SERVER-21543 Lengthen delay before deleting old journal files

Conflicts:
	jstests/mmap_v1/dur_remove_old_journals.js

2 files changed, 56 insertions, 43 deletions

diff --git a/jstests/mmap_v1/dur_remove_old_journals.js b/jstests/mmap_v1/dur_remove_old_journals.js
index 59f50f9c359..d885969c4de 100644
--- a/jstests/mmap_v1/dur_remove_old_journals.js
+++ b/jstests/mmap_v1/dur_remove_old_journals.js
@@ -1,57 +1,66 @@
-// this test makes sure that old journal files are removed
+/**
+ * Test that old journal files are eventually deleted.
+ */
 
 if (db.serverBuildInfo().bits == 32) {
-    print("skip on 32 bit systems");    
-}
-else {
-    // tunables
-    STRING_SIZE = 1024*1024;
-    NUM_TO_INSERT = 2.5*1024;
-    PATH = MongoRunner.dataDir + "/dur_remove_old_journals";
-    SYNC_DELAY = 5; // must be a number
-
-    conn = startMongodEmpty("--port", 30001, "--dbpath", PATH, "--dur", "--smallfiles", "--syncdelay", ''+SYNC_DELAY);
+    print("skip on 32 bit systems");
+} else {
+    var dbpath = MongoRunner.dataDir + "/dur_remove_old_journals";
+    var conn = MongoRunner.runMongod({
+        journal: "",
+        smallfiles: "",
+        syncdelay: 5,  // seconds between fsyncs.
+        dbpath: dbpath,
+    });
     db = conn.getDB("test");
 
-    longString = 'x';
-    while (longString.length < STRING_SIZE)
-        longString += longString;
+    // Returns true if j._0 exists.
+    function firstJournalFileExists() {
+        var files = listFiles(dbpath + "/journal");
+        for (var i = 0; i < files.length; i++) {
+            if (files[i].baseName === "j._0") {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    // Represents the cummulative total of the number of journal files created.
+    function getLatestJournalFileNum() {
+        var files = listFiles(dbpath + "/journal");
+        var latest = 0;
+        files.forEach(function(file) {
+            if (file.baseName !== "lsn") {
+                var fileNum = NumberInt(file.baseName[file.baseName.length - 1]);
+                latest = Math.max(latest, fileNum);
+            }
+        });
+        return latest;
+    }
+
+    var stringSize = 1024*1024;
+    var longString = new Array(stringSize).join("x");
 
-    numInserted = 0;
-    while (numInserted < NUM_TO_INSERT){
-        db.foo.insert({_id: numInserted++, s:longString});
+    // Insert some data to create the first journal file.
+    var numInserted = 0;
+    while (numInserted < 100) {
+        db.foo.insert({_id: numInserted++, s: longString});
+    }
+    assert.soon(firstJournalFileExists, "Should have created a journal file");
 
+    // Do writes until the first journal file is deleted, or we give up waiting.
+    var maxJournalFiles = 10;
+    while (firstJournalFileExists() && getLatestJournalFileNum() < maxJournalFiles) {
+        db.foo.insert({_id: numInserted++, s: longString});
 
         if (numInserted % 100 == 0){
-            print("numInserted: " + numInserted);
+            jsTestLog("numInserted: " + numInserted);
             db.adminCommand({fsync:1});
             db.foo.remove({});
             db.adminCommand({fsync:1});
         }
     }
 
-    sleepSecs = SYNC_DELAY + 15 // long enough for data file flushing and journal keep time
-    print("\nWaiting " + sleepSecs + " seconds...\n");
-    sleep(sleepSecs*1000);
-
-
-    files = listFiles(PATH + "/journal")
-    printjson(files);
-
-    var nfiles = 0;
-    files.forEach(function (file) {
-        assert.eq('string', typeof (file.name));    // sanity checking
-        if (/prealloc/.test(file.name)) {
-            ;
-        }
-        else {
-            nfiles++;
-        }
-    })
-
-    assert.eq(2, nfiles); // latest journal file and lsn
-
-    stopMongod(30001);
+    assert(!firstJournalFileExists(), "Expected to have deleted the first journal file by now");
+    MongoRunner.stopMongod(conn);
 }
-
-print("*** success ***");
diff --git a/src/mongo/db/storage/mmap_v1/dur_journal.cpp b/src/mongo/db/storage/mmap_v1/dur_journal.cpp
index 0ab2ff648ca..2888cbdec63 100644
--- a/src/mongo/db/storage/mmap_v1/dur_journal.cpp
+++ b/src/mongo/db/storage/mmap_v1/dur_journal.cpp
@@ -674,7 +674,11 @@ void Journal::removeUnneededJournalFiles() {
     while (!_oldJournalFiles.empty()) {
         JFile f = _oldJournalFiles.front();
 
-        if (f.lastEventTimeMs < _lastFlushTime + ExtraKeepTimeMs) {
+        // 'f.lastEventTimeMs' is the timestamp of the last thing in the journal file.
+        // '_lastFlushTime' is the start time of the last successful flush of the data files to
+        // disk. We can't delete this journal file until the last successful flush time is at least
+        // 10 seconds after 'f.lastEventTimeMs'.
+        if (f.lastEventTimeMs + ExtraKeepTimeMs < _lastFlushTime) {
             // eligible for deletion
             boost::filesystem::path p(f.filename);
             log() << "old journal file will be removed: " << f.filename << endl;