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One of my talbe has a multicolumn index with total 1011 characters. storage engine is InnoDB.

The same table was working just fine in mysql 5.6.26. but now when i upgraded to mysql 5.7.16 i get error Specified key was too long; max key length is 3072 bytes.

I know there's limist on total size of index. but the question is, why was it working in 5.6 and stopped working in 5.7. Is there some thing i can do without reducing the size of columns.

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  • dba.stackexchange.com/questions/49913/… Commented Oct 16, 2016 at 18:19
  • okay, but why does the same thing used to work in 5.6 -- we have been using 5.6 since two years without any errors Commented Oct 16, 2016 at 18:25

1 Answer 1

Reset to default
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The issue for us was the default character set. In old 5.6 version, my default character set was latin1, but when i installed 5.7.16 i did not change the character set and default was utf8, which resulted in larger column size, as utf takes more bytes, resulting in the error. changing the default character set back to latin1 and recreating table fixed the problem.

[mysqld] character-set-server=latin1 [client] default-character-set=latin1 [mysql] default-character-set=latin1
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