FT.AGGREGATE Strange Behavior

Redis modules RediSearch
1

I’m trying to migrate our redisearch queries from FT.SEARCH to FT.AGGREGATE. But I’m having problems with running them:

FT.SEARCH idx * returns all our records for an index just fine, but after simply changing it to FT.AGGREGATE idx *, it just returns a 1 and empty arrays, which is strange - what does the 1 mean and why are all arrays now empty:

1) (integer) 1
2) (empty array)
3) (empty array)
4) (empty array)
5) (empty array)
6) (empty array)
7) (empty array)
8) (empty array)
9) (empty array)

When using FT.AGGREGATE idx * WITHCURSOR COUNT 3, it returns:

1) 1) (integer) 1
   2) (empty array)
   3) (empty array)
   4) (empty array)
2) (integer) <cursor>

But then I do FT.CURSOR READ idx <cursor>, I get: Error: Server closed the connection, but I’m sure the cursor should not have timed out yet

2

Hi Cheng,

FT.AGGREGATE does not load any fields by default. You can use LOAD to add fields you wish to return or you can use LOAD * to load all fields.

Can you please share more info about the cursor? the error you report might be a server crash. What version of redis and redisearch are you using?

3

Hi,

Adding load * returns an error like this, what’s the right way to get all fields back?

FT.AGGREGATE idx * LOAD *
(error) Bad arguments for LOAD: Could not convert argument to expected type

I’m using: Redis server v=6.2.6 and redis-cli 6.2.6

4

@cheng what version of RediSearch are you using?

5

It should be RediSearch 2 v 2.0.6
and Redis version 6.0.6

6

@cheng LOAD * was added in 2.0.13.
The latest version is 2.2.10

7

Got it thanks. Is the FT.CURSOR READ error also version related? e.g.

> FT.AGGREGATE idx * LOAD 1 name WITHCURSOR COUNT 3
1) 1) (integer) 1
   2) 1) "name"
      2) "test3"
   3) 1) "name"
      2) "test4"
   4) 1) "name"
      2) "test2"
2) (integer) <cursor>
> FT.CURSOR READ idx <cursor>
Error: Server closed the connection
8

Do you get <cursor> in the reply? You should get a number.

Error: Server closed the connection - did your server crash? If so, can you please provide us with the full crash report?

9

Yes, I got the cursor and used it. I don’t see a crash in the server log, but I ran the same thing to another db using Redis version 6.2.3 and RediSearch 2 v 2.0.11, and the error went away. So I think it’s a version-related issue.

10

Good to hear the cursor is working for you now.
I have tried recreating the issue with v2.0.6 without success.
Can you provide further details about reproducing the issue?

11

Hm sure, I ran redis server, and then redis-cli, went through auth, then these commands-

> FT.AGGREGATE idx * LOAD 1 name WITHCURSOR COUNT 3
1) 1) (integer) 1
   2) 1) "name"
      2) "test3"
   3) 1) "name"
      2) "test4"
   4) 1) "name"
      2) "test2"
2) (integer) <cursor>
> FT.CURSOR READ idx <cursor>
Error: Server closed the connection

I don’t think there are more details to it.

12

But why do read docs states that the load hurts the performance of AGGREGATE queries ? I am bit confused in this.

Docs : Aggregations | Redis