34 lines
1.6 KiB
JavaScript
34 lines
1.6 KiB
JavaScript
// Test to make sure that a reverse cursor can correctly handle empty extents (SERVER-6980)
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// Create a collection with three small extents
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db.jstests_reversecursor.drop();
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db.runCommand({"create":"jstests_reversecursor", $nExtents: [4096,4096,4096]});
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// Function to check whether all three extents are non empty
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function extentsSpanned() {
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var extents = db.jstests_reversecursor.validate(true).extents;
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return (extents[0].firstRecord != "null" &&
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extents[1].firstRecord != "null" &&
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extents[2].firstRecord != "null");
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}
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// Insert enough documents to span all three extents
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a = 0;
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while (!extentsSpanned()) {
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db.jstests_reversecursor.insert({a:a++});
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}
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// Delete all the elements in the middle
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db.jstests_reversecursor.remove({a:{$gt:0,$lt:a-1}});
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// Make sure the middle extent is empty and that both end extents are not empty
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assert.eq(db.jstests_reversecursor.validate(true).extents[1].firstRecord, "null");
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assert.eq(db.jstests_reversecursor.validate(true).extents[1].lastRecord, "null");
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assert.neq(db.jstests_reversecursor.validate(true).extents[0].firstRecord, "null");
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assert.neq(db.jstests_reversecursor.validate(true).extents[0].lastRecord, "null");
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assert.neq(db.jstests_reversecursor.validate(true).extents[2].firstRecord, "null");
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assert.neq(db.jstests_reversecursor.validate(true).extents[2].lastRecord, "null");
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// Make sure that we get the same number of elements for both the forward and reverse cursors
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assert.eq(db.jstests_reversecursor.find().sort({$natural:1}).toArray().length, 2);
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assert.eq(db.jstests_reversecursor.find().sort({$natural:-1}).toArray().length, 2);
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