Source code for superduperdb.backends.query_dataset

import inspect
import random
import typing as t

from superduperdb.backends.base.query import Select
from superduperdb.misc.special_dicts import MongoStyleDict

    from superduperdb.base.datalayer import Datalayer
    from superduperdb.components.model import Mapping

[docs] class ExpiryCache(list): def __getitem__(self, index): item = super().__getitem__(index) del self[index] return item
[docs] class QueryDataset: """ A dataset class which can be used to define a torch dataset class. :param select: A select query object which defines the query to be executed. :param keys: A list of keys to be returned from the dataset. :param fold: The fold to be used for the dataset. :param suppress: A list of keys to be suppressed from the dataset. :param transform: A callable which can be used to transform the dataset. :param db: A ``DB`` object to be used for the dataset. :param ids: A list of ids to be used for the dataset. :param in_memory: A boolean flag to indicate if the dataset should be loaded in memory. :param extract: A key to be extracted from the dataset. """ def __init__( self, select: Select, mapping: t.Optional['Mapping'] = None, ids: t.Optional[t.List[str]] = None, fold: t.Union[str, None] = 'train', transform: t.Optional[t.Callable] = None, db: t.Optional['Datalayer'] = None, in_memory: bool = True, ): self._db = db self.transform = transform if fold is not None: = select.add_fold(fold) else: = select self.in_memory = in_memory if self.in_memory: if ids is None: self._documents = list(self.db.execute( else: self._documents = list( self.db.execute( ) else: if ids is None: self._ids = [ r[] for r in self.db.execute( ] else: self._ids = ids self.select_one = self.mapping = mapping @property def db(self): if self._db is None: from import build_datalayer self._db = build_datalayer() return self._db def __len__(self): if self.in_memory: return len(self._documents) else: return len(self._ids) def _get_item(self, input): out = input if self.mapping is not None: out = self.mapping(out) if self.transform is not None and self.mapping is not None: if self.mapping.signature == '*args,**kwargs': out = self.transform(*out[0], **out[1]) elif self.mapping.signature == '*args': out = self.transform(*out) elif self.mapping.signature == '**kwargs': out = self.transform(**out) elif self.mapping.signature == 'singleton': out = self.transform(out) elif self.transform is not None: out = self.transform(out) return out def __getitem__(self, item): if self.in_memory: input = self._documents[item] else: input = self.select_one( self._ids[item], self.db, encoders=self.db.datatypes ) input = MongoStyleDict(input.unpack(db=self.db)) return self._get_item(input)
[docs] class CachedQueryDataset(QueryDataset): """ This class which fetch the document corresponding to the given ``index``. This class prefetches documents from database and stores in the memory. This can drastically reduce database read operations and hence reduce the overall load on the database. """ _BACKFILL_INDEX = 0.2 def __init__( self, select: Select, mapping: t.Optional['Mapping'] = None, ids: t.Optional[t.List[str]] = None, fold: t.Union[str, None] = 'train', transform: t.Optional[t.Callable] = None, db=None, in_memory: bool = True, prefetch_size: int = 100, ): super().__init__( select=select, mapping=mapping, ids=ids, fold=fold, transform=transform, db=db, in_memory=in_memory, ) self.prefetch_size = prefetch_size def _fetch_cache(self): cache_ids = random.sample(self.ids, self._max_cache_size) return ExpiryCache( list(self.database.execute( ) @property def database(self): if self._database is None: from import build_datalayer self._database = build_datalayer() return self._database def _get_random_index(self, index): return int((index * len(self._cache)) / self._total_documents) def _backfill_cache(self): if len(self._cache) <= int(self._max_cache_size * self._BACKFILL_INDEX): self._cache = self._fetch_cache() def __len__(self): return self._total_documents def __getitem__(self, index): index = self._get_random_index(index) self._backfill_cache() input = self._cache[index] return self._get_item(input)
[docs] def query_dataset_factory(**kwargs): if kwargs.get('data_prefetch', False): return CachedQueryDataset(**kwargs) kwargs = { k: v for k, v in kwargs.items() if k in inspect.signature(QueryDataset.__init__).parameters } return QueryDataset(**kwargs)