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/**
* Test setting minSnapshotHistoryWindowInSeconds at runtime and that server keeps history for up to
* minSnapshotHistoryWindowInSeconds.
*
* @tags: [
* requires_majority_read_concern,
* requires_persistence,
* requires_replication
* ]
*/
(function() {
"use strict";
const replSet = new ReplSetTest({
nodes: 1,
nodeOptions: {
// Increase log verbosity for storage so we can see how the oldest_timestamp is set.
setParameter: {logComponentVerbosity: tojson({storage: 2})}
}
});
replSet.startSet();
replSet.initiate();
const collName = "coll";
const primary = replSet.getPrimary();
const primaryDB = primary.getDB('test');
const historyWindowSecs = 10;
assert.commandWorked(primaryDB.adminCommand(
{setParameter: 1, minSnapshotHistoryWindowInSeconds: historyWindowSecs}));
const insertTimestamp =
assert.commandWorked(primaryDB.runCommand({insert: collName, documents: [{_id: 0}]}))
.operationTime;
const startTime = Date.now();
jsTestLog(`Inserted one document at ${tojson(insertTimestamp)}`);
let nextId = 1;
// Test snapshot window with 1s margin.
const testMarginSecs = 1;
const testMarginMS = 1000;
let numSnapshotTooOld = 0;
// Test that reading from a snapshot at insertTimestamp is valid for up to historyWindowSecs minus
// the testMarginMS (as a buffer) to avoid races between the client's snapshot read and the update
// of the oldest timestamp in the server.
const testWindowMS = historyWindowSecs * 1000 - testMarginMS;
while (Date.now() - startTime < testWindowMS) {
// Test that reading from a snapshot at insertTimestamp is still valid.
const res = primaryDB.runCommand(
{find: collName, readConcern: {level: "snapshot", atClusterTime: insertTimestamp}});
if (res.operationTime.t - insertTimestamp.t > historyWindowSecs - testMarginSecs) {
// Too close to the window and we may get a false positive failure. Give up this test. This
// can happen on slow machines.
jsTestLog("Skipping test with operationTime: " + tojson(res.operationTime) +
" res: " + tojson(res));
if (res.code === ErrorCodes.SnapshotTooOld) {
numSnapshotTooOld++;
}
break;
} else {
// Otherwise, test that the snapshot read is still valid.
assert.commandWorked(
res, "failed to read at snapshot " + tojson(insertTimestamp) + " res: " + tojson(res));
}
// Perform writes to advance stable timestamp and oldest timestamp. We use majority writeConcern
// so that we can make sure the stable timestamp and the oldest timestamp are updated after each
// insert.
assert.commandWorked(primaryDB.runCommand(
{insert: collName, documents: [{_id: nextId}], writeConcern: {w: "majority"}}));
nextId++;
sleep(50);
}
// Sleep enough to make sure the insertTimestamp falls off the snapshot window.
const historyExpirationTime = startTime + historyWindowSecs * 1000;
sleep(historyExpirationTime + testMarginMS - Date.now());
// Perform another majority write to advance the stable timestamp and the oldest timestamp again.
assert.commandWorked(primaryDB.runCommand(
{insert: collName, documents: [{_id: nextId}], writeConcern: {w: "majority"}}));
// Test that reading from a snapshot at insertTimestamp returns SnapshotTooOld.
assert.commandFailedWithCode(
primaryDB.runCommand(
{find: collName, readConcern: {level: "snapshot", atClusterTime: insertTimestamp}}),
ErrorCodes.SnapshotTooOld);
numSnapshotTooOld++;
// Test that the SnapshotTooOld is recorded in serverStatus.
const serverStatusWT = assert.commandWorked(primaryDB.adminCommand({serverStatus: 1})).wiredTiger;
assert.eq(numSnapshotTooOld,
serverStatusWT["snapshot-window-settings"]["total number of SnapshotTooOld errors"],
tojson(serverStatusWT));
replSet.stopSet();
})();
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