rb://290, approved by Sunny

account for each merge run's start offset, so correct offsets are
paired up for multiple merge runs.

rb://377 approved by Marko

(innodb_mysql.result needs to be adjusted after this commit)

(InnoDB plugin branch)

Valgrind warning happpens because of uninitialized null bytes.
In row_sel_push_cache_row_for_mysql() function we fill fetch cache
with necessary field values, row_sel_store_mysql_rec() is called
for this and leaves null bytes untouched.
Later row_sel_pop_cached_row_for_mysql() rewrites table record
buffer with uninited null bytes. We can see the problem from the
test case:
At 'SELECT...' we call row_sel_push...->row_sel_store...->row_sel_pop_cached...
chain which rewrites table->record[0] buffer with uninitialized null bytes.
When we call 'UPDATE...' statement, compare_record uses this buffer and
valgrind warning occurs.
The fix is to init null bytes with default values.

this before.

for InnoDB plugin

dict_load_table(): Pass the correct tablespace flags to
fil_open_single_table_tablespace(). For ROW_FORMAT=COMPACT and REDUNDANT,
the tablespace flags are 0. The table flags would be 0 or DICT_TF_COMPACT.

introduced in bug fix #53592, since dict_table_t can sufficiently unique
identify the the table.

In semi-consistent read, only unlock freshly locked non-matching records.

lock_rec_lock_fast(): Return LOCK_REC_SUCCESS,
LOCK_REC_SUCCESS_CREATED, or LOCK_REC_FAIL instead of TRUE/FALSE.

enum db_err: Add DB_SUCCESS_LOCKED_REC for indicating a successful
operation where a record lock was created.

lock_sec_rec_read_check_and_lock(),
lock_clust_rec_read_check_and_lock(), lock_rec_enqueue_waiting(),
lock_rec_lock_slow(), lock_rec_lock(), row_ins_set_shared_rec_lock(),
row_ins_set_exclusive_rec_lock(), sel_set_rec_lock(),
row_sel_get_clust_rec_for_mysql(): Return DB_SUCCESS_LOCKED_REC if a
new record lock was created. Adjust callers.

row_unlock_for_mysql(): Correct the function documentation.

row_prebuilt_t::new_rec_locks: Correct the documentation.

In semi-consistent read, only unlock freshly locked non-matching records.

Define DB_SUCCESS_LOCKED_REC for indicating a successful operation
where a record lock was created.

lock_rec_lock_fast(): Return LOCK_REC_SUCCESS,
LOCK_REC_SUCCESS_CREATED, or LOCK_REC_FAIL instead of TRUE/FALSE.

lock_sec_rec_read_check_and_lock(),
lock_clust_rec_read_check_and_lock(), lock_rec_enqueue_waiting(),
lock_rec_lock_slow(), lock_rec_lock(), row_ins_set_shared_rec_lock(),
row_ins_set_exclusive_rec_lock(), sel_set_rec_lock(),
row_sel_get_clust_rec_for_mysql(): Return DB_SUCCESS_LOCKED_REC if a
new record lock was created. Adjust callers.

row_unlock_for_mysql(): Correct the function documentation.

row_prebuilt_t::new_rec_locks: Correct the documentation.

rw_lock_t: Remove magic_n unless UNIV_DEBUG is defined.
rw_lock_free(): Invalidate magic_n only after removing from rw_lock_list.

lock_rec_unlock(): Cache first_lock and rewrite while() loops as for().

btr_cur_optimistic_update(): Use common error handling return.

row_create_prebuilt(): Add Valgrind instrumentation.

row_undo_mod_upd_exist_sec(): Tolerate a failure to build the index entry
for a DYNAMIC or COMPRESSED table during crash recovery.

result file differs on embedded