page_zip_max_ins_size(): New function.
btr_cur_optimistic_insert(), btr_cur_optimistic_delete(),
btr_page_split_and_insert(), btr_compress(): Do not update the
ibuf free bits for non-leaf pages or pages belonging to a clustered index.
The insert buffer only covers operations on leaf pages of secondary indexes.
For pages covered by the insert buffer, limit the max_ins_size to
page_zip_max_ins_size().
buf_page_get_gen(): Merge the insert buffer after decompressing the page.
buf_page_io_complete(): Relax the assertion about ibuf_count. For
compressed-only pages, the insert buffer merge takes place
in buf_page_get_gen().
ibuf_index_page_calc_free_bits(), ibuf_index_page_calc_free_from_bits(),
ibuf_index_page_calc_free(), ibuf_update_free_bits_if_full(),
ibuf_update_free_bits_low(), ibuf_update_free_bits_for_two_pages_low(),
ibuf_set_free_bits_low(): Add the parameter zip_size. Limit the maximum
insert size to page_zip_max_ins_size().
buf_page_get_gen(). This saves one mutex operation per block request.
buf_page_get_gen(), various macros and functions: Add parameter zip_size.
btr_node_ptr_get_child(): Add parameter index.
fil_space_get_latch(): Add optional output parameter zip_size.
fil_space_get_zip_size(): Return 0 for space id==0, because the
system tablespace is never compressed.
fsp_header_init(): Remove the parameter zip_size.
ibuf_free_excess_pages(): Remove the parameter zip_size.
trx_rseg_t, trx_undo_t: Add field zip_size.
xdes_lst_get_next(): Remove, unused.
ibuf_reset_free_bits(): Remove, as there already is a similar function
ibuf_reset_free_bits_with_type().
ibuf_reset_free_bits_with_type(), ibuf_set_free_bits(),
ibuf_update_free_bits_if_full(), btr_leaf_page_release(),
buf_page_make_young(): Replace page_t with buf_block_t.
btr_compress(): Replace btr_page_get() with btr_block_get().
