Incorrect posix_fadvise in stream_one_file

[Raghavendra D Prabhu]

Earlier reported in lp:1095249

a)
stream_one_file(File file, xb_wstream_file_t *xbfile)
{
 uchar buf[XBSTREAM_BUFFER_SIZE];
 size_t bytes;

 posix_fadvise(file, 0, 0, POSIX_FADV_SEQUENTIAL);

 while ((bytes = my_read(file, buf, XBSTREAM_BUFFER_SIZE,
    MYF(MY_WME))) > 0) {
  if (xb_stream_write_data(xbfile, buf, bytes)) {
   msg("%s: xb_stream_write_data() failed.\n",
       my_progname);
   return 1;
  }
  posix_fadvise(file, 0, 0, POSIX_FADV_DONTNEED);

 }
......
.....

here, it is doing fadvise POSIX_FADV_SEQ which doubles the
readahead but in the loop it discards it everytime. It should
either do POSIX_FADV_DONTNEED at the end (outside the loop) or
use ranges with POSIX_FADV_DONTNEED in the loop.

b) There are many other places where it is used which will need to be checked (since with O_DIRECT used all of the posix_fadvise serve no purpose)

[Alexey Kopytov (akopytov)]

See also bug #1067485.

[Alexey Kopytov (akopytov)]

This was fixed along with bug #1093385 in 2.1.8. It is essentially a duplicate of that bug.

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PXB-35