how to get only the ids of redis stream entries - redis

Question

Is there a way to get only the ids that are contained in the stream? something like an XKEYS command?
XKEYS "test:stream"
=>
1599031407838-0
1599031407839-0

Answer 1

There is no way to get this with a Redis command.
You can get this with Lua Scripts - EVAL command.
Using the XRANGE command, you get the ids and the field-value pairs.
> XRANGE streamkey - +
1) 1) "1599077066502-0"
2) 1) "fielda"
2) "valuea"
3) "fieldb"
4) "valueb"
2) 1) "1599077076318-0"
2) 1) "fielda"
...
In a Lua Script you can discard the field-value pairs from the response, leaving just the IDs. This way at least you reduce the size of the response saving on network payload and Client Output Buffers.
This script would get you started:
local resp = redis.call('XRANGE', KEYS[1], ARGV[1], ARGV[2])
for key,value in ipairs(resp) do
resp[key] = value[1]
end
return resp
Use as
EVAL "local resp = redis.call('XRANGE', KEYS[1], ARGV[1], ARGV[2]) for key,value in ipairs(resp) do resp[key] = value[1] end return resp" 1 streamkey - +
with the key start end of your choice as parameters.
You get as response:
EVAL "local resp ... return resp" 1 streamkey - +
1) "1599077066502-0"
2) "1599077076318-0"
3) "1599077085694-0"
4) ...