help creating a memory only B-tree

bostic@sleepycat.com · *nix forums beginner Joined: 21 Jun 2005 Posts: 49

berkeleydb_user · *nix forums beginner Joined: 16 Mar 2005 Posts: 17

Guys

Am new to Berkeley DB. I heard its fast. I am tring to create a memory
only database and it seems to be very slow. For inserting 10000 keys
(average 10 bytes/key) its taking 8seconds!! I must be doing something
wrong. The library size is around 660KB. I built the library like this:

prompt$ make realclean
prompt$ env CC=gcc ../dist/configure --enable-smallbuild
prompt$ make

Here is the program to create the database.

main()
{
:
create_db();
:
test_ins()

}

int key_compare(DB *db, const DBT * a, const DBT * b)
{
int v;
unsigned s; /* smaller size */

if ( a->size < b->size ) {
s = a->size;
} else {
s = b->size;
}

v = memcmp(a->data, b->data, s);
if (v == 0) {
/* if first s bytes are same, the longer key is "bigger" */
return (a->size - b->size);
}

return v;
}

int create_db()
{
int flags;
DB_MPOOLFILE *mpf;

err =0;
//err = db_create(&dbp, dbenv, 0);
err = db_create(&dbp, NULL, 0);
if ( err ) return err;

flags = DB_CREATE;//DB_EXCL | DB_CREATE;

err = dbp->set_bt_compare(dbp, key_compare);
if ( err ) {
dbenv->err(dbenv, err, "dbp->set_bt_compare");
dbp->close(dbp, 0);
dbp = NULL;
}

mpf = dbp->mpf;
//mpf->set_flags(mpf, DB_MPOOL_NOFILE, 1);
mpf->set_maxsize(mpf, 0, 20000000);

//err = dbp->open(dbp, NULL, dbfile, NULL, DB_BTREE, flags, 0);
err = dbp->open(dbp, NULL, NULL, NULL, DB_BTREE, flags, 0);
if ( err ) {
dbenv->err(dbenv, err, "dbp->open");
dbp->close(dbp, 0);
dbp = NULL;
}

return err;
}

int test_ins()
{
DB_TXN * tid;
DBT key, data;
int i = 0;

err = 0;
:
if ( err == 0 ) {
while ( i < nr_insert ) {
key.size = strlen(list[i]);
key.data = list[i];
data.size = strlen(list[i]);
data.data = list[i];
if ( logging_enabled ) {
err = dbp->put(dbp, tid, &key, &data, DB_NOOVERWRITE);
}
else { err = dbp->put(dbp, NULL, &key,
&data, DB_NOOVERWRITE)
;
}
if ( err ) {
dbenv->err(dbenv, err, "dbp->put");
break;
}
i++;
}
}

fprintf(stderr, "inserted %d records\n", i);
return err;
}

Please help.

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