What a big database is and why there isn't anything like that.

Author: Szymon Lipiński
Published at: 2009-07-05

This a very simple question. Usually I hear something like this:

“Help me, my database is so slow because it is so big”

“What size?”

“Well… about 1,000 rows”.

That usually makes me laugh. Adding some indexes, and convincing programmers not to get all records with every select usually helps, and suddenly the database is not so big.

OK, when someone says that there are over 1M records that doesn’t mean that this database is big.

Lets define the big database some other way.

The number of rows shouldn’t be considered when classifying a database to be big. In databases we’ve got tables used for logging some data. So those tables can be really big, but who cares if they are not used? And we’ve got tables with much less data, but with many indices, which are used for many much more complicated queries.

Main problems with databases are all about the speed of getting the data. Depending on the database usage type. We can have problems with inserts, or updates, or selects.

Usually we more often select from a database than we change the data.

There is no such problem as The Big Database.

The problem is always The Slow Database.

So what is a slow database?

Database can be slow because there is too much data. Then usually we use indices, and speed all up to some extent. However sometimes we need to replace the server with something better and faster, more ram and faster drives, more CPUs and so on. And then the problem with the Slow (aka the Big) Database doesn’t exists. It suddenly looks like there is not a problem called The Big Database. The Database is a problem if it is slow, not big. Big doesn’t mean slow, and slow doesn’t mean big.

When a database is slow there are many ways to improve that. To some extent. After that I can say that the database is Big if it is still slow. But that simply means that the database, and all database operations don’t fit the server.

The database is Big, when it’s just too Slow for our requirements.

The comments are disabled. If you want to write something to me, you can use e.g. Twitter.