mem0ai/mem0 · error · Error

Cassandra vector store requires localDataCenter when…

Error message

Cassandra vector store requires localDataCenter when secureConnectBundle is not provided.

What it means

The cassandra-driver requires a localDataCenter (a.k.a. load-balancing DC) when connecting directly to a cluster without a cloud bundle. createClient() enforces this right after the contactPoints check, so direct connections fail fast at client creation when it is absent.

Solutions

Set localDataCenter in the config to your cluster's DC name — 'datacenter1' for a default single-node install
Find the DC name with nodetool status or cqlsh 'DESCRIBE CLUSTER' if unsure
If using Astra, switch to secureConnectBundle which removes the localDataCenter requirement

Example fix

// before
new Cassandra({ contactPoints: ['127.0.0.1'], collectionName: 'mem' });

// after
new Cassandra({
  contactPoints: ['127.0.0.1'],
  localDataCenter: 'datacenter1',
  collectionName: 'mem',
});

Defensive patterns

Strategy: validation

Validate before calling

function assertCassandraDc(config: any) {
  if (!config.secureConnectBundle && !config.localDataCenter) {
    throw new Error('Missing localDataCenter (default single-node: datacenter1)');
  }
}

Try / catch

try { const store = new Cassandra(cfg); } catch (e) { if (e instanceof Error && e.message.includes('localDataCenter')) { cfg.localDataCenter = 'datacenter1'; } throw e; }

Prevention

Document 'datacenter1' as the default for single-node installs
Include localDataCenter in every shared config template for direct connections

When it happens

Trigger: Configuring the Cassandra store with contactPoints but no localDataCenter and no secureConnectBundle. The contactPoints check passes, then this error is thrown on the next line.

Common situations: Default single-node Cassandra installs use 'datacenter1' and devs omit the field; multi-DC clusters where the correct DC name (e.g. 'us-east', 'dc1') is not obvious; migrating an Astra config (which needs no localDataCenter) to self-hosted.

Related errors

AI-assisted analysis of mem0ai/mem0@001c235229 (2026-08-15). Data as JSON: /api/errors/853b5e2a6785e513. Report an issue: GitHub.

Appendix: source

Thrown at mem0-ts/src/oss/src/vector_stores/cassandra.ts:346

    );
  }

  private async createClient(): Promise<CassandraClientLike> {
    const driver = this.driver ?? (await this.loadDriver());
    const clientConfig: Record<string, any> = {};

    if (this.secureConnectBundle) {
      clientConfig.cloud = {
        secureConnectBundle: this.secureConnectBundle,
      };
    } else {
      if (!this.contactPoints || this.contactPoints.length === 0) {
        throw new Error(
          "Cassandra vector store requires contactPoints when secureConnectBundle is not provided.",
        );
      }
      if (!this.localDataCenter) {
        throw new Error(
          "Cassandra vector store requires localDataCenter when secureConnectBundle is not provided.",
        );
      }
      clientConfig.contactPoints = this.contactPoints;
      clientConfig.localDataCenter = this.localDataCenter;
      clientConfig.protocolOptions = {
        port: this.port,
      };
    }

    if (this.protocolVersion !== undefined) {
      clientConfig.protocolOptions = {
        ...(clientConfig.protocolOptions || {}),
        maxVersion: this.protocolVersion,
      };
    }
    if (this.loadBalancingPolicy) {
      clientConfig.policies = {

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