Skip to content

symfonic.memory.backends.postgres_receipt_views

postgres_receipt_views

Exact opt-in PostgreSQL receipt views; raw PostgreSQL stays unadmitted.

PostgresReceiptGraph 

PostgresReceiptGraph(backend: Any, domain: Any)

Bases: _View

Graph view that cannot be forged by subclassing a raw PG backend.

Source code in src/symfonic/memory/backends/postgres_receipt_views.py 
25
26
27
def __init__(self, backend: Any, domain: Any) -> None:
    self._backend = backend
    self._domain = domain

PostgresReceiptVector 

PostgresReceiptVector(backend: Any, domain: Any)

Bases: _View

Vector view enlisted in the graph view's exact receipt domain.

Source code in src/symfonic/memory/backends/postgres_receipt_views.py 
25
26
27
def __init__(self, backend: Any, domain: Any) -> None:
    self._backend = backend
    self._domain = domain

arm_read_owner async 

arm_read_owner(domain: Any, journal: Any, scope: Any, owner: Any, revision: int) -> None

Lock the exact, uncompleted owned claim on the open read transaction.

The FOR UPDATE row lock holds until the read commits, so no journal unit of this invocation can advance its revision while candidates are read.

Source code in src/symfonic/memory/backends/postgres_receipt_views.py 
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
async def arm_read_owner(
    domain: Any, journal: Any, scope: Any, owner: Any, revision: int,
) -> None:
    """Lock the exact, uncompleted owned claim on the open read transaction.

    The FOR UPDATE row lock holds until the read commits, so no journal unit
    of this invocation can advance its revision while candidates are read.
    """
    from symfonic.memory.backends import postgres_operation_journal_codec as codec
    from symfonic.memory.backends.pool_transaction import bound_connection
    from symfonic.memory.backends.postgres_operation_journal import PostgresOperationJournal
    from symfonic.memory.backends.postgres_operation_receipt import PostgresReceiptDomain
    from symfonic.memory.storage_scope import NativeStorageScope

    if (
        type(domain) is not PostgresReceiptDomain
        or type(journal) is not PostgresOperationJournal
        or journal._domain is not domain
        or journal._uncertain
        or scope != NativeStorageScope.from_scope(owner.full_scope)
    ):
        raise MemoryContractError("PostgreSQL receipt read owner refused")
    conn = bound_connection(domain.pool)
    if conn is None:
        raise MemoryContractError("PostgreSQL receipt read owner needs its transaction")
    expected, verifier, expected_revision = journal._owner_binding(owner, revision)
    await codec.owned(conn, expected, verifier, expected_revision)