Finding non-expiring keys in Redis

Question

In my setup, the info command shows me the following:

[keys] => 1128
[expires] => 1125

I'd like to find those 3 keys without an expiration date. I've already checked the docs to no avail. Any ideas?

Answer 1

Modified from a site that I can't find now.

redis-cli keys  "*" | while read LINE ; do TTL=`redis-cli ttl "$LINE"`; if [ $TTL -eq  -1 ]; then echo "$LINE"; fi; done;

edit: Note, this is a blocking call.

Answer 2

@Waynn Lue's answer runs but uses the Redis KEYS command which Redis warns about:

Warning: consider KEYS as a command that should only be used in production environments with extreme care. It may ruin performance when it is executed against large databases.

Redis documentation recommends using SCAN.

redis-cli --scan | while read LINE ; do TTL=`redis-cli ttl "$LINE"`; if [ $TTL -eq  -1 ]; then echo "$LINE"; fi; done;

If you want to scan for a specific key pattern, use:

 redis-cli --scan --pattern "something*"

Answer 3

In case somebody is getting bad arguments or wrong number of arguments error, put double quotes around $LINE.

So,it would be

redis-cli keys  "*" | while read LINE ; do TTL=`redis-cli ttl "$LINE"`; if [ $TTL -eq  -1 ]; then echo "$LINE"; fi; done;

This happens when there are spaces in the key.

Answer 4

To me the accepted answer appears unusable for a medium-sized dataset, as it will run a redis-cli command for each and every key.

Instead I used this lua script to filter the keys inside the redis server:

local show_persistent = ARGV[1] ~= "expiring"

local keys = {}
for i, name in ipairs(redis.call("keys", "*")) do
    local persistent = redis.call("pttl", name) < 0
    if persistent == show_persistent then
        table.insert(keys, name)
    end
end

return keys

This can be called as

$ redis-cli --eval show-persistent-keys.lua

to get all keys without an expiration time. It also can be called as

$ redis-cli --eval show-persistent-keys.lua , expiring

to find the opposite key set of all keys with an expiration time set.

On the downside this may block for too long (appears fine for 1 M keys). I'd use scan instead but I happen to have to run this against a legacy Redis at version 2.6, which does not have scan available.

Answer 5

I needed to extract non-expiring keys from bigger (40GB) dataset, so using keys command was not suitable for me. So in case someone is looking for offline/non-blocking solution, you can use https://github.com/sripathikrishnan/redis-rdb-tools for extraction of non-expiring keys from redis rdb dump.

You can just install libraries via pip:

pip install rdbtools python-lzf

Then create simple parser which extracts keys and values which has expiration set to None:

from rdbtools import RdbParser, RdbCallback
from rdbtools.encodehelpers import bytes_to_unicode

class ParserCallback(RdbCallback):

    def __init__(self):
        super(ParserCallback, self).__init__(string_escape=None)

    def encode_key(self, key):
        return bytes_to_unicode(key, self._escape, skip_printable=True)

    def encode_value(self, val):
        return bytes_to_unicode(val, self._escape)

    def set(self, key, value, expiry, info):
        if expiry is None:
            print('%s = %s' % (self.encode_key(key), self.encode_value(value)))


callback = ParserCallback()
parser = RdbParser(callback)
parser.parse('/path/to/dump.rdb')

Answer 6

#!/usr/bin/env python

import argparse
import redis

p = argparse.ArgumentParser()
p.add_argument("-i", '--host', type=str, default="127.0.0.1", help="redis host", required=False)
p.add_argument("-p", '--port', type=int, default=6379, help="redis port", required=False)
p.add_argument("-n", '--db', type=int, default=0, help="redis database", required=False)

args = p.parse_args()

r = redis.Redis(host=args.host, port=args.port, db=args.db)

try:
    keys = r.keys()

    for key in keys:
        if r.ttl(key) < 0:
            print(key)
except KeyboardInterrupt:
    pass