Patch removes dict_index_t::stats_latch. Table/index statistics now
protected with dict_sys->mutex. That way statistics computation can
happen in parallel in several threads and dict_sys->mutex will be locked
only for a short period of time.
This patch is a joint work with Marko Mäkelä
dict_index_t:🔒 make mutable which allows to pass const pointer
when only lock is touched in an object
btr_height_get()
btr_get_size(): make index argument const for better type safety
btr_estimate_number_of_different_key_vals(): now returns computed values
instead of setting fields in dict_index_t directly
remove everything related to dict_index_t::stats_latch
dict_stats_index_set_n_diff(): now returns computed values instead
of setting fields in dict_index_t directly
dict_stats_analyze_index(): now returns computed values instead
of setting fields in dict_index_t directly
Reviewed by: Marko Mäkelä
commit de942c9f61 (MDEV-15983)
introduced a race condition that we inadequately fixed in
commit 93b69825ad (MDEV-16169).
Because fil_space_t::release() or fil_space_t::acquire() are
not protected by fil_system.mutex like their predecessors,
it is possible that stop_new_ops was set between the time
a thread checked fil_space_t::is_stopping() and invoked
fil_space_t::acquire().
In an execution trace, this happened in fil_system_t::keyrotate_next(),
causing an assertion failure in fil_delete_tablespace()
in the other thread that seeked to stop new operations.
We fix this bug by merging the flag fil_space_t::stop_new_ops
and the reference count fil_space_t::n_pending_ops into a
single word that is only being accessed by atomic memory operations.
fil_space_t::set_stopping(): Accessor for changing the state of
the former stop_new_ops flag.
fil_space_t::acquire(): Return whether the acquisition succeeded.
It would fail between set_stopping(true) and set_stopping(false).
This issue was originally reported by Fungo Wang, along with a fix, as
MySQL Bug #98990.
His suggested fix was applied as part of
mysql/mysql-server@a003fc373d
and released in MySQL 5.7.31.
i_s_metrics_fill(): Add the missing call to Field::set_notnull(),
and simplify some code.
Introduce a new ATTRIBUTE_NOINLINE to
ib::logger member functions, and add UNIV_UNLIKELY hints to callers.
Also, remove some crash reporting output. If needed, the
information will be available using debugging tools.
Furthermore, remove some fts_enable_diag_print output that included
indexed words in raw form. The code seemed to assume that words are
NUL-terminated byte strings. It is not clear whether a NUL terminator
is always guaranteed to be present. Also, UCS2 or UTF-16 strings would
typically contain many NUL bytes.
All tablespace metadata is buffered in fil_system. There is a LRU
mechanism, but that only controls the opening and closing of
fil_node_t::handle.
It is much more efficient and less error-prone to access data file names
by looking up the fil_space_t object rather than by essentially joining
each row with an access to SYS_DATAFILES via the InnoDB internal SQL parser.
dict_get_first_path(): Declare static. The function may only be needed
when loading or updating the data dictionary. Also, change a condition
in order to avoid a bogus GCC 10 -Wstringop-overflow warning for
mem_strdupl() about len==ULINT_UNDEFINED.
i_s_sys_tablespaces_fill_table(): Do not access other InnoDB internal
dictionary tables than SYS_TABLESPACES.
The column INFORMATION_SCHEMA.INNODB_MUTEXES.NAME is not populated ever since
commit 2e814d4702 applied the InnoDB changes from
MySQL 5.7.9 to MariaDB Server 10.2.2.
Since the same commit, the view is only providing information about
rw_lock_t, not any mutexes.
For now, let us convert the source code file name and line number of
the rw_lock_t creation into a name. A better option in the future might
be to store the information somewhere where it can be looked up by
mysql_pfs_key_t, and possibly to remove the CREATE_FILE and CREATE_LINE
columns.
dict_table_t::stats_latch_created: remove along with related stuff
dict_table_t::stats_latch: make value member, not pointer. And always lock this
for simplicity, even to stats cloned table.
based on the work of Sergey Vojtovich
The INFORMATION_SCHEMA plugin INNODB_SYS_VIRTUAL, which was introduced
in MariaDB 10.2.2 along with the dictionary table SYS_VIRTUAL,
is similar to other, much older and already stable plugins that
provide access to InnoDB dictionary tables.
dict_sys.lock(), dict_sys_lock(): Acquire both mutex and latch.
dict_sys.unlock(), dict_sys_unlock(): Release both mutex and latch.
dict_sys.assert_locked(): Assert that both mutex and latch are held.
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().
In MySQL 5.7.8 an extra level of pointer indirection was added to
dict_operation_lock and some other rw_lock_t without solid justification,
in mysql/mysql-server@52720f1772.
Let us revert that change and remove the rather useless rw_lock_t
constructor and destructor and the magic_n field. In this way,
some unnecessary pointer dereferences and heap allocation will be avoided
and debugging might be a little easier.
Try to fix the race conditions between
SET GLOBAL innodb_ft_aux_table = ...;
and access to the INFORMATION_SCHEMA tables that depend on
this variable.
innodb_ft_aux_table: Replaces
fts_internal_tbl_name,fts_internal_tbl_name2. Just store the
user-specified parameter as is.
innodb_ft_aux_table_id: The table_id corresponding to
SET GLOBAL innodb_ft_aux_table, or 0 if the table does not exist
or does not contain FULLTEXT INDEX. If the table is renamed later,
the INFORMATION_SCHEMA tables will continue to refer to the table.
If the table is dropped or rebuilt, the INFORMATION_SCHEMA tables
will not find the table.
fts_get_table_name(): Output to a caller-allocated buffer.
fts_get_table_name_prefix(): Use the lower-overhead allocation
ut_malloc() instead of mem_alloc().
This is based on mysql/mysql-server@d1584b9f38
in MySQL 5.7.4.
For tablespaces that do not reside on spinning storage, it does
not make sense to attempt to write nearby pages when writing out
dirty pages from the InnoDB buffer pool. It is actually detrimental
to performance and to the life span of flash ROM storage.
With this change, MariaDB will detect whether an InnoDB file resides
on solid-state storage. The detection has been implemented for Linux
and Microsoft Windows. For other systems, we will err on the safe side
and assume that files reside on SSD.
As part of this change, we will reduce the number of fstat() calls
when opening data files on POSIX systems and slightly clean up some
file I/O code.
FIXME: os_is_sparse_file_supported() on POSIX works in a destructive
manner. Thus, we can only invoke it when creating files, not when
opening them.
For diagnostics, we introduce the column ON_SSD to the table
INFORMATION_SCHEMA.INNODB_TABLESPACES_SCRUBBING. The table
INNODB_SYS_TABLESPACES might seem more appropriate, but its purpose
is to reflect the contents of the InnoDB system table SYS_TABLESPACES,
which we would like to remove at some point.
On Microsoft Windows, querying StorageDeviceSeekPenaltyProperty
sometimes returns ERROR_GEN_FAILURE instead of ERROR_INVALID_FUNCTION
or ERROR_NOT_SUPPORTED. We will silently ignore also this error,
and assume that the file does not reside on SSD.
On Linux, the detection will be based on the files
/sys/block/*/queue/rotational and /sys/block/*/dev.
Especially for USB storage, it is possible that
/sys/block/*/queue/rotational will wrongly report 1 instead of 0.
fil_node_t::on_ssd: Whether the InnoDB data file resides on
solid-state storage.
fil_system_t::ssd: Collection of Linux block devices that reside on
non-rotational storage.
fil_system_t::create(): Detect ssd on Linux based on the contents
of /sys/block/*/queue/rotational and /sys/block/*/dev.
fil_system_t::is_ssd(dev_t): Determine if a Linux block device is
non-rotational. Partitions will be identified with the containing
block device by assuming that the least significant 4 bits of the
minor number identify a partition, and that the "partition number"
of the entire device is 0.
The MDEV-11738/MDEV-11581 fix was supposed to add the column
ROTATING_OR_FLUSHING to the INFORMATION_SCHEMA table
INNODB_TABLESPACES_ENCRYPTION, but it also added that column to
INNODB_TABLESPACES_SCRUBBING in InnoDB (not XtraDB).
The extra column was never initialized. We will remove it,
because key rotation has nothing to do with the scrubbing of
tablespace data.
MariaDB data-at-rest encryption (innodb_encrypt_tables)
had repurposed the same unused data field that was repurposed
in MySQL 5.7 (and MariaDB 10.2) for the Split Sequence Number (SSN)
field of SPATIAL INDEX. Because of this, MariaDB was unable to
support encryption on SPATIAL INDEX pages.
Furthermore, InnoDB page checksums skipped some bytes, and there
are multiple variations and checksum algorithms. By default,
InnoDB accepts all variations of all algorithms that ever existed.
This unnecessarily weakens the page checksums.
We hereby introduce two more innodb_checksum_algorithm variants
(full_crc32, strict_full_crc32) that are special in a way:
When either setting is active, newly created data files will
carry a flag (fil_space_t::full_crc32()) that indicates that
all pages of the file will use a full CRC-32C checksum over the
entire page contents (excluding the bytes where the checksum
is stored, at the very end of the page). Such files will always
use that checksum, no matter what the parameter
innodb_checksum_algorithm is assigned to.
For old files, the old checksum algorithms will continue to be
used. The value strict_full_crc32 will be equivalent to strict_crc32
and the value full_crc32 will be equivalent to crc32.
ROW_FORMAT=COMPRESSED tables will only use the old format.
These tables do not support new features, such as larger
innodb_page_size or instant ADD/DROP COLUMN. They may be
deprecated in the future. We do not want an unnecessary
file format change for them.
The new full_crc32() format also cleans up the MariaDB tablespace
flags. We will reserve flags to store the page_compressed
compression algorithm, and to store the compressed payload length,
so that checksum can be computed over the compressed (and
possibly encrypted) stream and can be validated without
decrypting or decompressing the page.
In the full_crc32 format, there no longer are separate before-encryption
and after-encryption checksums for pages. The single checksum is
computed on the page contents that is written to the file.
We do not make the new algorithm the default for two reasons.
First, MariaDB 10.4.2 was a beta release, and the default values
of parameters should not change after beta. Second, we did not
yet implement the full_crc32 format for page_compressed pages.
This will be fixed in MDEV-18644.
This is joint work with Marko Mäkelä.
MySQL 5.7 introduced the class page_size_t and increased the size of
buffer pool page descriptors by introducing this object to them.
Maybe the intention of this exercise was to prepare for a future
where the buffer pool could accommodate multiple page sizes.
But that future never arrived, not even in MySQL 8.0. It is much
easier to manage a pool of a single page size, and typically all
storage devices of an InnoDB instance benefit from using the same
page size.
Let us remove page_size_t from MariaDB Server. This will make it
easier to remove support for ROW_FORMAT=COMPRESSED (or make it a
compile-time option) in the future, just by removing various
occurrences of zip_size.
