system.stores.IndexedMVCC module

Indexed transactional key-value store built on MVCC.

class system.stores.IndexedMVCC.IndexedTransactionalKeyValueStore(use_brute_force_validation: bool = False)

Bases: TransactionalKeyValueStore, IndexedACIDStore

A fully transactional versioned (MVCC) key value store adding support for indexes.

class IndexCatalogueEntry(index_properties: IndexProperties, index: KeyValueStore[object, str])

Bases: object

Entries used for the index catalog.

index_properties: IndexProperties

index: KeyValueStore[object, str]

create_index(index_name: str, attribute: str, operator: str) → None

See IndexedACIDStore.create_index().

Only equality indexes (operator "=") are supported; any other operator raises. Raises as well if an index with the given name already exists. The index is backed by a PythonDictionaryIndex and acts as a filter index, i.e. lookups return a superset of matches that still has to be post-filtered.

drop_index(index_name: str) → None

See IndexedACIDStore.drop_index().

Removes the index from both catalogues (by name and by properties). Raises if no index with the given name exists.

abort_transaction(TA_id: int) → None

See TransactionalKeyValueStore.abort_transaction().

Before delegating to the base implementation, de-indexes every work-in-progress version created by the transaction from all indexes, so the indexes stay consistent with the reverted store.

get_suitable_indexes(attribute: str, operator: str) → Iterator[IndexProperties]

See IndexedACIDStore.get_suitable_indexes().

update_object(object_id: str, updated_object: object, TA_id: int) → None

See TransactionalKeyValueStore.update_object().

After delegating to the base implementation, maintains all indexes for the change: the new object version is indexed and any superseded work-in-progress version of the same transaction is de-indexed.

delete_object(object_id: str, TA_id: int) → None

See TransactionalKeyValueStore.delete_object().

After delegating to the base implementation, de-indexes a superseded work-in-progress version of the same transaction (if any) from all indexes.