Hi, On July 21, 2020 10:45:37 AM PDT, Antonin Houska <a...@cybertec.at> wrote: >I don't quite understand this part of the comment of the xl_heap_header >structure: > >* NOTE: t_hoff could be recomputed, but we may as well store it because > * it will come for free due to alignment considerations. > >What are the alignment considerations? The WAL code does not appear to >assume >any alignment, and therefore it uses memcpy() to copy the structure >into a >local variable before accessing its fields. For example, >heap_xlog_insert().
Unless you declare them as packed, structs will add padding to align members correctly (if, and only if, the whole struct is stored well aligned). Regards, Andres -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
