Home/ Questions/Q 279227
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-12T05:00:52+00:00

Mysql uses B+ tree for implementing indexes. Lets say my primary index is of

  • 0

Mysql uses B+ tree for implementing indexes. Lets say my primary index is of type (name, age, city). Can someone throw some light how Mysql implements a B+ tree on these kinds of keys ?

My hunch is that it treats the whole tuple as a key and it treats it like a partial order. Eg:

(John, 24, New Jersey) < (John, 24, New York) < (John, 25, New Jersey) < (John, 25, New York)

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    (John, 24, New Jersey) < (John, 24, New York) < (John, 25, New Jersey) < (John, 25, New York)

    Yes, that’s why it is important in which order you lay out columns in a key.

    The key won’t be of any help if you do not look for values that can be satisfied from looking at the start of it – e.g. when you filter for age and/or city, but not for name, the key can’t be used. On the other hand, if you’d filter for name only, the key would be used.

    • 0