Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4

Tom Lane wrote:
> Gregory Stark <stark@enterprisedb.com> writes:
> > Tom Lane <tgl@sss.pgh.pa.us> writes:
> >> Ugh.  So apparently, we actually need to special-case Solaris to not
> >> believe that posix_fadvise works, or we'll waste cycles uselessly
> >> calling a do-nothing function.  Thanks, Sun.
>
> > Do we? Or do we just document that setting effective_cache_size on Solaris
> > won't help?
>
> I assume you meant effective_io_concurrency.  We'd still need a special
> case because the default is currently hard-wired at 1, not 0, if
> configure thinks the function exists.  Also there's a posix_fadvise call
> in xlog.c that that parameter doesn't control anyhow.

The attached patch prevents the posix_fadvise() probe in configure on
Solaris, and adds a comment why.  I have already documented why Solaris
can't do effective_io_concurrency.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +
Index: configure.in
===================================================================
RCS file: /cvsroot/pgsql/configure.in,v
retrieving revision 1.592
diff -c -c -r1.592 configure.in
*** configure.in    27 Mar 2009 19:58:11 -0000    1.592
--- configure.in    2 Apr 2009 21:23:36 -0000
***************
*** 1141,1150 ****
  AC_FUNC_ACCEPT_ARGTYPES
  PGAC_FUNC_GETTIMEOFDAY_1ARG

! AC_CHECK_FUNCS([cbrt dlopen fcvt fdatasync getpeereid getpeerucred getrlimit memmove poll posix_fadvise pstat
readlinksetproctitle setsid sigprocmask symlink sysconf towlower utime utimes waitpid wcstombs]) 

! AC_CHECK_DECLS(fdatasync, [], [], [#include <unistd.h>])
  AC_CHECK_DECLS(posix_fadvise, [], [], [#include <fcntl.h>])
  AC_CHECK_DECLS([strlcat, strlcpy])
  # This is probably only present on Darwin, but may as well check always
  AC_CHECK_DECLS(F_FULLFSYNC, [], [], [#include <fcntl.h>])
--- 1141,1157 ----
  AC_FUNC_ACCEPT_ARGTYPES
  PGAC_FUNC_GETTIMEOFDAY_1ARG

! AC_CHECK_FUNCS([cbrt dlopen fcvt fdatasync getpeereid getpeerucred getrlimit memmove poll pstat readlink setproctitle
setsidsigprocmask symlink sysconf towlower utime utimes waitpid wcstombs]) 

! # posix_fadvise() is a no-op on Solaris, so don't incur function overhead
! # by calling it, 2009-04-02
! # http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/lib/libc/port/gen/posix_fadvise.c
! if test "$PORTNAME" != "solaris"; then
! AC_CHECK_FUNCS(posix_fadvise);
  AC_CHECK_DECLS(posix_fadvise, [], [], [#include <fcntl.h>])
+ fi
+
+ AC_CHECK_DECLS(fdatasync, [], [], [#include <unistd.h>])
  AC_CHECK_DECLS([strlcat, strlcpy])
  # This is probably only present on Darwin, but may as well check always
  AC_CHECK_DECLS(F_FULLFSYNC, [], [], [#include <fcntl.h>])