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/**
* Verifies that nested SORT_MERGE plans are handled correctly by the SBE stage builder.
* Intended to reproduce SERVER-61496.
*/
(function() {
load("jstests/libs/analyze_plan.js"); // for 'getPlanStages'.
const conn = MongoRunner.runMongod();
const db = conn.getDB("test");
// Disable MatchExpression optimization so that we can craft simple queries that can be answered
// with a nested SORT_MERGE plan. If we allow optimization, then all of the nested $or predicates
// will be optimized away (all child predicates will be raised to children of the top level $or).
assert.commandWorked(
db.adminCommand({configureFailPoint: "disableMatchExpressionOptimization", mode: "alwaysOn"}));
const collName = jsTestName();
const nDocs = 100;
const idxSpec = {
a: 1,
b: -1
};
const queries = [
// Simple case: one top level SORT_MERGE which has two SORT_MERGE children with 2 IXSCAN
// leaves each.
{
query: {
$or: [
{$or: [{a: 2, b: 1}, {a: 4, b: 4}, {a: 2, b: 5}]},
{$or: [{a: 1, b: 2}, {a: 5, b: 5}]}
]
},
sortMergeCount: 3
},
// SORT_MERGE nested to 3 levels.
{
query: {
$or: [
{$or: [{$or: [{a: 2, b: 1}, {a: 4, b: 4}]}, {a: 3, b: 3}]},
{$or: [{a: 1, b: 2}, {a: 5, b: 5}]}
]
},
sortMergeCount: 4
}
];
const sortPatterns = [
// Basic case.
{
sort: {a: 1, b: 1},
cmpFn: (docOne, docTwo) =>
docOne.a < docTwo.a || (docOne.a === docTwo.a && docOne.b <= docTwo.b)
},
// Verify that an index key pattern which doesn't match the order of the sort pattern can still
// be used to satisfy the sort.
{
sort: {b: -1, a: 1},
cmpFn: (docOne, docTwo) =>
docOne.b > docTwo.b || (docOne.b === docTwo.b && docOne.a <= docTwo.a)
}
];
const coll = db[collName];
assert.commandWorked(coll.createIndex(idxSpec));
let docs = [];
for (let i = 0; i < nDocs; ++i) {
docs.push({
a: i % 6,
b: i % 7,
});
}
assert.commandWorked(coll.insert(docs));
for (const doc of queries) {
for (const sortPatternDoc of sortPatterns) {
const query = doc.query;
const sortPattern = sortPatternDoc.sort;
const sortFn = sortPatternDoc.cmpFn;
const expectedSortMergeCount = doc.sortMergeCount;
const explain = coll.find(query).sort(sortPattern).explain();
const sortMergeStages = getPlanStages(explain, "SORT_MERGE");
assert.eq(expectedSortMergeCount,
sortMergeStages.length,
"Incorrect number of SORT_MERGE stages; explain: " + tojson(explain));
const docs = coll.find(query).sort(sortPattern).toArray();
for (let i = 1; i < docs.length; ++i) {
assert(sortFn(docs[i - 1], docs[i]),
"Out of order results for " + tojson(query) +
"; sortPattern: " + tojson(sortPattern) + "; results: " + tojson(docs));
}
}
}
MongoRunner.stopMongod(conn);
})();
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