Database that can handle >500 millions rows
Pretty much every non-stupid database can handle a billion rows today easily. 500 million is doable even on 32 bit systems (albeit 64 bit really helps).
The main problem is:
- You need to have enough RAM. How much is enough depends on your queries.
- You need to have a good enough disc subsystem. This pretty much means if you want to do large selects, then a single platter for everything is totally out of the question. Many spindles (or a SSD) are needed to handle the IO load.
Both Postgres as well as Mysql can easily handle 500 million rows. On proper hardware.
MSSQL can handle that many rows just fine. The query time is completely dependent on a lot more factors than just simple row count.
For example, it's going to depend on:
- how many joins those queries do
- how well your indexes are set up
- how much ram is in the machine
- speed and number of processors
- type and spindle speed of hard drives
- size of the row/amount of data returned in the query
- Network interface speed / latency
It's very easy to have a small (less than 10,000 rows) table which would take a couple minutes to execute a query against. For example, using lots of joins, functions in the where clause, and zero indexes on a Atom processor with 512MB of total ram. ;)
It takes a bit more work to make sure all of your indexes and foreign key relationships are good, that your queries are optimized to eliminate needless function calls and only return the data you actually need. Also, you'll need fast hardware.
It all boils down to how much money you want to spend, the quality of the dev team, and the size of the data rows you are dealing with.
UPDATE Updating due to changes in the question.
The amount of information here is still not enough to give a real world answer. You are going to just have to test it and adjust your database design and hardware as necessary.
For example, I could very easily have 1 billion rows in a table on a machine with those specs and run a "select top(1) id from tableA (nolock)" query and get an answer in milliseconds. By the same token, you can execute a "select * from tablea" query and it take a while because although the query executed quickly, transferring all of that data across the wire takes awhile.
Point is, you have to test. Which means, setting up the server, creating some of your tables, and populating them. Then you have to go through performance tuning to get your queries and indexes right. As part of the performance tuning you're going to uncover not only how the queries need to be restructured but also exactly what parts of the machine might need to be replaced (ie: disk, more ram, cpu, etc) based on the lock and wait types.
I'd highly recommend you hire (or contract) one or two DBAs to do this for you.
Most databases can handle this, it's about what you are going to do with this data and how you do it. Lots of RAM will help.
I would start with PostgreSQL, it's for free and has no limits on RAM (unlike SQL Server Express) and no potential problems with licences (too many processors, etc.). But it's also my work :)