maria-discuss team mailing list archive

[Binarus <lists@xxxxxxxxxx>]

On 11.03.2016 10:56, Rhys.Campbell@xxxxxxxxxxxx wrote:
> Just a quick idea... Perhaps you can include an additional field in the unique index containing the length on the string. So
> 
> Str,	str_len
> 'a', 	1
> 'a ',	2
> 
> Unq index on (str, str_len). 
> 

Thanks for the suggestion. I already have read about that idea when researching the same problem for MySQL.

I think I could try this as a last resort, but it would require changes in the existing applications, and -more difficult- I should find out the maximum index length in indexes which contain several columns. As far as I know, the maximum index length with InnoDB is 767 bytes, and I already need these because my columns are mostly VARCHAR(255), charset UTF8. Now, if I add one of those columns to a unique index, thereby using all available index bytes, could I add a second column to the same index at all?

If I have to go this way as a last resort, I'll investigate ...

Binarus