Impl support for translating attribute expressions into pinot queries

[kotharironak]

Based on new the discussion, for the new AttributeExpression translate it to appropriate Pinot queries.

As part of this ticket, address the conversation to pinot queries for QS having AttributeExpression

• selection
• groupby
• order by
• filter

e.g of with AttributeExpression with subpath having filter clause

childFilter {
        lhs {
          AttributeExpression {
            attributeId: "API_TRACE.tags"
            subPath" "span.kind"
          }
        }
        operator: EQ
        rhs {
          literal {
            value {
              valueType: STRING
              string: "server"
            }
          }
        }
}

Pinot Query (selection, and limit are assumed), see filter expression for tags attribute for reference

select mapValue(tags__KEYS,'span.kind',tags__VALUES) FROM spanEventView 
WHERE tenant_id = '__default'  
AND mapValue(tags__KEYS,'span.kind',tags__VALUES) != ''
AND by mapValue(tags__KEYS,'span.kind',tags__VALUES) = 'server'
limit 10000

Reference:

See the reference UI ticket - hypertrace/hypertrace-ui#1099 and discussion.

---

As a part of this issue, the following subtasks would be required :

• Add and test support for handling simple attributeExpression #104
• Add and test support for handling complex attributeExpression #105

Few follow up PR's which will be required are :

• Add support for CONTAINS_KEY and NOT_CONTAINS_KEY for attributeExpression #122
• Add support for filtering map attributes using regex operator #109
• Replacing columnIdentifiers with attributeExpressions in preprocessing (tracked in fix: support for attribute expressions in selections #129)

[sarthak77]

We will currently have these 2 draft PR's stay as it is and they will be later merged appropriately :

• Added methods for handling custom group by #96
• Adding custom group by for map attributes #97

Doing this so that the whole process becomes simple and we will start with simple attributes first followed by the complex attributes.

[sarthak77]

I think the above 2 draft PR's will have to be eventually discarded as they contain only few changes but there are a lot of merge conflicts. Will incorporate their changes in new PR.

Closed #96. Changes have been forwarded in #107.
Closed #97. Changes have been forwarded in #107.