mirror of https://github.com/mongodb/mongo
64 lines
2.6 KiB
JavaScript
64 lines
2.6 KiB
JavaScript
/**
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* This test attempts to reproduce the bug described in SERVER-48002. This is a best-effort test
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* that will not detect this bug on every run, even if a bug exists.
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*
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* Snapshot isolation cannot be guaranteed for operations that ignore prepare conflicts.
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* This means that two reads of the same record in the same snapshot can return different results.
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* In practice, the DataCorruptionDetected assertion added by SERVER-40620 will trigger if an index
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* points to a non-existent record.
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*
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* Queries that ignore prepare conflicts and use an index to satisfy a read can read a key from an
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* index and fetch a record that appears to go missing within the same snapshot. This may happen
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* when the collection read races with a prepared transaction that commits and deletes the record.
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*
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*
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* @tags: [
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* uses_prepare_transaction,
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* uses_transactions,
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* ]
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*/
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import {ReplSetTest} from "jstests/libs/replsettest.js";
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const replTest = new ReplSetTest({nodes: 2});
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replTest.startSet();
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replTest.initiate();
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const primary = replTest.getPrimary();
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const dbName = "query_with_txn_prepared";
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const collName = "coll";
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assert.commandWorked(primary.getDB(dbName)[collName].createIndexes([{x: 1}]));
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const transactionShell = startParallelShell(async function () {
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const {PrepareHelpers} = await import("jstests/core/txns/libs/prepare_helpers.js");
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while (db.getSiblingDB("query_with_txn_prepared")["stopQueries"].find().count() == 0) {
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for (let i = 0; i < 100; ++i) {
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const session = db.getMongo().startSession();
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const sessionColl = session.getDatabase("query_with_txn_prepared")["coll"];
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session.startTransaction({readConcern: {level: "majority"}});
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if (Math.random() < 0.5) {
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assert.commandWorked(sessionColl.update({x: 1}, {x: 1}, {upsert: true}));
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} else {
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assert.commandWorked(sessionColl.remove({x: 1}));
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}
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const prepareTimestamp = PrepareHelpers.prepareTransaction(session);
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assert.commandWorked(PrepareHelpers.commitTransaction(session, prepareTimestamp));
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}
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}
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}, primary.port);
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for (let i = 0; i < 2000; ++i) {
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const result = primary.getDB(dbName)[collName].find({x: 1}).toArray();
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// Although there are either 0 or 1 documents in the collection at all times, it's possible
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// for more than 1 document to show up in the query due to yielding mechanics. See
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// SERVER-101381 for more information.
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assert.gte(result.length, 0, result);
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}
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assert.commandWorked(primary.getDB(dbName)["stopQueries"].insert({stop: 1}));
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transactionShell();
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replTest.stopSet();
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