# Changelog

## 2.0.0

Released 2026-09-18. Built on psycopg 3, for Python 3.11 and later and AgensGraph 2.17 and later.

### Reading

- Vertices, edges and paths come back as `Vertex`, `Edge` and `Path`, from either of the server's
  renderings: the text one by default, and the composite one per statement with `binary_=True`.
- `GraphId` identities, hashable values compared on identity, with metadata and user properties in
  separate namespaces.
- A property map is decoded the first time it is read, so a row whose properties are never read never
  pays for them.
- `read_numbers_exactly()` for property maps whose numbers must keep every digit.
- `stream()` reads a large result a chunk at a time through a server-side cursor.
- `agensgraph.columnar` exports to Arrow, pandas and polars.
- `to_json()`, `to_builtins()` and `json_default` hand graph values to anything that wants JSON.

### Writing

- `load_vertices()` and `load_edges()` copy elements in with binary `COPY`, and `load_vertex_frame()`
  and `load_edge_frame()` copy them from a DataFrame.
- `upsert_vertices()` and `upsert_edges()` write only what is not already there, keyed on a property or
  on the pair of vertices an edge joins, and refuse a key nothing keeps unique.
- `identity_map()` reads the identities edges need.
- Dense and sparse embedding vectors, `nearest()`, and vector indexes built the way a Cypher search
  matches them.
- A Python `str` parameter is sent as `text`, so a string means a string in Cypher and in SQL.
- Write counters per statement, `counts_=True`.

### Connections

- `AsyncConnection` and the awaiting pools, generated from the same code as the blocking ones.
- A pool with a generation counter, so one call retires every connection after a server restart;
  `drain()`; and `NullConnectionPool`, which keeps nothing.
- `Deadline` bounds the wait for a connection and the statements on it together; `conn.deadline()` does
  it on a connection with no pool.
- `RetryPolicy`: six recoveries rather than a yes or no, full jitter under a cap, and a process-wide
  allowance that time refills.
- `transaction_id()` and `resolve_commit()` find out what became of a commit whose answer was lost.
- TCP keepalive is asked for by default.
- A connection whose statement was interrupted is closed by its pool rather than lent out again.
- From AgensGraph 2.18.6 the session's graph is read from what the server reports.

### Catalogs

- `graphs()`, `labels()`, `declared_properties()`, `indexes()`, `constraints()`, `vector_indexes()` and
  `element_counts()`.
- `describe()` builds a graph's shape from the catalogs, installing nothing in the database.
- `ensure_labels()`, `ensure_indexes()` and `ensure_constraints()` work out what is missing and create it,
  or return the statements for a caller with no connection.

### Everything else

- `read_only_transaction()` for a statement you did not write, which refuses a role that can run
  programs on the server's host, and `check_single_statement()`.
- Query logging, OpenTelemetry spans, and the server's notices as values.
- `LISTEN` and `NOTIFY`, with a handler or an iterator.
- `pipeline_query()` reads a burst of statements in one round trip, and `pipeline_batch()` writes one.
- Failures keep row data out of what they print as; `safe_message()` gives the one line to hand on.
- `ReadOnlyGraphWrite`, `ConfigurationError` and `CapabilityError` for refusals the server's codes do not
  tell apart.
- The PEP 249 surface, `agensgraph.dbapi`, which SQLAlchemy's psycopg dialect can use.
- Every version string a release has reported parses.
- Ships `py.typed`.