Since the 10.5 split of the privileges, the required GRANTs
for various mariabackup operations has changed.
In the addition of tests, a number of mappings where incorrect:
The option --lock-ddl-per-table didn't require connection admin.
The option --safe-slave-backup requires SLAVE MONITOR even without
the --no-lock option.
Even though commit b817afaa1c passed
the test mariabackup.compress_qpress, that test turned out to be
too small to reveal one more problem that had previously been prevented
by the existence of ctrl_mutex. I did not realize that there can be
multiple concurrent callers to compress_write(). One of them is the
log copying thread; further callers are data file copying threads
(default: --parallel=1).
By default, there is only one compression worker thread
(--compress-threads=1).
compress_write(): Fix a race condition between threads that would
use the same worker thread object. Make thd->data_avail contain the
thread identifier of the submitter, and add thd->avail_cond to
notify other compress_write() threads that are waiting for a slot.
This reverts the revert 4f62dfe676
and fixes the hang that was introduced when ctrl_mutex was removed.
The test mariabackup.compress_qpress covers this code, but the
test is skipped if a stand-alone qpress executable is not available.
It is not available in many software repositories, possibly because
the code base has not been updated since 2010.
This was tested with an executable that was compile from the source
code at http://www.quicklz.com/qpress-11-source.zip (after adding
a missing #include <unistd.h> for the definition of isatty()).
Compared to the grandparent commit (before the revert), the changes
are as follows:
comp_thread_ctxt_t::done_cond: A separate condition for completed
compression, signaling that thd->to_len has been updated.
compress_write(): Replace some threads[i] with thd.
Reset thd->to_len = 0 after consuming the compressed data.
compress_worker_thread_func(): After consuming the uncompressed
data, set thd->data_avail = FALSE. After compressing, signal
thd->done_cond.
An interface to use memory-mapped I/O on the InnoDB redo log that
is stored in persistent memory was introduced
in commit 685d958e38 (MDEV-14425).
log_t::attach(): In mariadb-backup --backup, never attempt to
use memory-mapped I/O for reading the log file of the server.
xtrabackup_copy_logfile(): Assert !log_sys.is_pmem() and remove
the code to deal with a memory-mapped log.
This fixes a race condition scenario of the following type:
1. Backup parsed a mini-transaction from the memory-mapped buffer.
This took some time.
2. Meanwhile, the server might have overwritten this portion
of the circular log_sys.buf.
3. Backup copied the data to the output file while or after
the server had overwritten this portion of the file.
4. Backup failed to notice that a log overrun occurred.
The symptom of this was that a mariadb-backup --prepare of the
log failed. In the analyzed case, the error message was:
[ERROR] InnoDB: Missing FILE_CHECKPOINT(...)
This will also make it possible to run mariadb-backup --backup
under "rr replay".
The approach to handling corruption that was chosen by Oracle in
commit 177d8b0c12
is not really useful. Not only did it actually fail to prevent InnoDB
from crashing, but it is making things worse by blocking attempts to
rescue data from or rebuild a partially readable table.
We will try to prevent crashes in a different way: by propagating
errors up the call stack. We will never mark the clustered index
persistently corrupted, so that data recovery may be attempted by
reading from the table, or by rebuilding the table.
This should also fix MDEV-13680 (crash on btr_page_alloc() failure);
it was extensively tested with innodb_file_per_table=0 and a
non-autoextend system tablespace.
We should now avoid crashes in many cases, such as when a page
cannot be read or allocated, or an inconsistency is detected when
attempting to update multiple pages. We will not crash on double-free,
such as on the recovery of DDL in system tablespace in case something
was corrupted.
Crashes on corrupted data are still possible. The fault injection mechanism
that is introduced in the subsequent commit may help catch more of them.
buf_page_import_corrupt_failure: Remove the fault injection, and instead
corrupt some pages using Perl code in the tests.
btr_cur_pessimistic_insert(): Always reserve extents (except for the
change buffer), in order to prevent a subsequent allocation failure.
btr_pcur_open_at_rnd_pos(): Merged to the only caller ibuf_merge_pages().
btr_assert_not_corrupted(), btr_corruption_report(): Remove.
Similar checks are already part of btr_block_get().
FSEG_MAGIC_N_BYTES: Replaces FSEG_MAGIC_N_VALUE.
dict_hdr_get(), trx_rsegf_get_new(), trx_undo_page_get(),
trx_undo_page_get_s_latched(): Replaced with error-checking calls.
trx_rseg_t::get(mtr_t*): Replaces trx_rsegf_get().
trx_rseg_header_create(): Let the caller update the TRX_SYS page if needed.
trx_sys_create_sys_pages(): Merged with trx_sysf_create().
dict_check_tablespaces_and_store_max_id(): Do not access
DICT_HDR_MAX_SPACE_ID, because it was already recovered in dict_boot().
Merge dict_check_sys_tables() with this function.
dir_pathname(): Replaces os_file_make_new_pathname().
row_undo_ins_remove_sec(): Do not modify the undo page by adding
a terminating NUL byte to the record.
btr_decryption_failed(): Report decryption failures
dict_set_corrupted_by_space(), dict_set_encrypted_by_space(),
dict_set_corrupted_index_cache_only(): Remove.
dict_set_corrupted(): Remove the constant parameter dict_locked=false.
Never flag the clustered index corrupted in SYS_INDEXES, because
that would deny further access to the table. It might be possible to
repair the table by executing ALTER TABLE or OPTIMIZE TABLE, in case
no B-tree leaf page is corrupted.
dict_table_skip_corrupt_index(), dict_table_next_uncorrupted_index(),
row_purge_skip_uncommitted_virtual_index(): Remove, and refactor
the callers to read dict_index_t::type only once.
dict_table_is_corrupted(): Remove.
dict_index_t::is_btree(): Determine if the index is a valid B-tree.
BUF_GET_NO_LATCH, BUF_EVICT_IF_IN_POOL: Remove.
UNIV_BTR_DEBUG: Remove. Any inconsistency will no longer trigger
assertion failures, but error codes being returned.
buf_corrupt_page_release(): Replaced with a direct call to
buf_pool.corrupted_evict().
fil_invalid_page_access_msg(): Never crash on an invalid read;
let the caller of buf_page_get_gen() decide.
btr_pcur_t::restore_position(): Propagate failure status to the caller
by returning CORRUPTED.
opt_search_plan_for_table(): Simplify the code.
row_purge_del_mark(), row_purge_upd_exist_or_extern_func(),
row_undo_ins_remove_sec_rec(), row_undo_mod_upd_del_sec(),
row_undo_mod_del_mark_sec(): Avoid mem_heap_create()/mem_heap_free()
when no secondary indexes exist.
row_undo_mod_upd_exist_sec(): Simplify the code.
row_upd_clust_step(), dict_load_table_one(): Return DB_TABLE_CORRUPT
if the clustered index (and therefore the table) is corrupted, similar
to what we do in row_insert_for_mysql().
fut_get_ptr(): Replace with buf_page_get_gen() calls.
buf_page_get_gen(): Return nullptr and *err=DB_CORRUPTION
if the page is marked as freed. For other modes than
BUF_GET_POSSIBLY_FREED or BUF_PEEK_IF_IN_POOL this will
trigger a debug assertion failure. For BUF_GET_POSSIBLY_FREED,
we will return nullptr for freed pages, so that the callers
can be simplified. The purge of transaction history will be
a new user of BUF_GET_POSSIBLY_FREED, to avoid crashes on
corrupted data.
buf_page_get_low(): Never crash on a corrupted page, but simply
return nullptr.
fseg_page_is_allocated(): Replaces fseg_page_is_free().
fts_drop_common_tables(): Return an error if the transaction
was rolled back.
fil_space_t::set_corrupted(): Report a tablespace as corrupted if
it was not reported already.
fil_space_t::io(): Invoke fil_space_t::set_corrupted() to report
out-of-bounds page access or other errors.
Clean up mtr_t::page_lock()
buf_page_get_low(): Validate the page identifier (to check for
recently read corrupted pages) after acquiring the page latch.
buf_page_t::read_complete(): Flag uninitialized (all-zero) pages
with DB_FAIL. Return DB_PAGE_CORRUPTED on page number mismatch.
mtr_t::defer_drop_ahi(): Renamed from mtr_defer_drop_ahi().
recv_sys_t::free_corrupted_page(): Only set_corrupt_fs()
if any log records exist for the page. We do not mind if read-ahead
produces corrupted (or all-zero) pages that were not actually needed
during recovery.
recv_recover_page(): Return whether the operation succeeded.
recv_sys_t::recover_low(): Simplify the logic. Check for recovery error.
Thanks to Matthias Leich for testing this extensively and to the
authors of https://rr-project.org for making it easy to diagnose
and fix any failures that were found during the testing.
