AbortError: SCAN can't be processed. The connection is already closed.

[cague]

I have just two properties:
A = anything
AA = anything

Result:
cursor 0
cursor 1
cursor 3
AbortError: SCAN can't be processed. The connection is already closed.

function scanAsync( redis, cursor, pattern, set ) {
  return new Promise( ( resolve, reject ) => {
    scan( redis, cursor, pattern, set, resolve, reject );
  } );
}

function scan( redis, cursor, pattern, set, resolve, reject ) {
  console.log( "cursor", cursor );
  // Same result if using redis.scan( cursor, 'MATCH', pattern, 'COUNT', '1', function( err, res ) {
  redis.send_command( 'scan', [ cursor, 'MATCH', pattern, 'COUNT', '1' ], function( err, res ) {
    if ( err ) {
      throw err;
    }

    // Update the cursor position for the next scan
    cursor = res[ 0 ];
    // get the SCAN result for this iteration
    var keys = res[ 1 ];

    // Result is more or less than COUNT, or no keys may be returned.
    // SCAN may return the same key multiple times.
    if ( keys.length > 0 ) {
      keys.forEach( function( key, i ) {
        set.add( key );
      } );
    }

    // An iteration starts when the cursor is set to 0
    // and terminates when the cursor returned by the server is 0.
    if ( cursor === '0' ) {
      resolve( true );
    }
    else {
      scan( redis, cursor, pattern, set, resolve, reject );
    }
  } );
}

var myResults = new Set();
var redis = require( "redis" );

scanAsync( this.redis, '0', "A*", myResults ).then( function( value ) {
  console.log( value, "myResults", myResults, Array.from( myResults ) );
}, function( err ) {
  console.log( err );
} );

The server works ok:

mine:0>scan 0 'A*' 1
"ERR syntax error"
mine:0>scan 0 MATCH A* COUNT 1

1. "1"
2. 1. "AA"

mine:0>scan 1 MATCH A* COUNT 1

1. "3"
2. 1. "A"

mine:0>scan 3 MATCH A* COUNT 1

1. "0"

[BridgeAR]

@cague can you please format your code? You can for example use:

```js
// Your code that is formatted as JavaScript.
```

In general: this does not seem to be an issue with node_redis. The connection could be closed for multiple reasons.

[cague]

@BridgeAR
Thanks for the reply.
I think because the error is reproducible every time with the code I sent, there is a bug.
If there was anything random (if the code worked sometimes), I might suspect other reasons. But there isn't.

[danielsss]

@cague It seems that is caused by the connection and just like what @BridgeAR said

Also, I tried your code and it worked well.

version

• redis: "^2.8.0"
• node.js: "v10.15.1"
• redis-server: "5.0.5"

key/value

• sadd A 1 2 3
• sadd AA 1 2 3 4

code

function scanAsync( redis, cursor, pattern, set ) {
  return new Promise( ( resolve, reject ) => {
    scan( redis, cursor, pattern, set, resolve, reject );
  } );
}

function scan( redis, cursor, pattern, set, resolve, reject ) {
  console.log( "cursor", cursor );
  redis.send_command( 'scan', [ cursor, 'MATCH', pattern, 'COUNT', '1' ], function( err, res ) {
    if ( err ) {
      throw err;
    }
    cursor = res[ 0 ];
    var keys = res[ 1 ];

    if ( keys.length > 0 ) {
      keys.forEach( function( key, i ) {
        set.add( key );
      } );
    }
    if ( cursor === '0' ) {
      resolve( true );
    }
    else {
      scan( redis, cursor, pattern, set, resolve, reject );
    }
  } );
}

const myResults = new Set();
const redis = require("redis");
const client = new redis.createClient({port: 6378});

scanAsync(client, '0', "A*", myResults ).then( function( value ) {
  console.log( value, "myResults", myResults, Array.from( myResults ) );
  process.exit(0);
}, function( err ) {
  console.log( err );
  process.exit(1);
} );

output

cursor 0
cursor 1
true 'myResults' Set { 'AA', 'A' } [ 'AA', 'A' ]

[ishmam999]

In my case, whenever they find a data it quits. But when I set COUNT it works fine. I tried this for 150k data. I want to solve this without using the COUNT. As I might not know about the total keys in Redis.

Calling redis

async function (param) {

let cursor = '0'
while(true){
  const getAsync = promisify(this.client.scan).bind(this.client)
  const reply = await getAsync(cursor, 'MATCH', pattern)
  cursor = reply[0];
  console.log('test', reply[1])
  if(reply[1] != false){
    return reply[1]
  }
  if(cursor == 0){
    break
  }
}

}