Should not reach here: undefined

[caramboleyo-no2fa]

I am using stream to move a big data set, but it seems there is a cap of ~460 iterations that causes an error i dont understand.

This is my code:

let i = 0;
const stream = connection.query('SELECT * FROM schedules ORDER BY id ASC').stream();
stream.on('data', result => {
	stream.pause();
	db.collection('packages').deleteOne({ id: result.id }).then(() => {
		db.collection('packages').insertOne(result).then(() => {
			i++;
			if (i % 1000 === 0) {
				console.log('Processed', i);
			}
			stream.resume();
		});
	});
});
stream.on('end', () => {
	connection.end();
	mongoClient.close();
	console.log('Finished streaming', i);
});

      at readLengthCodedNumberExt (/home/bun/app/node_modules/mysql2/lib/packets/packet.js:231:13)
      at readLengthCodedString (/home/bun/app/node_modules/mysql2/lib/packets/packet.js:381:22)
      at next (32:68)
      at row (/home/bun/app/node_modules/mysql2/lib/commands/query.js:242:29)
      at execute (/home/bun/app/node_modules/mysql2/lib/commands/command.js:45:22)
      at handlePacket (/home/bun/app/node_modules/mysql2/lib/connection.js:481:34)
      at /home/bun/app/node_modules/mysql2/lib/connection.js:97:12
      at executePayload (/home/bun/app/node_modules/mysql2/lib/packet_parser.js:139:14)
      at /home/bun/app/node_modules/mysql2/lib/connection.js:104:25
227 |       res = resNumber.toString() === resString ? resNumber : resString;
228 |       return bigNumberStrings ? resString : res;
229 |     }
230 |     // eslint-disable-next-line no-console
231 |     console.trace();
232 |     throw new Error(`Should not reach here: ${tag}`);
                ^
error: Should not reach here: undefined
      at readLengthCodedNumberExt (/home/bun/app/node_modules/mysql2/lib/packets/packet.js:232:11)
      at readLengthCodedString (/home/bun/app/node_modules/mysql2/lib/packets/packet.js:381:22)
      at next (32:68)
      at row (/home/bun/app/node_modules/mysql2/lib/commands/query.js:242:29)
      at execute (/home/bun/app/node_modules/mysql2/lib/commands/command.js:45:22)
      at handlePacket (/home/bun/app/node_modules/mysql2/lib/connection.js:481:34)
      at /home/bun/app/node_modules/mysql2/lib/connection.js:97:12
      at executePayload (/home/bun/app/node_modules/mysql2/lib/packet_parser.js:139:14)
      at /home/bun/app/node_modules/mysql2/lib/connection.js:104:25
      at emit (node:events:183:48)

if i use async/await instead of thenables i have the same result, only when i dont do both it runs through, but then 3mio db operations stuck up in memory and make dev ops kill it.

all i want is to do this in the background a little slower.

[surjikal]

We're seeing this as well, on NodeJS.

We're using the promise API, so I'd expect the query promise to be rejected.

Unfortunately, that's not what's happening with this one. The error event gets emitted from something, and brings the whole process down.

Ignoring the actual error here...

I'd like to do some graceful handling; what's emitting this event?

I'm pretty sure it's this one, but not 100%:

const connection = await pool.getConnection();
connection.connection // <- this one