Question

I need to use a text column as primary key for my sqlite database.
I also have the possibility to use a hash function to get an 32bit/64bit int from my text values (I want to use as primary key). So I could use these int hash values instead my text value as primary keys.
But then I need to store the raw text value additionally in the table.

But I read that sqlite is using a rowid internally, So I don’t know if using a hash function will help anyway.

Will sqlite store the rowid or the text value (when I use it instead of the hash value) in their pages? When it stores the text value then I think it could blow off the pages and using a hash value would be better.

But I have a lack of knowledge here.
I hope you can help me.

Answer 1

Unfortunately yes, any indexes on strings (including usage as a primary key) take double space. Once for the value in the row, second time for the value in the index.

So if hashing meets your needs (you don’t need sorting, lookup by ranges), using it will be a good idea.