Serverless Function Best Practices

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Use connection pools that persist across function invocations

• Set the maximum connection pool size to 1, unless your function is multi-threaded and establishes multiple concurrent requests to your database within a single function instance.
• Do not set a minimum idle connection count. The connection pool should be free to open connections as needed.
• If supported by your pooling library, set the maximum lifetime on the connection pool to 30 minutes.

const { Pool } = require('pg')

let pool

const insertRows = async (p) => {
  const client = await p.connect()
  try {
    await client.query('INSERT INTO table (col1, col2) VALUES (val1, val2)')
  } catch (err) {
    console.log(err.stack)
  } finally {
    client.release()
  }
}

exports.handler = async (context) => {
  if (!pool) {
    const connectionString = process.env.DATABASE_URL
    pool = new Pool({
      connectionString,
      max: 1
    })
  }

  await insertRows(pool)
}

from psycopg2.pool import SimpleConnectionPool

pool = None

def query(p):
  conn = p.getconn()
  with conn.cursor() as cur:
      cur.execute("INSERT INTO table (col1, col2) VALUES (val1, val2)")
      conn.commit()

def lambda_handler(context):
    global pool

    if not pool:
        pool = SimpleConnectionPool(0, 1, dsn=os.environ['DATABASE_URL'])

    query(pool)

    return

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Use CockroachDB Standard

1. Create a CockroachDB Cloud account. If this is your first CockroachDB Cloud organization, it will be credited with $400 in free trial credits to get you started.
2. On the Get Started page, click Create cluster.
3. On the Select a plan page, select Standard.
4. On the Cloud & Regions page, select a cloud provider (GCP or AWS).
5. In the Regions section, select a region for the cluster. Refer to CockroachDB Cloud Regions for the regions where CockroachDB Standard clusters can be deployed. To create a multi-region cluster, click Add region and select additional regions.
6. Click Next: Capacity.
7. On the Capacity page, keep the Provisioned capacity at the default value of 2 vCPUs. Click Next: Finalize.
8. On the Finalize page, name your cluster. If an active free trial is listed in the right pane, you will not need to add a payment method, though you will need to do this by the end of the trial to maintain your organization’s clusters. Click Create cluster. Your cluster will be created in a few seconds and the Create SQL user dialog will display.

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Deploy serverless functions in the same region as your cluster

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See also

• Create and Deploy an AWS Lambda Function Built on CockroachDB
• Connect to your Cluster