MySQL Bugs: #36915: MyISAM max table size

Bug #36915	MyISAM max table size
Submitted:	23 May 2008 12:38	Modified:	28 May 2008 16:49
Reporter:	Roland Bouman	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:	5.1.23	OS:	Any
Assigned to:	Paul DuBois	CPU Architecture:	Any

Description:
http://dev.mysql.com/doc/refman/5.1/en/create-table.html:

"AVG_ROW_LENGTH

...If you don't specify either option, the maximum size for a table is 256TB of data by default..."

(this seems to imply that a bare MyISAM table's data file with no options can in the absence of a file system limit grow up to 256 *Terabyte*)

http://dev.mysql.com/doc/refman/5.1/en/full-table.html:

"MyISAM  creates tables to allow up to 256GB by default, but this limit can be changed up to the maximum allowable size of 65,536TB (2567 – 1 bytes)."

(this seems to imply that the default maximum is 256 *Gigabyte*)

From bug http://bugs.mysql.com/bug.php?id=24609 it may be concluded that the latter, 256Gb is correct - not 256Tb

Also note that in both occasions the figure is mentioned for a MyISAM *table*. However, the limitation is about file sizes. So, the text should be more clear and explain whether this pertains to the size of a data file, index file, both data and index files, or the sum of data and index files.

How to repeat:
na

Suggested fix:
na

Thank you for the bug report.

It should be 256TB, not 256GB. Former limit with 4-byte pointer size default was 4GB. With the current 6-byte default, it's raised to 4GB * 256 * 256  = 256TB.

It's a per-file limit.

Thank you for your bug report. This issue has been addressed in the documentation. The updated documentation will appear on our website shortly, and will be included in the next release of the relevant products.