In commit 412533b4a7 (MDEV-18582),
one of the counters that was ported from XtraDB is useless.
Innodb_buffered_aio_submitted would be 0 or 1, depending on whether
is_linux_native_aio_supported() was executed to the point where
it would be incremented.
Let us remove this counter, because it has no practical value.
Even if its value were 1, io_setup() can still fail and we may
end up with innodb_use_native_aio=0.
Tests with 4096-byte sector size confirm that it is
safe to use O_DIRECT with page_compressed tables.
That had been disabled on Linux, in an attempt to fix MDEV-21584
which had been filed for the O_DIRECT problems earlier.
The fil_node_t::block_size was being set mostly correctly until
commit 10dd290b4b (MDEV-17380)
introduced a regression in MariaDB Server 10.4.4.
fil_node_open_file(): Only avoid setting O_DIRECT on
ROW_FORMAT=COMPRESSED tables that use KEY_BLOCK_SIZE=1 or 2
(1024 or 2048 bytes).
fil_ibd_create(): Avoid setting O_DIRECT on ROW_FORMAT=COMPRESSED tables
that use KEY_BLOCK_SIZE=1 or 2 (1024 or 2048 bytes).
fil_node_t::find_metadata(): Require fstat() to be always invoked
outside Microsoft Windows, so that fil_node_t::block_size can be set.
fil_node_t::read_page0(): Rely on find_metadata() to assign block_size.
Thanks to Vladislav Vaintroub for testing this on Microsoft Windows
using an old-fashioned rotational hard disk with 4KiB sector size.
Reviewed by: Vladislav Vaintroub
This is a port of commit 00f620b27e
and commit 6505662c23 from 10.2.
This had been originally added in
mysql/mysql-server@192bb153b6
with the motivation to disable O_DIRECT for the dedicated tablespace
for temporary tables. In MariaDB Server,
commit 5eb539555b (MDEV-12227)
should be a better solution.
The code became orphaned later in
mysql/mysql-server@c61244c0e6
and it had been applied to MariaDB Server 10.2.2 in
commit 2e814d4702 and
commit fec844aca8.
Thanks to Vladislav Vaintroub for spotting this.
In commit 5e62b6a5e0 (MDEV-16264)
the logic of os_aio_init() was changed so that it will never fail,
but instead automatically disable innodb_use_native_aio (which is
enabled by default) if the io_setup() system call would fail due
to resource limits being exceeded. This is questionable, especially
because falling back to simulated AIO may lead to significantly
reduced performance.
srv_n_file_io_threads, srv_n_read_io_threads, srv_n_write_io_threads:
Change the data type from ulong to uint.
os_aio_init(): Remove the parameters, and actually return an error code.
thread_pool::configure_aio(): Do not silently fall back to simulated AIO.
Reviewed by: Vladislav Vaintroub
Since commit ea21d630be we
conditionally define a variable that only plays a role on
systems that support hole-punching (explicit creation of sparse files).
However, that broke debug builds on such systems.
It turns out that the debug_dbug label "ignore_punch_hole" is
not at all used in MariaDB server. It would be covered by
the MySQL 5.7 test innodb.table_compress. (Note: MariaDB 10.1
implemented page_compressed tables before something comparable
appeared in MySQL 5.7.)
For some reason, InnoDB debug tests on Windows fail due to rw_lock_t
if the function call overhead for some os_thread_ code is removed.
This change worked fine on Windows in combination with MDEV-24142.
tpool::aio::N_PENDING: Replaces OS_AIO_N_PENDING_IOS_PER_THREAD.
This limits two similar things: the number of outstanding requests
that a thread may io_submit(), and the number of completed requests
collected at a time by io_getevents().
This avoids flushing file metadata on NTFS , and writing to <drive>:\$Log
file. With heavy write workload this can consume up to 1/3 of the
server's IO bandwidth.
Reviewed by : Marko
Synchronous writes and calls to fdatasync(), fsync() or
FlushFileBuffers() would ruin performance. So, let us
submit asynchronous writes for the doublewrite buffer.
We submit a single request for the likely case that the
two doublewrite buffers are contiquous in the system tablespace.
buf_dblwr_t::flush_buffered_writes_completed(): The completion callback
of buf_dblwr_t::flush_buffered_writes().
os_aio_wait_until_no_pending_writes(): Also wait for doublewrite batches.
buf_dblwr_t::element::space: Remove. We can simply use
element::request.node->space instead.
Reviewed by: Vladislav Vaintroub
os_aio_userdata_t: Remove. It was basically duplicating IORequest.
buf_page_write_complete(): Take only IORequest as a parameter.
os_aio_func(), pfs_os_aio_func(): Replaced with os_aio() that has
no redundant parameters. There is only one caller, so there is no
point to pass __FILE__, __LINE__ as a parameter.
Merge n_pending_ios, n_pending_ops to std::atomic<uint32_t> n_pending.
Change some more fil_space_t members to uint32_t to reduce
the memory footprint.
fil_space_t::add(), fil_ibd_create(): Attach the already opened
handle to the tablespace, and enforce the fil_system.n_open limit.
dict_boot(): Initialize fil_system.max_assigned_id.
srv_boot(): Call srv_thread_pool_init() before anything else,
so that files should be opened in the correct mode on Windows.
fil_ibd_create(): Create the file in OS_FILE_AIO mode, just like
fil_node_open_file_low() does it.
dict_table_t::is_accessible(): Replaces fil_table_accessible().
Reviewed by: Vladislav Vaintroub
Also fixes MDEV-23929: innodb_flush_neighbors is not being ignored
for system tablespace on SSD
When the maximum configured number of file is exceeded, InnoDB will
close data files. We used to maintain a fil_system.LRU list and
a counter fil_node_t::n_pending to achieve this, at the huge cost
of multiple fil_system.mutex operations per I/O operation.
fil_node_open_file_low(): Implement a FIFO replacement policy:
The last opened file will be moved to the end of fil_system.space_list,
and files will be closed from the start of the list. However, we will
not move tablespaces in fil_system.space_list while
i_s_tablespaces_encryption_fill_table() is executing
(producing output for INFORMATION_SCHEMA.INNODB_TABLESPACES_ENCRYPTION)
because it may cause information of some tablespaces to go missing.
We also avoid this in mariabackup --backup because datafiles_iter_next()
assumes that the ordering is not changed.
IORequest: Fold more parameters to IORequest::type.
fil_space_t::io(): Replaces fil_io().
fil_space_t::flush(): Replaces fil_flush().
OS_AIO_IBUF: Remove. We will always issue synchronous reads of the
change buffer pages in buf_read_page_low().
We will always ignore some errors for background reads.
This should reduce fil_system.mutex contention a little.
fil_node_t::complete_write(): Replaces fil_node_t::complete_io().
On both read and write completion, fil_space_t::release_for_io()
will have to be called.
fil_space_t::io(): Do not acquire fil_system.mutex in the normal
code path.
xb_delta_open_matching_space(): Do not try to open the system tablespace
which was already opened. This fixes a file sharing violation in
mariabackup --prepare --incremental.
Reviewed by: Vladislav Vaintroub
innodb_preshutdown(): Terminate the encryption threads before
the page cleaner thread can be shut down.
innodb_shutdown(): Always wait for the encryption threads and
page cleaner to shut down.
srv_shutdown_all_bg_threads(): Wait for the encryption threads and
the page cleaner to shut down. (After an aborted startup,
innodb_shutdown() would not be called.)
row_get_background_drop_list_len_low(): Remove.
os_thread_count: Remove. Alternatively, at the end of
srv_shutdown_all_bg_threads() we could try to wait longer
for the count to reach 0. On some platforms, an assertion
os_thread_count==0 could fail even after a small delay,
even though in the core dump all threads would have exited.
srv_shutdown_threads(): Renamed from srv_shutdown_all_bg_threads().
Do not wait for the page cleaner to shut down, because the later
innodb_shutdown(), which may invoke
logs_empty_and_mark_files_at_shutdown(), assumes that it exists.
InnoDB stores a 32-bit page number in page headers and in some
data structures, such as FIL_ADDR (consisting of a 32-bit page number
and a 16-bit byte offset within a page). For better compile-time
error detection and to reduce the memory footprint in some data
structures, let us use a uint32_t for the page number, instead
of ulint (size_t) which can be 64 bits.
The buffer pool refactoring in MDEV-15053 and MDEV-22871 shifted
the performance bottleneck to the page flushing.
The configuration parameters will be changed as follows:
innodb_lru_flush_size=32 (new: how many pages to flush on LRU eviction)
innodb_lru_scan_depth=1536 (old: 1024)
innodb_max_dirty_pages_pct=90 (old: 75)
innodb_max_dirty_pages_pct_lwm=75 (old: 0)
Note: The parameter innodb_lru_scan_depth will only affect LRU
eviction of buffer pool pages when a new page is being allocated. The
page cleaner thread will no longer evict any pages. It used to
guarantee that some pages will remain free in the buffer pool. Now, we
perform that eviction 'on demand' in buf_LRU_get_free_block().
The parameter innodb_lru_scan_depth(srv_LRU_scan_depth) is used as follows:
* When the buffer pool is being shrunk in buf_pool_t::withdraw_blocks()
* As a buf_pool.free limit in buf_LRU_list_batch() for terminating
the flushing that is initiated e.g., by buf_LRU_get_free_block()
The parameter also used to serve as an initial limit for unzip_LRU
eviction (evicting uncompressed page frames while retaining
ROW_FORMAT=COMPRESSED pages), but now we will use a hard-coded limit
of 100 or unlimited for invoking buf_LRU_scan_and_free_block().
The status variables will be changed as follows:
innodb_buffer_pool_pages_flushed: This includes also the count of
innodb_buffer_pool_pages_LRU_flushed and should work reliably,
updated one by one in buf_flush_page() to give more real-time
statistics. The function buf_flush_stats(), which we are removing,
was not called in every code path. For both counters, we will use
regular variables that are incremented in a critical section of
buf_pool.mutex. Note that show_innodb_vars() directly links to the
variables, and reads of the counters will *not* be protected by
buf_pool.mutex, so you cannot get a consistent snapshot of both variables.
The following INFORMATION_SCHEMA.INNODB_METRICS counters will be
removed, because the page cleaner no longer deals with writing or
evicting least recently used pages, and because the single-page writes
have been removed:
* buffer_LRU_batch_flush_avg_time_slot
* buffer_LRU_batch_flush_avg_time_thread
* buffer_LRU_batch_flush_avg_time_est
* buffer_LRU_batch_flush_avg_pass
* buffer_LRU_single_flush_scanned
* buffer_LRU_single_flush_num_scan
* buffer_LRU_single_flush_scanned_per_call
When moving to a single buffer pool instance in MDEV-15058, we missed
some opportunity to simplify the buf_flush_page_cleaner thread. It was
unnecessarily using a mutex and some complex data structures, even
though we always have a single page cleaner thread.
Furthermore, the buf_flush_page_cleaner thread had separate 'recovery'
and 'shutdown' modes where it was waiting to be triggered by some
other thread, adding unnecessary latency and potential for hangs in
relatively rarely executed startup or shutdown code.
The page cleaner was also running two kinds of batches in an
interleaved fashion: "LRU flush" (writing out some least recently used
pages and evicting them on write completion) and the normal batches
that aim to increase the MIN(oldest_modification) in the buffer pool,
to help the log checkpoint advance.
The buf_pool.flush_list flushing was being blocked by
buf_block_t::lock for no good reason. Furthermore, if the FIL_PAGE_LSN
of a page is ahead of log_sys.get_flushed_lsn(), that is, what has
been persistently written to the redo log, we would trigger a log
flush and then resume the page flushing. This would unnecessarily
limit the performance of the page cleaner thread and trigger the
infamous messages "InnoDB: page_cleaner: 1000ms intended loop took 4450ms.
The settings might not be optimal" that were suppressed in
commit d1ab89037a unless log_warnings>2.
Our revised algorithm will make log_sys.get_flushed_lsn() advance at
the start of buf_flush_lists(), and then execute a 'best effort' to
write out all pages. The flush batches will skip pages that were modified
since the log was written, or are are currently exclusively locked.
The MDEV-13670 message "page_cleaner: 1000ms intended loop took" message
will be removed, because by design, the buf_flush_page_cleaner() should
not be blocked during a batch for extended periods of time.
We will remove the single-page flushing altogether. Related to this,
the debug parameter innodb_doublewrite_batch_size will be removed,
because all of the doublewrite buffer will be used for flushing
batches. If a page needs to be evicted from the buffer pool and all
100 least recently used pages in the buffer pool have unflushed
changes, buf_LRU_get_free_block() will execute buf_flush_lists() to
write out and evict innodb_lru_flush_size pages. At most one thread
will execute buf_flush_lists() in buf_LRU_get_free_block(); other
threads will wait for that LRU flushing batch to finish.
To improve concurrency, we will replace the InnoDB ib_mutex_t and
os_event_t native mutexes and condition variables in this area of code.
Most notably, this means that the buffer pool mutex (buf_pool.mutex)
is no longer instrumented via any InnoDB interfaces. It will continue
to be instrumented via PERFORMANCE_SCHEMA.
For now, both buf_pool.flush_list_mutex and buf_pool.mutex will be
declared with MY_MUTEX_INIT_FAST (PTHREAD_MUTEX_ADAPTIVE_NP). The critical
sections of buf_pool.flush_list_mutex should be shorter than those for
buf_pool.mutex, because in the worst case, they cover a linear scan of
buf_pool.flush_list, while the worst case of a critical section of
buf_pool.mutex covers a linear scan of the potentially much longer
buf_pool.LRU list.
mysql_mutex_is_owner(), safe_mutex_is_owner(): New predicate, usable
with SAFE_MUTEX. Some InnoDB debug assertions need this predicate
instead of mysql_mutex_assert_owner() or mysql_mutex_assert_not_owner().
buf_pool_t::n_flush_LRU, buf_pool_t::n_flush_list:
Replaces buf_pool_t::init_flush[] and buf_pool_t::n_flush[].
The number of active flush operations.
buf_pool_t::mutex, buf_pool_t::flush_list_mutex: Use mysql_mutex_t
instead of ib_mutex_t, to have native mutexes with PERFORMANCE_SCHEMA
and SAFE_MUTEX instrumentation.
buf_pool_t::done_flush_LRU: Condition variable for !n_flush_LRU.
buf_pool_t::done_flush_list: Condition variable for !n_flush_list.
buf_pool_t::do_flush_list: Condition variable to wake up the
buf_flush_page_cleaner when a log checkpoint needs to be written
or the server is being shut down. Replaces buf_flush_event.
We will keep using timed waits (the page cleaner thread will wake
_at least_ once per second), because the calculations for
innodb_adaptive_flushing depend on fixed time intervals.
buf_dblwr: Allocate statically, and move all code to member functions.
Use a native mutex and condition variable. Remove code to deal with
single-page flushing.
buf_dblwr_check_block(): Make the check debug-only. We were spending
a significant amount of execution time in page_simple_validate_new().
flush_counters_t::unzip_LRU_evicted: Remove.
IORequest: Make more members const. FIXME: m_fil_node should be removed.
buf_flush_sync_lsn: Protect by std::atomic, not page_cleaner.mutex
(which we are removing).
page_cleaner_slot_t, page_cleaner_t: Remove many redundant members.
pc_request_flush_slot(): Replaces pc_request() and pc_flush_slot().
recv_writer_thread: Remove. Recovery works just fine without it, if we
simply invoke buf_flush_sync() at the end of each batch in
recv_sys_t::apply().
recv_recovery_from_checkpoint_finish(): Remove. We can simply call
recv_sys.debug_free() directly.
srv_started_redo: Replaces srv_start_state.
SRV_SHUTDOWN_FLUSH_PHASE: Remove. logs_empty_and_mark_files_at_shutdown()
can communicate with the normal page cleaner loop via the new function
flush_buffer_pool().
buf_flush_remove(): Assert that the calling thread is holding
buf_pool.flush_list_mutex. This removes unnecessary mutex operations
from buf_flush_remove_pages() and buf_flush_dirty_pages(),
which replace buf_LRU_flush_or_remove_pages().
buf_flush_lists(): Renamed from buf_flush_batch(), with simplified
interface. Return the number of flushed pages. Clarified comments and
renamed min_n to max_n. Identify LRU batch by lsn=0. Merge all the functions
buf_flush_start(), buf_flush_batch(), buf_flush_end() directly to this
function, which was their only caller, and remove 2 unnecessary
buf_pool.mutex release/re-acquisition that we used to perform around
the buf_flush_batch() call. At the start, if not all log has been
durably written, wait for a background task to do it, or start a new
task to do it. This allows the log write to run concurrently with our
page flushing batch. Any pages that were skipped due to too recent
FIL_PAGE_LSN or due to them being latched by a writer should be flushed
during the next batch, unless there are further modifications to those
pages. It is possible that a page that we must flush due to small
oldest_modification also carries a recent FIL_PAGE_LSN or is being
constantly modified. In the worst case, all writers would then end up
waiting in log_free_check() to allow the flushing and the checkpoint
to complete.
buf_do_flush_list_batch(): Clarify comments, and rename min_n to max_n.
Cache the last looked up tablespace. If neighbor flushing is not applicable,
invoke buf_flush_page() directly, avoiding a page lookup in between.
buf_flush_space(): Auxiliary function to look up a tablespace for
page flushing.
buf_flush_page(): Defer the computation of space->full_crc32(). Never
call log_write_up_to(), but instead skip persistent pages whose latest
modification (FIL_PAGE_LSN) is newer than the redo log. Also skip
pages on which we cannot acquire a shared latch without waiting.
buf_flush_try_neighbors(): Do not bother checking buf_fix_count
because buf_flush_page() will no longer wait for the page latch.
Take the tablespace as a parameter, and only execute this function
when innodb_flush_neighbors>0. Avoid repeated calls of page_id_t::fold().
buf_flush_relocate_on_flush_list(): Declare as cold, and push down
a condition from the callers.
buf_flush_check_neighbor(): Take id.fold() as a parameter.
buf_flush_sync(): Ensure that the buf_pool.flush_list is empty,
because the flushing batch will skip pages whose modifications have
not yet been written to the log or were latched for modification.
buf_free_from_unzip_LRU_list_batch(): Remove redundant local variables.
buf_flush_LRU_list_batch(): Let the caller buf_do_LRU_batch() initialize
the counters, and report n->evicted.
Cache the last looked up tablespace. If neighbor flushing is not applicable,
invoke buf_flush_page() directly, avoiding a page lookup in between.
buf_do_LRU_batch(): Return the number of pages flushed.
buf_LRU_free_page(): Only release and re-acquire buf_pool.mutex if
adaptive hash index entries are pointing to the block.
buf_LRU_get_free_block(): Do not wake up the page cleaner, because it
will no longer perform any useful work for us, and we do not want it
to compete for I/O while buf_flush_lists(innodb_lru_flush_size, 0)
writes out and evicts at most innodb_lru_flush_size pages. (The
function buf_do_LRU_batch() may complete after writing fewer pages if
more than innodb_lru_scan_depth pages end up in buf_pool.free list.)
Eliminate some mutex release-acquire cycles, and wait for the LRU
flush batch to complete before rescanning.
buf_LRU_check_size_of_non_data_objects(): Simplify the code.
buf_page_write_complete(): Remove the parameter evict, and always
evict pages that were part of an LRU flush.
buf_page_create(): Take a pre-allocated page as a parameter.
buf_pool_t::free_block(): Free a pre-allocated block.
recv_sys_t::recover_low(), recv_sys_t::apply(): Preallocate the block
while not holding recv_sys.mutex. During page allocation, we may
initiate a page flush, which in turn may initiate a log flush, which
would require acquiring log_sys.mutex, which should always be acquired
before recv_sys.mutex in order to avoid deadlocks. Therefore, we must
not be holding recv_sys.mutex while allocating a buffer pool block.
BtrBulk::logFreeCheck(): Skip a redundant condition.
row_undo_step(): Do not invoke srv_inc_activity_count() for every row
that is being rolled back. It should suffice to invoke the function in
trx_flush_log_if_needed() during trx_t::commit_in_memory() when the
rollback completes.
sync_check_enable(): Remove. We will enable innodb_sync_debug from the
very beginning.
Reviewed by: Vladislav Vaintroub
Sometimes blockdev --getss returns 4096.
In that case ROW_FORMAT=COMPRESSED tables might violate
that 4096 bytes alignment.
This patch disables O_DIRECT for COMPRESSED tables.
OS_DATA_FILE_NO_O_DIRECT: new possible value for os_file_create() argument
fil_node_open_file(): do not O_DIRECT
ROW_FORMAT=COMPRESSED tables
AIO::is_linux_native_aio_supported(): minimal alignment in a general case
is 4096 and not 512.
LATCH_ID_OS_AIO_READ_MUTEX,
LATCH_ID_OS_AIO_WRITE_MUTEX,
LATCH_ID_OS_AIO_LOG_MUTEX,
LATCH_ID_OS_AIO_IBUF_MUTEX,
LATCH_ID_OS_AIO_SYNC_MUTEX: Remove. The tpool is not instrumented.
lock_set_timeout_event(): Remove.
srv_sys_mutex_key, srv_sys_t::mutex, SYNC_THREADS: Remove.
srv_slot_t::suspended: Remove. We only ever assigned this data member
true, so it is redundant.
ib_wqueue_wait(), ib_wqueue_timedwait(): Remove.
os_thread_join(): Remove.
os_thread_create(), os_thread_exit(): Remove redundant parameters.
These were missed in commit 5e62b6a5e0.
On some libc (like musl[1]), posix_fallocate() is a fallocate() syscall
wrapper, and does not include fallback code like glibc does. In that
case, EOPNOTSUPP is returned if underlying filesystem does not
support fallocate() with mode = 0.
This patch enables falling back to writing zeros when EOPNOTSUPP, fixes
some cases like running on filesystem without proper fallocate support
on Alpine.
[1]: https://git.musl-libc.org/cgit/musl/tree/src/fcntl/posix_fallocate.c?h=v1.2.1
Build failure was:
storage/innobase/os/os0proc.cc:144:3: error: use of undeclared identifier 'MEM_UNDEFINED'
MEM_UNDEFINED(ptr, size);
Assumed to be introduced in MDEV-20377
commit: c36834c832
- This issue is caused by a5584b13d1
(MDEV-15528). os_file_punch_hole() is added to fil_io() in MDEV-15528.
But it fails to handle failure of os_file_punch_hole(). InnoDB should
handle the DB_IO_NO_PUNCH_HOLE error and silently transform to
DB_SUCCESS. InnoDB should set the punch hole flag correctly when
tablespace is loaded
fil_node_t::read_page0(): Set the punch hole flag when tablespace is loaded
fil_io(): Handle the DB_IO_NO_PUNCH_HOLE error
buf_flush_free_pages(): Checks the punch hole condition earlier using
tablespace punch hole flag
In AddressSanitizer, we only want memory poisoning to happen
in connection with custom memory allocation or freeing.
The primary use of MEM_UNDEFINED is for declaring memory uninitialized
in Valgrind or MemorySanitizer. We do not want MEM_UNDEFINED to
have the unwanted side effect that AddressSanitizer would no longer
be able to complain about accessing unallocated memory.
MEM_UNDEFINED(): Define as no-op for AddressSanitizer.
MEM_MAKE_ADDRESSABLE(): Define as MEM_UNDEFINED() or
ASAN_UNPOISON_MEMORY_REGION().
MEM_CHECK_ADDRESSABLE(): Wrap also __asan_region_is_poisoned().
