1. 18 Aug, 2008 2 commits
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  3. 14 Aug, 2008 8 commits
  4. 13 Aug, 2008 14 commits
  5. 12 Aug, 2008 2 commits
    • Marc Alff's avatar
      Merge mysql-5.1-bugteam -> local bugfix branch · 6eb4de5d
      Marc Alff authored
      6eb4de5d
    • Marc Alff's avatar
      Bug#38296 (low memory crash with many conditions in a query) · 9b619d2d
      Marc Alff authored
      This fix is for 5.1 only : back porting the 6.0 patch manually
      
      The parser code in sql/sql_yacc.yy needs to be more robust to out of
      memory conditions, so that when parsing a query fails due to OOM,
      the thread gracefully returns an error.
      
      Before this fix, a new/alloc returning NULL could:
      - cause a crash, if dereferencing the NULL pointer,
      - produce a corrupted parsed tree, containing NULL nodes,
      - alter the semantic of a query, by silently dropping token values or nodes
      
      With this fix:
      - C++ constructors are *not* executed with a NULL "this" pointer
      when operator new fails.
      This is achieved by declaring "operator new" with a "throw ()" clause,
      so that a failed new gracefully returns NULL on OOM conditions.
      
      - calls to new/alloc are tested for a NULL result,
      
      - The thread diagnostic area is set to an error status when OOM occurs.
      This ensures that a request failing in the server properly returns an
      ER_OUT_OF_RESOURCES error to the client.
      
      - OOM conditions cause the parser to stop immediately (MYSQL_YYABORT).
      This prevents causing further crashes when using a partially built parsed
      tree in further rules in the parser.
      
      No test scripts are provided, since automating OOM failures is not
      instrumented in the server.
      Tested under the debugger, to verify that an error in alloc_root cause the
      thread to returns gracefully all the way to the client application, with
      an ER_OUT_OF_RESOURCES error.
      9b619d2d