Wait for all queries to complete?

I’ll start with an example:

const mysql = require('mysql2/promise');

let pool = mysql.createPool({
    user: dbVars.login,
    password: dbVars.password,
    host: 'dev-sql',
    connectionLimit: 10,
    namedPlaceholders: true,
});

let fullStruct = {
    server: {},
    databases: {},
};

pool.query("SELECT TIMEDIFF(NOW(), UTC_TIMESTAMP) offset").then(([timeOffsetRows]) => {
    fullStruct.server.timeOffset = timeOffsetRows[0].offset;
});


pool.query("SELECT IF(@@session.time_zone = 'SYSTEM', @@system_time_zone, @@session.time_zone) timeZone").then(([timeZoneRows]) => {
    fullStruct.server.timeZone = timeZoneRows[0].timeZone;
});

await pool.end();
console.log(fullStruct);

This results in an error:

Error: Pool is closed.

I believe this happens because I’m closing the pool/connection before one of the queries has started. Now I can fix this by pushing each of those query promises into an array and then calling Promise.all before pool.end, but littering my code with queries.push(...) is kind of gross.

Does mysql2 not track the queries internally? Is there no way for me to just say “wait for everything to complete before closing”?

[sidorares]

with await you could have something like this to execute in parallel (maybe not in one line and without crazy destructuring ):

  [  [ [fullStruct.server.timeOffset] ], [ [fullStruct.server.timeZone] ] ] =
      await Promise.all([ 
        pool.query("SELECT TIMEDIFF(NOW(), UTC_TIMESTAMP) offset"),
        pool.query("SELECT IF(@@session.time_zone = 'SYSTEM', @@system_time_zone, @@session.time_zone) timeZone") ]);         

process.nextTick might be not enough - when Promise is returned the promise handler itself might be called in different tick ( can’t tell for sure ), so you have race between promise handlers in .query() and .end() + query() internally is doing getConnection() + connection.query() asynchronously, so it becomes really hard to tell for sure if this line is called before this one regardless on the original order of high level api calls.

[sidorares]

Which has been fixed?

This one:

It doesn’t appear to be releasing the connection when there’s an error