What will happen if I changed the collation of my database?

Question

I am trying to increase performance in MySQL. once of the thing that I learned in using Latin1 charset is faster than using UTF8 because latin1 uses less bytes.. But I am wondering what will happen to the data if I changed the collation? in my application today most of the things are in Amerian english but I can't guarantee that there won't be any other languages stores as well. it someone store data other than english I don't really care about that data much.

My question: 1) if I changed the collation in my databases to latin1 what will happen to the data if it was not written in American English? 2) which lation1_? do I use latin1_bin, latin1_general_ci, or latin1_general_cs? and if possible what is the difference? 3) when changing the collation of the database do I need to also change the collation of each table separately?

Thanks

Answer 1

UTF 8 only uses extra bytes if it has strange characters. So really, you should NOT change your collation. it won't help. UTF 16 was developed to hold all characters of all languages, and yes, it uses 16 bits so if you were using utf16 I would suggest utf8 if you mostly had standard latin characters. utf 8 is the compromise. it has a special character that means "more bytes coming", and if it sees it, it groups the next ones together. But if all you have is latin characters, the bytes will be exactly the same number as with latin collation.

to answer specifically, you can set the default colation for new tables, but yes, you have to do it for each one of the existing ones. you could do it with an sql statement that lists the tables then runs the sql statement on each, to change it. (change 1 and notice the sql statement). but again, don't do it. utf8 is the standard for a reason. your performance issues are elsewhere.