MySQL: Row size too large (> 8126)

innodblinuxMySQLmysql-5.5

I have a table which has 300 columns in it. Each column is 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 the maximum number of bytes. So I create is using 300 TEXT fields. When I then try and insert data, I get the error:

Row size too large (> 8126).
Changing some columns to TEXT or BLOB or using ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED may help.
In current row format, BLOB prefix of 768 bytes is stored inline.

After reading up on this, I tried to change the table to use Barracuda format by specifying ROW_FORMAT=COMPRESSED. The issue now seems to be that when I try and create the table using that format, I get the same error.

CREATE TABLE T_ObjLarge__c (Id VARCHAR(18), Name VARCHAR(80),
ObjLarge_Field_1__c TEXT,
ObjLarge_Field_2__c TEXT,
...
ObjLarge_Field_300__c TEXT
) ROW_FORMAT=COMPRESSED ;

The error I get is:

Row size too large (> 8126).
Changing some columns to TEXT or BLOB may help.
In current row format, BLOB prefix of 0 bytes is stored inline.

I am using MySQL 5.5.31 on Linux mint. No indexes. I have tried DYNAMIC format; it behaves the same way.

Output of SHOW GLOBAL VARIABLES LIKE 'innodb_file_per_table';:

+--------------------------+-----------+
| Variable_name            | Value     |
+--------------------------+-----------+
| innodb_file_format       | Barracuda |
| innodb_file_format_check | ON        |
| innodb_file_format_max   | Barracuda |
| innodb_file_per_table    | ON        |
+--------------------------+-----------+

Best Answer

This is a very tough question to answer simply because you are going beyond InnoDB current limits.

Your question is not by any means unique. This has been addressed here before

By Me, Aug 14, 2012 : error 1118: row size too large. utf8 innodb
By Bill Karwin, Oct 06, 2011 : InnoDB create table error: "Row size too large"

I would also look into the character set you are currently using.

Bill Karwin said it best in his last paragraph

I also have to comment that I've never seen a well-designed table exceed the row size limit. It's a strong "code smell" that you're violating the repeating groups condition of First Normal Form.

You are going to have to define a better design. No business reason can ever justify it. Why?

Back on July 20, 2011, I answered this question: Too many columns in MySQL

I personally eyewitnessed this

In my earlier days as a developer, I worked at a company back in 1995 where DB2 was the main RDBMS. The company had a single table that had 270 columns, dozens of indexes, and had performance issues retrieving data. They contacted IBM and had consultants look over the architecture of their system, including this one monolithic table. The company was told "If you do not normalize this table in the next 2 years, DB2 will fail on queries doing Stage2 Processing (any queries requiring sorting on non-indexed columns)." This was told to a multi-trillion dollar company, to normalize a 270 column table. How much more so a 2000 column table.

A table with 300 TEXT columns is asking for same kind of trouble.

SUMMARY : Bill Karwin said it before and I agree: REDESIGN THE TABLE. That will circvumvent the row length issue for sure.

Related Solutions

MySQL – Understanding innodb_file_format Barracuda

So I'm answering this question almost 4 years late:

InnoDB file formats were conceived at a time when InnoDB was independent of the MySQL Server (for example: MySQL 5.1 could run two different versions of InnoDB).
The reason why you would not want to run Barracuda (in 2012) is that it could reduce flexibility in downgrading MySQL (i.e. after a failed upgrade, you want to move back to a version that can not read a newer format). i.e. there should be no technical reasons why Antelope is better.
In MySQL 5.7 the innodb_file_format option was deprecated. Since MySQL and InnoDB are no longer independent, and thus InnoDB can use the MySQL rules of upgrades and what backwards compatibility is required. No confusing setting required!
In MySQL 5.7, the default switched to Barracuda/DYNAMIC. Since all currently supported releases of MySQL can read this format, it is safe to move away from Antelope and still offer downgrade.
On a MySQL 5.7 server, Antelope tables will be upgraded to Barracuda/DYNAMIC on the next table rebuild (OPTIMIZE TABLE etc). That is unless they were specifically created with ROW_FORMAT=oldrowformat.
In MySQL 8.0, the option innodb_file_format is removed.

MySQL 5.7 also introduces the option innodb_default_row_format, which defaults to DYNAMIC. This addresses the point in your update.

Mysql – system wide way to change MariaDB to create tables using ROW_FORMAT = DYNAMIC

InnoDB has Limitations on row lengths and BLOBs. According to the MySQL Documentation:

The maximum row length, except for variable-length columns (VARBINARY, VARCHAR, BLOB and TEXT), is slightly less than half of a database page. That is, the maximum row length is about 8000 bytes. LONGBLOB and LONGTEXT columns must be less than 4GB, and the total row length, including BLOB and TEXT columns, must be less than 4GB.

If a row is less than half a page long, all of it is stored locally within the page. If it exceeds half a page, variable-length columns are chosen for external off-page storage until the row fits within half a page, as described in Section 14.3.12.2, “File Space Management”.

Although InnoDB supports row sizes larger than 65,535 bytes internally, MySQL itself imposes a row-size limit of 65,535 for the combined size of all columns:
mysql> CREATE TABLE t (a VARCHAR(8000), b VARCHAR(10000),
-> c VARCHAR(10000), d VARCHAR(10000), e VARCHAR(10000),
-> f VARCHAR(10000), g VARCHAR(10000)) ENGINE=InnoDB; ERROR 1118 (42000):
Row size too large. The maximum row size for the used table
type, not counting BLOBs, is 65535. You have to change some columns to
TEXT or BLOBs
See Section E.10.4, “Limits on Table Column Count and Row Size”.

You are going to have to recreate the mysqldump so that the Storage Engine is Specified. Perhaps just drop the --compatible=mssql from the mysqldump command. The end result is the that the table will remain a MyISAM table when being imported into MariaDB.

This is just a guess but look at the error message you posted. If a BLOB prefix is 768 bytes and you have 10 BLOBs, that 7680 bytes. That leaves you with 320 bytes. If the remaining datatypes exceed 320 bytes, then it is impossible to convert to InnoDB.

Since a TEXT column is the variant of a BLOB, converting to TEXT does nothing since the storage requirements for TEXT and BLOB field are identical.

Best Answer

Related Solutions

MySQL – Understanding innodb_file_format Barracuda

Mysql – system wide way to change MariaDB to create tables using ROW_FORMAT = DYNAMIC

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