fix semantics of the getChunkManager() method, add non-erroring version SERVER-3517

8 files changed, 24 insertions, 11 deletions

diff --git a/s/commands_admin.cpp b/s/commands_admin.cpp
index 6d3e398370c..53a4bee92b7 100644
--- a/s/commands_admin.cpp
+++ b/s/commands_admin.cpp
@@ -545,7 +545,7 @@ namespace mongo {
                     return false;
                 }
 
-                ChunkManagerPtr cm = config->getChunkManager( ns );
+                ChunkManagerPtr cm = config->getChunkManagerIfExists( ns );
                 if ( ! cm ) {
                     errmsg = "no chunk manager?";
                     return false;
diff --git a/s/commands_public.cpp b/s/commands_public.cpp
index eb19ef68fc3..cbb7c2374df 100644
--- a/s/commands_public.cpp
+++ b/s/commands_public.cpp
@@ -393,7 +393,6 @@ namespace mongo {
                     filter = cmdObj["query"].Obj();
 
                 DBConfigPtr conf = grid.getDBConfig( dbName , false );
-
                 if ( ! conf || ! conf->isShardingEnabled() || ! conf->isSharded( fullns ) ) {
                     ShardConnection conn( conf->getPrimary() , fullns );
 
@@ -413,7 +412,7 @@ namespace mongo {
                     }
 
                     // this collection got sharded
-                    ChunkManagerPtr cm = conf->getChunkManager( fullns , true );
+                    ChunkManagerPtr cm = conf->getChunkManagerIfExists( fullns , true );
                     if ( ! cm ) {
                         errmsg = "should be sharded now";
                         result.append( "root" , temp );
@@ -424,7 +423,7 @@ namespace mongo {
                 long long total = 0;
                 map<string,long long> shardCounts;
 
-                ChunkManagerPtr cm = conf->getChunkManager( fullns );
+                ChunkManagerPtr cm = conf->getChunkManagerIfExists( fullns );
                 while ( true ) {
                     if ( ! cm ) {
                         // probably unsharded now
@@ -442,7 +441,7 @@ namespace mongo {
                         if ( conn.setVersion() ) {
                             total = 0;
                             shardCounts.clear();
-                            cm = conf->getChunkManager( fullns );
+                            cm = conf->getChunkManagerIfExists( fullns );
                             conn.done();
                             hadToBreak = true;
                             break;
@@ -463,7 +462,7 @@ namespace mongo {
                             // my version is old
                             total = 0;
                             shardCounts.clear();
-                            cm = conf->getChunkManager( fullns , true );
+                            cm = conf->getChunkManagerIfExists( fullns , true );
                             hadToBreak = true;
                             break;
                         }
diff --git a/s/config.cpp b/s/config.cpp
index 82942eb5320..bc9903fa29c 100644
--- a/s/config.cpp
+++ b/s/config.cpp
@@ -185,6 +185,16 @@ namespace mongo {
         return true;
     }
 
+    ChunkManagerPtr DBConfig::getChunkManagerIfExists( const string& ns, bool shouldReload ){
+        try{
+            return getChunkManager( ns, shouldReload );
+        }
+        catch( AssertionException& e ){
+            warning() << "chunk manager not found for " << ns << causedBy( e ) << endl;
+            return ChunkManagerPtr();
+        }
+    }
+
     ChunkManagerPtr DBConfig::getChunkManager( const string& ns , bool shouldReload ) {
         BSONObj key;
         bool unique;
@@ -226,6 +236,7 @@ namespace mongo {
                 if ( v == oldVersion ) {
                     scoped_lock lk( _lock );
                     CollectionInfo& ci = _collections[ns];
+                    massert( 15882 , str::stream() << "not sharded after reloading from chunks : " << ns , ci.isSharded() );
                     return ci.getCM();
                 }
             }
@@ -252,7 +263,7 @@ namespace mongo {
             ci.resetCM( temp.release() );
         }
         
-        assert( ci.getCM().get() );
+        massert( 15883 , str::stream() << "not sharded after chunk manager reset : " << ns , ci.isSharded() );
         return ci.getCM();
     }
 
diff --git a/s/config.h b/s/config.h
index 6c8f8934aed..90c06cb0223 100644
--- a/s/config.h
+++ b/s/config.h
@@ -143,6 +143,7 @@ namespace mongo {
         bool isSharded( const string& ns );
 
         ChunkManagerPtr getChunkManager( const string& ns , bool reload = false );
+        ChunkManagerPtr getChunkManagerIfExists( const string& ns , bool reload = false );
 
         /**
          * @return the correct for shard for the ns
diff --git a/s/request.cpp b/s/request.cpp
index 2dc0beca4b5..36488cb5617 100644
--- a/s/request.cpp
+++ b/s/request.cpp
@@ -77,7 +77,9 @@ namespace mongo {
 
         if ( _config->isSharded( nsStr ) ) {
             _chunkManager = _config->getChunkManager( nsStr , reload );
-            uassert( 10193 ,  (string)"no shard info for: " + getns() , _chunkManager );
+            // TODO:  All of these uasserts are no longer necessary, getChunkManager() throws when
+            // not returning the right value.
+            uassert( 10193 ,  (string)"no shard info for: " + nsStr , _chunkManager );
         }
         else {
             _chunkManager.reset();
diff --git a/s/shard_version.cpp b/s/shard_version.cpp
index da712b8abad..4f84b0ae61e 100644
--- a/s/shard_version.cpp
+++ b/s/shard_version.cpp
@@ -96,7 +96,7 @@ namespace mongo {
         ChunkManagerPtr manager;
         const bool isSharded = conf->isSharded( ns );
         if ( isSharded ) {
-            manager = conf->getChunkManager( ns , authoritative );
+            manager = conf->getChunkManagerIfExists( ns , authoritative );
             // It's possible the chunk manager was reset since we checked whether sharded was true,
             // so must check this here.
             if( manager ) officialSequenceNumber = manager->getSequenceNumber();
diff --git a/s/strategy_shard.cpp b/s/strategy_shard.cpp
index db21ec05efb..c6b30e7965f 100644
--- a/s/strategy_shard.cpp
+++ b/s/strategy_shard.cpp
@@ -233,7 +233,7 @@ namespace mongo {
                     LOG( logLevel ) << "retrying insert because of StaleConfigException: " << e << " object: " << o << endl;
 
                     unsigned long long old = manager->getSequenceNumber();
-                    manager = conf->getChunkManager(ns);
+                    manager = conf->getChunkManagerIfExists(ns);
 
                     LOG( logLevel ) << "  sequenece number - old: " << old << " new: " << manager->getSequenceNumber() << endl;
 
diff --git a/s/writeback_listener.cpp b/s/writeback_listener.cpp
index bfab237fc84..ba982229bff 100644
--- a/s/writeback_listener.cpp
+++ b/s/writeback_listener.cpp
@@ -216,7 +216,7 @@ namespace mongo {
                             
                             if ( gle["code"].numberInt() == 9517 ) {
                                 log() << "writeback failed because of stale config, retrying attempts: " << attempts << endl;
-                                if( ! db->getChunkManager( ns , true ).get() ){
+                                if( ! db->getChunkManagerIfExists( ns , true ) ){
                                     uassert( 15881, str::stream() << "Could not reload chunk manager after " << attempts << " attempts.", attempts <= 4 );
                                     sleepsecs( attempts - 1 );
                                 }