In mariadb-backup --backup there are multiple mechanisms for ensuring that
a sufficient amount of the InnoDB write-ahead log (ib_logfile0) is being
copied at the end of the backup. The backup needs to include the latest
committed transaction. While further transaction commits are blocked by
BACKUP STAGE BLOCK_COMMIT, ongoing transactions may modify the database
contents and write log records. We were unnecessarily copying such log,
which would also cause further effort of rolling back incomplete
transactions after the backup is restored.
backup_wait_for_lsn(): Declare as static, and refactor some code
to separate functions backup_wait_for_lsn_low() and
backup_wait_timeout().
backup_wait_for_commit_lsn(): A new function to determine the current
LSN (within BACKUP STAGE BLOCK_COMMIT) and to wait for the log to be
copied until that. Invoked by BackupStages::stage_block_commit().
xtrabackup_backup_func(): Remove a condition that had already been
checked by a caller of backup_wait_timeout().
server_lsn_after_lock: Declare as a local variable in
BackupStages::stage_block_ddl().
log_copying_thread(), io_watching_thread(): Use metadata_last_lsn
instead of metadata_to_lsn as the stop condition.
BackupStages::stage_block_commit(): Ensure that the log tables
(in particular, mysql.general_log) will have been copied before
the BACKUP STAGE BLOCK_COMMIT is being followed by any further
SQL statements.
Reviewed by: Debarun Banerjee
Tested by: Matthias Leich
As part of commit 685d958e38 (MDEV-14425)
the parameter innodb_log_write_ahead_size was removed, because it was
thought that determining the physical block size would be a sufficient
replacement.
However, we can only determine the physical block size on Linux or
Microsoft Windows. On some file systems, the physical block size
is not relevant. For example, XFS uses a block size of 4096 bytes
even if the underlying block size may be smaller.
On Linux, we failed to determine the physical block size if
innodb_log_file_buffered=OFF was not requested or possible.
This will be fixed.
log_sys.write_size: The value of the reintroduced parameter
innodb_log_write_ahead_size. To keep it simple, this is read-only
and a power of two between 512 and 4096 bytes, so that the previous
alignment guarantees are fulfilled. This will replace the previous
log_sys.get_block_size().
log_sys.block_size, log_t::get_block_size(): Remove.
log_t::set_block_size(): Ensure that write_size will not be less
than the physical block size. There is no point to invoke this
function with 512 or less, because that is the minimum value of
write_size.
innodb_params_adjust(): Add some disabled code for adjusting
the minimum value and default value of innodb_log_write_ahead_size
to reflect the log_sys.write_size.
log_t::set_recovered(): Mark the recovery completed. This is the
place to adjust some things if we want to allow write_size>4096.
log_t::resize_write_buf(): Refer to write_size.
log_t::resize_start(): Refer to write_size instead of get_block_size().
log_write_buf(): Simplify some arithmetics and remove a goto.
log_t::write_buf(): Refer to write_size. If we are writing less than
that, do not switch buffers, but keep writing to the same buffer.
Move some code to improve the locality of reference.
recv_scan_log(): Refer to write_size instead of get_block_size().
os_file_create_func(): For type==OS_LOG_FILE on Linux, always invoke
os_file_log_maybe_unbuffered(), so that log_sys.set_block_size() will
be invoked even if we are not attempting to use O_DIRECT.
recv_sys_t::find_checkpoint(): Read the entire log header
in a single 12 KiB request into log_sys.buf.
Tested with:
./mtr --loose-innodb-log-write-ahead-size=4096
./mtr --loose-innodb-log-write-ahead-size=2048
MariaDB-backup needs to check for SLAVE MONITOR as that is
what is returned by SHOW GRANTS.
Update test to ensure that warnings about missing privileges
do not occur when the backup is successful.
Reviewer: Andrew Hutchings
Thanks Eugene for reporting the issue.
On Microsoft Windows, ReadFile() as well as WriteFile() limit the size
of the request to DWORD, which is 32 bits (at most 4 GiB - 1) also on
64-bit systems.
On FreeBSD, sysctl debug.iosize_max_clamp could limit the size of a
write request to INT_MAX. The size of a read request is always limited
to INT_MAX. This would allow the request size to be 4095 bytes more than
the Linux limit (0x7ffff000 according to "man 2 read" and "man 2 write").
On OpenBSD, Solaris and possibly NetBSD, the read request size is limited
to SSIZE_T_MAX, which would be half the current maximum
innodb_log_buffer_size. This should be not much of an issue anyway,
because on contemporary 64-bit platforms, the virtual addresses are
limited to 48 bits.
IBM AIX documentation mentions OFF_MAX which would apply when
a 64-bit application is running on a 32-bit kernel.
Let us declare innodb_log_buffer_size as 32-bit unsigned and make the
maximum 0x7ffff000, to be compatible with the least common
denominator (Linux).
The maximum innodb_sort_buffer_size already was 64 MiB,
which is not a problem.
SyncFileIO::execute(): Assert that the size of a synchronous read or
write request is limited to the maximum.
Reviewed by: Vladislav Vaintroub
Some fixes related to commit f838b2d799 and
Rows_log_event::do_apply_event() and Update_rows_log_event::do_exec_row()
for system-versioned tables were provided by Nikita Malyavin.
This was required by test versioning.rpl,trx_id,row.
The log_sys.lsn_lock is a very contended resource with a small
critical section in log_sys.append_prepare(). On many processor
microarchitectures, replacing the system call based log_sys.lsn_lock
with a pure spin lock would fare worse during high concurrency workloads,
wasting a significant amount of CPU cycles in the spin loop.
On other microarchitectures, we would see a significant amount of time
being spent in native_queued_spin_lock_slowpath() in the Linux kernel,
plus context switching between user and kernel address space. This was
pointed out by Steve Shaw from Intel Corporation.
Depending on the workload and the hardware implementation, it may be
useful to use a pure spin lock in log_sys.append_prepare().
We will introduce a parameter. The statement
SET GLOBAL INNODB_LOG_SPIN_WAIT_DELAY=50;
would enable a spin lock that will execute that many MY_RELAX_CPU()
operations (such as the x86 PAUSE instruction) between successive
attempts of acquiring the spin lock. The use of a system call based
log_sys.lsn_lock (which is the default setting) can be enabled by
SET GLOBAL INNODB_LOG_SPIN_WAIT_DELAY=0;
This patch will also introduce #ifdef LOG_LATCH_DEBUG
(part of cmake -DWITH_INNODB_EXTRA_DEBUG=ON) for more accurate
tracking of log_sys.latch ownership and reorganize the fields of
log_sys to improve the locality of reference and to reduce the
chances of false sharing.
When a spin lock is being used, it will be maintained in the
most significant bit of log_sys.buf_free. This is useful, because that is
one of the fields that is covered by the lock. For IA-32 or AMD64, we
implement the spin lock specially via log_t::lsn_lock_bts(), employing the
i386 LOCK BTS instruction. A straightforward std::atomic::fetch_or() would
translate into an inefficient loop around LOCK CMPXCHG.
mtr_t::spin_wait_delay: The value of innodb_log_spin_wait_delay.
mtr_t::finisher: Pointer to the currently used mtr_t::finish_write()
implementation. This allows to avoid introducing conditional branches.
We no longer invoke log_sys.is_pmem() at the mini-transaction level,
but we would do that in log_write_up_to().
mtr_t::finisher_update(): Update finisher when spin_wait_delay is
changed from or to 0 (the spin lock is changed to log_sys.lsn_lock or
vice versa).
Added support to BACKUP STAGE to maria-backup
This is a port of the code from ES 10.6
See MDEV-5336 for backup stages description.
The following old options are not supported by the new code:
--rsync ; This is because rsync will not work on tables
that are in used.
--no-backup-locks ; This is disabled as mariadb-backup will always
use backup locks for better performance.
Apparently, invoking fcntl(fd, F_SETFL, O_DIRECT) will lead to
unexpected behaviour on Linux bcachefs and possibly other file systems,
depending on the operating system version. So, let us avoid doing that,
and instead just attempt to pass the O_DIRECT flag to open(). This should
make us compatible with NetBSD, IBM AIX, as well as Solaris and its
derivatives.
This fix does not change the fact that we had only implemented
innodb_log_file_buffering=OFF on systems where we can determine the
physical block size (typically 512 or 4096 bytes).
Currently, those operating systems are Linux and Microsoft Windows.
HAVE_FCNTL_DIRECT, os_file_set_nocache(): Remove.
OS_FILE_OVERWRITE, OS_FILE_CREATE_PATH: Remove (never used parameters).
os_file_log_buffered(), os_file_log_maybe_unbuffered(): Helper functions.
os_file_create_simple_func(): When applicable, initially attempt to
open files in O_DIRECT mode.
os_file_create_func(): When applicable, initially attempt to
open files in O_DIRECT mode.
For type==OS_LOG_FILE && create_mode != OS_FILE_CREATE
we will first invoke stat(2) on the file name to find out if the size
is compatible with O_DIRECT. If create_mode == OS_FILE_CREATE, we will
invoke fstat(2) on the created log file afterwards, and may close and
reopen the file in O_DIRECT mode if applicable.
create_temp_file(): Support O_DIRECT. This is only used if O_TMPFILE is
available and innodb_disable_sort_file_cache=ON (non-default value).
Notably, that setting never worked on Microsoft Windows.
row_merge_file_create_mode(): Split from row_merge_file_create_low().
Create a temporary file in the specified mode.
Reviewed by: Vladislav Vaintroub
The innodb_changed_pages plugin only was part of XtraDB, never InnoDB.
It would be useful for incremental backups.
We will remove the code from mariadb-backup for now, because it cannot
serve any useful purpose until the server part has been implemented.
Postfix for a6290a5bc5, in 10.11
where OS_DATA_FILE_NO_O_DIRECT gets used. Same #ifdef conditions
as other uses of OS_DATA_FILE_NO_O_DIRECT.
Noticed on aarch64-macos builder.
Most things where wrong in the test suite.
The one thing that was a bug was that table_map_id was in some places
defined as ulong and in other places as ulonglong. On Linux 64 bit this
is not a problem as ulong == ulonglong, but on windows this caused failures.
Fixed by ensuring that all instances of table_map_id are ulonglong.
opt_kill_long_query_type being an enum could be 0 corresponding
to ALL. When ALL is specified, the CONNECTION ADMIN is still
required.
Also check REPLICA MONITOR privilege and make the tests
find the results by recording stderr.
Noticed thanks to bug report by Tim van Dijen.
Fixes: 79b58f1ca8
This is a port of the Percona Server commit 5265f42e290573e9591f8ca28ab66afc051f89a3
which is the same as their bug PXB-1807: xtrabackup does not accept fractional values for
innodb_max_dirty_pages_pct
Problem:
Variable specified as double in MySQL server, but read as long in the
xtrabackup. This causes xtrabackup to fail at startup when the value
contains decimal point.
Fix:
Make xtrabackup to interpret the value as double to be compatible with
server.
Problem:
The file backup-my.cnf from the backup directory was loaded by
"mariabackup --prepare" only in case of the explicit --target-dir given.
It was not loaded from the default directory ./xtrabackup_backupfiles/
in case if the explicit --target-dir was missing.
In other words, it worked as follows:
1. When started as "mariabackup --prepare --target-dir=DIR", mariabackup:
a. loads defaults from "DIR/backup-my.cnf"
b. processes data files in the specified directory DIR
2. When started as "mariabackup --prepare", mariabackup:
a. does not load defaults from "./xtrabackup_backupfiles/backup-my.cnf"
b. processes data files in the default directory "./xtrabackup_backupfiles/"
This patch fixes the second scenario, so it works as follows:
2. When started as "mariabackup --prepare", mariabackup:
a. loads defaults from "./xtrabackup_backupfiles/backup-my.cnf"
b. processes data files in the default directory "./xtrabackup_backupfiles/"
This change fixes (among others) the problem with the
"Can't open shared library '/file_key_management.so'" error
reported when "mariabackup --prepare" is used without --target-dir
in combinaton with the encryption plugin.
Revert the patch for MDEV-18917, which removed this functionality.
This restores that mariabackup --prepare recovers the transactional
binlog position from the redo log, and writes it to the file
xtrabackup_binlog_pos_innodb.
This position is updated only on every InnoDB commit. This means that
if the last event in the binlog at the time of backup is a DDL or
non-transactional update, the recovered position from --no-lock will
be behind the state of the backup.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
The motivation of introducing the parameter
innodb_purge_rseg_truncate_frequency in
mysql/mysql-server@28bbd66ea5 and
mysql/mysql-server@8fc2120fed
seems to have been to avoid stalls due to freeing undo log pages
or truncating undo log tablespaces. In MariaDB Server,
innodb_undo_log_truncate=ON should be a much lighter operation
than in MySQL, because it will not involve any log checkpoint.
Another source of performance stalls should be
trx_purge_truncate_rseg_history(), which is shrinking the history list
by freeing the undo log pages whose undo records have been purged.
To alleviate that, we will introduce a purge_truncation_task that will
offload this from the purge_coordinator_task. In that way, the next
innodb_purge_batch_size pages may be parsed and purged while the pages
from the previous batch are being freed and the history list being shrunk.
The processing of innodb_undo_log_truncate=ON will still remain the
responsibility of the purge_coordinator_task.
purge_coordinator_state::count: Remove. We will ignore
innodb_purge_rseg_truncate_frequency, and act as if it had been
set to 1 (the maximum shrinking frequency).
purge_coordinator_state::do_purge(): Invoke an asynchronous task
purge_truncation_callback() to free the undo log pages.
purge_sys_t::iterator::free_history(): Free those undo log pages
that have been processed. This used to be a part of
trx_purge_truncate_history().
purge_sys_t::clone_end_view(): Take a new value of purge_sys.head
as a parameter, so that it will be updated while holding exclusive
purge_sys.latch. This is needed for race-free access to the field
in purge_truncation_callback().
Reviewed by: Vladislav Lesin
The MDEV-29693 conflict resolution is from Monty, as well as is
a bug fix where ANALYZE TABLE wrongly built histograms for
single-column PRIMARY KEY.
Also includes a fix for safe_malloc error reporting.
Other things:
- Copied main.log_slow from 10.4 to avoid mtr issue
Disabled test:
- spider/bugfix.mdev_27239 because we started to get
+Error 1429 Unable to connect to foreign data source: localhost
-Error 1158 Got an error reading communication packets
- main.delayed
- Bug#54332 Deadlock with two connections doing LOCK TABLE+INSERT DELAYED
This part is disabled for now as it fails randomly with different
warnings/errors (no corruption).
There are many filesystem related errors that can occur with
MariaBackup. These already outputed to stderr with a good description of
the error. Many of these are permission or resource (file descriptor)
limits where the assertion and resulting core crash doesn't offer
developers anything more than the log message. To the user, assertions
and core crashes come across as poor error handling.
As such we return an error and handle this all the way up the stack.
