Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
The background is that from 2 or 3 unsigned integers I want something unique. I’ve done cantor pairs but they grow out of an BIGINT UNSIGNED when using 3.
Now I’m into hashing, first I went with MD5 and char(32) but know I’m into CRC32 with INT UNSIGNED since it’s numeric, therefore fast. The goal is high performance reading from this index.
Is hashing the only way? Can I maintain a reasonable collision probability for ~200,000 rows?
You can use
binary(12)(12 bytes) which can uniquely store three 4 byte integers.Or
decimal(30)which also can do that and doesn’t require you to first convert the integers to a binary encoding (just 0 pad them to 10 digits and append them together, MySql will do the conversion for you).