Skip to main content

CockroachDB integrations

还没翻译译自英文(docs.langchain.com)本页 68 段都还没译

CockroachDB is a distributed SQL database built on a transactional and strongly-consistent key-value store. It scales horizontally, survives disk, machine, rack, and even datacenter failures with minimal latency disruption and no manual intervention.

Key features:

  • Distributed SQL: Scale out while maintaining ACID guarantees
  • Native vector support: Built-in VECTOR type (v24.2+) and C-SPANN indexes (v25.2+)
  • PostgreSQL compatible: Drop-in replacement for PostgreSQL applications
  • Global replication: Multi-region deployments with low latency
  • Automatic sharding: Data automatically distributed across nodes
  • SERIALIZABLE isolation: Strongest isolation level by default

Installation and Setup

Install the LangChain integration:

pip install langchain-cockroachdb

Requires CockroachDB v25.4 or later.

Get your CockroachDB connection string

You'll need a CockroachDB cluster. Choose one option:

Option 1: CockroachDB Cloud (Recommended)

  1. Sign up at cockroachlabs.cloud
  2. Create a free cluster
  3. Get your connection string: cockroachdb://user:pass@host:26257/db?sslmode=verify-full

Option 2: Docker (Development)

docker run -d --name cockroachdb -p 26257:26257 \
  cockroachdb/cockroach:latest start-single-node --insecure

Connection string: cockroachdb://root@localhost:26257/defaultdb?sslmode=disable

Option 3: Local Binary

Download from cockroachlabs.com/docs/releases

Integrations

Vector Store

CockroachDB can be used as a vector store with native VECTOR type and C-SPANN distributed indexes.

Key features:

  • Native vector support (v24.2+)
  • C-SPANN indexes optimized for distributed systems (v25.2+)
  • Advanced metadata filtering
  • Hybrid search combining full-text and vector similarity (v0.3.0+)
  • Multi-tenancy with prefix columns
  • Horizontal scalability

See the CockroachDB entry in the vector stores overview for links to detailed usage.

Quick example:

from langchain_cockroachdb import AsyncCockroachDBVectorStore, CockroachDBEngine
from langchain_openai import OpenAIEmbeddings

# Initialize
engine = CockroachDBEngine.from_connection_string(
    "cockroachdb://user:pass@host:26257/db"
)

await engine.ainit_vectorstore_table(
    table_name="documents",
    vector_dimension=1536,
)

vectorstore = AsyncCockroachDBVectorStore(
    engine=engine,
    embeddings=OpenAIEmbeddings(),
    collection_name="documents",
)

# Use it
ids = await vectorstore.aadd_texts(["Hello world"])
results = await vectorstore.asimilarity_search("Hi", k=1)

Hybrid search (v0.3.0+) runs full-text and vector search in parallel and fuses the ranked results, using reciprocal rank fusion by default:

from langchain_cockroachdb import HybridSearchConfig

# create_tsvector=True adds the TSVECTOR column and GIN index
await engine.ainit_vectorstore_table(
    table_name="documents",
    vector_dimension=1536,
    create_tsvector=True,
)

vectorstore = AsyncCockroachDBVectorStore(
    engine=engine,
    embeddings=OpenAIEmbeddings(),
    collection_name="documents",
    hybrid_search_config=HybridSearchConfig(),
)

# The regular search methods now do hybrid search transparently
results = await vectorstore.asimilarity_search("distributed database performance", k=5)

Chat Message History

Store conversation history in CockroachDB for persistent, distributed chat applications.

Key features:

  • Distributed storage with automatic replication
  • Strong consistency (SERIALIZABLE)
  • Session-based organization
  • High availability

See CockroachDB chat history documentation for detailed usage.

Quick example:

from langchain_cockroachdb import CockroachDBChatMessageHistory, CockroachDBEngine
import uuid

engine = CockroachDBEngine.from_connection_string(CONNECTION_STRING)

chat_history = CockroachDBChatMessageHistory(
    session_id=str(uuid.uuid4()),
    engine=engine,
    table_name="chat_history",
)

from langchain.messages import HumanMessage, AIMessage

await chat_history.aadd_message(HumanMessage(content="Hello!"))
await chat_history.aadd_message(AIMessage(content="Hi there!"))

messages = await chat_history.aget_messages()

Sharing an engine reuses its connection pool and retry policy.

LangGraph Checkpointer

Persist LangGraph workflow state in CockroachDB for short-term memory, human-in-the-loop interactions, and fault tolerance.

Both sync (CockroachDBSaver) and async (AsyncCockroachDBSaver) implementations are available.

Tip

Call checkpointer.setup() (or await checkpointer.setup()) the first time you use the CockroachDB checkpointer to create the required tables.

SyncAsync

import os
from langchain.chat_models import init_chat_model
from langgraph.graph import StateGraph, MessagesState, START
from langchain_cockroachdb import CockroachDBSaver

model = init_chat_model(model="claude-haiku-4-5-20251001")

DB_URI = os.environ["COCKROACHDB_URI"]
# Example: "cockroachdb://user:password@host:26257/defaultdb?sslmode=verify-full"
with CockroachDBSaver.from_conn_string(DB_URI) as checkpointer:
    # checkpointer.setup()

    def call_model(state: MessagesState):
        response = model.invoke(state["messages"])
        return {"messages": response}

    builder = StateGraph(MessagesState)
    builder.add_node(call_model)
    builder.add_edge(START, "call_model")

    graph = builder.compile(checkpointer=checkpointer)

    config = {"configurable": {"thread_id": "1"}}

    stream = graph.stream_events(
        {"messages": [{"role": "user", "content": "hi! I'm bob"}]},
        config,
        version="v3",
    )
    for snapshot in stream.values:
        snapshot["messages"][-1].pretty_print()

    stream = graph.stream_events(
        {"messages": [{"role": "user", "content": "what's my name?"}]},
        config,
        version="v3",
    )
    for snapshot in stream.values:
        snapshot["messages"][-1].pretty_print()

Note

See Get your CockroachDB connection string above for connection options including CockroachDB Cloud (recommended for production), Docker, and local binary installs. For local development, sslmode=disable is acceptable; always use sslmode=verify-full in production.

Tip

The checkpointer uses raw psycopg3 connections (not SQLAlchemy) for compatibility with LangGraph's checkpoint interface. The from_conn_string factory accepts cockroachdb:// URLs and converts them automatically.

Row-Level TTL (v0.2.1+)

Automatically expire old checkpoint data using CockroachDB's Row-Level TTL:

with CockroachDBSaver.from_conn_string(DB_URI) as checkpointer:
    checkpointer.setup()

    # Expire checkpoints older than 30 days, clean up daily
    checkpointer.enable_ttl(ttl_interval="30 days", cron="@daily")

    # Use the checkpointer normally -- old data is cleaned up automatically
    graph = builder.compile(checkpointer=checkpointer)

    # To disable TTL later:
    # checkpointer.disable_ttl()

Async variant: await checkpointer.aenable_ttl(ttl_interval="7 days", cron="@hourly")

Note

TTL deletion is eventual -- expired rows remain queryable until CockroachDB's background job runs on the specified cron schedule.

Performance optimizations (v0.2.1+)

The checkpointer includes several optimizations for low-latency reads:

  • Batch fetching: list() fetches all blobs and writes in 2 batch queries instead of 2 per checkpoint
  • Raw BYTEA: Uses psycopg3 binary protocol instead of hex-encoding blobs in SQL
  • Prepared statements: prepare_threshold defaults to 5 and can be changed in from_conn_string
  • Concurrent setup: setup() is safe to run from several processes at once
  • Connection pools (v0.4.1+): For long-running services, pass a psycopg_pool connection pool rather than a single connection. A saver on a pool runs operations concurrently, each on its own pooled connection, so one saver can serve many agents; set the pool's max_size for the number of agents running at once. A saver on a single connection runs one operation at a time, and it cannot recover once that connection drops, which includes from_conn_string(..., pipeline=True)
  • Atomic writes (v0.4.1+): A checkpoint write with several statements goes to the database as one batch, so a write that is cancelled partway saves nothing. It still takes one round trip

Multi-tenancy

Isolate vector data by tenant using an opt-in namespace column. When enabled, all CRUD and search operations are scoped to the specified namespace.

CockroachDB's C-SPANN indexes support prefix columns, so namespace filtering uses the vector index directly without a separate scan.

from langchain_cockroachdb import AsyncCockroachDBVectorStore, CockroachDBEngine
from langchain_openai import OpenAIEmbeddings

engine = CockroachDBEngine.from_connection_string(CONNECTION_STRING)

# Create the table with a namespace column
await engine.ainit_vectorstore_table(
    table_name="documents",
    vector_dimension=1536,
    namespace_column="namespace",
)

# Create a vectorstore scoped to a specific tenant
vectorstore = AsyncCockroachDBVectorStore(
    engine=engine,
    embeddings=OpenAIEmbeddings(),
    collection_name="documents",
    namespace="tenant_a",
)

# All operations are scoped to tenant_a
ids = await vectorstore.aadd_texts(["Tenant A document"])
results = await vectorstore.asimilarity_search("query", k=5)

Document ids must be unique across namespaces. Ids the library generates always are, and adding a document whose id already belongs to another namespace raises ValueError without writing anything.

Retries and resilience (v0.4.0+)

Every operation retries transient CockroachDB errors: serialization failures (40001), ambiguous results (40003), connection errors (08xxx), node drains (57P01) and the CockroachDB range and node failures 58C00 and 58C01. All writes are idempotent, so a retry after an ambiguous result never duplicates data. Configure it once on the engine:

from langchain_cockroachdb import RETRYABLE_SQLSTATES, CockroachDBEngine, RetryPolicy

engine = CockroachDBEngine.from_connection_string(
    CONNECTION_STRING,
    retry_policy=RetryPolicy(
        max_attempts=8,
        # Optional for multi-region apps that set statement_timeout:
        retryable_sqlstates=RETRYABLE_SQLSTATES | {"57014"},
        attempt_timeout=10,
    ),
)

The vector store and chat history inherit the engine's policy. The checkpointers accept retry_policy too; give them a psycopg_pool connection pool so dropped connections are replaced. Since v0.4.1, a pooled checkpointer also retries whenever psycopg reports its connection broken, which covers TLS connections that drop on CockroachDB Cloud.

Why CockroachDB for AI applications?

Distributed by design

  • Horizontal scalability: Add nodes to handle more load
  • Multi-region deployments: Serve users globally with low latency
  • Automatic rebalancing: Data distributes automatically across nodes

Production-ready reliability

  • High availability: Survives node, rack, and datacenter failures
  • Zero-downtime upgrades: Rolling updates without downtime
  • Backups and restores: Point-in-time recovery

Vector search at scale

  • C-SPANN indexes: Distributed approximate nearest neighbor search
  • Native vector type: First-class support for embeddings
  • Real-time indexing: No rebuild needed for new vectors
  • Multi-tenancy: Prefix columns for efficient tenant isolation

PostgreSQL compatibility

  • Easy migration: Drop-in replacement for PostgreSQL
  • Familiar SQL: Standard PostgreSQL syntax
  • Existing tools: Works with PostgreSQL drivers and tools

Resources

Support