[QUESTIONS] lo_write cannot > 640Kb? memory leaks? - Mailing list pgsql-hackers

Hi all,

    Can anybody pinpoint where is wrong on lo_write(and possibly
lo_read)?  I tried to lo_import(and lo_write)  few MegaBytes of data
with large_object but it was painfully SLOW!  So I simplified the
problem, just test "testlo.c" under test/examples directory

    with few MegaBytes of file X.dat

    and printout debug messages like this with lo_import ()->
importFile() in main()

    IT CANNOT LO_WRITE > 640KB !!!  WHY?

testlo.c-------------------
...
in importFile()
{
...
//    with BUFSIZE -> 1024 or 8*1024 or 64*1024 i.e.  1K, 8K, 64K, ...
 /*
  * read in from the Unix file and write to the inversion file
  */
 while ((nbytes = read(fd, buf, BUFSIZE)) > 0)
 {
   printf("COUNT [%d]   %d Kb\n", ++count, count*BUFSIZE/1024);
  tmp = lo_write(conn, lobj_fd, buf, nbytes);
...
if (tmp < nbytes)
  {
   fprintf(stderr, "error while reading \"%s\"", filename);
  }
  printf("READ %d , WRITE %d\n", nbytes, tmp);
_________________________

./testlo template1 X.dat out

....
importing file "in" ...
COUNT [1]   0 Kb
READ 65536 , WRITE 65536
COUNT [2]   64 Kb
...
READ 65536 , WRITE 65536
COUNT [9]   512 Kb
error while reading "in"READ 65536 , WRITE -1
COUNT [10]   576 Kb
error while reading "in"READ 65536 , WRITE -1
COUNT [11]   640 Kb
________________________________________________

and "strace ./testlo template1 in out" shows

...
write(3, "F \0", 3)                     = 3
write(3, "\0\0\3\273\0\0\0\2\0\0\0\4\0\0\0"..., 1024) = 1024
write(3, "\331\5\200\t\317\t\331]\334\331E"..., 64512) = 64512
write(3, "\213\r\30Lv\10I\211\312\1\322\1\312"..., 20) = 20
read(4, "EERROR:  no empty local buffer.\n"..., 1024) = 33
write(2, "error while reading \"in\"", 24error while reading "in") = 24
read(5, "\0\0\0\0\1\310\272\300\276\345\t"..., 65536) = 65536
write(1, "COUNT [10]   576 Kb\n", 20COUNT [10]   576 Kb
)   = 20
write(3, "F \0", 3)                     = 3
write(3, "\0\0\3\273\0\0\0\2\0\0\0\4\0\0\0"..., 1024) = 1024
write(3, "\'j\4j\4h\4\273j\10\241\30Lv\10H"..., 64512) = 64512
write(3, "\331\311\331]\370\331E\370\336\311"..., 20) = 20
read(4, "EERROR:  cannot read block 62 of"..., 1024) = 45
write(2, "error while reading \"in\"", 24error while reading "in") = 24
read(5, "u5hp\366v\10\350pk\374\377\203\304"..., 65536) = 65536
write(1, "COUNT [11]   640 Kb\n", 20COUNT [11]   640 Kb
...
___________________________________________________________

So I lo_open/lo_lseek(SEEK_END)/lo_write/lo_close() INSIDE of the loop,
it solved the problem, which means MEM LEAKS or buffer size problem?
And just
   lobj_fd = lo_open(conn, lobjId, INV_WRITE| INV_READ);
...
 /*
  * read in from the Unix file and write to the inversion file
  */
 while ((nbytes = read(fd, buf, BUFSIZE)) > 0)
 {
   printf("COUNT [%d]   %d Kb\n", ++count, count*BUFSIZE/1024);
   o_lseek(conn, lobj_fd, 0, SEEK_END);
   tmp = lo_write(conn, lobj_fd, buf, nbytes);
...

Also solved the problem...  But I want reliable(lo_read/lo_write) large
object with BIG data.

Please Help me out.

C.S.Park