The invariant of write-ahead logging is that before any change to a
page is written to the data file, the corresponding log record must
must first have been durably written.
In crash recovery, there were some sloppy checks for this. Let us
implement accurate checks and flag an inconsistency as a hard error,
so that we can avoid further corruption of a corrupted database.
For data extraction from the corrupted database, innodb_force_recovery
can be used.
Before recovery is reading any data pages or invoking
buf_dblwr_t::recover() to recover torn pages from the
doublewrite buffer, InnoDB will have parsed the log until the
final LSN and updated log_sys.lsn to that. So, we can rely on
log_sys.lsn at all times. The doublewrite buffer recovery has been
refactored in such a way that the recv_sys.dblwr.pages may be consulted
while discovering files and their page sizes, but nothing will be
written back to data files before buf_dblwr_t::recover() is invoked.
recv_max_page_lsn, recv_lsn_checks_on: Remove.
recv_sys_t::validate_checkpoint(): Validate the write-ahead-logging
condition at the end of the recovery.
recv_dblwr_t::validate_page(): Keep track of the maximum LSN
(if we are checking a non-doublewrite copy of a page) but
do not complain LSN being in the future. The doublewrite buffer
is a special case, because it will be read early during recovery.
Besides, starting with commit 762bcb81b5bf9bbde61fed59afb26417f4ce1e86
the dblwr=true copies of pages may legitimately be "too new".
recv_dblwr_t::find_page(): Find a valid page with the smallest
FIL_PAGE_LSN that is in the valid range for recovery.
recv_dblwr_t::restore_first_page(): Replaced by find_page().
Only buf_dblwr_t::recover() will write to data files.
buf_dblwr_t::recover(): Simplify the message output. Do attempt
doublewrite recovery on user page read error. Ignore doublewrite
pages whose FIL_PAGE_LSN is outside the usable bounds. Previously,
we could wrongly recover a too new page from the doublewrite buffer.
It is unlikely that this could have lead to an actual error.
Write back all recovered pages from the doublewrite buffer here,
including for the first page of any tablespace.
buf_page_is_corrupted(): Distinguish the return values
CORRUPTED_FUTURE_LSN and CORRUPTED_OTHER.
buf_page_check_corrupt(): Return the error code DB_CORRUPTION
in case the LSN is in the future.
Datafile::read_first_page_flags(): Split from read_first_page().
Take a copy of the first page as a parameter.
recv_sys_t::free_corrupted_page(): Take the file as a parameter
and return whether a message was displayed. This avoids some duplicated
and incomplete error messages.
buf_page_t::read_complete(): Remove some redundant output and always
display the name of the corrupted file. Never return DB_FAIL;
use it only in internal error handling.
IORequest::read_complete(): Assume that buf_page_t::read_complete()
will have reported any error.
fil_space_t::set_corrupted(): Return whether this is the first time
the tablespace had been flagged as corrupted.
Datafile::validate_first_page(), fil_node_open_file_low(),
fil_node_open_file(), fil_space_t::read_page0(),
fil_node_t::read_page0(): Add a parameter for a copy of the
first page, and a parameter to indicate whether the FIL_PAGE_LSN
check should be suppressed. Before buf_dblwr_t::recover() is
invoked, we cannot validate the FIL_PAGE_LSN, but we can trust the
FSP_SPACE_FLAGS and the tablespace ID that may be present in a
potentially too new copy of a page.
Reviewed by: Debarun Banerjee
- innodb.doublewrite_debug should avoid the checkpoint
before killing the server. So used debug sync and
innodb_flush_sync to avoid the checkpoint completely.
Test case allowed to skip on MSAN builder due to extra
checkpoint.
- Split the doublewrite test into two test (doublewrite,
doublewrite_debug) to reduce the execution time of the test
- Removed big_test tag for the newly added test case
- Made doublewrite test as non-debug test
- Added search pattern to make sure that InnoDB uses doublewrite buffer
- Replaced all kill_mysqld.inc with shutdown_mysqld.inc and
zero shutdown timeout
- Removed the case where fsp_flags got corrupted. Because from commit
3da5d047b8d8c193a872c5ae6c3fb213218117bc (MDEV-31851) onwards,
doublewrite buffer removes the conversion the fsp flags from buggy
10.1 format
Thanks to Marko Mäkelä for providing the non-debug test
