[英]MongoDB perl driver : different result after aggregation
我有收藏“書”:
{
"_id" : ObjectId("54901b078b823f2014080700"),
"title" : "title1",
"available" : 0,
"time" : 14318789245,
"score" : 1,
"categories" : ["fiction","humor"]
},
{
"_id" : ObjectId("54901b078b823f2014080701"),
"title" : "title2",
"available" : 1,
"time" : 14318789745,
"score" : 1,
"score_fiction": 5,
"categories" : ["fiction",]
}
...
{
"_id" : ObjectId("54901b078b823f2014080751"),
"title" : "titleN",
"available" : 1,
"time" : 14318789545,
"score" : 4,
"score_fiction": 2,
}
我將使用以下腳本對其進行匯總:
my $books = $mango->db('test')->collection('books')->aggregate([
{'$match' => {categories => fiction}},
{'$project' =>
{
'av' => {'$cmp' => ['$available', 0] },
title => 1,
scr => {'$ifNull' => ['$score_fiction' , '$score'] },
time =>1}
},
{'$sort' => {av => -1, scr => -1, time => -1}},
{'$limit' => 10}
]);
while (my $book = $books->next) {
print $book->{title} . " [" . $book->{scr} . "]\n";
運行5-7后,我得到兩個不同的結果:
當我在mongo的shell中運行此聚合管道時,它可以正確排序。
db.books.aggregate([{'$match' : {categories : 'fiction'},
{'$project' : {'av' : {'$cmp' : ['$available', 0] },
title : 1,
scr : {'$ifNull' : ['$score_fiction' , '$score'] },
time:1}},
{'$sort' : {av : -1,scr :-1, time : -1}},
{'$limit': 10}]);
問題出在司機還是我的頭上?
PS我嘗試了Mango和官方的MongoDB驅動程序,但是結果是一樣的。
{'$ sort'=> {av => -1,scr => -1,時間=> -1}},
如果您使用的是隨機散列順序的最新Perl,則可能是問題所在。 sort子句必須是有序文檔。 有關操作方法,請參見https://metacpan.org/pod/Mango::BSON#bson_doc 。
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