CODEWITHSUNDEEP
ruby-on-railsrdbms
Thomas Tremble
Thomas Tremble

Reputation: 291

Rails Very Large Table

Rails likes to use autoincrement 32bit ints as primary keys on tables. What do people do when they get close to the limits of 32bit int # of rows in a table?

Upvotes: 1

Views: 402

Answers (2)

Gazler
Gazler

Reputation: 84180

You could change the key to a bigint? That is an 8-byte (64-bit) integer. It gives you up to 9 quantillion instead of 4 billion. There isn't a native migration though, you'd have to do something like:

execute("ALTER TABLE massive_table CHANGE id id BIGINT")

EDIT Apparently specifying a limit on the field as Alex suggested does allow for bigints in both PostgreSQL and mySQL.

Upvotes: 3

Alex Korban
Alex Korban

Reputation: 15136

You could use 8-byte id fields. Rails doesn't provide types to create long integer or double precision columns, however it can be done using the :limit parameter:

create_table :my_table do |t|
  t.integer :long_int_column, :limit => 8
  t.float :double_column, :limit => 53
end

8 and 53 are magic numbers. This works for PostgreSQL and MySQL databases, but I haven't tried any others.

If you're altering a table, then you can write

change_column :my_table, :my_col, :integer, :limit => 8

The alternative to 8-byte id fields is to handle id rollover in some way. That would depend on the specifics of your data and application.

Upvotes: 1

Related Questions