Hello everybody, when I use BerkelyDB, I find that I use the db_del function. But the DB file has not become small , maybe it just made a mark. Is there any method can make DB files smaller? what method ? By the way, when run after the production , there will be three file, __db.001, __db.002, __db.003, what is the action of three files ? thanks a lot!

#!/usr/bin/perl -w
use warnings;
use BerkeleyDB;
$|=1;
my $env=new BerkeleyDB::Env
    -Home=>'/home/y6cme/perl5',
    -Flags=>DB_CREATE|DB_INIT_MPOOL
|| die;
my %hash;
my $db=tie(%hash,"BerkeleyDB::Btree",
       -Filename=>"test.db",
      -Flags=>DB_CREATE,
       -Env=>$env)
|| die;
for(1..10000){
    $hash{$_}=$_;
}
untie $db;
undef %hash;
my $db2=tie(%hash2,"BerkeleyDB::Btree",
       -Filename=>"test.db",
      -Flags=>DB_CREATE,
       -Env=>$env)
|| die;
for(1..10000){
    $db2->db_del($_);
}
untie $db2;
undef %hash2;
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