Redis/Jedis - Delete by pattern?
It seems, for Jedis, to "delete by pattern" is basically getting all the keys of a specific pattern then loop through it.
ie
Set<String> keys = jedis.keys(pattern);
for (String key : keys) {
jedis.del(key);
}
KEYS is not recommended to use due to its inefficiencies when used in production. Please see https://redis.io/commands/keys. Instead, it is better to use SCAN. Additionally, a more efficient call than repeated calls to jedis.del() is to make one single call to jedis to remove the matching keys, passing in an array of keys to delete. A more efficient solution is presented below:
Set<String> matchingKeys = new HashSet<>();
ScanParams params = new ScanParams();
params.match("sample_pattern:*");
try(Jedis jedis = jedisPoolFactory.getPool().getResource()) {
String nextCursor = "0";
do {
ScanResult<String> scanResult = jedis.scan(nextCursor, params);
List<String> keys = scanResult.getResult();
nextCursor = scanResult.getStringCursor();
matchingKeys.addAll(keys);
} while(!nextCursor.equals("0"));
if (matchingKeys.size() == 0) {
return;
}
jedis.del(matchingKeys.toArray(new String[matchingKeys.size()]));
}
You should try using eval. I'm no Lua expert, but this code works.
private static final String DELETE_SCRIPT_IN_LUA =
"local keys = redis.call('keys', '%s')" +
" for i,k in ipairs(keys) do" +
" local res = redis.call('del', k)" +
" end";
public void deleteKeys(String pattern) {
Jedis jedis = null;
try {
jedis = jedisPool.getResource();
if (jedis == null) {
throw new Exception("Unable to get jedis resource!");
}
jedis.eval(String.format(DELETE_SCRIPT_IN_LUA, pattern));
} catch (Exception exc) {
if (exc instance of JedisConnectionException && jedis != null) {
jedisPool.returnBrokenResource(jedis);
jedis = null;
}
throw new RuntimeException("Unable to delete that pattern!");
} finally {
if (jedis != null) {
jedisPool.returnResource(jedis);
}
}
}
And then call:
deleteKeys("temp:keys:*");
This guarantees a one server-side call, multiple delete operation.