We introduce the following settable Boolean global variables:
innodb_log_file_write_through: Whether writes to ib_logfile0 are
write-through (disabling any caching, as in O_SYNC or O_DSYNC).
innodb_data_file_write_through: Whether writes to any InnoDB data files
(including the temporary tablespace) are write-through.
innodb_data_file_buffering: Whether the file system cache is enabled
for InnoDB data files.
All these parameters are OFF by default, that is, the file system cache
will be disabled, but any hardware caching is enabled, that is,
explicit calls to fsync(), fdatasync() or similar functions are needed.
On systems that support FUA it may make sense to enable write-through,
to avoid extra system calls.
If the deprecated read-only start-up parameter is set to one of the
following values, then the values of the 4 Boolean flags (the above 3
plus innodb_log_file_buffering) will be set as follows:
O_DSYNC:
innodb_log_file_write_through=ON, innodb_data_file_write_through=ON,
innodb_data_file_buffering=OFF, and
(if supported) innodb_log_file_buffering=OFF.
fsync, littlesync, nosync, or (Microsoft Windows specific) normal:
innodb_log_file_write_through=OFF, innodb_data_file_write_through=OFF,
and innodb_data_file_buffering=ON.
Note: fsync() or fdatasync() will only be disabled if the separate
parameter debug_no_sync (in the code, my_disable_sync) is set.
In mariadb-backup, the parameter innodb_flush_method will be ignored.
The Boolean parameters can be modified by SET GLOBAL while the
server is running. This will require reopening the ib_logfile0
or all currently open InnoDB data files.
We will open files straight in O_DSYNC or O_SYNC mode when applicable.
Data files we will try to open straight in O_DIRECT mode when the
page size is at least 4096 bytes. For atomically creating data files,
we will invoke os_file_set_nocache() to enable O_DIRECT afterwards,
because O_DIRECT is not supported on some file systems. We will also
continue to invoke os_file_set_nocache() on ib_logfile0 when
innodb_log_file_buffering=OFF can be fulfilled.
For reopening the ib_logfile0, we use the same logic that was developed
for online log resizing and reused for updates of
innodb_log_file_buffering.
Reopening all data files is implemented in the new function
fil_space_t::reopen_all().
Reviewed by: Vladislav Vaintroub
Tested by: Matthias Leich
The MDEV-25004 test innodb_fts.versioning is omitted because ever since
commit 685d958e38 InnoDB would not allow
writes to a database where the redo log file ib_logfile0 is missing.
to copy datafile
- Mariabackup fails to copy the undo log tablespace when it undergoes
truncation. So Mariabackup should detect the redo log which does
undo tablespace truncation and also backup should read the minimum
file size of the tablespace and ignore the error while reading.
- Throw error when innodb undo tablespace read failed, but backup
doesn't find the redo log for undo tablespace truncation
io_watching_thread(): Declare as a detachable thread, similar to
log_copying_thread().
stop_backup_threads(): Wait for both log_copying_thread and
io_watching_thread to clear their flags. Expect log_sys.mutex
to be held by the caller.
xtrabackup_backup_func(): Initialize log_copying_stop before
creating io_watching_thread. This prevents a race condition
where io_watching_thread() could wait on the condition variable
before it had been fully initialized. This race condition would
cause a hang in the GNU libc implementation of pthread_cond_destroy()
at the end of stop_backup_threads().
This race condition was introduced in
commit 38fd7b7d91 (MDEV-21452).
The variable was not really being used for anything. The parameters
innodb_read_io_threads, innodb_write_io_threads have replaced
innodb_file_io_threads.
- Mariabackup fails to open the undo tablespaces while applying delta
files to the corresponding data file. Mariabackup opens the
undo tablespaces first time in srv_undo_tablespaces_init() and does
tries to open the undo tablespaces in xtrabackup_apply_deltas() with
conflicting mode and leads to the failure.
- Mariabackup should close the undo tablespaces before applying
the incremental delta files.
os_file_read(): Merged with os_file_read_no_error_handling().
Crashing on a partial page read is as unhelpful as crashing on a
corrupted page read (commit 0b47c126e3).
Report the file name if it is available via IORequest.
trx_sys_t::undo_log_nonempty: Set to true if there are undo logs
to rollback and purge.
The algorithm for re-creating the undo tablespace when
trx_sys_t::undo_log_nonempty is disabled:
1) trx_sys_t::reset_page(): Reset the TRX_SYS page and assign all
rollback segment slots from 1..127 to FIL_NULL
2) Free the rollback segment header page of system tablespace
for the slots 1..127
3) Update the binlog and WSREP information in system tablespace
rollback segment header
Step (1), (2) and Step (3) should happen atomically within a
single mini-transaction.
4) srv_undo_delete_old_tablespaces(): Delete the old undo tablespaces
present in the undo log directory
5) Make checkpoint to get rid of old undo log tablespaces redo logs
6) Assign new start space id for the undo log tablespaces
7) Re-create the specified undo log tablespaces. InnoDB uses same
mtr for this one and step (6)
8) Make checkpoint again, so that server or mariabackup
can read the undo log tablespace page0 before applying
the redo logs
srv_undo_tablespaces_reinit(): Recreate the undo log tablespaces.
It does reset trx_sys page, delete the old undo tablespaces,
update the binlog offset, write set replication checkpoint
in system rollback segment page
trx_rseg_update_binlog_offset(): Added 2 new parameters to pass
binlog file name and binlog offset
trx_rseg_array_init(): Return error if the rollback segment
slot points to non-existent tablespace
srv_undo_tablespaces_init(): Added new parameter mtr
to initialize all undo tablespaces
trx_assign_rseg_low(): Allow the transaction to use the rollback
segment slots(1..127) even if InnoDB failed to change to the
requested innodb_undo_tablespaces=0
srv_start(): Override the user specified value of
innodb_undo_tablespaces variable with already existing actual
undo tablespaces
wf_incremental_process(): Detects whether TRX_SYS page has been
modified since last backup. If it is then incremental backup
fails and throws the information about taking full backup again
xb_assign_undo_space_start(): Removed the function. Because
undo001 has first undo space id value in page0
Added test case to test the scenario during startup and mariabackup
incremental process too.
Reviewed-by : Marko Mäkelä
Tested-by : Matthias Leich
mariadb-backup: Add the Boolean option --innodb-log-file-buffering
(default ON) to control whether the server's ib_logfile0 should be
accessed via the file system cache during --backup. We may be retrying
reads of the last log block very frequently, which may cause I/O stalls
when the file system cache is being bypassed.
This addresses a regression that was introduced in
commit 4c0cd953ab (MDEV-28766).
On some affected systems, it may make sense to additionally
SET GLOBAL innodb_log_file_buffering=OFF on the server for the
duration of making a backup.
In commit 28325b0863
a compile-time option was introduced to disable the macros
DBUG_ENTER and DBUG_RETURN or DBUG_VOID_RETURN.
The parameter name WITH_DBUG_TRACE would hint that it also
covers DBUG_PRINT statements. Let us do that: WITH_DBUG_TRACE=OFF
shall disable DBUG_PRINT() as well.
A few InnoDB recovery tests used to check that some output from
DBUG_PRINT("ib_log", ...) is present. We can live without those checks.
Reviewed by: Vladislav Vaintroub
Let us use the normal platform-specific preprocessor symbols
__linux__, __sun__, _AIX instead of some homebrew ones.
The preprocessor symbol UNIV_HPUX must have lost its meaning
by f6deb00a56 (note: the symbol
UNIV_HPUX10 is being checked for, but only UNIV_HPUX is defined).
xb_read_delta_metadata(): For ROW_FORMAT=COMPRESSED tables, initialize
the info.zip_size with the physical page size and let info.page_size
remain the logical page size, like xb_delta_open_matching_space()
expects it to be ever since
commit 0a1c3477bf (MDEV-18493).
Changing the mariabackup history table from PERCONA_SCHEMA.xtrabackup_history
to mysql.mariabackup_history.
Additionally, extending xb_history.test for better coverage:
- Recording the fact that the history table is created during
"mariabackup --history" invocation when it does not exist.
- Recording the history table structure (adding SHOW CREATE TABLE)
- Recording how --history vs --history=foo affect the "name" column
of the history table.
- Recording the fact that two consequent executions of
"mariabackup --history[=foo]" insert into the history table
incrementally, without truncating it on every execution.
