GestaltDB

GestaltDB is a pure Python graph database toolkit for attributed graphs. It stores nodes, edges, labels, typed adjacency records, and property indexes on embedded key-value backends.

Documentation: https://mylonasc.github.io/gestaltdb/

Install From PyPI

With pip:

python -m pip install gestaltdb

With uv:

uv add gestaltdb

Install columnar ingestion dependencies:

python -m pip install "gestaltdb[arrow,polars]"

Install all optional backends and serializers:

python -m pip install "gestaltdb[all]"

Optional extras include lmdb, leveldb, rocksdb, arrow, polars, fast-ingest, msgpack, protobuf, bloom, docs, dev, and all.

Basic Example

from tempfile import TemporaryDirectory

from gestaltdb.graphdb import Edge, GraphDB, Node
from gestaltdb.kvstores import LevelDBStore
from gestaltdb.serializers import PickleSerializer

with TemporaryDirectory() as tmpdir:
    graph = GraphDB(LevelDBStore(path=f"{tmpdir}/graph"), PickleSerializer())

    graph.put_node(Node(node_id="alice", labels=["Person"], properties={"name": "Alice"}))
    graph.put_node(Node(node_id="bob", labels=["Person"], properties={"name": "Bob"}))
    graph.put_edge(Edge(
        edge_id="alice-knows-bob",
        source="alice",
        target="bob",
        properties={"type": "knows", "since": 2024},
    ))

    result = graph.query('MATCH (a:Person {name: "Alice"}) MATCH (a)-[:knows]->(b) RETURN a.id, b.name')
    print(result.records)

    graph.close()

Arrow Ingestion Example

This example ingests entity columns from PyArrow arrays. JSONSerializer lets GestaltDB build node and edge payloads from structured columns.

from tempfile import TemporaryDirectory

import pyarrow as pa

from gestaltdb.graphdb import GraphDB
from gestaltdb.kvstores import LevelDBStore
from gestaltdb.serializers import JSONSerializer
from gestaltdb import IndexMaintenanceMode

with TemporaryDirectory() as tmpdir:
    graph = GraphDB(LevelDBStore(path=f"{tmpdir}/graph"), JSONSerializer())

    graph.create_node_property_index("name")

    result = graph.ingest_arrow(
        pa.array(["alice", "bob", "carol"]),
        pa.array(["alice-knows-bob", "bob-knows-carol"]),
        pa.array(["alice", "bob"]),
        pa.array(["bob", "carol"]),
        pa.array(["knows", "knows"]),
        labels=pa.array([["Person"], ["Person"], ["Person"]]),
        node_properties={"name": pa.array(["Alice", "Bob", "Carol"]), "age": pa.array([34, 36, 29])},
        edge_properties={"since": pa.array([2024, 2025])},
        index_mode=IndexMaintenanceMode.DEFER_REBUILD,
    )
    print(result)  # {'nodes': 3, 'edges': 2, 'rebuilt_indexes': ..., 'stale_indexes': ()}

    result = graph.query('MATCH (a:Person {name: "Alice"}) MATCH (a)-[:knows]->(b) RETURN a.id, b.name')
    print(result.records)

    graph.close()

Polars Ingestion Example

This example ingests the same graph from Polars DataFrames. Property columns are converted into node and edge payloads during ingestion.

from tempfile import TemporaryDirectory

import polars as pl

from gestaltdb.graphdb import GraphDB
from gestaltdb.kvstores import LevelDBStore
from gestaltdb.serializers import JSONSerializer
from gestaltdb import IndexMaintenanceMode

nodes = pl.DataFrame({
    "node_id": ["alice", "bob", "carol"],
    "labels": [["Person"], ["Person"], ["Person"]],
    "name": ["Alice", "Bob", "Carol"],
    "age": [34, 36, 29],
})

edges = pl.DataFrame({
    "edge_id": ["alice-knows-bob", "bob-knows-carol"],
    "source": ["alice", "bob"],
    "target": ["bob", "carol"],
    "edge_type": ["knows", "knows"],
    "since": [2024, 2025],
})

with TemporaryDirectory() as tmpdir:
    graph = GraphDB(LevelDBStore(path=f"{tmpdir}/graph"), JSONSerializer())
    graph.create_node_property_index("name")

    graph.ingest_polars(
        nodes,
        edges,
        node_property_columns=["name", "age"],
        edge_property_columns=["since"],
        index_mode=IndexMaintenanceMode.DEFER_REBUILD,
    )

    result = graph.query('MATCH (a:Person) MATCH (a)-[:knows]->(b) RETURN a.name, b.name ORDER BY a.name')
    print(result.records)

    graph.close()

Install From A Checkout

From a local checkout:

uv sync

Install into another project:

uv add /path/to/gestaltdb

With pip:

python -m pip install /path/to/gestaltdb

Backend and Ingestion Recommendations

For the current library:

• Use LevelDBStore for small local graphs, examples, and straightforward embedded use.
• Use PyRexStore/RocksDB for large append-only loads and Arrow/Polars columnar ingestion.
• Use LMDBStore when LMDB's storage model is desirable and you can size map_size ahead of loading.
• Use JSONSerializer with GraphDB.ingest_polars or GraphDB.ingest_arrow when input data is already tabular and JSON-compatible.
• Use pre-serialized node_value and edge_value columns when upstream data already has serializer-compatible payload bytes.
• Keep IndexMaintenanceMode.MAINTAIN for incremental writes that need indexes ready immediately.
• Use IndexMaintenanceMode.DEFER or DEFER_REBUILD for bulk loads when you want to move secondary-index work out of the write path.

Measured locally on 100k nodes and 500k edges, RocksDB native columnar ingestion was 1.16x faster end-to-end than LevelDB on the same Python JSON payload path, and Polars JSON payload construction was 1.86x faster than Python JSON serialization. Deferred indexing made the write phase 8.72x faster, but immediate full rebuild made total ingest-plus-rebuild 17.2% slower for that subset. Treat these as workload-specific guidance and benchmark your graph shape, serializer, and indexes.

Features

• Attributed Node and Edge objects with stable IDs.
• Native node labels and typed edge traversal through edge.properties["type"].
• LMDB, LevelDB, and RocksDB/PyRex storage backends.
• Pickle, JSON, MessagePack, and Protobuf serializers.
• Label, relationship type, property, composite, and range indexes.
• Grammar-based, read-only Cypher subset for indexed scans, typed traversal, three-valued expressions, ordering, pagination, and chained MATCH clauses.
• Bulk and columnar ingestion helpers for Arrow and Polars.
• Typed path and subgraph sampling.

See the full documentation for backend selection, indexing, Cypher syntax, ingestion, sampling, and benchmarks.