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    BUG#23443: user-defined variables can consume too much memory in the · 4fe1561f
    unknown authored
               server
    
    The problem was that when memory was exhausted HEAP engine could crash
    (GROUP BY uses HEAP TABLE).  Alternatively, if SET was used, it could
    report an error "You may only use constant expressions with SET" instead
    of "Out of memory (Needed NNNNNN bytes)".
    
    The solution is:
     - pass MY_WME to (some) calls to my_malloc() to get correct message.
     - fix heap_write() so that the first key is skipped during cleanup
       on ENOMEM because it wasn't inserted and doesn't have to be
       deleted.
    
    No test case is provided because we can't test out-of-memory behaviour
    in our current test framework.
    
    
    heap/hp_block.c:
      If allocation fails, write an error message.
    heap/hp_write.c:
      On ENOMEM, skip the first key in cleanup, as it wasn't inserted yet.
    sql/item_func.cc:
      Add MY_WME so that OOM error will be reported.
    4fe1561f
hp_write.c 7.38 KB