Implement proper patern match translation between PG and ES

Author: gruuya

pg_es_fdw/__init__.py

@@ -321,7 +321,7 @@ def _handle_aggregation_response(self, query, response, aggs, group_clauses):
             for agg_name in aggs:
                 if agg_name == "count.*":
                     # COUNT(*) is a special case, since it doesn't have a
-                    # corresponding aggregation primitice in ES
+                    # corresponding aggregation primitive in ES
                     result[agg_name] = response["hits"]["total"]["value"]
                     continue
 

pg_es_fdw/_es_query.py

@@ -1,3 +1,4 @@
+import re
 try:
     from multicorn import ANY
 except ImportError:
@@ -22,6 +23,20 @@
 }
 
 
+def _convert_pattern_match_to_es(expr):
+    def _pg_es_pattern_map(matchobj):
+        if matchobj.group(0) == "%":
+            return "*"
+        elif matchobj.group(0) == "_":
+            return "?"
+        elif matchobj.group(0) == "\%":
+            return "%"
+        elif matchobj.group(0) == "\_":
+            return "_"
+
+    return re.sub(r'\\?%|\\?_', _pg_es_pattern_map, expr)
+
+
 def _base_qual_to_es(col, op, value, column_map=None):
     if column_map:
         col = column_map.get(col, col)
@@ -44,7 +59,7 @@ def _base_qual_to_es(col, op, value, column_map=None):
         return {"bool": {"must_not": {"term": {col: value}}}}
 
     if op == "~~":
-        return {"wildcard": {col: value.replace("%", "*")}}
+        return {"wildcard": {col: _convert_pattern_match_to_es(value)}}
 
     # For unknown operators, get everything
     return {"match_all": {}}