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// Verifies mongos uses a versioned routing table to target subsequent requests for snapshot reads.
//
// @tags: [
// requires_fcv_46,
// requires_find_command,
// requires_persistence,
// requires_sharding,
// uses_multi_shard_transaction,
// uses_transactions,
// ]
(function() {
"use strict";
load("jstests/sharding/libs/sharded_transactions_helpers.js");
function expectChunks(st, ns, chunks) {
for (let i = 0; i < chunks.length; i++) {
assert.eq(chunks[i],
st.s.getDB("config").chunks.count({ns: ns, shard: st["shard" + i].shardName}),
"unexpected number of chunks on shard " + i);
}
}
const dbName = "test";
const collName = "foo";
const ns = dbName + '.' + collName;
const st = new ShardingTest({
shards: 3,
mongos: 1,
config: 1,
other: {
rs0: {nodes: 2},
rs1: {nodes: 2},
rs2: {nodes: 2},
// Disable expiring old chunk history to ensure the transactions are able to read from a
// shard that has donated a chunk, even if the migration takes longer than the amount of
// time for which a chunk's history is normally stored (see SERVER-39763).
configOptions: {
setParameter: {
"failpoint.skipExpiringOldChunkHistory": "{mode: 'alwaysOn'}",
minSnapshotHistoryWindowInSeconds: 600
}
},
rsOptions: {setParameter: {minSnapshotHistoryWindowInSeconds: 600}}
}
});
// Set up one sharded collection with 2 chunks, both on the primary shard.
assert.commandWorked(
st.s.getDB(dbName)[collName].insert({_id: -5}, {writeConcern: {w: "majority"}}));
assert.commandWorked(
st.s.getDB(dbName)[collName].insert({_id: 5}, {writeConcern: {w: "majority"}}));
assert.commandWorked(st.s.adminCommand({enableSharding: dbName}));
st.ensurePrimaryShard(dbName, st.shard0.shardName);
assert.commandWorked(st.s.adminCommand({shardCollection: ns, key: {_id: 1}}));
assert.commandWorked(st.s.adminCommand({split: ns, middle: {_id: 0}}));
expectChunks(st, ns, [2, 0, 0]);
// Temporarily move a chunk to Shard2, to avoid picking a global read timestamp before the
// sharding metadata cache collections are created.
assert.commandWorked(st.s.adminCommand({moveChunk: ns, find: {_id: 5}, to: st.shard2.shardName}));
assert.commandWorked(st.s.adminCommand({moveChunk: ns, find: {_id: 5}, to: st.shard1.shardName}));
expectChunks(st, ns, [1, 1, 0]);
// First command targets the first chunk, the second command targets the second chunk.
const kCommandTestCases = [
{
name: "aggregate",
commands: [
{aggregate: collName, pipeline: [{$match: {_id: -5}}], cursor: {}},
{aggregate: collName, pipeline: [{$match: {_id: 5}}], cursor: {}}
]
},
{
name: "find",
commands: [{find: collName, filter: {_id: -5}}, {find: collName, filter: {_id: 5}}]
}
];
const TestMode = {
TRANSACTION: 'TRANSACTION',
CAUSAL_CONSISTENCY: 'CAUSAL_CONSISTENCY',
SNAPSHOT: 'SNAPSHOT',
SNAPSHOT_AT_CLUSTER_TIME: 'SNAPSHOT_AT_CLUSTER_TIME'
};
function runTest(testCase, testMode, readPreferenceMode) {
const cmdName = testCase.name;
// Clone commands so we can modify readConcern and readPreference.
const targetChunk1Cmd = Object.assign({}, testCase.commands[0]);
const targetChunk2Cmd = Object.assign({}, testCase.commands[1]);
targetChunk1Cmd["$readPreference"] = {mode: readPreferenceMode};
targetChunk2Cmd["$readPreference"] = {mode: readPreferenceMode};
jsTestLog(`Testing ${cmdName} in mode ${testMode}`);
expectChunks(st, ns, [1, 1, 0]);
st.refreshCatalogCacheForNs(st.s, ns);
let session, db;
switch (testMode) {
case TestMode.TRANSACTION:
session = st.s.startSession({causalConsistency: false});
session.startTransaction({readConcern: {level: "snapshot"}});
db = session.getDatabase(dbName);
break;
case TestMode.CAUSAL_CONSISTENCY:
session = st.s.startSession({causalConsistency: true});
db = session.getDatabase(dbName);
db[collName].findOne(); // Establish a timestamp in the session.
break;
case TestMode.SNAPSHOT:
db = st.s.getDB(dbName);
targetChunk1Cmd.readConcern = targetChunk2Cmd.readConcern = {level: "snapshot"};
break;
case TestMode.SNAPSHOT_AT_CLUSTER_TIME:
db = st.s.getDB(dbName);
const opTime = st.s.getDB(dbName).runCommand({ping: 1}).operationTime;
targetChunk1Cmd.readConcern = {level: "snapshot", atClusterTime: opTime};
break;
}
// Establish a read timestamp.
let res = assert.commandWorked(db.runCommand(targetChunk1Cmd));
assert.sameMembers([{_id: -5}],
res.cursor.firstBatch,
`expected to find document in first chunk, command` +
` ${tojson(targetChunk1Cmd)} returned ${tojson(res)}`);
const targetChunk1CmdTimestamp = res.cursor.atClusterTime;
jsTestLog(`Chunk 1 command replied with timestamp ${tojson(targetChunk1CmdTimestamp)}`);
// Move a chunk from Shard1 to Shard2 outside of the transaction, and update it. This will
// happen at a later logical time than the read timestamp.
assert.commandWorked(
st.s.adminCommand({moveChunk: ns, find: {_id: 5}, to: st.shard2.shardName}));
res = assert.commandWorked(st.s.getDB(dbName).runCommand({
update: collName,
updates: [{q: {_id: 5}, u: {$set: {x: true}}}],
writeConcern: {w: "majority"}
}));
jsTestLog(`Updated chunk 2 at timestamp ${tojson(res.operationTime)}`);
st.refreshCatalogCacheForNs(st.s, ns);
if (testMode === TestMode.SNAPSHOT_AT_CLUSTER_TIME) {
targetChunk2Cmd.readConcern = {level: "snapshot", atClusterTime: targetChunk1CmdTimestamp};
}
res = assert.commandWorked(db.runCommand(targetChunk2Cmd));
switch (testMode) {
case TestMode.CAUSAL_CONSISTENCY:
case TestMode.SNAPSHOT:
// We may or may not see the result of the update above.
assert.eq(1,
res.cursor.firstBatch.length,
`expected to find document in second chunk, command` +
` ${tojson(targetChunk2Cmd)} returned ${tojson(res)}`);
assert.eq(5,
res.cursor.firstBatch[0]._id,
`expected to find {_id: 5} in second chunk, command` +
` ${tojson(targetChunk2Cmd)} returned ${tojson(res)}`);
break;
case TestMode.TRANSACTION:
case TestMode.SNAPSHOT_AT_CLUSTER_TIME:
// Must not see the update's result.
assert.sameMembers([{_id: 5}],
res.cursor.firstBatch,
`expected to find document in second chunk, command` +
` ${tojson(targetChunk2Cmd)} returned ${tojson(res)}`);
break;
}
if (testMode === TestMode.TRANSACTION) {
assert.commandWorked(session.commitTransaction_forTesting());
}
// Move the chunk back to Shard1 and clear updated field for the next iteration.
assert.commandWorked(st.s.getDB(dbName).runCommand({
update: collName,
updates: [{q: {_id: 5}, u: {$unset: {x: true}}}],
writeConcern: {w: "majority"}
}));
assert.commandWorked(
st.s.adminCommand({moveChunk: ns, find: {_id: 5}, to: st.shard1.shardName}));
}
for (let testCase of kCommandTestCases) {
for (let testMode of Object.values(TestMode)) {
for (let readPreferenceMode of ["primary", "secondary"]) {
if (readPreferenceMode === "secondary" && testMode === TestMode.TRANSACTION) {
// Transactions aren't supported on secondaries.
continue;
}
runTest(testCase, testMode, readPreferenceMode);
}
}
}
st.stop();
})();
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