Node js stop long process task when Promise reject it - node.js

Question

I create a promise function to processing a long-time query task. Some time the task will block for hours. I want set a time out to stop the task. Below is the code.
It can return error message correctly, but it still running connection.execute() for long time before stop. So how can stop it immediately when it return reject message?
Thanks!
function executeQuery(connection, query) {
return new Promise((resolve, reject) => {
"use strict";
//long time query
connection.execute(query, function (err, results) {
if (err) reject('Error when fetch data');
else resolve(results);
clearTimeout(t);
});
let t = setTimeout(function () {
reject('Time Out');
}, 10);
})
(async () => {
"use strict";
oracle.outFormat = oracle.OBJECT;
try {
let query = fs.readFileSync("query.sql").toString();
let results = await executeQuery(connection, query);
console.log(results.rows);
} catch (e) {
console.log(`error:${e}`);
}

Answer 1

So how can stop it immediately when it return reject message?
According to the docs, you can use connection.break:
return new Promise((resolve, reject) => {
connection.execute(query, (err, results) => {
if (err) reject(err);
else resolve(results);
clearTimeout(t);
});
const t = setTimeout(() => {
connection.break(reject); // is supposed to call the execute callback with an error
}, 10);
})
Make sure to also release the connection in a finally block.

Answer 2

Try this (using bluebird promises):
var execute = Promise.promisify(connection.execute);
function executeQuery(connection, query) {
return execute.call(connection, query)
.timeout(10000)
.then(function (results) {
// handle results here
})
.catch(Promise.TimeoutError, function (err) {
// handle timeout error here
});
.catch(function (err) {
// handle other errors here
});
};
If this still blocks, there's a possibility that the database driver you are using is actually synchronous rather than asynchronous. In that case, that driver would be incompatible with the node event loop and you may want to look into another one.

Answer 3

As Bergi mentioned, you'll need to use the connection.break method.
Given the following function:
create or replace function wait_for_seconds(
p_seconds in number
)
return number
is
begin
dbms_lock.sleep(p_seconds);
return 1;
end;
Here's an example of its use:
const oracledb = require('oracledb');
const config = require('./dbConfig.js');
let conn;
let err;
let timeout;
oracledb.getConnection(config)
.then((c) => {
conn = c;
timeout = setTimeout(() => {
console.log('Timeout expired, invoking break');
conn.break((err) => {
console.log('Break finished', err);
});
}, 5000);
return conn.execute(
`select wait_for_seconds(10)
from dual`,
[],
{
outFormat: oracledb.OBJECT
}
);
})
.then(result => {
console.log(result.rows);
clearTimeout(timeout);
})
.catch(err => {
console.log('Error in processing', err);
if (/^Error: ORA-01013/.test(err)) {
console.log('The error was related to the timeout');
}
})
.then(() => {
if (conn) { // conn assignment worked, need to close
return conn.close();
}
})
.catch(err => {
console.log('Error during close', err)
});
Keep in mind that the setTimeout call is just before the execute (because of the return statement). That timeout will start counting down immediately. However, the execute call isn't guaranteed to start immediately as it uses a thread from the thread pool and it may have to wait till one is available. Just something to keep in mind...