log_phys_t::page_checksum(): Validate an OPT_PAGE_CHECKSUM record.
mtr_t::is_logged(): Return whether log should be written.
mtr_t::set_log_mode_sub(const mtr_t&): Set the logging mode of
a sub-minitransaction when another mini-transaction is holding
latches on some modified pages. When creating or freeing BLOB pages,
we may only write OPT_PAGE_CHECKSUM records in the main mini-transaction,
after all changes have been written to the log.
MTR_LOG_SUB: Log mode for a sub-mini-transaction.
FIXME: Occasionally, the test innodb_zip.wl5522_debug_zip would fail
the check on an undo log page, with OPT_PAGE_CHECKSUM written
immediately after FREE_PAGE. This is not reliably reproducible.
MDEV-28601 InnoDB history list length was reverted to 32 bits
srv_do_purge(): In commit edde1f6e0d5f5a0115a5253c9b8d428af132f2d1
when the de-facto 32-bit trx_sys_t::history_size() was replaced with
32-bit trx_sys.rseg_history_len, some more variables were changed
from ulint (size_t) to uint32_t.
The history list length is the number of committed transactions whose
undo logs are waiting to be purged. Each TRX_RSEG_HISTORY list is
storing the number of entries in a 32-bit field and each transaction
will occupy at least one undo log page. It is thinkable that the
length of each TRX_RSEG_HISTORY list may approach the maximum
representable number. The number cannot be exceeded, because the
rollback segment header is allocated from the same tablespace as
the undo log header pages it is pointing to, and because the page
numbers of a tablespace are stored in 32 bits. In any case, it is
possible that the total number of unpurged committed transactions
cannot be represented in 32 but 39 bits (corresponding to
128 rollback segments and undo tablespaces).
MDEV-28668 Recovery or backup of INSERT may be incorrect
page_cur_insert_rec_low(): When checking for common bytes with
the preceding record, exclude the header bytes of next_rec
that could have been updated by this function.
The scenario where this caused corruption was an insert of
a node pointer record. The child page number was written as
0x203 but recovered as 0x103 because the n_owned field of next_rec
was changed from 1 to 2 before the comparison was invoked.