MDEV-37792 MSAN: use-of-uninitialized-value on DELETE from sequence t…#4843
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MDEV-37792 MSAN: use-of-uninitialized-value on DELETE from sequence t…#4843
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…able SEQUENCE is a pseudo-engine intended to produce sequential numbers. This engine has HTON_HIDDEN flag, and optimizer costs for such engines are zeroed and marked with MEM_UNDEFINED() macro. However, some code paths still examine optimizer costs during execution of queries involving SEQUENCE tables. For example, deletion from a sequence table, despite being invalid, still evaluates costs of access to the table before producing an error. This makes MSAN trigger on the error "use-of-uninitialized-value". Not to overcomplicate the logic for handling such scenarios, this patch simply removes MEM_UNDEFINED() macro for engines with HTON_HIDDEN flag.
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…able
SEQUENCE is a pseudo-engine intended to produce sequential numbers. This engine has HTON_HIDDEN flag, and optimizer costs for such engines are zeroed and marked with MEM_UNDEFINED() macro.
However, some code paths still examine optimizer costs during execution of queries involving SEQUENCE tables. For example, deletion from a sequence table, despite being invalid, still evaluates costs of access to the table before producing an error. This makes MSAN trigger on the error "use-of-uninitialized-value".
Not to overcomplicate the logic for handling such scenarios, this patch simply removes MEM_UNDEFINED() macro for engines with HTON_HIDDEN flag.