--- a/server/migractions.py	Thu Apr 21 16:33:55 2011 +0200
+++ b/server/migractions.py	Thu Apr 21 12:35:41 2011 +0200
@@ -162,7 +162,7 @@
 
     # server specific migration methods ########################################
 
-    def backup_database(self, backupfile=None, askconfirm=True):
+    def backup_database(self, backupfile=None, askconfirm=True, format='native'):
         config = self.config
         repo = self.repo_connect()
         # paths
@@ -185,16 +185,24 @@
         # backup
         tmpdir = tempfile.mkdtemp()
         try:
+            failed = False
             for source in repo.sources:
                 try:
-                    source.backup(osp.join(tmpdir, source.uri), self.confirm)
+                    source.backup(osp.join(tmpdir, source.uri), self.confirm, format=format)
                 except Exception, ex:
                     print '-> error trying to backup %s [%s]' % (source.uri, ex)
                     if not self.confirm('Continue anyway?', default='n'):
                         raise SystemExit(1)
                     else:
-                        break
-            else:
+                        failed = True
+            with open(osp.join(tmpdir, 'format.txt'), 'w') as format_file:
+                format_file.write('%s\n' % format)
+            with open(osp.join(tmpdir, 'versions.txt'), 'w') as version_file:
+                versions = repo.get_versions()
+                for cube, version in versions.iteritems():
+                    version_file.write('%s %s\n' % (cube, version))
+                    
+            if not failed:
                 bkup = tarfile.open(backupfile, 'w|gz')
                 for filename in os.listdir(tmpdir):
                     bkup.add(osp.join(tmpdir, filename), filename)
@@ -207,7 +215,7 @@
             shutil.rmtree(tmpdir)
 
     def restore_database(self, backupfile, drop=True, systemonly=True,
-                         askconfirm=True):
+                         askconfirm=True, format='native'):
         # check
         if not osp.exists(backupfile):
             raise ExecutionError("Backup file %s doesn't exist" % backupfile)
@@ -229,13 +237,18 @@
             bkup = tarfile.open(backupfile, 'r|gz')
             bkup.extractall(path=tmpdir)
             bkup.close()
+        if osp.isfile(osp.join(tmpdir, 'format.txt')):
+            with open(osp.join(tmpdir, 'format.txt')) as format_file:
+                written_format = format_file.readline().strip()
+                if written_format in ('portable', 'native'):
+                    format = written_format
         self.config.open_connections_pools = False
         repo = self.repo_connect()
         for source in repo.sources:
             if systemonly and source.uri != 'system':
                 continue
             try:
-                source.restore(osp.join(tmpdir, source.uri), self.confirm, drop)
+                source.restore(osp.join(tmpdir, source.uri), self.confirm, drop, format)
             except Exception, exc:
                 print '-> error trying to restore %s [%s]' % (source.uri, exc)
                 if not self.confirm('Continue anyway?', default='n'):

--- a/server/serverctl.py	Thu Apr 21 16:33:55 2011 +0200
+++ b/server/serverctl.py	Thu Apr 21 12:35:41 2011 +0200
@@ -691,19 +691,20 @@
         'Continue anyway?' % filename):
         raise ExecutionError('Error while deleting remote dump at /tmp/%s' % filename)
 
-def _local_dump(appid, output):
+
+def _local_dump(appid, output, format='native'):
     config = ServerConfiguration.config_for(appid)
     config.quick_start = True
     mih = config.migration_handler(connect=False, verbosity=1)
-    mih.backup_database(output, askconfirm=False)
+    mih.backup_database(output, askconfirm=False, format=format)
     mih.shutdown()
 
-def _local_restore(appid, backupfile, drop, systemonly=True):
+def _local_restore(appid, backupfile, drop, systemonly=True, format='native'):
     config = ServerConfiguration.config_for(appid)
     config.verbosity = 1 # else we won't be asked for confirmation on problems
     config.quick_start = True
     mih = config.migration_handler(connect=False, verbosity=1)
-    mih.restore_database(backupfile, drop, systemonly, askconfirm=False)
+    mih.restore_database(backupfile, drop, systemonly, askconfirm=False, format=format)
     repo = mih.repo_connect()
     # version of the database
     dbversions = repo.get_versions()
@@ -777,6 +778,12 @@
           'default' : False,
           'help': 'Use sudo on the remote host.'}
          ),
+        ('format',
+         {'short': 'f', 'default': 'native', 'type': 'choice',
+          'choices': ('native', 'portable'),
+          'help': '"native" format uses db backend utilities to dump the database. '
+                  '"portable" format uses a database independent format'}
+         ),
         )
 
     def run(self, args):
@@ -785,7 +792,9 @@
             host, appid = appid.split(':')
             _remote_dump(host, appid, self.config.output, self.config.sudo)
         else:
-            _local_dump(appid, self.config.output)
+            _local_dump(appid, self.config.output, format=self.config.format)
+
+
 
 
 class DBRestoreCommand(Command):
@@ -811,13 +820,33 @@
           'instance data. In that case, <backupfile> is expected to be the '
           'timestamp of the backup to restore, not a file'}
          ),
+        ('format',
+         {'short': 'f', 'default': 'native', 'type': 'choice',
+          'choices': ('native', 'portable'),
+          'help': 'the format used when dumping the database'}),
         )
 
     def run(self, args):
         appid, backupfile = args
+        if self.config.format == 'portable':
+            # we need to ensure a DB exist before restoring from portable format
+            if not self.config.no_drop:
+                try:
+                    CWCTL.run(['db-create', '--automatic', appid])
+                except SystemExit, exc:
+                    # continue if the command exited with status 0 (success)
+                    if exc.code:
+                        raise
         _local_restore(appid, backupfile,
                        drop=not self.config.no_drop,
-                       systemonly=not self.config.restore_all)
+                       systemonly=not self.config.restore_all,
+                       format=self.config.format)
+        if self.config.format == 'portable':
+            try:
+                CWCTL.run(['db-rebuild-fti', appid])
+            except SystemExit, exc:
+                if exc.code:
+                    raise
 
 
 class DBCopyCommand(Command):
@@ -850,6 +879,12 @@
           'default' : False,
           'help': 'Use sudo on the remote host.'}
          ),
+        ('format',
+         {'short': 'f', 'default': 'native', 'type': 'choice',
+          'choices': ('native', 'portable'),
+          'help': '"native" format uses db backend utilities to dump the database. '
+                  '"portable" format uses a database independent format'}
+         ),
         )
 
     def run(self, args):
@@ -861,8 +896,9 @@
             host, srcappid = srcappid.split(':')
             _remote_dump(host, srcappid, output, self.config.sudo)
         else:
-            _local_dump(srcappid, output)
-        _local_restore(destappid, output, not self.config.no_drop)
+            _local_dump(srcappid, output, format=self.config.format)
+        _local_restore(destappid, output, not self.config.no_drop,
+                       self.config.format)
         if self.config.keep_dump:
             print '-> you can get the dump file at', output
         else:

--- a/server/sources/__init__.py	Thu Apr 21 16:33:55 2011 +0200
+++ b/server/sources/__init__.py	Thu Apr 21 12:35:41 2011 +0200
@@ -139,11 +139,11 @@
             return -1
         return cmp(self.uri, other.uri)
 
-    def backup(self, backupfile, confirm):
+    def backup(self, backupfile, confirm, format='native'):
         """method called to create a backup of source's data"""
         pass
 
-    def restore(self, backupfile, confirm, drop):
+    def restore(self, backupfile, confirm, drop, format='native'):
         """method called to restore a backup of source's data"""
         pass
 

--- a/server/sources/native.py	Thu Apr 21 16:33:55 2011 +0200
+++ b/server/sources/native.py	Thu Apr 21 12:35:41 2011 +0200
@@ -28,21 +28,29 @@
 
 __docformat__ = "restructuredtext en"
 
-from pickle import loads, dumps
+try:
+    from cPickle import loads, dumps
+    import cPickle as pickle
+except ImportError:
+    from pickle import loads, dumps
+    import pickle
 from threading import Lock
 from datetime import datetime
 from base64 import b64decode, b64encode
 from contextlib import contextmanager
-from os.path import abspath
+from os.path import abspath, basename
 import re
 import itertools
+import zipfile
+import logging
+import sys
 
 from logilab.common.compat import any
 from logilab.common.cache import Cache
 from logilab.common.decorators import cached, clear_cache
 from logilab.common.configuration import Method
 from logilab.common.shellutils import getlogin
-from logilab.database import get_db_helper
+from logilab.database import get_db_helper, sqlgen
 
 from yams import schema2sql as y2sql
 from yams.schema import role_name
@@ -354,24 +362,44 @@
                 _pool.pool_reset()
                 self.repo._free_pool(_pool)
 
-    def backup(self, backupfile, confirm):
+    def backup(self, backupfile, confirm, format='native'):
         """method called to create a backup of the source's data"""
-        self.close_pool_connections()
-        try:
-            self.backup_to_file(backupfile, confirm)
-        finally:
-            self.open_pool_connections()
+        if format == 'portable':
+            self.repo.fill_schema()
+            self.set_schema(self.repo.schema)
+            helper = DatabaseIndependentBackupRestore(self)
+            self.close_pool_connections()
+            try:
+                helper.backup(backupfile)
+            finally:
+                self.open_pool_connections()
+        elif format == 'native':
+            self.close_pool_connections()
+            try:
+                self.backup_to_file(backupfile, confirm)
+            finally:
+                self.open_pool_connections()
+        else:
+            raise ValueError('Unknown format %r' % format)
 
-    def restore(self, backupfile, confirm, drop):
+
+    def restore(self, backupfile, confirm, drop, format='native'):
         """method called to restore a backup of source's data"""
         if self.repo.config.open_connections_pools:
             self.close_pool_connections()
         try:
-            self.restore_from_file(backupfile, confirm, drop=drop)
+            if format == 'portable':
+                helper = DatabaseIndependentBackupRestore(self)
+                helper.restore(backupfile)
+            elif format == 'native':
+                self.restore_from_file(backupfile, confirm, drop=drop)
+            else:
+                raise ValueError('Unknown format %r' % format)
         finally:
             if self.repo.config.open_connections_pools:
                 self.open_pool_connections()
 
+
     def init(self, activated, source_entity):
         self.init_creating(source_entity._cw.pool)
 
@@ -1564,3 +1592,218 @@
         login = rset.rows[0][0]
         authinfo['email_auth'] = True
         return self.source.repo.check_auth_info(session, login, authinfo)
+
+class DatabaseIndependentBackupRestore(object):
+    """Helper class to perform db backend agnostic backup and restore
+
+    The backup and restore methods are used to dump / restore the
+    system database in a database independent format. The file is a
+    Zip archive containing the following files:
+
+    * format.txt: the format of the archive. Currently '1.0'
+    * tables.txt: list of filenames in the archive tables/ directory
+    * sequences.txt: list of filenames in the archive sequences/ directory
+    * versions.txt: the list of cube versions from CWProperty
+    * tables/<tablename>.<chunkno>: pickled data
+    * sequences/<sequencename>: pickled data
+
+    The pickled data format for tables and sequences is a tuple of 3 elements:
+    * the table name
+    * a tuple of column names
+    * a list of rows (as tuples with one element per column)
+
+    Tables are saved in chunks in different files in order to prevent
+    a too high memory consumption. 
+    """
+    def __init__(self, source):
+        """
+        :param: source an instance of the system source
+        """
+        self._source = source
+        self.logger = logging.getLogger('cubicweb.ctl')
+        self.logger.setLevel(logging.INFO)
+        self.logger.addHandler(logging.StreamHandler(sys.stdout))
+        self.schema = self._source.schema
+        self.dbhelper = self._source.dbhelper
+        self.cnx = None
+        self.cursor = None
+        self.sql_generator = sqlgen.SQLGenerator()
+
+    def get_connection(self):
+        return self._source.get_connection()
+
+    def backup(self, backupfile):
+        archive=zipfile.ZipFile(backupfile, 'w')
+        self.cnx = self.get_connection()
+        try:
+            self.cursor = self.cnx.cursor()
+            self.cursor.arraysize=100
+            self.logger.info('writing metadata')
+            self.write_metadata(archive)
+            for seq in self.get_sequences():
+                self.logger.info('processing sequence %s', seq)
+                self.write_sequence(archive, seq)
+            for table in self.get_tables():
+                self.logger.info('processing table %s', table)
+                self.write_table(archive, table)
+        finally:
+            archive.close()
+            self.cnx.close()
+        self.logger.info('done')
+
+    def get_tables(self):
+        non_entity_tables = ['entities',
+                             'deleted_entities',
+                             'transactions',
+                             'tx_entity_actions',
+                             'tx_relation_actions',
+                             ]
+        etype_tables = []
+        relation_tables = []
+        prefix = 'cw_'
+        for etype in self.schema.entities():
+            eschema = self.schema.eschema(etype)
+            print etype, eschema.final
+            if eschema.final:
+                continue
+            etype_tables.append('%s%s'%(prefix, etype))
+        for rtype in self.schema.relations():
+            rschema = self.schema.rschema(rtype)
+            if rschema.final or rschema.inlined:
+                continue
+            relation_tables.append('%s_relation' % rtype)
+        return non_entity_tables + etype_tables + relation_tables
+
+    def get_sequences(self):
+        return ['entities_id_seq']
+
+    def write_metadata(self, archive):
+        archive.writestr('format.txt', '1.0')
+        archive.writestr('tables.txt', '\n'.join(self.get_tables()))
+        archive.writestr('sequences.txt', '\n'.join(self.get_sequences()))
+        versions = self._get_versions()
+        versions_str = '\n'.join('%s %s' % (k,v)
+                                 for k,v in versions)
+        archive.writestr('versions.txt', versions_str)
+
+    def write_sequence(self, archive, seq):
+        sql = self.dbhelper.sql_sequence_current_state(seq)
+        columns, rows_iterator = self._get_cols_and_rows(sql)
+        rows = list(rows_iterator)
+        serialized = self._serialize(seq, columns, rows)
+        archive.writestr('sequences/%s' % seq, serialized)
+
+    def write_table(self, archive, table):
+        sql = 'SELECT * FROM %s' % table
+        columns, rows_iterator = self._get_cols_and_rows(sql)
+        self.logger.info('number of rows: %d', self.cursor.rowcount)
+        if table.startswith('cw_'): # entities
+            blocksize = 2000
+        else: # relations and metadata
+            blocksize = 10000
+        if self.cursor.rowcount > 0:
+            for i, start in enumerate(xrange(0, self.cursor.rowcount, blocksize)):
+                rows = list(itertools.islice(rows_iterator, blocksize))
+                serialized = self._serialize(table, columns, rows)
+                archive.writestr('tables/%s.%04d' % (table, i), serialized)
+                self.logger.debug('wrote rows %d to %d (out of %d) to %s.%04d',
+                                  start, start+len(rows)-1,
+                                  self.cursor.rowcount,
+                                  table, i)
+        else:
+            rows = []
+            serialized = self._serialize(table, columns, rows)
+            archive.writestr('tables/%s.%04d' % (table, 0), serialized)
+
+    def _get_cols_and_rows(self, sql):
+        process_result = self._source.iter_process_result
+        self.cursor.execute(sql)
+        columns = (d[0] for d in self.cursor.description)
+        rows = process_result(self.cursor)
+        return tuple(columns), rows
+
+    def _serialize(self, name, columns, rows):
+        return dumps((name, columns, rows), pickle.HIGHEST_PROTOCOL)
+
+    def restore(self, backupfile):
+        archive = zipfile.ZipFile(backupfile, 'r')
+        self.cnx = self.get_connection()
+        self.cursor = self.cnx.cursor()
+        sequences, tables, table_chunks = self.read_metadata(archive, backupfile)
+        for seq in sequences:
+            self.logger.info('restoring sequence %s', seq)
+            self.read_sequence(archive, seq)
+        for table in tables:
+            self.logger.info('restoring table %s', table)
+            self.read_table(archive, table, sorted(table_chunks[table]))
+        self.cnx.close()
+        archive.close()
+        self.logger.info('done')
+
+    def read_metadata(self, archive, backupfile):
+        formatinfo = archive.read('format.txt')
+        self.logger.info('checking metadata')
+        if formatinfo.strip() != "1.0":
+            self.logger.critical('Unsupported format in archive: %s', formatinfo)
+            raise ValueError('Unknown format in %s: %s' % (backupfile, formatinfo))
+        tables = archive.read('tables.txt').splitlines()
+        sequences = archive.read('sequences.txt').splitlines()
+        file_versions = self._parse_versions(archive.read('versions.txt'))
+        versions = set(self._get_versions())
+        if file_versions != versions:
+            self.logger.critical('Unable to restore : versions do not match')
+            self.logger.critical('Expected:\n%s', '\n'.join(list(sorted(versions))))
+            self.logger.critical('Found:\n%s', '\n'.join(list(sorted(file_versions))))
+            raise ValueError('Unable to restore : versions do not match')
+        table_chunks = {}
+        for name in archive.namelist():
+            if not name.startswith('tables/'):
+                continue
+            filename = basename(name)
+            tablename, _ext = filename.rsplit('.', 1)
+            table_chunks.setdefault(tablename, []).append(name)
+        return sequences, tables, table_chunks
+
+    def read_sequence(self, archive, seq):
+        seqname, columns, rows = loads(archive.read('sequences/%s' % seq))
+        assert seqname == seq
+        assert len(rows) == 1
+        assert len(rows[0]) == 1
+        value = rows[0][0]
+        sql = self.dbhelper.sql_restart_sequence(seq, value)
+        self.cursor.execute(sql)
+        self.cnx.commit()
+
+    def read_table(self, archive, table, filenames):
+        merge_args = self._source.merge_args
+        self.cursor.execute('DELETE FROM %s' % table)
+        self.cnx.commit()
+        row_count = 0
+        for filename in filenames:
+            tablename, columns, rows = loads(archive.read(filename))
+            assert tablename == table
+            if not rows:
+                continue
+            insert = self.sql_generator.insert(table,
+                                               dict(zip(columns, rows[0])))
+            for row in rows:
+                self.cursor.execute(insert, merge_args(dict(zip(columns, row)), {}))
+            row_count += len(rows)
+            self.cnx.commit()
+        self.logger.info('inserted %d rows', row_count)
+
+
+    def _parse_versions(self, version_str):
+        versions = set()
+        for line in version_str.splitlines():
+            versions.add(tuple(line.split()))
+        return versions
+
+    def _get_versions(self):
+        version_sql = 'SELECT cw_pkey, cw_value FROM cw_CWProperty'
+        versions = []
+        self.cursor.execute(version_sql)
+        for pkey, value in self.cursor.fetchall():
+            if pkey.startswith(u'system.version'):
+                versions.append((pkey, value))
+        return versions