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Backend question · Databases & SQL › Connections & pooling

With a node-postgres Pool of max: 10, this endpoint hangs forever after about ten requests. Why?

app.get('/report', async (req, res) => {
  const client = await pool.connect();
  const { rows } = await client.query('SELECT * FROM report');
  res.json(rows);
});
The client is never released, so all ten connections stay checked out and pool.connect() waits indefinitely for a free one

"The client is never released" is correct. A client from pool.connect() must be returned with client.release(). Put the release in a finally block, so an error does not leak the client. Once all ten clients are checked out, new callers wait in the pool's queue forever.

"PostgreSQL's default max_connections is 10" is wrong: the default is 100. Also note that for a single statement, pool.query() checks out a client and releases it for you.