141 lines
4.6 KiB
JavaScript
141 lines
4.6 KiB
JavaScript
/**
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* Tests the $first and $last accumulators in $group.
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*
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* @tags: [
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* requires_fcv_81,
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* ]
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*/
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const coll = db.jstests_aggregation_firstlast;
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coll.drop();
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/** Check expected $first and $last result values. */
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function assertFirstLast(expectedFirst, expectedLast, stages, expression) {
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let pipeline = [{$sort: {_id: 1}}];
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if (stages) {
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pipeline = pipeline.concat(stages);
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}
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expression = expression || "$b";
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pipeline.push({$group: {_id: "$a", first: {$first: expression}, last: {$last: expression}}});
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const result = coll.aggregate(pipeline).toArray();
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for (let i = 0; i < result.length; ++i) {
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if (result[i]._id === 1) {
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// Check results for group _id 1.
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assert.eq(expectedFirst, result[i].first);
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assert.eq(expectedLast, result[i].last);
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return;
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}
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}
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throw new Error('Expected $group _id "1" is missing');
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}
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// One document.
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assert.commandWorked(coll.insert({a: 1, b: 1}));
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assertFirstLast(1, 1);
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// Two documents.
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assert.commandWorked(coll.insert({a: 1, b: 2}));
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assertFirstLast(1, 2);
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// Three documents.
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assert.commandWorked(coll.insert({a: 1, b: 3}));
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assertFirstLast(1, 3);
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// Another 'a' key value does not affect outcome.
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assert(coll.drop());
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assert.commandWorked(coll.insert({a: 3, b: 0}));
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assert.commandWorked(coll.insert({a: 1, b: 1}));
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assert.commandWorked(coll.insert({a: 1, b: 2}));
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assert.commandWorked(coll.insert({a: 1, b: 3}));
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assert.commandWorked(coll.insert({a: 2, b: 0}));
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assertFirstLast(1, 3);
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// Additional pipeline stages do not affect outcome if order is maintained.
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assertFirstLast(1, 3, [{$project: {x: "$a", y: "$b"}}, {$project: {a: "$x", b: "$y"}}]);
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// Additional pipeline stages affect outcome if order is modified.
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assertFirstLast(3, 1, [{$sort: {b: -1}}]);
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// Skip and limit affect the results seen.
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assert(coll.drop());
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assert.commandWorked(coll.insert({a: 1, b: 1}));
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assert.commandWorked(coll.insert({a: 1, b: 2}));
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assert.commandWorked(coll.insert({a: 1, b: 3}));
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assertFirstLast(1, 2, [{$limit: 2}]);
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assertFirstLast(2, 3, [{$skip: 1}, {$limit: 2}]);
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assertFirstLast(2, 2, [{$skip: 1}, {$limit: 1}]);
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// Mixed type values.
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assert.commandWorked(coll.insert({a: 1, b: "foo"}));
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assertFirstLast(1, "foo");
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assert(coll.drop());
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assert.commandWorked(coll.insert({a: 1, b: "bar"}));
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assert.commandWorked(coll.insert({a: 1, b: true}));
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assertFirstLast("bar", true);
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// Value null.
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assert(coll.drop());
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assert.commandWorked(coll.insert({a: 1, b: null}));
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assert.commandWorked(coll.insert({a: 1, b: 2}));
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assertFirstLast(null, 2);
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assert(coll.drop());
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assert.commandWorked(coll.insert({a: 1, b: 2}));
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assert.commandWorked(coll.insert({a: 1, b: null}));
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assertFirstLast(2, null);
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assert(coll.drop());
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assert.commandWorked(coll.insert({a: 1, b: null}));
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assert.commandWorked(coll.insert({a: 1, b: null}));
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assertFirstLast(null, null);
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// Value missing.
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assert(coll.drop());
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assert.commandWorked(coll.insert({a: 1}));
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assert.commandWorked(coll.insert({a: 1, b: 2}));
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assertFirstLast(undefined, 2);
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assert(coll.drop());
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assert.commandWorked(coll.insert({a: 1, b: 2}));
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assert.commandWorked(coll.insert({a: 1}));
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assertFirstLast(2, undefined);
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assert(coll.drop());
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assert.commandWorked(coll.insert({a: 1}));
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assert.commandWorked(coll.insert({a: 1}));
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assertFirstLast(undefined, undefined);
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// Dotted field.
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assert(coll.drop());
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assert.commandWorked(coll.insert({a: 1, b: [{c: 1}, {c: 2}]}));
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assert.commandWorked(coll.insert({a: 1, b: [{c: 6}, {}]}));
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assertFirstLast([1, 2], [6], [], "$b.c");
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// Computed expressions.
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assert(coll.drop());
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assert.commandWorked(coll.insert({a: 1, b: 1}));
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assert.commandWorked(coll.insert({a: 1, b: 2}));
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assertFirstLast(1, 0, [], {$mod: ["$b", 2]});
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assertFirstLast(0, 1, [], {$mod: [{$add: ["$b", 1]}, 2]});
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// Multikey projections without sort. Sort-handling logic correctly preserves the projection if some
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// sort exists. Here, we ensure that arrays do not get unwound.
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assert(coll.drop());
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assert.commandWorked(coll.insertOne({mk: [1, 2, 3], notMk: 4}));
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assert.commandWorked(coll.createIndex({notMk: 1, mk: 1}));
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assert.commandWorked(coll.createIndex({notMk: -1, mk: -1}));
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const runAndConfirmResult = (pipeline, expected) => {
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const result = coll.aggregate(pipeline).toArray();
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assert.eq(result, expected);
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};
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runAndConfirmResult([{$group: {_id: "$notMk", acc: {$first: "$mk"}}}], [{_id: 4, acc: [1, 2, 3]}]);
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runAndConfirmResult([{$group: {_id: "$notMk", acc: {$last: "$mk"}}}], [{_id: 4, acc: [1, 2, 3]}]);
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runAndConfirmResult(
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[{$match: {notMk: {$eq: 4}}}, {$group: {_id: "$notMk", acc: {$last: "$mk"}}}],
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[{_id: 4, acc: [1, 2, 3]}],
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);
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