Redis iterate over key groups - redis

Question

I'm would like to check that all my keys in redis are correct.
I'm storing the keys in groups like so:
userid:fname
userid:lname
userid:age
...
I would like to iterate over the them by grouping them by userid and then check each group from fname, lname and age.
How can I do this?

Answer 1

ScanParams params = new ScanParams();
params.match("userid:fname*");
// Use "0" to do a full iteration of the collection.
ScanResult<String> scanResult = jedis.scan("0", params);
List<String> keys = scanResult.getResult();
Repeat above code for lname and age. Or, match user:id and then filter the groups using a regex and iterating through keys.
EDIT: For large collections (millions of keys), a scan result will return a few tens of elements. Adjust your code accordingly to continue scanning until the whole collection of keys has been scanned:
ScanParams params = new ScanParams();
params.match("userid:fname*");
// An iteration starts at "0": http://redis.io/commands/scan
ScanResult<String> scanResult = jedis.scan("0", params);
List<String> keys = scanResult.getResult();
String nextCursor = scanResult.getStringCursor();
int counter = 0;
while (true) {
for (String key : keys) {
addKeyToProperGroup(key);
}
// An iteration also ends at "0"
if (nextCursor.equals("0")) {
break;
}
scanResult = jedis.scan(nextCursor, params);
nextCursor = scanResult.getStringCursor();
keys = scanResult.getResult();
}

Answer 2

You can use Redis based java.util.Iterator and java.lang.Iterable interfaces offered by Redisson Redis client.
Here is an example:
RedissonClient redissonClient = RedissonClient.create(config);
RKeys keys = redissonClient.getKeys();
// default batch size on each SCAN invocation is 10
for (String key: keys.getKeys()) {
...
}
// default batch size on each SCAN invocation is 250
for (String key: keys.getKeys(250)) {
...
}