SERVER-8594 fix clearTmpCollections for collections with indexes

2 files changed, 24 insertions, 9 deletions

diff --git a/jstests/slowNightly/temp_namespace.js b/jstests/slowNightly/temp_namespace.js
index bd96e2fdb63..54ee3bfa4f2 100644
--- a/jstests/slowNightly/temp_namespace.js
+++ b/jstests/slowNightly/temp_namespace.js
@@ -6,18 +6,22 @@ path = '/data/db/'+testname
 conn = startMongodEmpty("--port", 30000, "--dbpath", path, "--smallfiles", "--noprealloc", "--nopreallocj");
 d = conn.getDB('test')
 d.runCommand({create: testname+'temp1', temp: true});
+d[testname+'temp1'].ensureIndex({x:1});
 d.runCommand({create: testname+'temp2', temp: 1});
+d[testname+'temp2'].ensureIndex({x:1});
 d.runCommand({create: testname+'keep1', temp: false});
 d.runCommand({create: testname+'keep2', temp: 0});
 d.runCommand({create: testname+'keep3'});
 d[testname+'keep4'].insert({});
 
-assert.eq(d.system.namespaces.count({name: /temp\d$/}) , 2)
+assert.eq(d.system.namespaces.count({name: /temp\d$/}) , 2) // collections
+assert.eq(d.system.namespaces.count({name: /temp\d\.\$.*$/}) , 4) //indexes (2 _id + 2 x)
 assert.eq(d.system.namespaces.count({name: /keep\d$/}) , 4)
 stopMongod(30000);
 
 conn = startMongodNoReset("--port", 30000, "--dbpath", path, "--smallfiles", "--noprealloc", "--nopreallocj");
 d = conn.getDB('test')
-assert.eq(d.system.namespaces.count({name: /temp\d$/}) , 0)
+assert.eq(d.system.namespaces.count({name: /temp\d$/}) , 0) // collections
+assert.eq(d.system.namespaces.count({name: /temp\d\.\$.*$/}) , 0) //indexes
 assert.eq(d.system.namespaces.count({name: /keep\d$/}) , 4)
 stopMongod(30000);
diff --git a/src/mongo/db/database.cpp b/src/mongo/db/database.cpp
index dbb6249535d..76a2055ab80 100644
--- a/src/mongo/db/database.cpp
+++ b/src/mongo/db/database.cpp
@@ -236,30 +236,41 @@ namespace mongo {
         Lock::assertWriteLocked( name );
         Client::Context ctx( name );
 
-        shared_ptr<Cursor> cursor = theDataFileMgr.findAll( name + ".system.namespaces" );
+        string systemNamespaces =  name + ".system.namespaces";
+
+        // Note: we build up a toDelete vector rather than dropping the collection inside the loop
+        // to avoid modifying the system.namespaces collection while iterating over it since that
+        // would corrupt the cursor.
+        vector<string> toDelete;
+        shared_ptr<Cursor> cursor = theDataFileMgr.findAll(systemNamespaces);
         while ( cursor && cursor->ok() ) {
-            BSONObj x = cursor->current();
+            BSONObj nsObj = cursor->current();
             cursor->advance();
 
-            BSONElement e = x.getFieldDotted( "options.temp" );
+            BSONElement e = nsObj.getFieldDotted( "options.temp" );
             if ( !e.trueValue() )
                 continue;
 
-            string ns = x["name"].String();
+            string ns = nsObj["name"].String();
 
             // Do not attempt to drop indexes
             if ( !NamespaceString::normal(ns.c_str()) )
                 continue;
 
+            toDelete.push_back(ns);
+        }
+
+        for (size_t i=0; i < toDelete.size(); i++) {
+            const string& ns = toDelete[i];
+
             string errmsg;
             BSONObjBuilder result;
-            dropCollection( ns, errmsg, result );
+            dropCollection(ns, errmsg, result);
 
             if ( errmsg.size() > 0 ) {
-                warning() << "could not delete temp collection: " << x
+                warning() << "could not delete temp collection: " << ns
                           << " because of: " << errmsg << endl;
             }
-
         }
     }