Support common function in SQL/PPL query engine

[chloe-zh]

Related design is presented in issue #182

Todo list

• Support the common functionality by pushing it down to the search engine
• Enable common function in SQL and PPL syntax and parser, including all the available parameters
• Make sure the function in new engine is compatible with the old engine support
• Add unit tests. (Unit tests are mandatory for all code changes.)
• Add integration test cases for common
• Update user manual

Function details

The common function maps to the common terms query used in the search engine. This query is a modern alternative to stopwords which improves the precision and recall of search results (by taking stopwords into account), without sacrificing performance.

Syntax:
common(field_expression, query_expression[, option=<option_value>]*)

Available options:

• analyzer
• cutoff_frequency
• high_frequency_operator
• low_frequency_operator
• minimum_should_match
• boost

Sample query:

# Search query 1
GET my_index/_search
{
  "query": {
    "common": {
      "message": {
        "query": "this is bonsai cool",
        "cutoff_frequency": 0.001
      }
    }
  }
}

# SQL
SELECT * FROM my_index WHERE common(message, "this is bonsai cool", cutoff_frequency=0.001)

# PPL
source=my_index | where common(message, "this is bonsai cool", cutoff_frequency=0.001)

[acarbonetto]

OpenSearch doesn't support common, the function is obsolete. Can we close this ticket?

[acarbonetto]

@anirudha common terms is marked as deprecated, see explanation here: https://github.com/opensearch-project/OpenSearch/blob/main/server/src/main/java/org/opensearch/index/query/CommonTermsQueryBuilder.java#L64

TL;DR: MatchQuery does the same thing.