• Michael Paquier's avatar
    Fix issues with Windows' stat() for files pending on deletion · de1510e2
    Michael Paquier authored
    The code introduced by bed90759 to enhance the stat() implementation on
    Windows for file sizes larger than 4GB fails to properly detect files
    pending for deletion with its method based on NtQueryInformationFile()
    or GetFileInformationByHandleEx(), as proved by Alexander Lakhin in a
    custom TAP test of his own.
    
    The method used in the implementation of open() to sleep and loop when
    when failing on ERROR_ACCESS_DENIED (EACCES) is showing much more
    stability, so switch to this method.  This could still lead to issues if
    the permission problem stays around for much longer than the timeout of
    1 second used, but that should (hopefully) never happen in
    performance-critical paths.  Still, there could be a point in increasing
    the timeouts for the sake of machines that handle heavy loads.
    
    Note that WIN32's open() now uses microsoft_native_stat() as it should
    be similar to stat() when working around issues with concurrent file
    deletions.
    
    I have spent some time testing this patch with pgbench in combination
    of the SQL functions from genfile.c, as well as running the TAP test
    provided on the thread with MSVC builds, and this looks much more
    stable than the previous method.
    
    Author: Alexander Lakhin
    Reviewed-by: Tom Lane, Michael Paquier,	Justin Pryzby
    Discussion: https://postgr.es/m/c3427edf-d7c0-ff57-90f6-b5de3bb62709@gmail.com
    Backpatch-through: 14
    de1510e2
open.c 5.87 KB