N1ql 4.5 order by performance

Couchbase Server
,
3

So, I changed the query to be

SELECT * FROM store WHERE _type=“Product” AND updated IS NOT NULL ORDER BY updated DESC LIMIT 30

The time is always ~4s
Ah, all the documents have “updated” with a value

Here the explain:

[
{
“plan”: {
"#operator": “Sequence”,
"~children": [
{
"#operator": “Sequence”,
"~children": [
{
"#operator": “IndexScan”,
“index”: “ALL__updated2”,
“index_id”: “95395d770a48a8a4”,
“keyspace”: “store”,
“namespace”: “default”,
“spans”: [
{
“Range”: {
“High”: [
“successor(“Product”)”
],
“Inclusion”: 0,
“Low”: [
"“Product”",
“null”
]
}
}
],
“using”: “gsi”
},
{
"#operator": “Fetch”,
“keyspace”: “store”,
“namespace”: “default”
},
{
"#operator": “Parallel”,
"~child": {
"#operator": “Sequence”,
"~children": [
{
"#operator": “Filter”,
“condition”: “(((store._type) = “Product”) and ((store.updated) is not null))”
},
{
"#operator": “InitialProject”,
“result_terms”: [
{
“expr”: “self”,
“star”: true
}
]
}
]
}
}
]
},
{
"#operator": “Order”,
“limit”: “30”,
“sort_terms”: [
{
“desc”: true,
“expr”: “(store.updated)”
}
]
},
{
"#operator": “Limit”,
“expr”: “30”
},
{
"#operator": “FinalProject”
}
]
},
“text”: “SELECT * FROM store WHERE _type=“Product” AND updated IS NOT NULL ORDER BY updated DESC LIMIT 30”
}
]