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// test short-circuiting of $and and $or in
// $project stages to a $const boolean
var t = db.jstests_aggregation_server6192;
t.drop();
t.save( {x: true} );
function assertOptimized(pipeline, v) {
var explained = t.runCommand("aggregate", {
pipeline: pipeline,
explain: true
});
printjson({input: pipeline, output: explained});
assert("stages" in explained);
assert("$project" in explained.stages[1]);
var projectStage = explained.stages[1]["$project"];
assert.eq(projectStage.a["$const"], v, "ensure short-circuiting worked");
}
function assertNotOptimized(pipeline) {
var explained = t.runCommand("aggregate", {
pipeline: pipeline,
explain: true
});
printjson({input: pipeline, output: explained});
assert("stages" in explained);
assert("$project" in explained.stages[1]);
var projectStage = explained.stages[1]["$project"];
assert(!("$const" in projectStage.a), "ensure no short-circuiting");
}
// short-circuiting for $and
assertOptimized([ {$project: {a: {$and: [0, '$x']}}} ], false);
assertOptimized([ {$project: {a: {$and: [0, 1, '$x']}}} ], false);
assertOptimized([ {$project: {a: {$and: [0, 1, '', '$x']}}} ], false);
assertOptimized([ {$project: {a: {$and: [1, 0, '$x']}}} ], false);
assertOptimized([ {$project: {a: {$and: [1, '', 0, '$x']}}} ], false);
assertOptimized([ {$project: {a: {$and: [1, 1, 0, 1]}}} ], false);
// short-circuiting for $or
assertOptimized([ {$project: {a: {$or: [1, '$x']}}} ], true);
assertOptimized([ {$project: {a: {$or: [1, 0, '$x']}}} ], true);
assertOptimized([ {$project: {a: {$or: [1, '', '$x']}}} ], true);
assertOptimized([ {$project: {a: {$or: [0, 1, '$x']}}} ], true);
assertOptimized([ {$project: {a: {$or: ['', 0, 1, '$x']}}} ], true);
assertOptimized([ {$project: {a: {$or: [0, 0, 0, 1]}}} ], true);
// examples that should not short-circuit
assertNotOptimized([ {$project: {a: {$and: [1, '$x']}}} ]);
assertNotOptimized([ {$project: {a: {$or: [0, '$x']}}} ]);
assertNotOptimized([ {$project: {a: {$and: ['$x', '$x']}}} ]);
assertNotOptimized([ {$project: {a: {$or: ['$x', '$x']}}} ]);
assertNotOptimized([ {$project: {a: {$and: ['$x']}}} ]);
assertNotOptimized([ {$project: {a: {$or: ['$x']}}} ]);
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