Linked Questions

64 votes
4 answers
140k views

Which is faster, InnoDB or MyISAM?

How can MyISAM be "faster" than InnoDB if MyISAM needs to do disk reads for the data? InnoDB uses the buffer pool for indexes and data, and MyISAM just for the index?
jcho360's user avatar
  • 1,999
60 votes
6 answers
32k views

Performance implications of MySQL VARCHAR sizes

Is there a performance difference in MySQL between varchar sizes? For example, varchar(25) and varchar(64000). If not, is there a reason not to declare all varchars with the max size just to ensure ...
BenV's user avatar
  • 4,903
23 votes
2 answers
36k views

Does an empty column value occupy same storage space as a filled column value?

I have a table with 2 columns. The type of both columns is set to varchar(38). If I create a row with an empty value for one of the columns, will it take same storage space as if the value was not ...
Haris ur Rehman's user avatar
15 votes
4 answers
29k views

MySQL LOAD DATA INFILE slows by 80% after a few gigs of input with InnoDB engine

I'm loading a 100GB file via LOAD DATA INFILE. I've had good success with MyISAM, a few hours and done. I'm trying it now using InnoDB. The load starts fast at over 10MB/sec (watching the table file ...
David Parks's user avatar
8 votes
1 answer
11k views

Do you still use MyISAM or prefer Aria storage engine?

If Aria storage engine (previously called Maria) is the "new" MyISAM, which supports transaction and automatic crash recovery: Why still use MyISAM ? Should changing storage engine from MyISAM to ...
jcho360's user avatar
  • 1,999
11 votes
1 answer
11k views

MySQL table with 100,000 records queried often

I have a single database of about 100 tables to store various kinds of information. The most important table is our order table which is used to store customers orders and is over 100000 records as ...
sheldon's user avatar
  • 111
6 votes
3 answers
8k views

InnoDB vs MyISAM with many indexes

I am not sure if there is a right or wrong answer to this question, as I suppose it severely depends on the situation, but for the sake of a mental exercise, I'll go ahead and ask it anyway: I have a ...
Battle_707's user avatar
3 votes
2 answers
9k views

How does mysql decide if concurrent insert is possible for a MyISAM table?

For "concurrent inserts", MySQL reference manual has the following explanation: The MyISAM storage engine supports concurrent inserts to reduce contention between readers and writers for a given ...
Haluk's user avatar
  • 619
7 votes
2 answers
2k views

Will my database index be more performant with a smaller varchar size?

We're using Mysql 5.7 We have an index over a varchar(255) column in a table of ~ 500M rows. select distinct varchar_column from table yields seven results, with the max length 21. A DBA consultant ...
Michael Glass's user avatar
1 vote
1 answer
13k views

MySQL my.cnf Optimization

We are an email marketing company and we recently switched our setup to MySQL. We need to configure MySQL (my.cnf) for extreme performance. We have tried to configure my.cnf but heavy queries got ...
Umair's user avatar
  • 193
5 votes
1 answer
6k views

Varchar index - will hashing value make it faster?

I have a VARCHAR(1000) column in a table. It will contain strings that will not be guaranteed to be unique. I have a query that searches this column as part of a WHERE IN clause, the list of values in ...
Peter Kelly's user avatar
4 votes
2 answers
2k views

Why database has char data type when varchar is more efficient?

I understand the basic difference between CHAR and VARCHAR datatype that CHAR takes up fixed length whereas VARCHAR takes up space based on the content being stored. But if VARCHAR is so efficient in ...
Kamalakannan J's user avatar
6 votes
1 answer
4k views

Optimizing MySQL for Read-Only?

We have 14 GB worth of CSV's which total 138 million rows. I imported this into a MySQL table first with InnoDB, and then tried again with MyISAM. In both cases, a simple SELECT on primary key (...
tiredofcoding's user avatar
5 votes
3 answers
2k views

Clustered index performance consideration in MySQL & PostgreSQL

In MySQL/InnoDB, the clustered index is synonymous with the primary key, so picking up a poor primary key affect your db performance, i.e. use of UUID as PK is a performance killer for database write. ...
Yoga's user avatar
  • 549
6 votes
2 answers
2k views

Choosing MyISAM over InnoDB for these project requirements; and long term options

Sorry for the long post, but I had to give as much info as possible to make this very vague question more specific. My project's aim is to let users search a (huge) database of variety of products. ...
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