Genezzo::Contrib::Clustered::Clustered - Shared data cluster support for Genezzo
genprepundo.pl gendba.pl >@havok.sql >@syshook.sql >@clustered.sql
Genezzo is an extensible database with SQL and DBI. It is written in Perl. Basic routines inside Genezzo are overridden via Havok SysHooks. Override routines will (eventually) provide support for shared data clusters. Routines will provide transactions, distributed locking, undo, and recovery. Today these routines support a single-user single-threaded database, and provide basic transactional commit and rollback via undo. Locking routines are currently stubs.
All blocks are $Genezzo::Block::Std::DEFBLOCKSIZE
(block 0)
Frozen data structure stored via Genezzo::Block::RDBlock->HPush()
{ "procs" => $processes, "blocks_per_proc" => $blocks_per_process, "files" => { per fileidx => { fileidx, filename, full_filename, blocksize, numblocks, hdrsize } } };
(block 1 to $processes+1) ----------processid(10)---------------- to end of block 1st character is status: - = clear C = committed R = rolledback P = pending
(array of $blocks_per_process * $processes)
These are written paired (for recoverability), so only half number is actually available.
Undo blocks contain multiple rows. 1st row is {"tx"}, a transaction id. following rows are {"f" = $fileno, "b" = $blockno}. All are Frozen data structures stored via Genezzo::Block::RDBlock->HPush().
The list of fileno/blockno indicate which blocks should be replaced if the transaction rolls back, or which blocks should have the process id cleared (not yet implemented) if the transaction commits.
At process startup undo blocks for the process are initially all written with tx 0, so we can distinguish when we move to a block left over from a previous transaction.
The before image of each block is written at the tail of the file where it originates, at position $declared_file_length + $blocknum. So when this module is enabled data files actually grow to twice their declared size. Note dynamic data file growth (increase_by) is not supported with this module.
Wraps Genezzo::BufCa::BCFile::ReadBlock
Wraps Genezzo::BufCa::DirtyScalar::STORE
Wraps Genezzo::GenDBI::Kgnz_Commit
Wraps Genezzo::GenDBI::Kgnz_Rollback
none
No Distributed/clustered functionality today. Still single machine, single process, single user, single threaded. This is pre-alpha software; don't use it to store any data you hope to see again!
For more information, please visit the Genezzo homepage at http://www.genezzo.com
also http://eric_rollins.home.mindspring.com/genezzo/ClusteredGenezzoDesign.html and http://eric_rollins.home.mindspring.com/genezzo/cluster.html
Eric Rollins, rollins@acm.org
Copyright (C) 2005 by Eric Rollins. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Address bug reports and comments to rollins@acm.org
To install Genezzo::Contrib::Clustered::Clustered, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Genezzo::Contrib::Clustered::Clustered
CPAN shell
perl -MCPAN -e shell install Genezzo::Contrib::Clustered::Clustered
For more information on module installation, please visit the detailed CPAN module installation guide.