Mysql Error 1071 Max Key Length

here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring mysql innodb increase max key length developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask specified key was too long; max key length is 767 bytes mysql Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 6.2 million programmers, just like you, helping each other. Join mysql innodb_large_prefix them; it only takes a minute: Sign up #1071 - Specified key was too long; max key length is 767 bytes up vote 194 down vote favorite 43 When I executed the following command: ALTER TABLE `mytable` ADD UNIQUE index column size too large. the maximum column size is 767 bytes. ( `column1` , `column2` ); I got this error message: #1071 - Specified key was too long; max key length is 767 bytes Information about column1 and column2: column1 varchar(20) utf8_general_ci column2 varchar(500) utf8_general_ci I think varchar(20) only requires 21 bytes while varchar(500) only requires 501 bytes. So the total bytes are 522, less than 767. So why did I get the error message? #1071 - Specified key was too long; max key length is 767 bytes mysql byte

Mysql Max Key Length

varchar mysql-error-1071 share|improve this question edited May 23 '11 at 21:32 OMG Ponies 199k37360417 asked Nov 29 '09 at 3:18 Steven 5,2993480112 Because its not 520 bytes, but rather, 2080 bytes, which far exceeds 767 bytes, you could do column1 varchar(20) and column2 varchar(170). if you want a character/byte equiv, use latin1 –Rahly Dec 18 '15 at 0:21 add a comment| 17 Answers 17 active oldest votes up vote 137 down vote accepted 767 bytes is the stated prefix limitation for InnoDB tables - its 1,000 bytes long for MyISAM tables. According to the response to this issue, you can get the key to apply by specifying a subset of the column rather than the entire amount. IE: ALTER TABLE `mytable` ADD UNIQUE ( column1(15), column2(200) ); Tweak as you need to get the key to apply, but I wonder if it would be worth it to review your data model regarding this entity to see if there's improvements that would allow you to implement the intended business rules without hitting the MySQL limitation. share|improve this answer edited Oct 15 '14 at 20:20 The Alchemist 2,6901017 answered Nov 29 '09 at 3:52 OMG Ponies 199k37360417 To apply by specifying a subset of the column rather than the entire amount. A good solution. –Steven Nov 29 '09 at 4:14 @OMGPonies: Do you happen to know, if DB2/MSSQL/Oracle have th

18:54 Reporter: Bent Vangli Email Updates: Status: Not a Bug Impact on me: None Category:MySQL Server: MyISAM storage engine Severity:S2 (Serious) Version:4.1.7 OS:Linux (Linux (Fedora

Error 1709 (hy000): Index Column Size Too Large. The Maximum Column Size Is 767 Bytes.

Core 2)) Assigned to: Matt Lord View Add Comment Files Developer Edit mysql max key length is 3072 bytes Submission View Progress Log Contributions [13 Nov 2004 12:28] Bent Vangli Description: When I try to execute the following django.db.utils.operationalerror: (1071, 'specified key was too long; max key length is 767 bytes') SQL statement: CREATE TABLE phpgw_lang ( lang varchar(5) NOT NULL DEFAULT '', app_name varchar(100) NOT NULL DEFAULT 'common', message_id varchar(255) NOT NULL DEFAULT '', content text, PRIMARY KEY(lang,app_name,message_id) ); I got MySQL http://stackoverflow.com/questions/1814532/1071-specified-key-was-too-long-max-key-length-is-767-bytes Error: 1071, Specified key was too long; max key length is 1000 bytes When I shorten message_id to varchar(228) it works. varchar(229) doesn't. I am using UTF8 as default charset on my MySQL engine. I cannot see anything wrong with above statement. However, I probarly got this error because multibyte preferable UTF8 character set uses much more bytes than the number of characters. Looking https://bugs.mysql.com/bug.php?id=6604 at the numbers, you find (5 + 100 + 228) * 3 = 999, which is less than 1000. and contrary (5 + 100 + 229) * 3 = 1002. I looks like MySQL are using a factor of 3, maybe hardcoded? But in normal western languages this is normally much less than 3 times, maybe more like 1.2 - 1.5. I Had put this on Serious Severity because it disables the possibility to install eGroupWare from http://www.egroupware.org/ using MySQL 4.1.x. With very best regards Bent Vangli PS! I do compile and install from source. If guided to sourcefiles involved, I may do some testing. How to repeat: Run above statement on a MySQL 4.1.7 with UTF8 as default charset on a Fedora Core 2 (Linux kernel 2.6). Proberly also on other OS using UTF8. Suggested fix: Suggestion 1: Add a runtime or compiler variable/setting allowing to increase this 1000 bytes limit, or suggestion 2: Count characters only, and eventually discards bytes after 1000, or suggestion 3: Add a runtime or compiler option allowing for adjusting the expected characters/bytes factor for UTF8 multibyte. [14 Nov 2004 18:54] Matt L

CI MySQL Sandbox MariaDB data chef Adtech Twitter GitHub RSS Using Innodb_large_prefix to Avoid ERROR 1071 If you've ever tried to add an index that includes a long varchar http://mechanics.flite.com/blog/2014/07/29/using-innodb-large-prefix-to-avoid-error-1071/ column to an InnoDB table in MySQL, you may have seen this error: 1 ERROR 1071 (42000): Specified key was too long; max key length is 767 bytes The character limit depends on the character set you use. For example if you use latin1 then the largest column you can index is varchar(767), but if max key you use utf8 then the limit is varchar(255). There is also a separate 3072 byte limit per index. The 767 byte limit is per column, so you can include multiple columns (each 767 bytes or smaller) up to 3072 total bytes per index, but no column longer than 767 bytes. (MyISAM is a little different. It has max key length a 1000 byte index length limit, but no separate column length limit within that). One workaround for these limits is to only index a prefix of the longer columns, but what if you want to index more than 767 bytes of a column in InnoDB? In that case you should consider using innodb_large_prefix, which was introduced in MySQL 5.5.14 and allows you to include columns up to 3072 bytes long in InnoDB indexes. It does not affect the index limit, which is still 3072 bytes as quoted in the manual: The InnoDB internal maximum key length is 3500 bytes, but MySQL itself restricts this to 3072 bytes. This limit applies to the length of the combined index key in a multi-column index. Read on for details and examples about innodb_large_prefix. Here are a few pre-requisites for using innodb_large_prefix: At the database level you have to use innodb_file_format=BARRACUDA At the table level you have to use ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED The default file format is still Antelope for backwards compatibi