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Using mysql.createPool(): Getting "ER_CON_COUNT_ERROR: Too many connections"

See original GitHub issue

We used to use mysql.createConnection(), but recently switched to start using connection pools (mysql.createPool()). Once we did the switch we started getting the following errors when running a load test, ER_CON_COUNT_ERROR: Too many connections.

Any idea why this could be happening? When we switched back to calling createConnection() we don’t get the error.

We had setup the pool with connectionLimit: 30. We called pool.query() instead of calling pool.getConnection() connection.query() and then connection.release() after each query. What we understood was that pool.query() does that for you, and calling getConnection explicitly was for transactions etc.

Everything else is the same.