In response to Dr. Hagen Höpfner, who asked:
"... MyISAM does not provide a page concept.
Studying the source code I now found some functions that seam to
handle pages, e.g. in myisam/mi_write.c ... As I understood correctly,
these functions regard the btree-index. Am I right?"
mi_write() performs the write of both the index pages, and
the MyISAM record. The index blocks are written first, in the
subroutines _mi_ck_write_btree() and _mi_ck_write_tree() (for
bulk inserts). Most of the functions in mi_write.c concern the
writing of these index blocks. After the index blocks are
written (in mi_write()), you should see the code which looks
something like:
if (!(info->opt_flag & OPT_NO_ROWS))
{
if ((*share->write_record)(info,record))
goto err;
share->state.checksum+=info->checksum;
}
I believe this is where the main record (non-paged isam) is written.
The write_record member variable is a function pointer to one of the
read or write methods of the record cache, and is done this way to
facilitate easy transition from memory writes to disk writes using
the IO_CACHE struct. Look at the _my_b_write macro(s) for more info-
rmation. It's been a little while since I looked at the code for this,
so if I have gotten something incorrect, or missed something big,
please let me (and Dr. Höpfner) know.
Cheers,
Jay Pipes
