mirror of https://github.com/mongodb/mongo
51 lines
1.5 KiB
JavaScript
51 lines
1.5 KiB
JavaScript
// Confirms that the mapReduce reduce function will process data sets larger than 16MB.
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// @tags: [
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// # mapReduce does not support afterClusterTime.
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// does_not_support_causal_consistency,
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// does_not_support_stepdowns,
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// requires_fastcount,
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// uses_map_reduce_with_temp_collections,
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// ]
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(function() {
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"use strict";
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const coll = db.mr_bigobject;
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coll.drop();
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const outputColl = db.mr_bigobject_out;
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outputColl.drop();
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const largeString = Array.from({length: 6 * 1024 * 1024}, _ => "a").join("");
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const bulk = coll.initializeUnorderedBulkOp();
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for (let i = 0; i < 5; i++)
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bulk.insert({_id: i, s: largeString});
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assert.commandWorked(bulk.execute());
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// MapReduce succeeds when the reduce function processes single-key data sets larger than 16MB.
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const mapFn = function() {
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emit(1, this.s);
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};
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let reduceFn = function(k, v) {
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return 1;
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};
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assert.commandWorked(coll.mapReduce(mapFn, reduceFn, {out: {"merge": outputColl.getName()}}));
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assert.eq([{_id: 1, value: 1}], outputColl.find().toArray());
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// The reduce function processes the expected amount of data.
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reduceFn = function(k, v) {
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total = 0;
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for (let i = 0; i < v.length; i++) {
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const x = v[i];
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if (typeof (x) == "number")
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total += x;
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else
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total += x.length;
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}
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return total;
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};
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assert.commandWorked(coll.mapReduce(mapFn, reduceFn, {out: {"merge": outputColl.getName()}}));
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assert.eq([{_id: 1, value: coll.count() * largeString.length}], outputColl.find().toArray());
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}());
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