bzr push into mysql-5.1-telco-7.0 branch (ole.john.aske:4639 to 4640)

[Ole John Aske]

 4640 Ole John Aske	2011-11-09
      SPJ Fix of buffered rows possible refering garbage after reorg'ed memory pages:
      
      When the SPJ block buffer rows, it also convert the RowPtr from a RT_SECTION
      to RT_LINEAR type as part of ::storeRow(). After ::storeRow has allocated
      memory for the row itself, it is put into a 'map' by add_to_map().
      
      However, as add:to_map() also does its own memory alloc, that may
      trigger a reorg of the memory page in order to reclaim free'ed memory blocks.
      
      Such a reorg will may cause the previously allocated row to be moved, and
      the previously memory rowptr to become invalid - thus referring garbage.
      
      Solution is to refetch the ptr after add_to_map() and fill in the
      returned RowPtr& as the final action.
      
      .... No MTR test as I am only able to reproduce this with my rewritten
      calculate_batch_size() + some additional hack for testing that. These hacks
      effectively force a really tiny 'BatchByteSize' to be calculated. That in
      turn cause lots of repeated fetching (and buffering) from bushy scan queries.

    modified:
      storage/ndb/src/kernel/blocks/dbspj/DbspjMain.cpp
 4639 jonas oreland	2011-11-08
      ndb - bump version to 7.0.29

    modified:
      configure.in
      storage/ndb/ndb_configure.m4
=== modified file 'storage/ndb/src/kernel/blocks/dbspj/DbspjMain.cpp'
--- a/storage/ndb/src/kernel/blocks/dbspj/DbspjMain.cpp	2011-10-31 09:49:29 +0000
+++ b/storage/ndb/src/kernel/blocks/dbspj/DbspjMain.cpp	2011-11-09 08:39:50 +0000
@@ -2187,12 +2187,6 @@ Dbspj::storeRow(Ptr<Request> requestPtr,
     jam();
     return DbspjErr::OutOfRowMemory;
   }
-
-  row.m_type = RowPtr::RT_LINEAR;
-  row.m_row_data.m_linear.m_row_ref = ref;
-  row.m_row_data.m_linear.m_header = (RowPtr::Header*)(dstptr + linklen);
-  row.m_row_data.m_linear.m_data = dstptr + linklen + headlen;
-
   memcpy(dstptr + linklen, headptr, 4 * headlen);
   copy(dstptr + linklen + headlen, dataPtr);
 
@@ -2205,9 +2199,30 @@ Dbspj::storeRow(Ptr<Request> requestPtr,
   else
   {
     jam();
-    return add_to_map(requestPtr, treeNodePtr, row.m_src_correlation, ref);
+    Uint32 error = add_to_map(requestPtr, treeNodePtr, row.m_src_correlation, ref);
+    if (unlikely(error))
+      return error;
+  }
+
+  /**
+   * Refetch pointer to alloc'ed row memory  before creating RowPtr 
+   * as above add_to_xxx may mave reorganized memory causing
+   * alloced row to be moved.
+   */
+  Uint32 * rowptr = 0;
+  if (ref.m_allocator == 0)
+  {
+    jam();
+    rowptr = get_row_ptr_stack(ref);
+  }
+  else
+  {
+    jam();
+    rowptr = get_row_ptr_var(ref);
   }
 
+//ndbrequire(rowptr==dstptr);  // It moved which we now do handle
+  setupRowPtr(treeNodePtr, row, ref, rowptr);
   return 0;
 }
 

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