I know how a B-Tree works in-memory, it's easy enough to implement. However, I don't know how to find a data layout that works effectively on disk, such that: The number of entries in the B-Tree c...

We are in the process of migrating from MySQL to PGSQL and we have a 100 million row table. When I was trying to ascertain how much space both systems use, I found much less difference for tables, ...

I have a simple table which has a user_birthday field with a type of date (which can be NULL value) CREATE TABLE users ( user_id bigserial NOT NULL, user_email text NOT NULL, user_password text...

Consider the below Mongo index strategy and the query, Index: db.collec.ensureIndex({a:1,b:1,c:1}); Query: db.collec.find({"a":"valueA"},{"_id":0,"a":1,"c":1}).sort({"c":-1}).limit(150) The ...

I am writing a simple tool to check duplicate files(i.e. files having same data). The mechanism is to generate hashes for each file using sha-512 algorithm and then store these hashes in MYSQL data...

Since database data is organized in 8k pages in a B-tree, and likewise for PK information information, it should be possible for each table in the database to calculate the height of the B-Tree. Th...

I have a table with multiple indexes, several of which duplicate the same columns: Index 1 columns: X, B, C, D Index 2 columns: Y, B, C, D Index 3 columns: Z, B, C, D I'm not very knowledgeable ...