1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
|
/**
* Tests that "$_internalReadAtClusterTime" is supported by the "dbHash" command.
*
* @tags: [uses_transactions]
*/
(function() {
"use strict";
const rst = new ReplSetTest({nodes: 2});
rst.startSet();
const replSetConfig = rst.getReplSetConfig();
replSetConfig.members[1].priority = 0;
rst.initiate(replSetConfig);
const primary = rst.getPrimary();
const secondary = rst.getSecondary();
const session = primary.startSession({causalConsistency: false});
const db = session.getDatabase("test");
let txnNumber = 0;
// We prevent the replica set from advancing oldest_timestamp. This ensures that the snapshot
// associated with 'clusterTime' is retained for the duration of this test.
rst.nodes.forEach(conn => {
assert.commandWorked(conn.adminCommand({
configureFailPoint: "WTPreserveSnapshotHistoryIndefinitely",
mode: "alwaysOn",
}));
});
// We insert a document and save the md5sum associated with the opTime of that write.
assert.commandWorked(db.mycoll.insert({_id: 1}, {writeConcern: {w: "majority"}}));
const clusterTime = db.getSession().getOperationTime();
let res = assert.commandWorked(db.runCommand({
dbHash: 1,
$_internalReadAtClusterTime: clusterTime,
}));
const hash1 = {
collections: res.collections,
md5: res.md5
};
// We insert another document to ensure the collection's contents have a different md5sum now.
// We use a w=majority write concern to ensure that the insert has also been applied on the
// secondary by the time we go to run the dbHash command later. This avoids a race where the
// replication subsystem could be applying the insert operation when the dbHash command is run
// on the secondary.
assert.commandWorked(db.mycoll.insert({_id: 2}, {writeConcern: {w: "majority"}}));
// However, using $_internalReadAtClusterTime to read at the opTime of the first insert should
// return the same md5sum as it did originally.
res = assert.commandWorked(db.runCommand({
dbHash: 1,
$_internalReadAtClusterTime: clusterTime,
}));
const hash2 = {
collections: res.collections,
md5: res.md5
};
assert.eq(hash1, hash2, "primary returned different dbhash after second insert");
{
const secondarySession = secondary.startSession({causalConsistency: false});
const secondaryDB = secondarySession.getDatabase("test");
// Using $_internalReadAtClusterTime to read at the opTime of the first insert should return
// the same md5sum on the secondary as it did on the primary.
res = assert.commandWorked(secondaryDB.runCommand({
dbHash: 1,
$_internalReadAtClusterTime: clusterTime,
}));
const secondaryHash = {collections: res.collections, md5: res.md5};
assert.eq(hash1, secondaryHash, "primary and secondary have different dbhash");
}
{
const otherSession = primary.startSession({causalConsistency: false});
const otherDB = otherSession.getDatabase("test");
// We perform another insert inside a separate transaction to cause a MODE_IX lock to be
// held on the collection.
otherSession.startTransaction();
assert.commandWorked(otherDB.mycoll.insert({_id: 3}));
// It should be possible to run the "dbHash" command with "$_internalReadAtClusterTime"
// concurrently.
res = assert.commandWorked(db.runCommand({
dbHash: 1,
$_internalReadAtClusterTime: clusterTime,
}));
const hash3 = {collections: res.collections, md5: res.md5};
assert.eq(hash1, hash3, "primary returned different dbhash after third insert");
// However, the "dbHash" command should block behind the transaction if
// "$_internalReadAtClusterTime" wasn't specified.
res = assert.commandFailedWithCode(db.runCommand({dbHash: 1, maxTimeMS: 1000}),
ErrorCodes.MaxTimeMSExpired);
assert.commandWorked(otherSession.abortTransaction_forTesting());
otherSession.endSession();
}
{
const otherSession = primary.startSession({causalConsistency: false});
const otherDB = otherSession.getDatabase("test");
// We create another collection inside a separate session to modify the collection catalog
// at an opTime later than 'clusterTime'. This prevents further usage of the snapshot
// associated with 'clusterTime' for snapshot reads.
assert.commandWorked(otherDB.runCommand({create: "mycoll2"}));
assert.commandFailedWithCode(
db.runCommand({dbHash: 1, $_internalReadAtClusterTime: clusterTime}),
ErrorCodes.SnapshotUnavailable);
otherSession.endSession();
}
session.endSession();
rst.stopSet();
})();
|
