H2 datastore EXTREMELY slow? (NOT Really! See EDIT)

Question

I just tested the H2 datastore (with Datanucleus 2.x)

The performance is VERY slow. 1/3 of Postgres and 1/10 of MySQL (aprox.)

I was very pleased by the "specs" but i cannot see them in "real usage". http://www.h2database.com/html/performance.html

Is there any performance tuning that i might be missing?

EDIT:

H2 is not SLOW. Is one of the fastest RDBMS i have tested to date!

I need help explaining WHY i need to CONNECT to the database using the WEB MANAGER (H2 console) to get the fantastic speed of this DB engine... I accidentally tested my app when CONNECTED through the H2 WEB console "et voilá", problem solved.

Why?

Answer 1

By default, H2 closes the database when the last connection is closed. If your application closes the only connection after each operation, the database is opened and closed a lot, which is quite slow.

There are multiple ways to solve this problem:

• use a connection pool, or
• keep a 'sentinel' connection open for as long as the application runs, or
• use delayed database closing by appending ;DB_CLOSE_DELAY=10 to the database URL

Answer 2

Sounds like you have a host lookup problem; 5 seconds is a typical DNS timeout.