Very basic Redis index and search not working - redisearch

Question

I'm starting with Redis (v7) and the lettucemod (v3.1.6), and trying to simulate an index/search sample found in redis docs. But I'm not able to get the right result. Below the sequence of actions taken in redis-cli:
root#redis01:~# redis-server --version
Redis server v=7.0.7 sha=00000000:0 malloc=jemalloc-5.2.1 bits=64 build=2260280010e18db8
root#redis01:~# redis-cli
127.0.0.1:6379> info modules
# Modules
module:name=ReJSON,ver=20008,api=1,filters=0,usedby=[search],using=[],options=[handle-io-errors]
module:name=search,ver=20405,api=1,filters=0,usedby=[],using=[ReJSON],options=[]
127.0.0.1:6379> FT.CREATE itemIdx ON JSON PREFIX 1 36: SCHEMA $.encoding AS encoding TEXT
OK
127.0.0.1:6379> FT._LIST
1) "itemIdx"
127.0.0.1:6379> JSON.SET 36:1 $ '{"encoding":"utf-8"}'
OK
127.0.0.1:6379> JSON.GET 36:1
"{\"encoding\":\"utf-8\"}"
127.0.0.1:6379> FT.SEARCH itemIdx '*'
1) (integer) 1
2) "36:1"
3) 1) "$"
2) "{\"encoding\":\"utf-8\"}"
127.0.0.1:6379> FT.SEARCH itemIdx '#encoding:utf-8'
1) (integer) 0
127.0.0.1:6379> FT.SEARCH itemIdx '#encoding:(tf)'
1) (integer) 0
Any help would be very appreciated.
Joan.

Answer 1

Let's start from the second query,
127.0.0.1:6379> FT.SEARCH itemIdx '#encoding:(tf)'
1) (integer) 0
It's missing a * to indicate it's a suffix query see: Infix/Suffix matching
127.0.0.1:6379> FT.SEARCH itemIdx '#encoding:*tf'
1) (integer) 1
2) "36:1"
3) 1) "$"
2) "{\"encoding\":\"utf-8\"}"
As for the first query,
127.0.0.1:6379> FT.SEARCH itemIdx '#encoding:utf-8'
1) (integer) 0
By default RediSearch escape some of the characters ,.<>{}[]"':;!##$%^&*()-+=~ to read more about it see: Tokenization
This is why the following works:
127.0.0.1:6379> FT.SEARCH itemIdx '#encoding:utf'
1) (integer) 1
2) "36:1"
3) 1) "$"
2) "{\"encoding\":\"utf-8\"}"
The simple way to work around this default escaping is to "escape it":
127.0.0.1:6379> JSON.SET 36:1 $ '{"encoding":"utf\\-8"}'
OK
127.0.0.1:6379> FT.SEARCH itemIdx '#encoding:utf\-8'
1) (integer) 1
2) "36:1"
3) 1) "$"
2) "{\"encoding\":\"utf\\\\-8\"}"
Other ways can include setting the slop between the words, or changing the default escaping.