Re: [HACKERS] pg_stat_file() and length/size - Mailing list pgsql-patches

Bruce Momjian wrote:
> I am thinking the proper term for the first column of pg_stat_file() is
> "size", not "length".
>
>     test=> select * from pg_stat_file('.');
>      length |         atime          |         mtime          |         ctime          | isdir
>     --------+------------------------+------------------------+------------------------+-------
>
>         512 | 2005-08-13 23:06:38-04 | 2005-08-13 23:06:54-04 | 2005-08-13 23:06:54-04 | t
>     (1 row)

I have renamed the column from length to size.  I also renamed the
timestamp columns to be more meaningful:

    test=> select (pg_stat_file('.')).*;
     size |         access         |      modification      |         change         | creation | isdir
    ------+------------------------+------------------------+------------------------+----------+-------
      512 | 2005-08-15 18:10:10-04 | 2005-08-15 17:30:28-04 | 2005-08-15 17:30:28-04 |          | t
    (1 row)

(Anyone have a better name for "change"?)

In doing this I also realized the ctime on Unix is change time (file
contents or inode), while on Win32 ctime is file creation time.  I split
the ctime column into "change" and "creation", and one is null on each
platform.  Above is the Unix output.  I have also updated the catalog
version.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073
Index: doc/src/sgml/func.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/func.sgml,v
retrieving revision 1.280
diff -c -c -r1.280 func.sgml
*** doc/src/sgml/func.sgml    13 Aug 2005 19:02:32 -0000    1.280
--- doc/src/sgml/func.sgml    15 Aug 2005 22:35:59 -0000
***************
*** 9414,9425 ****
     </indexterm>
     <para>
      <function>pg_stat_file()</> returns a record containing the file
!     length, last accessed timestamp, last modified timestamp,
!     creation timestamp, and a boolean indicating if it is a directory.
!     Typical usages include:
  <programlisting>
  SELECT * FROM pg_stat_file('filename');
! SELECT (pg_stat_file('filename')).mtime;
  </programlisting>
     </para>

--- 9414,9426 ----
     </indexterm>
     <para>
      <function>pg_stat_file()</> returns a record containing the file
!     size, last accessed timestamp, last modified timestamp,
!     last file status change timestamp (Unix platforms only),
!     file creation timestamp (Win32 only), and a boolean indicating
!     if it is a directory.  Typical usages include:
  <programlisting>
  SELECT * FROM pg_stat_file('filename');
! SELECT (pg_stat_file('filename')).modification;
  </programlisting>
     </para>

Index: src/backend/catalog/system_views.sql
===================================================================
RCS file: /cvsroot/pgsql/src/backend/catalog/system_views.sql,v
retrieving revision 1.20
diff -c -c -r1.20 system_views.sql
*** src/backend/catalog/system_views.sql    15 Aug 2005 16:25:17 -0000    1.20
--- src/backend/catalog/system_views.sql    15 Aug 2005 22:35:59 -0000
***************
*** 346,353 ****
                           'timestamptz',
                           'timestamptz',
                           'timestamptz',
                           'bool'],
!   proargmodes = ARRAY['i'::"char", 'o', 'o', 'o', 'o', 'o'],
!   proargnames = ARRAY['filename'::text,
!                       'length', 'atime', 'mtime', 'ctime','isdir']
  WHERE oid = 'pg_stat_file(text)'::regprocedure;
--- 346,354 ----
                           'timestamptz',
                           'timestamptz',
                           'timestamptz',
+                          'timestamptz',
                           'bool'],
!   proargmodes = ARRAY['i'::"char", 'o', 'o', 'o', 'o', 'o', 'o'],
!   proargnames = ARRAY['filename'::text, 'size', 'access', 'modification',
!               'change', 'creation', 'isdir']
  WHERE oid = 'pg_stat_file(text)'::regprocedure;
Index: src/backend/utils/adt/genfile.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/genfile.c,v
retrieving revision 1.4
diff -c -c -r1.4 genfile.c
*** src/backend/utils/adt/genfile.c    13 Aug 2005 19:02:34 -0000    1.4
--- src/backend/utils/adt/genfile.c    15 Aug 2005 22:36:00 -0000
***************
*** 154,161 ****
      text       *filename_t = PG_GETARG_TEXT_P(0);
      char        *filename;
      struct stat fst;
!     Datum        values[5];
!     bool        isnull[5];
      HeapTuple    tuple;
      TupleDesc    tupdesc;

--- 154,161 ----
      text       *filename_t = PG_GETARG_TEXT_P(0);
      char        *filename;
      struct stat fst;
!     Datum        values[6];
!     bool        isnull[6];
      HeapTuple    tuple;
      TupleDesc    tupdesc;

***************
*** 175,200 ****
       * This record type had better match the output parameters declared
       * for me in pg_proc.h (actually, in system_views.sql at the moment).
       */
!     tupdesc = CreateTemplateTupleDesc(5, false);
      TupleDescInitEntry(tupdesc, (AttrNumber) 1,
!                        "length", INT8OID, -1, 0);
      TupleDescInitEntry(tupdesc, (AttrNumber) 2,
!                        "atime", TIMESTAMPTZOID, -1, 0);
      TupleDescInitEntry(tupdesc, (AttrNumber) 3,
!                        "mtime", TIMESTAMPTZOID, -1, 0);
      TupleDescInitEntry(tupdesc, (AttrNumber) 4,
!                        "ctime", TIMESTAMPTZOID, -1, 0);
      TupleDescInitEntry(tupdesc, (AttrNumber) 5,
                         "isdir", BOOLOID, -1, 0);
      BlessTupleDesc(tupdesc);

      values[0] = Int64GetDatum((int64) fst.st_size);
      values[1] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_atime));
      values[2] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_mtime));
      values[3] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
!     values[4] = BoolGetDatum(fst.st_mode & S_IFDIR);
!
!     memset(isnull, false, sizeof(isnull));

      tuple = heap_form_tuple(tupdesc, values, isnull);

--- 175,209 ----
       * This record type had better match the output parameters declared
       * for me in pg_proc.h (actually, in system_views.sql at the moment).
       */
!     tupdesc = CreateTemplateTupleDesc(6, false);
      TupleDescInitEntry(tupdesc, (AttrNumber) 1,
!                        "size", INT8OID, -1, 0);
      TupleDescInitEntry(tupdesc, (AttrNumber) 2,
!                        "access", TIMESTAMPTZOID, -1, 0);
      TupleDescInitEntry(tupdesc, (AttrNumber) 3,
!                        "modification", TIMESTAMPTZOID, -1, 0);
      TupleDescInitEntry(tupdesc, (AttrNumber) 4,
!                        "change", TIMESTAMPTZOID, -1, 0);
      TupleDescInitEntry(tupdesc, (AttrNumber) 5,
+                        "creation", TIMESTAMPTZOID, -1, 0);
+     TupleDescInitEntry(tupdesc, (AttrNumber) 6,
                         "isdir", BOOLOID, -1, 0);
      BlessTupleDesc(tupdesc);

+     memset(isnull, false, sizeof(isnull));
+
      values[0] = Int64GetDatum((int64) fst.st_size);
      values[1] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_atime));
      values[2] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_mtime));
+     /* Unix has file status change time, while Win32 has creation time */
+ #if !defined(WIN32) && !defined(__CYGWIN__)
      values[3] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
!     isnull[4] = true;
! #else
!     isnull[3] = true;
!     values[4] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
! #endif
!     values[5] = BoolGetDatum(fst.st_mode & S_IFDIR);

      tuple = heap_form_tuple(tupdesc, values, isnull);

Index: src/include/catalog/catversion.h
===================================================================
RCS file: /cvsroot/pgsql/src/include/catalog/catversion.h,v
retrieving revision 1.299
diff -c -c -r1.299 catversion.h
*** src/include/catalog/catversion.h    15 Aug 2005 16:25:18 -0000    1.299
--- src/include/catalog/catversion.h    15 Aug 2005 22:36:01 -0000
***************
*** 53,58 ****
   */

  /*                            yyyymmddN */
! #define CATALOG_VERSION_NO    200508151

  #endif
--- 53,58 ----
   */

  /*                            yyyymmddN */
! #define CATALOG_VERSION_NO    200508152

  #endif