MySQL Bugs: #31179: Add support to symlink *.frm files

Bug #31179	Add support to symlink *.frm files
Submitted:	24 Sep 2007 20:41	Modified:	25 Sep 2007 17:23
Reporter:	Dan Gregory	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server	Severity:	S4 (Feature request)
Version:	5.0.45	OS:	Solaris
Assigned to:		CPU Architecture:	Any

Description:
The rename function in mysql seems to not rename symlinked .frm files even though the .MYD and .MYI files are correctly renamed in both database and data directories.  It doesn't make since that the .frm file has to be in a different location that the data and index files especially for myisampacked (aka read-only) tables.

How to repeat:
create a myisam table, foo
move the .frm, .MYD, and .MYI files to /a/different/directory
ln -s /a/different/directory/foo.* /database/directory/
echo "rename foo to foo_1" | mysql database
ls -l /database/directory/foo.*

The long listing will show foo_1.frm -> /a/different/directory/foo.frm

Suggested fix:
Have ./sql/sql_table.cc:mysql_rename_table() use my_rename_with_symlink(from,to,ext) instead of rename_file_ext(from,to,ext).

Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://dev.mysql.com/doc/ and the instructions on
how to report a bug at http://bugs.mysql.com/how-to-report.php

According to http://dev.mysql.com/doc/refman/5.1/en/symbolic-links-to-tables.html "The .frm file must never be a symbolic link (as indicated previously, only the data and index files can be symbolic links). Attempting to do this (for example, to make synonyms) produces incorrect results."

Sorry, I know it's not a bug.  I'm curious the technical reasons why the limit is imposed.  I see no reason why it can't be a symlink for myisam tables.

Thank you for the feedback.

Changed status as this is feature request now. Synopsis can be "Add support to symlink *.frm files"

--updated synopsis