in CREATE TABLE and ALTER TABLE with AVG_ROW_LENGTH={1,2,4,8,16}.

Introduce FIL_PAGE_ZBLOB_DATA as a synonym for FIL_PAGE_FILE_FLUSH_LSN.

btr_store_big_rec_extern_fields(): Make the assertion about
dict_table_zip_size() more accurate.

buf_LRU_get_free_block(), buf_block_alloc(): Add parameter zip_size.

buf_calc_zblob_page_checksum(): Remove. Replace with page_zip_calc_checksum().

buf_page_init(): Remove parameter zip_size.

buf_page_io_complete(): Add a placeholder for handling compressed pages.

trx_doublewrite_page_inside(): Remove redundant function.

page_zip_write_rec(): Relax an overly tight assertion about blob_no.

buf_page_print(): Print also compressed pages.  Add parameter zip_size.

buf_flush_init_for_writing(): Stamp the fields on a compressed B-tree index
page.

Add the header field FIL_PAGE_ZBLOB_SPACE_ID as an alias of FIL_PAGE_PREV.

page_zip_calc_checksum(): New function.

page_zip_compress(): Avoid copying the fields that are written in
buf_flush_init_for_writing().

page_zip_header_cmp(): New function for comparing those fields of the
page header that will not be written in buf_flush_init_for_writing().

recompressing the page.

buf_flush_init_for_writing(): Calculate the checksum with the actual zip_size.

buf_calc_zblob_page_checksum(): Skip the field FIL_PAGE_SPACE_OR_CHKSUM.

trx_sys_doublewrite_init_or_restore_page(): Use the actual zip_size.

page_cur_insert_rec_low(): If page_zip_alloc() fails, try compressing the
whole page afterwards.

btr_page_reorganize_low(): Rename new_page to temp_page.

btr_store_big_rec_extern_fields(): FIL_PAGE_TYPE is 2 bytes, not 4.

buf_page_init(), buf_page_create(), buf_read_page_low(),
buf_page_init_for_read(): Add parameter zip_size.

buf_page_init_for_backup_restore(),
recv_apply_log_recs_for_backup(): Enclose in #ifdef UNIV_HOTBACKUP.

Enclose some debug code in #ifdef UNIV_LOG_REPLICATE.

page_zip_write_header_log(): Replace page_zip with a pointer to
the uncompressed page.

page_zip_write_rec(): Relax an assertion about blob_no + n_ext.

page_copy_rec_list_to_created_page_write_log(): Allow logging to be disabled.

and to the file space header (FSP_PAGE_ZIP_SIZE, renamed from
FSP_LOWEST_NO_WRITE).

fil_space_struct: Add zip_size.

dict_table_struct: Embed zip_size in flags.

dict_table_zip_size(): Infer zip_size from table->flags.

dict_sys_tables_get_zip_size(): Read zip_size from SYS_TABLES.TYPE.

fil_space_get_zip_size(): Read zip_size from the file space header.

Add the redo log entry type MLOG_ZIP_FILE_CREATE.

page_zip_alloc(): Add parameter "mtr" and log successful calls
to page_zip_compress().

page_zip_write_blob_ptr(), page_zip_write_node_ptr(): Write the offset on
the uncompressed page, because mlog_write_initial_log_record_fast()
does not do so.

page_zip_write_header_log(), page_zip_parse_write_header(): Encode the
offset in one byte.

MLOG_ZIP_LIST_START_COPY and MLOG_ZIP_LIST_END_COPY.

btr_compress(): Simplify a debug assertion.

page_zip_compress_write_log(), page_zip_parse_compress(): New functions.

page_cur_parse_insert_rec(): Simplify the code.

page_parse_create_zip(): Removed.

page_create_zip(), page_copy_rec_list_end(),
page_copy_rec_list_start(): Invoke page_zip_compress_write_log().

btr_page_create(): Remove parameters "prev" and "next".  The pointers
to adjacent B-tree pages will be set in the caller before any user
records are inserted.

Remove the redo log entry type MLOG_ZIP_ROOT_RAISE, since
btr_root_raise_and_insert() will not defer modifications to
the compressed page.

btr_attach_half_pages(): Add parameter new_page_zip.

crash recovery of uncompressed tables.

MLOG_ZIP_COMPRESS and MLOG_ZIP_DECOMPRESS with higher-level entry types.
Implement the logging and crash recovery of MLOG_ZIP_PAGE_CREATE.

page_create_zip(): New function for creating a compressed B-tree page.

page_parse_create_zip(): New function for applying a MLOG_ZIP_PAGE_CREATE
redo log record.

btr_page_create(): Remove the prototype.  Add parameters page_zip, level,
prev, and next.

btr0btr.c: Eliminate page_zip_compress() calls where possible.

page_zip_alloc(), page_zip_compress(), page_zip_decompress(),
page_zip_clear_rec(): Remove parameter mtr.

recv_parse_or_apply_log_rec_body(): Handle MLOG_ZIP_PAGE_CREATE.
Add TODO comments for the other added redo log entry types.

assume that the operation always succeeds.

page_zip_parse_write_blob_ptr(): New function for applying the redo log
record MLOG_ZIP_WRITE_BLOB_PTR.

page_zip_write_blob_ptr(): Write the necessary information to the redo log.

page0zip.c: Tighten the assertions to ensure that blob_ptr < page_zip->n_blobs.

page_zip_write_node_ptr(): Use memcpy() instead of mach_write_to_4().

page_zip_parse_write_header(): New function for applying the redo log of
MLOG_ZIP_WRITE_HEADER.

page_zip_parse_write_node_ptr(): Mark the log corrupted if !page_zip.

page_zip_parse_write_node_ptr(): New function to apply a redo log of
MLOG_ZIP_WRITE_NODE_PTR.

page_zip_write_node_ptr(): Write all needed information to the redo log.

page_zip_write_header_log(): Write all necessary information to the redo log.

dict_mem_table_create(): Account for DICT_TF_COMPRESSED in a debug assertion.

btr_store_big_rec_extern_fields(), btr_free_externally_stored_field(),
btr_copy_externally_stored_field(): Implement the disk format for
compressed BLOB pages.

btr_copy_externally_stored_field(): Improve error reporting and handling
when decompressing BLOB pages.

buf_flush_init_for_writing(), buf_page_is_corrupted(), buf_page_print():
Account for compressed BLOB pages (FIL_PAGE_TYPE_ZBLOB).

buf_calc_zblob_page_checksum(): New function.

Replace btr_page_get_level() with page_is_leaf() where possible.

row_purge_upd_exist_or_extern(): Remove obsolete TODO comment.

dtuple_convert_big_rec(): Replace a flag variable with goto.

btr_store_big_rec_extern_fields(): Assert that page_zip is non-NULL
if and only if dict_table_is_zip() holds.

btr_free_externally_stored_field(): Observe dict_table_is_zip().
Allow page_zip==NULL even if dict_table_is_zip().  Remove the
related TODO comment in row_purge_upd_exist_or_extern().

page_zip_available(): uncompressed_size already includes
PAGE_ZIP_DIR_SLOT_SIZE.

page_zip_decompress(): Remove bogus assertion d_stream.next_out == last.
Do not subtract BTR_EXTERN_FIELD_REF_SIZE from d_stream.avail_in when
decompressing records, because the records may be deleted later in
page_zip_apply_log(), and no BLOB pointers are allocated for deleted
records.

row_purge_upd_exist_or_extern().

btr_page_split_and_insert(): Avoid dereferencing pointers to garbage on
the old page.

btr_cur_pessimistic_insert(): Pass pointer to big_rec_vec to
btr_cur_optimistic_insert().

trx_undo_prev_version_build(): Only invoke rec_set_field_extern_bits()
if n_ext_vect > 0.

row_ins_index_entry_low(): Simplify a debug assertion.

page_copy_rec_list_end_no_locks(): Make the loop slightly more readable.

page_delete_rec_list_end(): Delete records on compressed pages one by one.

page_zip_get_n_prev_extern(): Ignore deleted records.

page_zip_write_rec(): Remove bogus debug assertion about the BLOB pointer
being zero-filled.  It would fail when reallocating records from the page
heap or when updating records in place.

copy BLOB pointers.

page_zip_dir_find_free_low(): New function,
split from page_zip_dir_find_free().

Add comments about processing the records in heap_no order.

Fix some typographic errors in comments and improve formatting.

page_zip_decompress(): Initialize (clear) the BLOB pointers in deleted records.

page_zip_clear_rec(): Relocate page_zip_validate() assertions, so that they
will not fail if a record containing BLOB pointers is being deleted.

Note that page_zip_validate() will fail if page_zip_clear_rec() is unable
to clear the record.

page_zip_decompress(): Pass size = d_stream.avail_in + 1
to page_zip_apply_log(), since the terminating NUL byte is not included
in the space reserved for the compressed data stream.

page_zip_clear_rec(): Clear also node pointer fields.

Wrap ut_malloc() and ut_free() as page_zip_alloc() and page_zip_free().

page_delete_rec_list_end(): Do not invoke page_zip_clear_rec().

page_zip_clear_rec(): Remove the global declaration.  Add an assertion
that the record must be on the free list.  Copy onl rec_offs_data_size()
bytes before attempting to clear the record and to compress the page.

page_zip_compress(), page_zip_write_rec(): Remove debug assertions that
trx_id, roll_ptr and node_ptr of deleted records be zero-filled.

page_zip_write_rec(): Allow the record to be delete-marked.

page_zip_write_trx_id_and_roll_ptr(): Write roll_ptr after trx_id,
not over it.

page_cur_search_with_match(): Add a page_zip_validate() debug assertion.

page_validate(): Add a missing space to a fprintf() format string.

page_zip_compress(): Add a debug check that the trx_id and roll_ptr columns
of deleted records are zero-filled.  This should provide some detection
against misdirected writes.

page_zip_decompress(): Correct typos in comments.

btr_page_get_father_for_rec(): Remove redundant assertion.
Add UNIV_UNLIKELY to an assertion-like test.

btr_validate_level(): Add debug assertions on page_zip_validate().

page_zip_compress(): Remove bogus assertion.

page_zip_write_rec(): Assert that the record written is neither delete-marked
nor deleted.

page_zip_compress(): Assert that trx_id and roll_ptr are zero for
deleted records.

page_zip_clear_rec(): Remove comment about need for redo logging.
This operationg is already logged on a higher level.

page_delete_rec_list_end(): Always invoke page_zip_clear_rec()
on compressed pages.

Restore page_zip_clear_rec() to the global scope.
Invoke it in page_delete_rec_list_end().

Add debug assertions to page0zip.c to guard against overwriting data
on the compressed page.

operations on BLOB columns.  There are some bugs in the code, because
test-insert and a few other tests fail.

page_mem_free(): Add parameter index.  Decrement PAGE_N_RECS here.
Move some operations to page_zip_dir_delete().

page_zip_clear_rec(): Make this a static function.

page_zip_dir_delete(): Add parameters index and offsets.
Decrement PAGE_N_RECS and clear info_bits and n_owned.

page_zip_get_n_prev_extern(): Correct the synopsis and the algorithm.
Add parameter page_zip.  Search the records in heap_no order instead
of collation order.

page_zip_compress(), page_zip_decompress(): Only copy BLOB pointers
and increment n_blobs for records that have not been deleted.

page_zip_clear_rec(): Clear trx_id and roll_ptr on the compressed page.

page_zip_dir_delete(): Decrement PAGE_N_RECS.  Shift the array of
BLOB pointers.  Call page_zip_clear_rec().

page_zip_dir_add_slot(): Shift the array of BLOB pointers to make
space of roll_ptr and trx_id.

page_cur_delete_rec(): Do not decrement PAGE_N_RECS or call
page_zip_clear_rec(), as page_mem_free() already does it.