1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
|
// SERVER-393 Test indexed matching with $exists.
t = db.jstests_exists6;
t.drop();
t.ensureIndex( {b:1} );
t.save( {} );
t.save( {b:1} );
t.save( {b:null} );
checkExists = function( query ) {
// Constraint on 'b' is trivial, so a BasicCursor is the default cursor type.
assert.eq( 'BasicCursor', t.find( query ).explain().cursor );
// Index bounds include all elements.
assert.eq( [ [ { $minElement:1 }, { $maxElement:1 } ] ], t.find( query ).hint( {b:1} ).explain().indexBounds.b );
// All keys must be scanned.
assert.eq( 3, t.find( query ).hint( {b:1} ).explain().nscanned );
// 2 docs will match.
assert.eq( 2, t.find( query ).hint( {b:1} ).itcount() );
}
checkExists( {b:{$exists:true}} );
checkExists( {b:{$not:{$exists:false}}} );
checkMissing = function( query ) {
// Constraint on 'b' is nontrivial, so a BtreeCursor is the default cursor type.
assert.eq( 'BtreeCursor b_1', t.find( query ).explain().cursor );
// Scan null index keys.
assert.eq( [ [ null, null ] ], t.find( query ).explain().indexBounds.b );
// Two existing null keys will be scanned.
assert.eq( 2, t.find( query ).explain().nscanned );
// One doc is missing 'b'.
assert.eq( 1, t.find( query ).hint( {b:1} ).itcount() );
}
checkMissing( {b:{$exists:false}} );
checkMissing( {b:{$not:{$exists:true}}} );
// Now check existence of second compound field.
t.ensureIndex( {a:1,b:1} );
t.save( {a:1} );
t.save( {a:1,b:1} );
t.save( {a:1,b:null} );
checkExists = function( query ) {
// Index bounds include all elements.
assert.eq( [ [ { $minElement:1 }, { $maxElement:1 } ] ], t.find( query ).explain().indexBounds.b );
// All keys must be scanned.
assert.eq( 3, t.find( query ).explain().nscanned );
// 2 docs will match.
assert.eq( 2, t.find( query ).hint( {a:1,b:1} ).itcount() );
}
checkExists( {a:1,b:{$exists:true}} );
checkExists( {a:1,b:{$not:{$exists:false}}} );
checkMissing = function( query ) {
// Scan null index keys.
assert.eq( [ [ null, null ] ], t.find( query ).explain().indexBounds.b );
// Two existing null keys will be scanned.
assert.eq( 2, t.find( query ).explain().nscanned );
// One doc is missing 'b'.
assert.eq( 1, t.find( query ).hint( {a:1,b:1} ).itcount() );
}
checkMissing( {a:1,b:{$exists:false}} );
checkMissing( {a:1,b:{$not:{$exists:true}}} );
|
