Files
mongo/jstests/core/snapshot_queries.js

54 lines
1.7 KiB
JavaScript

// Regression test for edge cases in which .snapshot() queries could historically miss documents or
// return the same document twice.
(function() {
'use strict';
var cursor;
var coll = db.snapshot_queries;
coll.drop();
//
// Test that a large update to the document we just returned won't cause us to return it again.
//
for (var i = 0; i < 3; i++) {
assert.writeOK(coll.insert({_id: i}));
}
cursor = coll.find().batchSize(2).snapshot();
assert.eq(0, cursor.next()["_id"]);
assert.eq(1, cursor.next()["_id"]);
// Force a document move (on MMAP) while the query is yielded for a getMore.
var bigString = Array(1024*1024).toString()
assert.writeOK(coll.update({_id: 1}, {$set: {padding: bigString}}));
assert.eq(2, cursor.next()["_id"]);
assert(!cursor.hasNext());
//
// Test that a large update to the document we are about to return won't cause us to skip that
// doc.
//
coll.drop();
assert.writeOK(coll.insert({_id: 0, padding: Array(1000).toString()}));
for (var i = 1; i <= 3; i++) {
assert.writeOK(coll.insert({_id: i}));
}
// On MMAP, this will leave space at the beginning of the collection. A document can be moved
// into this free space.
assert.writeOK(coll.remove({_id: 0}));
cursor = coll.find().snapshot().batchSize(2);
assert.eq(1, cursor.next()["_id"]);
assert.eq(2, cursor.next()["_id"]);
// Force a document move (on MMAP) while the query is yielded for a getMore.
assert.writeOK(coll.update({_id: 3}, {$set: {padding: Array(100).toString()}}));
assert.eq(3, cursor.next()["_id"]);
assert(!cursor.hasNext());
})();