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i am useing spring redisTemplate and redis scan

it works find in condition of single node.

but in cluster enviroment it could not work

i can't get a data.

is there way to get a scan data in clust enviroment?

here is my spring redisTemplate code.

        //String key="products:aa";
        //String key="products:aac";
        //String key="products:ab";
        //String key="products:ac";


        String workKey="products:aa*";
        ScanOptions options = ScanOptions.scanOptions().match(workKey).count(100).build();

        ScanOptions options1 = ScanOptions.scanOptions().build();
        RedisConnectionFactory factory = redisTemplate.getConnectionFactory();
        RedisConnection conn = factory.getConnection();
        Cursor<byte[]> cursor = conn.scan(options);
        List<Product> result = new ArrayList<Product>();
        while(cursor.hasNext()){
            String key=new String((byte[]) cursor.next());
            Product pa=getById(key.replace("products:",""));
            result.add(pa);
        }

        //result 
        //String key="products:aa";
        //String key="products:aac";
james
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2 Answers2

2

Scan is a command for single redis node. If you do want to use it in cluster, first get nodes list in the cluster, and run scan for each node.

Mobility
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    Do you know where in the docs it says this https://redis.io/commands/scan? I’m sure you are right but is there a list of which redis commands are cluster ok and which you need to poll each node? – Andrew Arrow Oct 16 '18 at 19:39
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    If the command that may involve multiple keys, such as `mget`, `mset`, or `scan`, `keys` it should not supported by default. – Shaun Xu Oct 18 '18 at 03:37
1

Yes agreed, Scan used for single node.You have to scan for each node [master] of cluster. Below are example to delete all keys with matched string in cluster mode with predis.

/* Remove Multiple Keys with matched text */

public function removeMatchedKeys($keyName){
    $allRedisHost = array(host1,host2)
    if(!empty($allRedisHost ) && is_array($allRedisHost )) {
        foreach($allRedisHost as $key=>$host) {
            $singleRedisNode =  new Predis\Client("tcp://$host:6379");
            $it = NULL;
            $arr_keys_arr = array();
            $searchKeyName= $prefix.":".$keyName.":*";
            $i=0;
            foreach (new Iterator\Keyspace($singleRedisNode, $searchKeyName) as $actualKey) {
                $actualKey = str_replace($prefix . ':', '', $actualKey);
                $this->predis->del($actualKey);
                $i++;
            }
        }
    }
}

Here "Iterator\Keyspace" internally use scan method. Only need to include Iterator class [Predis\Collection\Iterator].

JYOTI RATHORE
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