107 views

Information schema not showing reliable information?

I'm currently migrating from SQL Server to MySQL. When i try to match the number of rows i query information_Schema.tables. I noticed that there are some differences between the migrated information ...
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1answer
193 views

Hardware specs for MySQL database with millions of records

For 35 million records I have this table CREATE TABLE IF NOT EXISTS `records` ( `code` varchar(12) NOT NULL, `type` varchar(255) NOT NULL, `used` set('y','n') NOT NULL default 'n', PRIMARY ...
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0answers
48 views

Migrated servers… Innodb tables stayed innodb, but database is showns as MyISAM. Problem?

I moved servers. I exported DB on old, imported to new. Kept getting syntax error on import until I tried no compression. Weird, but it worked. I was skeptical so I compared the two carefully and ...
2
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1answer
482 views

Why is ORDER BY LIMIT 1 so much faster than MAX?

Here are my two queries: select sts_in from sta_session where sts_user_id=2006 AND sts_sessid!='0jitkt80gg3avere03tqk4lhi6' order by sts_in desc limit 1; And select max(sts_in) from ...
0
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1answer
37 views

Which are the differences and advantages on single INDEX or compound INDEX?

I have two INDEX on a n:m relationship table as you can see on pics below: Now I can have this also: My questions: What is the advantage from last way(pic compound) over the two first? Can ...
0
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2answers
202 views

Multiple WHERE IN on multiple columns

I am not very experienced with sql queries and looking for an efficient way to perform the same WHERE IN condition on multiple columns. More specifically, i'm doing the following: SELECT a, b FROM ...
3
votes
0answers
83 views

Flexible and robust way to cull older data?

I am no DBA and that is becoming more apparent daily, as such I am having trouble keeping my query times reasonable. I have about 3.57 Million records ( at about 3.43 GB ) and it takes about 2 minutes ...
5
votes
1answer
127 views

'SELECT my_table.id' slower than 'SELECT my_table.*'

Running MySQL with InnoDB: I have a SELECT wide_table.* query that I want to refine to SELECT wide_table.id since that's all the calling code needs. Testing it out I've found that the execution time ...
2
votes
2answers
636 views

Would increasing innodb buffer pool size prevent a mysql crash?

My server keeps running out of memory for mysql. I keep getting. 150708 3:39:09 [ERROR] /usr/sbin/mysqld: Out of memory (Needed 258064 bytes) When I looked in my.cnf I saw that ...
1
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1answer
177 views

MySql Innodb corruption recovery

I have a MySql database, just containing Innodb tables, that seems to have corrupted itself. It replicates to another server and it has corrupted that one too! The symptom is that I can restart the ...
0
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1answer
1k views

Cannot Start mySQL Daemon with Error “mysqld from pid file … ended”

I cannot get MySQL to run. It was working just fine hours ago, but upon starting, repeatedly ends without telling me very much. Here are my logs [myusername@location ~/mysql]$ ./bin/mysqld_safe --log-...
2
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0answers
83 views

Mysql Match…against query performance in InnoDB Mysql 5.6

I need to search records in the table which contains millions of records. I have recently updated Mysql version from 5.1 to 5.6. I was using like in query which was taking around 15 sec to 30 sec. ...
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1answer
196 views

Optimizing Queries HAVING COUNT and INSERT…ON DUPLICATE KEY UPDATE

There are two main queries I'm tying to improve, one question is much more conceptual and learning about databases and another is much more straightforward. Both cases deal with the same table It has ...
2
votes
1answer
387 views

MariaDB 10 InnoDB Partition with Data Directory

mysql --version mysql Ver 15.1 Distrib 10.0.20-MariaDB, for Linux (x86_64) using readline 5.1 I have a MariaDB 10 installed, though I tried with the 5.5 release in the CentOS repos. I'm ...
1
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1answer
71 views

mysql replication and innodb_file_per_table

Is it possible for the master (5.1) to have innodb_file_per_table = 0 and for the slave (5.1 or 5.5) to have innodb_file_per_table = 1 ?
0
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2answers
385 views

Performance impact of adding a foreign key to a 1M rows table

I have an ecommerce database running MariaDB + InnoDB, which has a table to store the transactions (T) and another which stores quotes (Q). I'd like to make a connection between T and Q by adding a ...
0
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0answers
110 views

Dropping a corrupt table in innodb_force_recovery 6

As often happens in mysterious shutdowns during large queries, things ran afowl with InnoDB on my XAMPP MySQL installation (Windows 7 x64). I rebooted and ran Startup Repair, then loaded MySQL to ...
1
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4answers
238 views

SQL retrieve last elements of table using group by like behaviour

I am trying without success to retrieve the last version of all articles in a table. The table structure: CREATE TABLE `journalarticle` ( `uuid_` varchar(75) DEFAULT NULL, `articleId` varchar(75)...
1
vote
3answers
90 views

guideline for calling optimize table after alter table?

Should I be calling 'optimize table' when changing datatypes of columns, adding indexes or dropping indexes, assuming a table with millions of rows, heavily used, both for reading and writing (InnoDB)....
0
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2answers
262 views

How to check innodb history list length?

The output for show engine innodb status has the history list length as a number, but that output is hard to parse, and there's just too much data when all you want is a single value. Is the value ...
2
votes
0answers
174 views

innodb update with limit locks all matching (ignores limit)

For a query similar to this: UPDATE myinnotable1 SET value=5,updated=now(),status=1 WHERE status>10 AND message="match msg" LIMIT 1; I found that innodb engine locks ALL rows matching criteria ...
0
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1answer
927 views

.ibd file is missing and alter table discard tablespace crashing the server

Data file(.ibd) for one of my mysql table is missing in data directory. As read in some articles i want to resolve the issue by discarding tablespace first ,import the tablespace (cfg file of said ...
1
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2answers
226 views

Auto incrementing a column based on another

I have an application which generates invoice_id's. These id's need to be unique. The issue is that a client can have more than one invoice depending on what plan they are on. It could be 2, 3 or 4. ...
-1
votes
1answer
486 views

Mysql InnoDB vs Mongodb write performance

I need to increment a counter each time a web page is rendered. When I use mongodb to do that, I can do about 16000 writes per second on a 4 cores/8 threads CPU on a regular disk. When I use Mysql ...
2
votes
1answer
280 views

MySQL Performance: conditionnal left outer join vs where only

I have three tables: FORUM ( id PRIMARY KEY, public BOOLEAN ) MESSAGE ( id PRIMARY KEY, content VARCHAR(255), user_id NULL FOREIGNKEY user.id, forum_id FOREIGNKEY forum.id) USER( id PRIMARY KEY, ...
0
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1answer
181 views

Aruba-MySQL: can't create/change table to engine=INNODB

We have our database stored in aruba (mysql.aruba.it) where there is a table called "task". Because of many changes in the requirements we decided to drop the table and create it again from 0 with ...
0
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0answers
258 views

Should innodb_buffer_pool_size be much larger than the innodb_buffer_pool_bytes_data?

Our old server had 32GB total RAM, 18GB allocated to innodb_buffer_pool_size. It also had 10GB for the php_memory_limit. The new one had 16GB RAM, 9GB for innodb, 5GB for php. The same application ...
1
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0answers
63 views

Mariadb support rtree index on innodb soon?

I was looking through mariadb bug list online (https://mariadb.atlassian.net/secure/RapidBoard.jspa?rapidView=24&projectKey=MDEV), but I am unfamiliar with JIRA so I am not sure exactly what I am ...
2
votes
1answer
270 views

innodb , mysql Indexes difference when adding index

When I am altering one of my MySQL table to add an index I am getting below error in error log. Table a/b contains 4 indexes inside InnoDB, which is different from the number of indexes 3 defined ...
2
votes
3answers
183 views

All My Databases Are Gone?

Today I changed my username and password in MySQL and I logged into phpmyadmin to see that all my databases were gone. I've tried changing the datapath but then I realized I didn't see any of my ...
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1answer
339 views

How important is InnoDB versus MyISAM? [duplicate]

Does it really matter if the default storage engine is InnoDB? My default storage engine is MyISAM
2
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1answer
107 views

Innobackupex apply-log should be done before emergency restore or after each backup?

Basically Percona Innobackupex consist with three steps: 1. Backup 2. Apply log 3. Copy back restore during emergency My question: When should I do apply log? Is it after each backup or before ...
1
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1answer
96 views

MySQL Crashing every few days

Our website hasn't launched yet so we're gaining little to no traffic at the moment. For some strange reason MySQL seems to crash every 2-3 days unexpectedly. Here's the SQL log of the crash 2015-06-...
1
vote
1answer
31 views

Completely removing InnoDb tables

To cut a long story short, I deleted several .idb files and then tried to re-import them from a .sql file. I'd imagine there is some relic of the old tables somewhere. Does anyone know what to remove ...
1
vote
3answers
540 views

Are TEXT fields stored separately from the row in MySQL-ISAM?

We have a "notes" table and some of the queries are getting very slow even though we're not searching on the note contents. We're wondering if moving the note content into a separate table would speed ...
1
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1answer
180 views

MySQL Database Keeps Crashing

Our mysql instance is keep crashing after every 5-10 minutes very frequently. We have around 600 databases on that instance. I think 600 is not a big number of databases given the size of databases ...
1
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1answer
230 views

Optimize slave .ibd tables, where slave has innodb_file_per_table and master does not

We are trying to reclaim file space on our replication server. The space we want to reduce are .ibd files on the slave. We have a simple Master -> Slave (read only) replication setup, for some reason, ...
0
votes
1answer
168 views

Hash index for InnoDB

I saw a database schema that looked like this CREATE TABLE foo ( name_hash bigint, name varachar(500), a varchar(500), b varchar(500), ... PRIMARY KEY (name_hash), KEY ... ...
0
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0answers
54 views

Index pages in innodb file when innodb_file_per_table = ON

I have MySQL 5.5, and innodb_file_per_table was always in config file. After some time of using MySQL DB was produced big ibdata1 file, but i don't know how explain why this file is so big, i try to ...
1
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0answers
773 views

Reclaim disk space after dropping table(innodb_file_per_table = ON), strange scenario

I know it is often asking question. But I can't find answer for my scenario with specific condition. We use MySQL 5.5 We have always(I am sure) innodb_file_per_table = ON option in our mysql ...
1
vote
2answers
239 views

Difference between Handler_write and Innodb_data_writes

Handler write is the number of requests to insert a row in a table. InnoDB data writes is the total number of data writes. Questions are Does inserting a row count as a disk write? If I do an ...
0
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0answers
47 views

MYSQL taking 17.5 GB of RAM

This is what top shows how MySQL is taking a large amount of memory. VIRT RES SHR S 3967 mysql 20 0 17.5g 1.4g 7008 S 41.2 2.3 17426:16 mysqld this is ...
0
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0answers
164 views

MySql Innodb Database Slow INSERT Query to Remote Server

I have searched thoroughly on how to improve general performance of my database which is hosted on Hostgator. I have mostly come across performance tuning strategies which are catered to only local or ...
5
votes
3answers
184 views

MySQL Index Creation Internals

Right now there are two ways to build an index of a table in MySQL: Create the table structure first, then import the data and add indexes later. Create the table structure with indexes and then ...
4
votes
2answers
239 views

Optimal engine for small lookup tables in MySQL

I have following question: I am designing web application with several dozens of small lookup tables: These tables usualy contain three columns (ID, Name, Description) and a couple of rows (mostly ...
0
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0answers
51 views

Does MySQL InnoDB locks multiple rows with READ_COMMITTED isolation level?

I am in trouble while resolving LOCK WAIT TIMEOUT EXCEED error with MySQL InnoDB. I have gone through this article and it says if we use isolation level READ_COMMITTED then my update query should ...
0
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0answers
47 views

insert/update query running slow to specifi tables

I am monitoring MySQL client connections and queries run time. Found some insert/update queries to specific tables are slow than expected. I know the tables which are slow are big in size > 600K, i ...
1
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3answers
108 views

SQL self join with condition

I have table like: bu_id bu_name parent_id 1 DefaultBU NULL 601 bu1 1 602 bu2 601 603 bu3 NULL 604 bu4 603 I want to retrieve the ...
0
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3answers
4k views

Migrate Jira to MySql - Unknown system variable 'storage_engine'

I'm migrating JIRA in Windows from HSQL to MySQL and I got stuck with the message Unknown system variable 'storage_engine'. Though I created a backup, installed MySQL and copied J connector to libs ...
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1answer
140 views

Can we restore mysql db without .ibd & .frm files?

I have a data folder and the database folder with .frm & .ibd files is missing, any way to restore the database? Currently the data folder has: ibdata1 ib_logfile0 ib_logfile1