Bitcoin Forum

Bitcoin => Bitcoin Technical Support => Topic started by: grondilu on January 01, 2012, 09:51:44 AM

Title: opening the database with Perl
Post by: grondilu on January 01, 2012, 09:51:44 AM

I can see in the bitcointools 's python code that database are DB_BTREE, so I tried:

Code:

use DB_File;
my $db = tie my %h, 'DB_File', ".bitcoin/blockindex.dat", O_RDONLY, 0644, $DB_BTREE;
END { undef $db, untie %h if defined $db }

printf "%s: %d\n", $_, length($_) for keys %h;

but this gives me only one line:

main: 4

What am I missing? I can understand the the data is a bit serialized or something but I had expexted to have at least a bigger entry.

Title: Re: opening the database with Perl
Post by: 2112 on January 01, 2012, 10:58:25 AM

Quote from: grondilu on January 01, 2012, 09:51:44 AM

main: 4
What am I missing?

All Berkeley DB database files in Satoshi client are "multiple database capable". In effect they are B-trees of B-trees, where top-level B-tree contains only one node with key "main".

I don't know how to get to the 2nd-level B-tree in Perl. Probably it is documented somewhere.

Title: Re: opening the database with Perl
Post by: grondilu on January 02, 2012, 10:39:12 AM

I finally managed to open the database using the BerkeleyDB module instead of DB_File.

In short:

Code:

tie my %blkindex, 'BerkeleyDB::Btree',
-Filename => 'blkindex.dat',
-Subname => 'main',

I still have to figure out the equivalent of the 'cursor.set_range("\x0ablockindex")' in Gavin's bitcointools, though.