btr_compress(): Defer any tree modifications until the records
have successfully been copied.
row_purge_remove_sec_if_poss_low(): Simplify the setting of
the return status.
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.
Fix the way how btr_free_externally_stored_field() is called in purge.
btr_free_externally_stored_field(): Add parameter field_ref that points
directly to the BLOB reference. Use rec, offsets, page_zip, and i
only for the page_zip_write_blob_ptr() call.
row_purge_upd_exist_or_extern(): Do not assume that the undo log contains
the entire record. Only pass the BLOB reference to
btr_free_externally_stored_field().
BLOB pointers, trx_id, and roll_ptr.
btr_empty(), btr_create(), page_create(): Add parameter "index", as some
index information will be encoded on the compressed page.
Define REC_NODE_PTR_SIZE as 4.
Allow btr_page_reorganize() and btr_page_reorganize_low() to fail.
Define the error code DB_ZIP_OVERFLOW.
Make row_ins_index_entry_low() static.
page0zip: Encode the index, log reorganized records, and store uncompressed
fields separately from the compressed data stream.
