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Arun Kuruvila authored
WITH CERTAIN MAX_HEAP_TABLE_SIZE VALUES Description: When the system variable 'max_heap_table_size' is set to 20GB, the server crashes on creation of a temporary tables or tables using MEMORY storage engine. Analysis: The variable 'max_record' determines the amount heap allocated for the records of the table. This value is determined using the 'max_heap_table_size' variable. 'records_in_block' in turn uses the max_records to determine the number of records per block. When the 'max_heap_table_size' is set to 20GB, then the 'records_in_block' is calculated to a value of 2^28. The size of the block determined by multiplying the 'records_in_block' and 'recbuffer' results in overflow and hence the value becomes zero. As a result, zero bytes of the heap is allocated for the table. This will result in a server crash when the table is accessed. Fix: The variables 'records_in_block' and 'recbuffer' are typecasted to 'unsigned long' while calculating the size of the block.
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