[massive store] Reintroduce methods that are necessary to properly handle master/slave configuration
Related to #15538303
# coding: utf-8
# copyright 2015-2016 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb is free software: you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb. If not, see <http://www.gnu.org/licenses/>.
import logging
from copy import copy
from collections import defaultdict
from itertools import chain
from base64 import b64encode
from six.moves import range
from yams.constraints import SizeConstraint
from cubicweb.dataimport import stores, pgstore
class MassiveObjectStore(stores.RQLObjectStore):
"""Store for massive import of data, with delayed insertion of meta data.
WARNINGS:
- This store may only be used with PostgreSQL for now, as it relies
on the COPY FROM method, and on specific PostgreSQL tables to get all
the indexes.
- This store can only insert relations that are not inlined (i.e.,
which do *not* have inlined=True in their definition in the schema),
unless they are specified as entity attributes.
It should be used as follows:
store = MassiveObjectStore(cnx)
eid_p = store.prepare_insert_entity('Person',
cwuri='http://dbpedia.org/toto',
name='Toto')
eid_loc = store.prepare_insert_entity('Location',
cwuri='http://geonames.org/11111',
name='Somewhere')
store.prepare_insert_relation(eid_p, 'lives_in', eid_loc)
store.flush()
...
store.commit()
store.finish()
Full-text indexation is not handled, you'll have to reindex the proper entity types by yourself
if desired.
"""
def __init__(self, cnx,
on_commit_callback=None, on_rollback_callback=None,
slave_mode=False,
eids_seq_range=10000,
metagen=None):
""" Create a MassiveObject store, with the following attributes:
- cnx: CubicWeb cnx
- eids_seq_range: size of eid range reserved by the store for each batch
"""
super(MassiveObjectStore, self).__init__(cnx)
self.on_commit_callback = on_commit_callback
self.on_rollback_callback = on_rollback_callback
self.slave_mode = slave_mode
self.eids_seq_range = eids_seq_range
if metagen is None:
metagen = stores.MetadataGenerator(cnx)
self.metagen = metagen
self.logger = logging.getLogger('dataimport.massive_store')
self.sql = cnx.system_sql
self.schema = self._cnx.vreg.schema
self.default_values = get_default_values(self.schema)
self.get_next_eid = lambda g=self._get_eid_gen(): next(g)
self._dbh = PGHelper(cnx)
cnx.read_security = False
cnx.write_security = False
self._data_entities = defaultdict(list)
self._data_relations = defaultdict(list)
self._initialized = set()
self._constraints_dropped = self.slave_mode
def _get_eid_gen(self):
""" Function getting the next eid. This is done by preselecting
a given number of eids from the 'entities_id_seq', and then
storing them"""
while True:
last_eid = self._cnx.repo.system_source.create_eid(self._cnx, self.eids_seq_range)
for eid in range(last_eid - self.eids_seq_range + 1, last_eid + 1):
yield eid
# master/slaves specific API
def master_init_etype(self, etype):
"""Initialize database for insertion of entities of the given etype.
This is expected to be called once, usually by the master store in master/slaves
configuration.
"""
self._drop_metadata_constraints_if_necessary()
tablename = 'cw_%s' % etype.lower()
self._dbh.drop_constraints(tablename)
self._dbh.drop_indexes(tablename)
self.sql('CREATE TABLE IF NOT EXISTS cwmassive_initialized'
'(retype text, type varchar(128))')
self.sql("INSERT INTO cwmassive_initialized VALUES (%(e)s, 'etype')", {'e': etype})
self.sql('ALTER TABLE %s ADD COLUMN extid VARCHAR(256)' % tablename)
def master_init_rtype(self, rtype):
"""Initialize database for insertion of relation of the given rtype.
This is expected to be called once, usually by the master store in master/slaves
configuration.
"""
assert not self._cnx.vreg.schema.rschema(rtype).inlined
self._drop_metadata_constraints_if_necessary()
tablename = '%s_relation' % rtype.lower()
self._dbh.drop_constraints(tablename)
self._dbh.drop_indexes(tablename)
self.sql('CREATE TABLE IF NOT EXISTS cwmassive_initialized'
'(retype text, type varchar(128))')
self.sql("INSERT INTO cwmassive_initialized VALUES (%(e)s, 'rtype')", {'e': rtype})
self.sql('CREATE TABLE %s_tmp (eid_from integer, eid_to integer)' % tablename)
def master_insert_etype_metadata(self, etype):
"""Massive insertion of meta data for a given etype, based on SQL statements.
In master/slabes configuration, you'll usually want to call it from the master once all
slaves have finished (at least slaves won't call it automatically, so that's your
reponsability).
"""
# insert standard metadata relations
for rtype, eid in self.metagen.base_etype_rels(etype).items():
self._insert_meta_relation(etype, eid, '%s_relation' % rtype)
# insert cw_source, is and is_instance_of relations (normally handled by the system source)
self._insert_meta_relation(etype, self.metagen.source.eid, 'cw_source_relation')
eschema = self.schema[etype]
self._insert_meta_relation(etype, eschema.eid, 'is_relation')
for parent_eschema in chain(eschema.ancestors(), [eschema]):
self._insert_meta_relation(etype, parent_eschema.eid, 'is_instance_of_relation')
# finally insert records into the entities table
self.sql("INSERT INTO entities (eid, type, extid) "
"SELECT cw_eid, '%s', extid FROM cw_%s "
"WHERE NOT EXISTS (SELECT 1 FROM entities WHERE eid=cw_eid)"
% (etype, etype.lower()))
# SQL utilities #########################################################
def _drop_metadata_constraints_if_necessary(self):
"""Drop constraints and indexes for the metadata tables if necessary."""
if not self._constraints_dropped:
self._drop_metadata_constraints()
self._constraints_dropped = True
def _drop_metadata_constraints(self):
"""Drop constraints and indexes for the metadata tables.
They will be recreated by the `finish` method.
"""
rtypes = [rtype for rtype in self.metagen.meta_relations
if not self.schema.rschema(rtype).final]
rtypes += ('is_instance_of', 'is', 'cw_source')
for rtype in rtypes:
self._dbh.drop_constraints(rtype + '_relation')
self._dbh.drop_indexes(rtype + '_relation')
# don't drop constraints for the entities table, the only one is the primary key's index on
# eid and we want to keep it
self._dbh.drop_indexes('entities')
def restart_eid_sequence(self, start_eid):
self.sql(self._cnx.repo.system_source.dbhelper.sql_restart_numrange(
'entities_id_seq', initial_value=start_eid))
self._cnx.commit()
# store api ################################################################
def prepare_insert_entity(self, etype, **kwargs):
"""Given an entity type, attributes and inlined relations, returns the inserted entity's
eid.
"""
if not self.slave_mode and etype not in self._initialized:
self._initialized.add(etype)
self.master_init_etype(etype)
attrs = self.metagen.base_etype_attrs(etype)
data = copy(attrs) # base_etype_attrs is @cached, a copy is necessary
data.update(kwargs)
if 'eid' not in data:
# If eid is not given and the eids sequence is set, use the value from the sequence
eid = self.get_next_eid()
data['eid'] = eid
# XXX default values could be set once for all in base entity
default_values = self.default_values[etype]
missing_keys = set(default_values) - set(data)
data.update((key, default_values[key]) for key in missing_keys)
self.metagen.init_entity_attrs(etype, data['eid'], data)
self._data_entities[etype].append(data)
return data['eid']
def prepare_insert_relation(self, eid_from, rtype, eid_to, **kwargs):
"""Insert into the database a relation ``rtype`` between entities with eids ``eid_from``
and ``eid_to``.
Relation must not be inlined.
"""
if not self.slave_mode and rtype not in self._initialized:
self._initialized.add(rtype)
self.master_init_rtype(rtype)
self._data_relations[rtype].append({'eid_from': eid_from, 'eid_to': eid_to})
def flush(self):
"""Flush the data"""
self.flush_entities()
self.flush_relations()
def commit(self):
"""Commit the database transaction."""
self.on_commit()
super(MassiveObjectStore, self).commit()
def finish(self):
"""Remove temporary tables and columns."""
if self.slave_mode:
raise RuntimeError('Store cleanup is not allowed in slave mode')
self.logger.info("Start cleaning")
# Get all the initialized etypes/rtypes
if self._dbh.table_exists('cwmassive_initialized'):
cu = self.sql('SELECT retype, type FROM cwmassive_initialized')
for retype, _type in cu.fetchall():
self.logger.info('Cleanup for %s' % retype)
if _type == 'rtype':
# Cleanup relations tables
self._cleanup_relations(retype)
self.sql('DELETE FROM cwmassive_initialized WHERE retype = %(e)s',
{'e': retype})
self._dbh.restore_indexes_and_constraints()
# Delete the meta data table
self.sql('DROP TABLE IF EXISTS cwmassive_initialized')
self.commit()
# FLUSH #################################################################
def on_commit(self):
if self.on_commit_callback:
self.on_commit_callback()
def on_rollback(self, exc, etype, data):
if self.on_rollback_callback:
self.on_rollback_callback(exc, etype, data)
self._cnx.rollback()
else:
raise exc
def flush_relations(self):
"""Flush the relations data."""
for rtype, data in self._data_relations.items():
if not data:
# There is no data for these etype for this flush round.
continue
buf = pgstore._create_copyfrom_buffer(data, ('eid_from', 'eid_to'))
if not buf:
# The buffer is empty. This is probably due to error in _create_copyfrom_buffer
raise ValueError
cursor = self._cnx.cnxset.cu
# Push into the tmp table
cursor.copy_from(buf, '%s_relation_tmp' % rtype.lower(),
null='NULL', columns=('eid_from', 'eid_to'))
# Clear data cache
self._data_relations[rtype] = []
def flush_entities(self):
"""Flush the entities data."""
for etype, data in self._data_entities.items():
if not data:
# There is no data for these etype for this flush round.
continue
# XXX It may be interresting to directly infer the columns' names from the schema
# XXX For now, the _create_copyfrom_buffer does a "row[column]"
# which can lead to a key error.
# Thus we should create dictionary with all the keys.
columns = set()
for d in data:
columns.update(d)
_data = []
_base_data = dict.fromkeys(columns)
for d in data:
_d = _base_data.copy()
_d.update(d)
_data.append(_d)
buf = pgstore._create_copyfrom_buffer(_data, columns)
if not buf:
# The buffer is empty. This is probably due to error in _create_copyfrom_buffer
raise ValueError('Error in buffer creation for etype %s' % etype)
columns = ['cw_%s' % attr for attr in columns]
cursor = self._cnx.cnxset.cu
try:
cursor.copy_from(buf, 'cw_%s' % etype.lower(), null='NULL', columns=columns)
except Exception as exc:
self.on_rollback(exc, etype, data)
# Clear data cache
self._data_entities[etype] = []
if not self.slave_mode:
self.master_insert_etype_metadata(etype)
def _cleanup_relations(self, rtype):
""" Cleanup rtype table """
# Push into relation table while removing duplicate
self.sql('INSERT INTO %(r)s_relation (eid_from, eid_to) SELECT DISTINCT '
'T.eid_from, T.eid_to FROM %(r)s_relation_tmp AS T '
'WHERE NOT EXISTS (SELECT 1 FROM %(r)s_relation AS TT WHERE '
'TT.eid_from=T.eid_from AND TT.eid_to=T.eid_to);' % {'r': rtype})
# Drop temporary relation table
self.sql('DROP TABLE %(r)s_relation_tmp' % {'r': rtype.lower()})
def _insert_meta_relation(self, etype, eid_to, rtype):
self.sql("INSERT INTO %s (eid_from, eid_to) SELECT cw_eid, %s FROM cw_%s "
"WHERE NOT EXISTS (SELECT 1 FROM entities WHERE eid=cw_eid)"
% (rtype, eid_to, etype.lower()))
def get_size_constraints(schema):
"""analyzes yams ``schema`` and returns the list of size constraints.
The returned value is a dictionary mapping entity types to a
sub-dictionnaries mapping attribute names -> max size.
"""
size_constraints = {}
# iterates on all entity types
for eschema in schema.entities():
# for each entity type, iterates on attribute definitions
size_constraints[eschema.type] = eschema_constraints = {}
for rschema, aschema in eschema.attribute_definitions():
# for each attribute, if a size constraint is found,
# append it to the size constraint list
maxsize = None
rdef = rschema.rdef(eschema, aschema)
for constraint in rdef.constraints:
if isinstance(constraint, SizeConstraint):
maxsize = constraint.max
eschema_constraints[rschema.type] = maxsize
return size_constraints
def get_default_values(schema):
"""analyzes yams ``schema`` and returns the list of default values.
The returned value is a dictionary mapping entity types to a
sub-dictionnaries mapping attribute names -> default values.
"""
default_values = {}
# iterates on all entity types
for eschema in schema.entities():
# for each entity type, iterates on attribute definitions
default_values[eschema.type] = eschema_constraints = {}
for rschema, _ in eschema.attribute_definitions():
# for each attribute, if a size constraint is found,
# append it to the size constraint list
if eschema.default(rschema.type) is not None:
eschema_constraints[rschema.type] = eschema.default(rschema.type)
return default_values
class PGHelper(object):
"""This class provides some helper methods to manipulate a postgres database metadata (index and
constraints).
"""
def __init__(self, cnx):
self.sql = cnx.system_sql
# Deals with pg schema, see #3216686
pg_schema = cnx.repo.config.system_source_config.get('db-namespace') or 'public'
self.pg_schema = pg_schema
def drop_indexes(self, tablename):
"""Drop indexes and constraints, storing them in a table for later restore."""
# Create a table to save the constraints, it allows reloading even after crash
self.sql('CREATE TABLE IF NOT EXISTS cwmassive_constraints(sql TEXT, insert_order SERIAL)')
indexes = self.table_indexes(tablename)
for name, query in indexes.items():
self.sql('INSERT INTO cwmassive_constraints(sql) VALUES (%(sql)s)', {'sql': query})
self.sql('DROP INDEX %s' % name)
def drop_constraints(self, tablename):
self.sql('CREATE TABLE IF NOT EXISTS cwmassive_constraints(sql TEXT, insert_order SERIAL)')
constraints = self.table_constraints(tablename)
for name, query in constraints.items():
self.sql('INSERT INTO cwmassive_constraints(sql) VALUES (%(sql)s)', {'sql': query})
self.sql('ALTER TABLE %s DROP CONSTRAINT %s' % (tablename, name))
def restore_indexes_and_constraints(self):
"""Restore indexes and constraints."""
if not self.table_exists('cwmassive_constraints'):
return
cu = self.sql('SELECT sql, insert_order FROM cwmassive_constraints '
'ORDER BY insert_order DESC')
for query, order in cu.fetchall():
self.sql(query)
self.sql('DELETE FROM cwmassive_constraints WHERE insert_order=%(order)s',
{'order': order})
self.sql('DROP TABLE cwmassive_constraints')
def table_exists(self, tablename):
"""Return True if the given table already exists in the database."""
cu = self.sql('SELECT 1 from information_schema.tables '
'WHERE table_name=%(t)s AND table_schema=%(s)s',
{'t': tablename, 's': self.pg_schema})
return bool(cu.fetchone())
def table_indexes_constraints(self, tablename):
"""Return one dictionary with all indexes by name, another with all constraints by name,
for the given table.
"""
indexes = self.table_indexes(tablename)
constraints = self.table_constraints(tablename)
_indexes = {}
for name, query in indexes.items():
# Remove pkey indexes (automatically created by constraints)
# Specific cases of primary key, see #3224079
if name not in constraints:
_indexes[name] = query
return _indexes, constraints
def table_indexes(self, tablename):
"""Return a dictionary of indexes {index name: index sql}, constraints included."""
indexes = {}
for name in self._index_names(tablename):
indexes[name] = self._index_sql(name)
return indexes
def table_constraints(self, tablename):
"""Return a dictionary of constraints {constraint name: constraint sql}."""
constraints = {}
for name in self._constraint_names(tablename):
query = self._constraint_sql(name)
constraints[name] = 'ALTER TABLE %s ADD CONSTRAINT %s %s' % (tablename, name, query)
return constraints
def _index_names(self, tablename):
"""Return the names of all indexes in the given table (including constraints.)"""
cu = self.sql("SELECT c.relname FROM pg_catalog.pg_class c "
"JOIN pg_catalog.pg_index i ON i.indexrelid = c.oid "
"JOIN pg_catalog.pg_class c2 ON i.indrelid = c2.oid "
"LEFT JOIN pg_catalog.pg_user u ON u.usesysid = c.relowner "
"LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace "
"WHERE c.relkind IN ('i','') "
" AND c2.relname = %(t)s "
" AND i.indisprimary = FALSE "
" AND n.nspname NOT IN ('pg_catalog', 'pg_toast') "
" AND pg_catalog.pg_table_is_visible(c.oid);", {'t': tablename})
return [name for name, in cu.fetchall()]
def _constraint_names(self, tablename):
"""Return the names of all constraints in the given table."""
cu = self.sql("SELECT i.conname FROM pg_catalog.pg_class c "
"JOIN pg_catalog.pg_constraint i ON i.conrelid = c.oid "
"JOIN pg_catalog.pg_class c2 ON i.conrelid=c2.oid "
"LEFT JOIN pg_catalog.pg_user u ON u.usesysid = c.relowner "
"LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace "
"WHERE c2.relname = %(t)s "
"AND n.nspname NOT IN ('pg_catalog', 'pg_toast') "
"AND pg_catalog.pg_table_is_visible(c.oid)", {'t': tablename})
return [name for name, in cu.fetchall()]
def _index_sql(self, name):
"""Return the SQL to be used to recreate the index of the given name."""
return self.sql('SELECT pg_get_indexdef(c.oid) FROM pg_catalog.pg_class c '
'LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace '
'WHERE c.relname = %(r)s AND n.nspname=%(n)s',
{'r': name, 'n': self.pg_schema}).fetchone()[0]
def _constraint_sql(self, name):
"""Return the SQL to be used to recreate the constraint."""
return self.sql('SELECT pg_get_constraintdef(c.oid) FROM pg_catalog.pg_constraint c '
'LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.connamespace '
'WHERE c.conname = %(r)s AND n.nspname=%(n)s',
{'r': name, 'n': self.pg_schema}).fetchone()[0]