btr_search_hash_table_validate(), btr_search_validate(): Add the
parameter THD for checking if the statement has been killed.
Any non-QUICK CHECK TABLE will validate the entire adaptive hash index
for all InnoDB tables, which may be extremely slow when running
multiple concurrent CHECK TABLE.
- InnoDB AHI tries to access the concurrent instant alter column,
leads to asan failure. Instant alter column should acquire the
clustered index search latch in exclusive mode before changing
the table cache definition.
- Removed the default parameter for the function
btr_search_drop_page_hash_index()
- Addressed the DWITH_INNODB_AHI=0 compilation failure
by passing two parameters from all callers of
btr_search_drop_page_hash_index()
btr_search_guess_on_hash() would only acquire an index page latch if it
is invoked with ahi_latch=NULL. If it's invoked from
row_sel_try_search_shortcut_for_mysql() with ahi_latch!=NULL, a page
will not be latched, and row_search_mvcc() will get a pointer to the
record, which can be changed by some other transaction before the record
was stored in result buffer with row_sel_store_mysql_rec() call.
ahi_latch argument of btr_cur_search_to_nth_level_func() and
btr_pcur_open_with_no_init_func() is used only for
row_sel_try_search_shortcut_for_mysql().
btr_cur_search_to_nth_level_func(..., ahi_latch !=0, ...) is invoked
only from btr_pcur_open_with_no_init_func(..., ahi_latch !=0, ...),
which, in turns, is invoked only from
row_sel_try_search_shortcut_for_mysql().
I suppose that separate case with ahi_latch!=0 was intentionally
implemented to protect row_sel_store_mysql_rec() call in
row_search_mvcc() just after row_sel_try_search_shortcut_for_mysql()
call. After the ahi_latch was moved from row_seach_mvcc() to
row_sel_try_search_shortcut_for_mysql(), there is no need in it at all
if btr_search_guess_on_hash() latches a page unconditionally. And if
btr_search_guess_on_hash() latched the page, any access to the record in
row_sel_try_search_shortcut_for_mysql() after btr_pcur_open_with_no_init()
call will be protected with the page latch.
The fix is to remove ahi_latch argument from
btr_pcur_open_with_no_init_func(), btr_cur_search_to_nth_level_func()
and btr_search_guess_on_hash().
There will not be test, as to test it we need to freeze some SELECT
execution in the point between row_sel_try_search_shortcut_for_mysql()
and row_sel_store_mysql_rec() calls in row_search_mvcc(), and to change
the record in some other transaction to let row_sel_store_mysql_rec() to
store changed record in result buffer. Buf we can't do this with the
fix, as the page will be latched in btr_search_guess_on_hash() call.
Reason:
=======
Race condition between btr_search_drop_hash_index() and
btr_search_lazy_free(). One thread does resizing of buffer pool
and clears the ahi on all pages in the buffer pool, frees the
index and table while removing the last reference. At the same time,
other thread access index->heap in btr_search_drop_hash_index().
Solution:
=========
Acquire the respective ahi latch before checking index->freed()
btr_search_drop_page_hash_index(): Added new parameter to indicate
that drop ahi entries only if the index is marked as freed
btr_search_check_marked_free_index(): Acquire all ahi latches and
return true if the index was freed
This implements memory transaction support for:
* Intel Restricted Transactional Memory (RTM), also known as TSX-NI
(Transactional Synchronization Extensions New Instructions)
* POWER v2.09 Hardware Trace Monitor (HTM) on GNU/Linux
transactional_lock_guard, transactional_shared_lock_guard:
RAII lock guards that try to elide the lock acquisition
when transactional memory is available.
buf_pool.page_hash: Try to elide latches whenever feasible.
Related to the InnoDB change buffer and ROW_FORMAT=COMPRESSED
tables, this is not always possible.
In buf_page_get_low(), memory transactions only work reasonably
well for validating a guessed block address.
TMLockGuard, TMLockTrxGuard, TMLockMutexGuard: RAII lock guards
that try to elide lock_sys.latch and related latches.
Typically, index_lock and fil_space_t::latch will be held for a longer
time than the spin loop in latch acquisition would be waiting for.
Let us avoid spin loops for those as well as dict_sys.latch, which
could be held in exclusive mode for a longer time (while loading
metadata into the buffer pool and the dictionary cache).
Performance testing on a dual Intel Xeon E5-2630 v4 (2 NUMA nodes)
suggests that the buffer pool page latch (block_lock) benefits from a
spin loop in both read-only and read-write workloads where the working
set is slightly larger than the buffer pool. Presumably, most contention
would occur on leaf page latches. Contention on upper level pages in
the buffer pool should intuitively last longer.
We introduce srw_spin_lock and srw_spin_mutex to allow users of
srw_lock or srw_mutex to opt in for the spin loop.
On Microsoft Windows, a spin loop variant was and will not be available;
srw_mutex and srw_lock will simply wrap SRWLOCK.
That is, on Microsoft Windows, the parameters innodb_sync_spin_loops
and innodb_spin_wait_delay will only affect block_lock.
This is a complete rewrite of DROP TABLE, also as part of other DDL,
such as ALTER TABLE, CREATE TABLE...SELECT, TRUNCATE TABLE.
The background DROP TABLE queue hack is removed.
If a transaction needs to drop and create a table by the same name
(like TRUNCATE TABLE does), it must first rename the table to an
internal #sql-ib name. No committed version of the data dictionary
will include any #sql-ib tables, because whenever a transaction
renames a table to a #sql-ib name, it will also drop that table.
Either the rename will be rolled back, or the drop will be committed.
Data files will be unlinked after the transaction has been committed
and a FILE_RENAME record has been durably written. The file will
actually be deleted when the detached file handle returned by
fil_delete_tablespace() will be closed, after the latches have been
released. It is possible that a purge of the delete of the SYS_INDEXES
record for the clustered index will execute fil_delete_tablespace()
concurrently with the DDL transaction. In that case, the thread that
arrives later will wait for the other thread to finish.
HTON_TRUNCATE_REQUIRES_EXCLUSIVE_USE: A new handler flag.
ha_innobase::truncate() now requires that all other references to
the table be released in advance. This was implemented by Monty.
ha_innobase::delete_table(): If CREATE TABLE..SELECT is detected,
we will "hijack" the current transaction, drop the table in
the current transaction and commit the current transaction.
This essentially fixes MDEV-21602. There is a FIXME comment about
making the check less failure-prone.
ha_innobase::truncate(), ha_innobase::delete_table():
Implement a fast path for temporary tables. We will no longer allow
temporary tables to use the adaptive hash index.
dict_table_t::mdl_name: The original table name for the purpose of
acquiring MDL in purge, to prevent a race condition between a
DDL transaction that is dropping a table, and purge processing
undo log records of DML that had executed before the DDL operation.
For #sql-backup- tables during ALTER TABLE...ALGORITHM=COPY, the
dict_table_t::mdl_name will differ from dict_table_t::name.
dict_table_t::parse_name(): Use mdl_name instead of name.
dict_table_rename_in_cache(): Update mdl_name.
For the internal FTS_ tables of FULLTEXT INDEX, purge would
acquire MDL on the FTS_ table name, but not on the main table,
and therefore it would be able to run concurrently with a
DDL transaction that is dropping the table. Previously, the
DROP TABLE queue hack prevented a race between purge and DDL.
For now, we introduce purge_sys.stop_FTS() to prevent purge from
opening any table, while a DDL transaction that may drop FTS_
tables is in progress. The function fts_lock_table(), which will
be invoked before the dictionary is locked, will wait for
purge to release any table handles.
trx_t::drop_table_statistics(): Drop statistics for the table.
This replaces dict_stats_drop_index(). We will drop or rename
persistent statistics atomically as part of DDL transactions.
On lock conflict for dropping statistics, we will fail instantly
with DB_LOCK_WAIT_TIMEOUT, because we will be holding the
exclusive data dictionary latch.
trx_t::commit_cleanup(): Separated from trx_t::commit_in_memory().
Relax an assertion around fts_commit() and allow DB_LOCK_WAIT_TIMEOUT
in addition to DB_DUPLICATE_KEY. The call to fts_commit() is
entirely misplaced here and may obviously break the consistency
of transactions that affect FULLTEXT INDEX. It needs to be fixed
separately.
dict_table_t::n_foreign_key_checks_running: Remove (MDEV-21175).
The counter was a work-around for missing meta-data locking (MDL)
on the SQL layer, and not really needed in MariaDB.
ER_TABLE_IN_FK_CHECK: Replaced with ER_UNUSED_28.
HA_ERR_TABLE_IN_FK_CHECK: Remove.
row_ins_check_foreign_constraints(): Do not acquire
dict_sys.latch either. The SQL-layer MDL will protect us.
This was reviewed by Thirunarayanan Balathandayuthapani
and tested by Matthias Leich.
Let us try to avoid code bloat for the common case that
performance_schema is disabled at runtime, and use
ATTRIBUTE_NOINLINE member functions for instrumented latch acquisition.
Also, let us distinguish lock waits from non-contended lock requests
by using write_lock,read_lock for the requests that lead to waits,
and try_write_lock,try_read_lock for the wait-free lock acquisitions.
Actual 'try' operations are not being instrumented at all.
Many InnoDB rw-locks unnecessarily depend on the complex
InnoDB rw_lock_t implementation that support the SX lock mode
as well as recursive acquisition of X or SX locks.
One of them is the bunch of adaptive hash index search latches,
instrumented as btr_search_latch in PERFORMANCE_SCHEMA.
Let us introduce a simpler lock for those in order to
reduce overhead.
srw_lock: A simple read-write lock that does not support recursion.
On Microsoft Windows, this wraps SRWLOCK, only adding
runtime overhead if PERFORMANCE_SCHEMA is enabled.
On Linux (all architectures), this is implemented with
std::atomic<uint32_t> and the futex system call.
On other platforms, we will wrap mysql_rwlock_t with
zero runtime overhead.
The PERFORMANCE_SCHEMA instrumentation differs
from InnoDB rw_lock_t in that we will only invoke
PSI_RWLOCK_CALL(start_rwlock_wrwait) or
PSI_RWLOCK_CALL(start_rwlock_rdwait)
if there is an actual conflict.
In commit bf3c862faa we introduced
an assertion that may dereference a null pointer.
This regression was caught by running the following:
./mtr --parallel=auto --suite=innodb \
--mysqld=--loose-innodb-adaptive-hash-index
The adaptive hash index is disabled by default since
commit 88cdfc5c7d (MDEV-20487)
and hence the problem was not caught earlier.
Commit bf3c862faa
accidentally introduced two bugs.
btr_search_update_hash_ref(): Pass the correct parameter part->heap.
btr_search_sys_t::free(): Free all memory.
Thanks to Michael Widenius and Thirunarayanan Balathandayuthapani
for pointing out these bugs.
btr_search_sys::parts[]: A single structure for the partitions of
the adaptive hash index. Replaces the 3 separate arrays:
btr_search_latches[], btr_search_sys->hash_tables,
btr_search_sys->hash_tables[i]->heap.
hash_table_t::heap, hash_table_t::adaptive: Remove.
ha0ha.cc: Remove. Move all code to btr0sea.cc.
Problem:
========
During buffer pool resizing, InnoDB recreates the dictionary hash
tables. Dictionary hash table reuses the heap of AHI hash tables.
It leads to memory corruption.
Fix:
====
- While disabling AHI, free the heap and AHI hash tables. Recreate the
AHI hash tables and assign new heap when AHI is enabled.
- btr_blob_free() access invalid page if page was reallocated during
buffer poolresizing. So btr_blob_free() should get the page from
buf_pool instead of using existing block.
- btr_search_enabled and block->index should be checked after
acquiring the btr_search_sys latch
- Moved the buffer_pool_scan debug sync to earlier before accessing the
btr_search_sys latches to avoid the hang of truncate_purge_debug
test case
- srv_printf_innodb_monitor() should acquire btr_search_sys latches
before AHI hash tables.
If the InnoDB buffer pool contains many pages for a table or index
that is being dropped or rebuilt, and if many of such pages are
pointed to by the adaptive hash index, dropping the adaptive hash index
may consume a lot of time.
The time-consuming operation of dropping the adaptive hash index entries
is being executed while the InnoDB data dictionary cache dict_sys is
exclusively locked.
It is not actually necessary to drop all adaptive hash index entries
at the time a table or index is being dropped or rebuilt. We can let
the LRU replacement policy of the buffer pool take care of this gradually.
For this to work, we must detach the dict_table_t and dict_index_t
objects from the main dict_sys cache, and once the last
adaptive hash index entry for the detached table is removed
(when the garbage page is evicted from the buffer pool) we can free
the dict_table_t and dict_index_t object.
Related to this, in MDEV-16283, we made ALTER TABLE...DISCARD TABLESPACE
skip both the buffer pool eviction and the drop of the adaptive hash index.
We shifted the burden to ALTER TABLE...IMPORT TABLESPACE or DROP TABLE.
We can remove the eviction from DROP TABLE. We must retain the eviction
in the ALTER TABLE...IMPORT TABLESPACE code path, so that in case the
discarded table is being re-imported with the same tablespace identifier,
the fresh data from the imported tablespace will replace any stale pages
in the buffer pool.
rpl.rpl_failed_drop_tbl_binlog: Remove the test. DROP TABLE can
no longer be interrupted inside InnoDB.
fseg_free_page(), fseg_free_step(), fseg_free_step_not_header(),
fseg_free_page_low(), fseg_free_extent(): Remove the parameter
that specifies whether the adaptive hash index should be dropped.
btr_search_lazy_free(): Lazily free an index when the last
reference to it is dropped from the adaptive hash index.
buf_pool_clear_hash_index(): Declare static, and move to the
same compilation unit with the bulk of the adaptive hash index
code.
dict_index_t::clone(), dict_index_t::clone_if_needed():
Clone an index that is being rebuilt while adaptive hash index
entries exist. The original index will be inserted into
dict_table_t::freed_indexes and dict_index_t::set_freed()
will be called.
dict_index_t::set_freed(), dict_index_t::freed(): Note that
or check whether the index has been freed. We will use the
impossible page number 1 to denote this condition.
dict_index_t::n_ahi_pages(): Replaces btr_search_info_get_ref_count().
dict_index_t::detach_columns(): Move the assignment n_fields=0
to ha_innobase_inplace_ctx::clear_added_indexes().
We must have access to the columns when freeing the
adaptive hash index. Note: dict_table_t::v_cols[] will remain
valid. If virtual columns are dropped or added, the table
definition will be reloaded in ha_innobase::commit_inplace_alter_table().
buf_page_mtr_lock(): Drop a stale adaptive hash index if needed.
We will also reduce the number of btr_get_search_latch() calls
and enclose some more code inside #ifdef BTR_CUR_HASH_ADAPT
in order to benefit cmake -DWITH_INNODB_AHI=OFF.
Thanks to MDEV-15058, there is only one InnoDB buffer pool.
Allocating buf_pool statically removes one level of pointer indirection
and makes code more readable, and removes the awkward initialization of
some buf_pool members.
While doing this, we will also declare some buf_pool_t data members
private and replace some functions with member functions. This is
mostly affecting buffer pool resizing.
This is not aiming to be a complete rewrite of buf_pool_t to
a proper class. Most of the buffer pool interface, such as
buf_page_get_gen(), will remain in the C programming style
for now.
buf_pool_t::withdrawing: Replaces buf_pool_withdrawing.
buf_pool_t::withdraw_clock_: Replaces buf_withdraw_clock.
buf_pool_t::create(): Repalces buf_pool_init().
buf_pool_t::close(): Replaces buf_pool_free().
buf_bool_t::will_be_withdrawn(): Replaces buf_block_will_be_withdrawn(),
buf_frame_will_be_withdrawn().
buf_pool_t::clear_hash_index(): Replaces buf_pool_clear_hash_index().
buf_pool_t::get_n_pages(): Replaces buf_pool_get_n_pages().
buf_pool_t::validate(): Replaces buf_validate().
buf_pool_t::print(): Replaces buf_print().
buf_pool_t::block_from_ahi(): Replaces buf_block_from_ahi().
buf_pool_t::is_block_field(): Replaces buf_pointer_is_block_field().
buf_pool_t::is_block_mutex(): Replaces buf_pool_is_block_mutex().
buf_pool_t::is_block_lock(): Replaces buf_pool_is_block_lock().
buf_pool_t::is_obsolete(): Replaces buf_pool_is_obsolete().
buf_pool_t::io_buf: Make default-constructible.
buf_pool_t::io_buf::create(): Delayed 'constructor'
buf_pool_t::io_buf::close(): Early 'destructor'
HazardPointer: Make default-constructible. Define all member functions
inline, also for derived classes.
The -Wconversion in GCC seems to be stricter than in clang.
GCC at least since version 4.4.7 issues truncation warnings for
assignments to bitfields, while clang 10 appears to only issue
warnings when the sizes in bytes rounded to the nearest integer
powers of 2 are different.
Before GCC 10.0.0, -Wconversion required more casts and would not
allow some operations, such as x<<=1 or x+=1 on a data type that
is narrower than int.
GCC 5 (but not GCC 4, GCC 6, or any later version) is complaining
about x|=y even when x and y are compatible types that are narrower
than int. Hence, we must rewrite some x|=y as
x=static_cast<byte>(x|y) or similar, or we must disable -Wconversion.
In GCC 6 and later, the warning for assigning wider to bitfields
that are narrower than 8, 16, or 32 bits can be suppressed by
applying a bitwise & with the exact bitmask of the bitfield.
For older GCC, we must disable -Wconversion for GCC 4 or 5 in such
cases.
The bitwise negation operator appears to promote short integers
to a wider type, and hence we must add explicit truncation casts
around them. Microsoft Visual C does not allow a static_cast to
truncate a constant, such as static_cast<byte>(1) truncating int.
Hence, we will use the constructor-style cast byte(~1) for such cases.
This has been tested at least with GCC 4.8.5, 5.4.0, 7.4.0, 9.2.1, 10.0.0,
clang 9.0.1, 10.0.0, and MSVC 14.22.27905 (Microsoft Visual Studio 2019)
on 64-bit and 32-bit targets (IA-32, AMD64, POWER 8, POWER 9, ARMv8).
dict_sys_t::create(): Renamed from dict_init().
dict_sys_t::close(): Renamed from dict_close().
dict_sys_t::add(): Sliced from dict_table_t::add_to_cache().
dict_sys_t::remove(): Renamed from dict_table_remove_from_cache().
dict_sys_t::prevent_eviction(): Renamed from
dict_table_move_from_lru_to_non_lru().
dict_sys_t::acquire(): Replaces dict_move_to_mru() and some more logic.
dict_sys_t::resize(): Renamed from dict_resize().
dict_sys_t::find(): Replaces dict_lru_find_table() and
dict_non_lru_find_table().
Also, related to MDEV-15522, MDEV-17304, MDEV-17835,
remove the Galera xtrabackup tests, because xtrabackup never worked
with MariaDB Server 10.3 due to InnoDB redo log format changes.
main.derived_cond_pushdown: Move all 10.3 tests to the end,
trim trailing white space, and add an "End of 10.3 tests" marker.
Add --sorted_result to tests where the ordering is not deterministic.
main.win_percentile: Add --sorted_result to tests where the
ordering is no longer deterministic.
Also fixes MDEV-14727, MDEV-14491
InnoDB: Error: Waited for 5 secs for hash index ref_count (1) to drop to 0
by replacing the flawed wait logic in dict_index_remove_from_cache_low().
On DISCARD TABLESPACE, there is no need to drop the adaptive hash index.
We must drop it on IMPORT TABLESPACE, and eventually on DROP TABLE or
DROP INDEX. As long as the dict_index_t object remains in the cache
and the table remains inaccessible, the adaptive hash index entries
to orphaned pages would not do any harm. They would be dropped when
buffer pool pages are reused for something else.
btr_search_drop_page_hash_when_freed(), buf_LRU_drop_page_hash_batch():
Remove the parameter zip_size, and pass 0 to buf_page_get_gen().
buf_page_get_gen(): Ignore zip_size if mode==BUF_PEEK_IF_IN_POOL.
buf_LRU_drop_page_hash_for_tablespace(): Drop the adaptive hash index
even if the tablespace is inaccessible.
buf_LRU_drop_page_hash_for_tablespace(): New global function, to drop
the adaptive hash index.
buf_LRU_flush_or_remove_pages(), fil_delete_tablespace():
Remove the parameter drop_ahi.
dict_index_remove_from_cache_low(): Actively drop the adaptive hash index
if entries exist. This should prevent InnoDB hangs on DROP TABLE or
DROP INDEX.
row_import_for_mysql(): Drop any adaptive hash index entries for the table.
row_drop_table_for_mysql(): Drop any adaptive hash index for the table,
except if the table resides in the system tablespace. (DISCARD TABLESPACE
does not apply to the system tablespace, and we do no want to drop the
adaptive hash index for other tables than the one that is being dropped.)
row_truncate_table_for_mysql(): Drop any adaptive hash index entries for
the table, except if the table resides in the system tablespace.
Bind more InnoDB parameters directly to MYSQL_SYSVAR and
remove "shadow variables".
innodb_change_buffering: Declare as ENUM, not STRING.
innodb_flush_method: Declare as ENUM, not STRING.
innodb_log_buffer_size: Bind directly to srv_log_buffer_size,
without rounding it to a multiple of innodb_page_size.
LOG_BUFFER_SIZE: Remove.
SysTablespace::normalize_size(): Renamed from normalize().
innodb_init_params(): A new function to initialize and validate
InnoDB startup parameters.
innodb_init(): Renamed from innobase_init(). Invoke innodb_init_params()
before actually trying to start up InnoDB.
srv_start(bool): Renamed from innobase_start_or_create_for_mysql().
Added the input parameter create_new_db.
SRV_ALL_O_DIRECT_FSYNC: Define only for _WIN32.
xb_normalize_init_values(): Merge to innodb_init_param().
