When we do run a complex query, the following problem is discovered
- Complex query : has sort condition or one or more logical operator (AND/OR/NOT)

First, If the number of entities exists more than "Limit" property's value and the query has one or more logical operator (AND/OR/NOT), it does not work correctly. because each node handle limited entities.

Second, Cursor should be used to cut the final result, but it is used to dealing with the results of each node to cut.

for example

	entities : [
		{
			"uuid":A,
			"name":"peter",
			"group:"groupA",
			"age":30
		},
		{
			"uuid":B,
			"name":"smith",
			"group:"groupA",
			"age":51
		},
		{
			"uuid":C,
			"name":"noil",
			"group:"groupB",
			"age":25
		},
		{
			"uuid":D,
			"name":"brown",
			"group:"groupB",
			"age":32
		},
		{
			"uuid":E,
			"name":"south",
			"group:"groupA",
			"age":84
		},
		{
			"uuid":F,
			"name":"bill",
			"group:"groupB",
			"age":17
		}
	]

	The first problem

	query : select * where group='groupA' and age>30 (limit=2)

	we expect the result

	[
		{
			"uuid":B,
			"name":"smith",
			"group:"groupA",
			"age":51
		},
		{
			"uuid":E,
			"name":"south",
			"group:"groupA",
			"age":84
		}
	]

	but the code will make the result below

	[
		{
			"uuid":B,
			"name":"smith",
			"group:"groupA",
			"age":51
		}
	]

	The second problem

	query : select * where (not group='groupA') order by age asc (limit=2, cursor=D)

	we expect the result

	[
		{
			"uuid":D,
			"name":"brown",
			"group:"groupB",
			"age":32
		}
	]

	but the code will make the result below

	[
		{
			"uuid":D,
			"name":"brown",
			"group:"groupB",
			"age":32
		},
		{
			"uuid":E,
			"name":"south",
			"group:"groupA",
			"age":84
		}
	]