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
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.
log_group_read_log_seg() returns error when:
1) Calculated log block number does not correspond to read log block
number. This can be caused by:
a) Garbage or an incompletely written log block. We can exclude this
case by checking log block checksum if it's enabled(see innodb-log-checksums,
encrypted log block contains checksum always).
b) The log block is overwritten. In this case checksum will be correct and
read log block number will be greater then requested one.
2) When log block length is wrong. In this case recv_sys->found_corrupt_log
is set.
3) When redo log block checksum is wrong. In this case innodb code
writes messages to error log with the following prefix: "Invalid log
block checksum."
The fix processes all the cases above.
Add CRC32C code to mysys. The x86-64 implementation uses PCMULQDQ in addition to CRC32 instruction
after Intel whitepaper, and is ported from rocksdb code.
Optimized ARM and POWER CRC32 were already present in mysys.
Parse SHOW SLAVE STATUS output for the "Using_Gtid" column. If the value
is "No", then old log file and position is backed up, otherwise gtid_slave_pos
is backed up.
In commit fe39d02f51 (MDEV-20638)
we removed some wake-up signaling of the master thread that should
have been there, to ensure a steady log checkpointing workload.
Common sense suggests that the commit omitted some necessary calls
to srv_inc_activity_count(). But, an attempt to add the call to
trx_flush_log_if_needed_low() as well as to reinstate the function
innobase_active_small() did not restore the performance for the
case where sync_binlog=1 is set.
Therefore, we will revert the entire commit in MariaDB Server 10.2.
In MariaDB Server 10.5, adding a srv_inc_activity_count() call to
trx_flush_log_if_needed_low() did restore the performance, so we
will not revert MDEV-20638 across all versions.
Regretfully, the parameter innodb_log_checksums was introduced
in MySQL 5.7.9 (the first GA release of that series) by
mysql/mysql-server@af0acedd88
which partly replaced a parameter that had been introduced in 5.7.8
mysql/mysql-server@22ba38218e
as innodb_log_checksum_algorithm.
Given that the CRC-32C operations are accelerated on many processor
implementations (AMD64 with SSE4.2; since MDEV-22669 also on IA-32
with SSE4.2, POWER 8 and later, ARMv8 with some extensions)
and by lookup tables when only generic SISD instructions are available,
there should be no valid reason to disable checksums.
In MariaDB 10.5.2, as a preparation for MDEV-12353, MDEV-19543 deprecated
and ignored the parameter innodb_log_checksums altogether. This should
imply that after a clean shutdown with innodb_log_checksums=OFF one
cannot upgrade to MariaDB Server 10.5 at all.
Due to these problems, let us deprecate the parameter innodb_log_checksums
and honor it only during server startup.
The command SET GLOBAL innodb_log_checksums will always set the
parameter to ON.
The parameters innodb_thread_concurrency and innodb_commit_concurrency
were useful years ago when both computing resources and the implementation
of some shared data structures were limited. MySQL 5.0 or 5.1 had trouble
scaling beyond 8 concurrent connections. Most of the scalability bottlenecks
have been removed since then, and the transactions per second delivered
by MariaDB Server 10.5 should not dramatically drop upon exceeding the
'optimal' number of connections.
Hence, enabling any concurrency throttling for InnoDB actually makes
things worse. We have seen many customers mistakenly setting this to a
small value like 16 or 64 and then complaining the server was slow.
Ignoring the parameters allows us to remove some normally unused code
and data structures, which could slightly improve performance.
innodb_thread_concurrency, innodb_commit_concurrency,
innodb_replication_delay, innodb_concurrency_tickets,
innodb_thread_sleep_delay, innodb_adaptive_max_sleep_delay:
Deprecate and ignore; hard-wire to 0.
The column INFORMATION_SCHEMA.INNODB_TRX.trx_concurrency_tickets
will always report 0.
- Due to commit fe95cb2e40 (MDEV-16125),
InnoDB master thread does not need to call srv_resume_thread()
and therefore there is no need to wake up the thread.
Due to the above patch, InnoDB should remove the following dead code.
srv_check_activity(): Makes the parameter as in,out and returns the
recent activity value
innobase_active_small(): Removed
srv_active_wake_master_thread(): Removed
srv_wake_master_thread(): Removed
srv_active_wake_master_thread_low(): Removed
Simplify srv_master_thread() and remove switch cases, added the assert.
Replace srv_wake_master_thread() with srv_inc_activity_count()
INNOBASE_WAKE_INTERVAL: Removed
On FreeBSD, perl isn't in /usr/bin, its in /usr/local/bin or
elsewhere in the path.
Like storage/{maria/unittest/,}ma_test_* , we use /usr/bin/env to
find perl and run it.
MDEV-21298: mariabackup doesn't read from the [mariadbd] and [mariadbd-X.Y]
server option groups from configuration files
MDEV-21301: mariabackup doesn't read [mariadb-backup] option group in
configuration file
All three issues require to change the same code, that is why their
fixes are joined in one commit.
The fix is in invoking load_defaults_or_exit() and handle_options() for
backup-specific groups separately from client-server groups to let the last
handle_options() call fail on unknown backup-specific options.
The order of options procesing is the following:
1) Load server groups and process server options, ignore unknown
options
2) Load client groups and process client options, ignore unknown
options
3) Load backup groups and process client-server options, exit on
unknown option
4) Process --mysqld-args command line options, ignore unknown options
New global flag my_handle_options_init_variables was added to have
ability to invoke handle_options() for the same allowed options set
several times without re-initialising previously set option values.
--password value destroying is moved from option processing callback to
mariabackup's handle_options() function to have ability to invoke server's
handle_options() several times for the same possible allowed options
set.
Galera invokes wsrep_sst_mariabackup.sh with mysqld command line
options to configure mariabackup as close to the server as possible.
It is not known what server options are supported by mariabackup when the
script is invoked. That is why new mariabackup option "--mysqld-args" is added,
all unknown options that follow this option will be silently ignored.
wsrep_sst_mariabackup.sh was also changed to:
- use "--mysqld-args" mariabackup option to pass mysqld options,
- remove deprecated innobackupex mode,
- remove unsupported mariabackup options:
--encrypt
--encrypt-key
--rebuild-indexes
--rebuild-threads
* FreeBSD calls amd64 what Linux calls x86_64
* signal returns void (*)(int)
* struct pam_message has char*, not const char*
* krb5_free_unparsed_name exists, but is deprecated
Existing implementation used my_checksum (from mysys)
for calculating table checksum and binlog checksum.
This implementation was optimized for powerpc only and lacked
SIMD implementation for x86 (using clmul) and ARM
(using ACLE) instead used zlib-crc32.
mariabackup had its own copy of the crc32 implementation
using hardware optimized implementation only for x86 and lagged
hardware based implementation for powerpc and ARM.
Patch helps unifies all such calls and help aggregate all of them
using an unified interface my_checksum().
Said unification also enables hardware optimized calls for all
architecture viz. x86, ARM, POWERPC.
Default always fallback to zlib crc32.
Thanks to Daniel Black for reviewing, fixing and testing
PowerPC changes. Thanks to Marko and Daniel for early code feedback.
When my_vsnprintf() is patched, the code protected disabled with
'WAITING_FOR_BUGFIX_TO_VSPRINTF' should be enabled again. Also all %b
formats in this patch should be revert to %s again
