SERVER-20638 Reading profiling level shouldn't create databases that don't exist

Setting the profiling level will still create the database.

(cherry picked from commit e5883822fd2fc777fd3e3e6b766f54e2caa8e594)

5 files changed, 54 insertions, 13 deletions

diff --git a/jstests/core/profile1.js b/jstests/core/profile1.js
index f3e13324b10..39c525eeedc 100644
--- a/jstests/core/profile1.js
+++ b/jstests/core/profile1.js
@@ -56,11 +56,11 @@ try {
     
     // create a msg for later if there is a failure.
     var msg = "";
-    profileItems.forEach(function(d) {msg += "profile doc: " + d.ns + " " + d.op + " " + tojson(d.query ? d.query : d.command)});    
+    profileItems.forEach(function(d) {msg += "profile doc: " + d.ns + " " + d.op + " " + tojson(d.query ? d.query : d.command) + "\n"});    
     msg += tojson(db.system.profile.stats());
 
     // If these nunmbers don't match, it is possible the collection has rolled over (set to 32MB above in the hope this doesn't happen)
-    assert.eq( 3, profileItems.length , "E2 -- " + msg  );
+    assert.eq( 2, profileItems.length , "E2 -- " + msg  );
     
     /* Make sure we can't drop if profiling is still on */
     assert.throws( function(z){ db.getCollection("system.profile").drop(); } )
diff --git a/jstests/core/profile_no_such_db.js b/jstests/core/profile_no_such_db.js
new file mode 100644
index 00000000000..e11d93ca66c
--- /dev/null
+++ b/jstests/core/profile_no_such_db.js
@@ -0,0 +1,38 @@
+// Test that reading the profiling level doesn't create databases, but setting it does.
+(function (db) {
+'use strict';
+
+function dbExists() {
+    return Array.contains(db.getMongo().getDBNames(), db.getName());
+}
+
+db = db.getSiblingDB('profile_no_such_db'); // Note: changes db argument not global var.
+assert.commandWorked(db.dropDatabase());
+assert(!dbExists());
+
+// Reading the profiling level shouldn't create the database.
+var defaultProfilingLevel = db.getProfilingLevel();
+assert(!dbExists());
+
+// This test assumes that the default profiling level hasn't been changed.
+assert.eq(defaultProfilingLevel, 0);
+
+[0,1,2].forEach(function(level) {
+    jsTest.log('Testing profiling level ' + level);
+
+    // Setting the profiling level creates the database.
+    // Note: in storage engines other than MMAPv1 setting the profiling level to 0 puts the database
+    // in a weird state where it exists internally, but doesn't show up in listDatabases, and won't
+    // exist if you restart the server.
+    var res = db.setProfilingLevel(level);
+    assert.eq(res.was, defaultProfilingLevel);
+    assert(dbExists() || level == 0);
+    assert.eq(db.getProfilingLevel(), level);
+
+    // Dropping the db reverts the profiling level to the default.
+    assert.commandWorked(db.dropDatabase());
+    assert.eq(db.getProfilingLevel(), defaultProfilingLevel);
+    assert(!dbExists());
+});
+
+}(db));
diff --git a/jstests/slow2/sharding_jscore_passthrough.js b/jstests/slow2/sharding_jscore_passthrough.js
index be1580b7a9a..404fbd829dc 100644
--- a/jstests/slow2/sharding_jscore_passthrough.js
+++ b/jstests/slow2/sharding_jscore_passthrough.js
@@ -69,7 +69,7 @@ files.forEach(function(x) {
         'apitest_db|' +
         'cursor6|' +
         'copydb-auth|' +
-        'profile\\d*|' +
+        'profile.*|' +
         'dbhash|' +
         'dbhash2|' +
         'median|' +
@@ -91,7 +91,7 @@ files.forEach(function(x) {
         'shellkillop|' +
         'update4|' +
         'update_setOnInsert|' +
-        'profile\\d*|' +
+        'profile.*|' +
         'max_time_ms|' + // Will be fixed when SERVER-2212 is resolved.
         'fts_querylang|' + // Will be fixed when SERVER-9063 is resolved.
         'fts_projection' +
diff --git a/src/mongo/db/dbcommands.cpp b/src/mongo/db/dbcommands.cpp
index d9749c57b7c..d59ddbfc132 100644
--- a/src/mongo/db/dbcommands.cpp
+++ b/src/mongo/db/dbcommands.cpp
@@ -342,20 +342,23 @@ public:
         // Needs to be locked exclusively, because creates the system.profile collection
         // in the local database.
         ScopedTransaction transaction(txn, MODE_IX);
-        Lock::DBLock dbXLock(txn->lockState(), dbname, MODE_X);
-        Client::Context ctx(txn, dbname);
+        AutoGetDb ctx(txn, dbname, MODE_X);
+        Database* db = ctx.getDb();
 
         BSONElement e = cmdObj.firstElement();
-        result.append("was", ctx.db()->getProfilingLevel());
+        result.append("was", db ? db->getProfilingLevel() : serverGlobalParams.defaultProfile);
         result.append("slowms", serverGlobalParams.slowMS);
 
         int p = (int)e.number();
         Status status = Status::OK();
 
-        if (p == -1)
-            status = Status::OK();
-        else if (p >= 0 && p <= 2) {
-            status = ctx.db()->setProfilingLevel(txn, p);
+        if (p >= 0 && p <= 2) {
+            if (!db) {
+                // When setting the profiling level, create the database if it didn't already exist.
+                // When just reading the profiling level, we do not create the database.
+                db = dbHolder().openDb(txn, dbname);
+            }
+            status = db->setProfilingLevel(txn, p);
         }
 
         const BSONElement slow = cmdObj["slowms"];
diff --git a/src/mongo/shell/db.js b/src/mongo/shell/db.js
index 2b5fec4b89d..cbe996d44d1 100644
--- a/src/mongo/shell/db.js
+++ b/src/mongo/shell/db.js
@@ -154,7 +154,7 @@ DB.prototype.createCollection = function(name, opt) {
  *  @return SOMETHING_FIXME or null on error
  */
 DB.prototype.getProfilingLevel  = function() {
-    var res = this._dbCommand( { profile: -1 } );
+    var res = assert.commandWorked(this._dbCommand( { profile: -1 } ));
     return res ? res.was : null;
 }
 
@@ -426,7 +426,7 @@ DB.prototype.setProfilingLevel = function(level,slowms) {
     var cmd = { profile: level };
     if ( isNumber( slowms ) )
         cmd["slowms"] = slowms;
-    return this._dbCommand( cmd );
+    return assert.commandWorked(this._dbCommand( cmd ));
 }
 
 /**