fix some compaction issues

arangod/VocBase/VocShaper.cpp

@@ -633,6 +633,8 @@ TRI_shape_t const* VocShaper::findShape(TRI_shape_t* shape, bool create) {
 
     char const* m = static_cast<char const*>(slotInfo.mem) +
                     sizeof(triagens::wal::shape_marker_t);
+
+    TRI_ASSERT(m != nullptr);
     TRI_shape_t const* result = reinterpret_cast<TRI_shape_t const*>(m);
 
     {

arangod/VocBase/compactor.cpp

@@ -40,7 +40,6 @@
 #include "VocBase/vocbase.h"
 #include "VocBase/VocShaper.h"
 
-
 static char const* ReasonNoDatafiles =
     "skipped compaction because collection has no datafiles";
 static char const* ReasonCompactionBlocked =
@@ -400,7 +399,12 @@ static void RenameDatafileCallback(TRI_datafile_t* datafile, void* data) {
         document, compactor->_fid, false);
 
     if (dfi != nullptr) {
-      *dfi = context->_dfi;
+      // use original statistics as a base
+      dfi->_numberDead         -= context->_dfi._numberDead;
+      dfi->_sizeDead           -= context->_dfi._sizeDead;
+      
+      dfi->_numberDeletion     = context->_dfi._numberDeletion;
+      // note: the compactor does not change (num|size)Alive|Shapes|Attributes|Transactions
     } else {
       LOG_ERROR("logic error: could not find compactor file information");
     }
@@ -441,6 +445,7 @@ static bool Compactifier(TRI_df_marker_t const* marker, void* data,
 
   compaction_context_t* context = static_cast<compaction_context_t*>(data);
   TRI_document_collection_t* document = context->_document;
+  TRI_voc_fid_t const targetFid = context->_compactor->_fid;
 
   // new or updated document
   if (marker->_type == TRI_DOC_MARKER_KEY_DOCUMENT ||
@@ -457,15 +462,21 @@ static bool Compactifier(TRI_df_marker_t const* marker, void* data,
     bool deleted = (found == nullptr || found->_rid > d->_rid);
 
     if (deleted) {
+      // found a dead document
+      context->_dfi._numberDead += 1;
+      context->_dfi._sizeDead += AlignedSize(marker);
       LOG_TRACE("found a stale document: %s", key);
       return true;
     }
 
     // we found an index entry with a revision id <= the marker revision
     auto oldPtr = found->getDataPtr();
-    if (!TRI_IsWalDataMarkerDatafile(oldPtr) &&
+    auto const isWalDataMarker = TRI_IsWalDataMarkerDatafile(oldPtr);
+    if (!isWalDataMarker &&
         oldPtr != static_cast<void const*>(marker)) {
       // the index points to a datafile marker, but not to THIS marker
+      context->_dfi._numberDead += 1;
+      context->_dfi._sizeDead += AlignedSize(marker);
       return true;
     }
 
@@ -487,10 +498,15 @@ static bool Compactifier(TRI_df_marker_t const* marker, void* data,
 
     // let marker point to the new position
     found2->setDataPtr(result);
+    // update fid in case it changes
+    if (!isWalDataMarker && found2->_fid != targetFid) {
+      found2->_fid = targetFid;
+    }
 
-    // update datafile info
+    // keep track of alive stats
     context->_dfi._numberAlive += 1;
     context->_dfi._sizeAlive += AlignedSize(marker);
+
   }
 
   // deletions
@@ -960,6 +976,38 @@ static void CompactifyDatafiles(TRI_document_collection_t* document,
         }
       }
     }
+      
+    if (n > 1) {
+      // this is a merge of multiple datafiles...
+      // now fuse the statistics of datafile 1..n into the 0th datafile's statistics
+      TRI_WRITE_LOCK_DATAFILES_DOC_COLLECTION(document);
+
+      TRI_doc_datafile_info_t* dst = TRI_FindDatafileInfoDocumentCollection(document, compactor->_fid, false);
+
+      if (dst != nullptr) {
+        for (size_t k = 1; k < n; ++k) {
+          auto compaction = static_cast<compaction_info_t const*>(TRI_AtVector(compactions, k));
+          TRI_doc_datafile_info_t* src = TRI_FindDatafileInfoDocumentCollection(document, compaction->_datafile->_fid, false);
+
+          if (src != nullptr) {
+            dst->_numberAlive        += src->_numberAlive;
+            dst->_numberDead         += src->_numberDead;
+            dst->_numberDeletion     += src->_numberDeletion;
+            dst->_numberShapes       += src->_numberShapes;
+            dst->_numberAttributes   += src->_numberAttributes;
+            dst->_numberTransactions += src->_numberTransactions;
+            dst->_sizeAlive          += src->_sizeAlive;
+            dst->_sizeDead           += src->_sizeDead;
+            dst->_sizeShapes         += src->_sizeShapes;
+            dst->_sizeAttributes     += src->_sizeAttributes;
+            dst->_sizeTransactions   += src->_sizeTransactions;
+          }
+        }
+      }
+
+      TRI_WRITE_UNLOCK_DATAFILES_DOC_COLLECTION(document);
+    }
+
 
     for (i = 0; i < n; ++i) {
       compaction_info_t* compaction =

arangod/VocBase/datafile.cpp

@@ -1906,14 +1906,12 @@ bool TRI_CloseDatafile(TRI_datafile_t* datafile) {
       return false;
     }
 
-    else {
-      datafile->close(datafile);
-      datafile->_data = 0;
-      datafile->_next = 0;
-      datafile->_fd = -1;
+    datafile->close(datafile);
+    datafile->_data = nullptr;
+    datafile->_next = nullptr;
+    datafile->_fd = -1;
 
-      return true;
-    }
+    return true;
   } else if (datafile->_state == TRI_DF_STATE_CLOSED) {
     LOG_WARNING("closing an already closed datafile '%s'",
                 datafile->getName(datafile));