Mongodb使用lookup链表查询后排序合计数据后的排序慢

<span class="tag"><code</span> <span class="atn">class</span><span class="pun">=</span><span class="atv">"language-json"</span><span class="tag">>
[
{
'$match': {
'KPfProfileId': {
'$in': [
42177743503074
]
}
}
}, {
'$lookup': {
'from': 'KeywordReportV1', 
'let': {
'kwId': '$KKeywordId'
}, 
'pipeline': [
{
'$match': {
'$expr': {
'$and': [
{
'$eq': [
'$kwId', '$$kwId'
]
}, {
'$gte': [
'$ReportTime', 1663603200
]
}, {
'$gt': [
'$Impr', 0
]
}
]
}
}
}, {
'$project': {
'_id': 0, 
'Spend': 1
}
}
], 
'as': 'KeywordReportV1s'
}
}, {
'$addFields': {
'spend': {
'$sum': '$KeywordReportV1s.Spend'
}
}
}, {
'$match': {
'spend': {
'$gt': 0
}
}
}, {
'$sort': {
'spend': -1
}
}
]</span><span class="pln">
</span><span class="tag"></code></span>