Hi experts,
I'm using BDB-JE, and I want to preload the databases into memory when
my applicationloads up... However, I can't seem to get
Database.preload() to work.

I have over 1Gig of data the files in my bdb environment --but when I
call Database.preload(), the memory footprint of my process barely goes
up (only a few MB), whereas I was expecting the memory to max out.

I'm running my java process using -Xmx1500m option, and also have set
my environment config to use cachePercent=80%.

I've tried calling preload(0,0), which according to my interpretation
of the javadocs, should cause BDB to load as much of the indexes into
memory as possible.
I've also tried to call preload(1000000000, 1000000000), but that
doesn't seem to behave any differently.

Any ideas of what might be causing my problems?

Thanks!
~Heng

Hi Heng,

How many records are in the database, and what is the key size? Using
this information we can estimate the memory size for the index.

Please be aware that preload loads the index nodes only -- it does not
load the leaf nodes, in other words, it does not load the record data.
If you want to preload everything, use a cursor to walk through the
entire database instead of calling preload.

To verify that you're setting the cache size correctly, please print
out the stats after opening the environment as follows:

System.out.println(env.getStats(null));

Mark

Thanks for the tips, Mark.

We now iterate through the entire database using Cursor.getNext(), and
the preloading works as we wish it to --
--- although the preloading takes a bit long (~1 hr).

Are there any tricks to help load the leaf nodes into memory faster?
(btw, our environment is opened as read-only).

Thanks,
~Heng