`toLower()` does not support in `lookup`

[foesa]

In Nebula Graph version v2.5.0, the following statement is not supported:

(root@nebula) [basketballplayer]> LOOKUP ON player WHERE player.name CONTAINS toLower("L") \
                               ->         YIELD player.name, player.age;
[ERROR (-1009)]: SemanticError: Expression (player.name CONTAINS toLower("L")) not supported yet

But in the previous version, the statement has a return value as follows:

nebula> LOOKUP ON player WHERE player.name CONTAINS toLower("L") \
        YIELD player.name, player.age;
+-------------+---------------------+------------+
| VertexID    | player.name         | player.age |
+-------------+---------------------+------------+
| "player145" | "JaVale McGee"      | 31         |
+-------------+---------------------+------------+
| "player144" | "Shaquille O'Neal"  | 47         |
+-------------+---------------------+------------+
| "player102" | "LaMarcus Aldridge" | 33         |
+-------------+---------------------+------------+

[Yichen Wang]

This case has been added in this pr. It's weird if this is not supported in the master branch. Could you verify the version of Nebula service?

[min.wu]

show the graph version

[CBS]

I don't agree to support this syntax. This syntax will result in a full index scan. It's a departure from our original design.

[CBS]

If there is such a need, it is best to use full-text index.

[min.wu]

There must be something wrong with the developing, testing, and releasing process.
How is this tested and released?

[foesa]

[kyle.cao]

I don't agree to support this syntax. This syntax will result in a full index scan. It's a departure from our original design.

@bright-starry-sky lookup on player also result in a full tag scan. Should we disable these scenarios?

[min.wu]

@Sophie-Xie loop PM

[Yichen Wang]

@whitewum In the off-line discussion with @bright-starry-sky , he states that this scenario should be processed using full-text search, since this query triggers a full index scan, and will potentially result in a slow query. @bright-starry-sky also talked about this with Sherman, and they had an agreement on this.

So we decide to not support this kind of filter, and I will refactor this PR and submit it to the nebula repo.

[min.wu]

@Sophie-Xie is it proper to add to change log in release note?