hi, I have researched buffer manager with postgresql9.4.18. For exact result, I must change IO style to Direct IO. Then I changed the align and O_DIRECT flags according to the version, and set the options at compile time.
However, when I run postgres with the modified version, I get ERROR: could not read block 0 in file "global/XXXXX": Bad address as soon as I started the program. But I do not have any idea where the code was changed with a wrong way. I tried changing ext4 to xfs because of file system problem, but the same problem occurred. Which part can I find a problem with the above error? or Do you have guesswork where the problem is? ᐧ
