Problem:
=======
- Redundant table fails to insert into the table after
instant drop blob column. Instant drop column only marking
the column as hidden and consecutive insert statement tries
to insert NULL value for the dropped BLOB column and returns
the fixed length of the blob type as 65535. This lead to
row size too large error.
Fix:
====
For redundant table, if the non-fixed dropped column can be null
then set the length of the field type as 0.
- InnoDB fails to set the index information or index number
for the spatial index error HA_ERR_NULL_IN_SPATIAL.
row_build_spatial_index_key(): Initialize the tmp_mbr array completely.
check_if_supported_inplace_alter(): Fix the spelling mistake of alter
This also fixes part of MDEV-29835 Partial server freeze
which is caused by violations of the latching order that was
defined in https://dev.mysql.com/worklog/task/?id=6326
(WL#6326: InnoDB: fix index->lock contention). Unless the
current thread is holding an exclusive dict_index_t::lock,
it must acquire page latches in a strict parent-to-child,
left-to-right order. Not all cases of MDEV-29835 are fixed yet.
Failure to follow the correct latching order will cause deadlocks
of threads due to lock order inversion.
As part of these changes, the BTR_MODIFY_TREE mode is modified
so that an Update latch (U a.k.a. SX) will be acquired on the
root page, and eXclusive latches (X) will be acquired on all pages
leading to the leaf page, as well as any left and right siblings
of the pages along the path. The DEBUG_SYNC test innodb.innodb_wl6326
will be removed, because at the time the DEBUG_SYNC point is hit,
the thread is actually holding several page latches that will be
blocking a concurrent SELECT statement.
We also remove double bookkeeping that was caused due to excessive
information hiding in mtr_t::m_memo. We simply let mtr_t::m_memo
store information of latched pages, and ensure that
mtr_memo_slot_t::object is never a null pointer.
The tree_blocks[] and tree_savepoints[] were redundant.
buf_page_get_low(): If innodb_change_buffering_debug=1, to avoid
a hang, do not try to evict blocks if we are holding a latch on
a modified page. The test innodb.innodb-change-buffer-recovery
will be removed, because change buffering may no longer be forced
by debug injection when the change buffer comprises multiple pages.
Remove a debug assertion that could fail when
innodb_change_buffering_debug=1 fails to evict a page.
For other cases, the assertion is redundant, because we already
checked that right after the got_block: label. The test
innodb.innodb-change-buffering-recovery will be removed, because
due to this change, we will be unable to evict the desired page.
mtr_t::lock_register(): Register a change of a page latch
on an unmodified buffer-fixed block.
mtr_t::x_latch_at_savepoint(), mtr_t::sx_latch_at_savepoint():
Replaced by the use of mtr_t::upgrade_buffer_fix(), which now
also handles RW_S_LATCH.
mtr_t::set_modified(): For temporary tables, invoke
buf_page_t::set_modified() here and not in mtr_t::commit().
We will never set the MTR_MEMO_MODIFY flag on other than
persistent data pages, nor set mtr_t::m_modifications when
temporary data pages are modified.
mtr_t::commit(): Only invoke the buf_flush_note_modification() loop
if persistent data pages were modified.
mtr_t::get_already_latched(): Look up a latched page in mtr_t::m_memo.
This avoids many redundant entries in mtr_t::m_memo, as well as
redundant calls to buf_page_get_gen() for blocks that had already
been looked up in a mini-transaction.
btr_get_latched_root(): Return a pointer to an already latched root page.
This replaces btr_root_block_get() in cases where the mini-transaction
has already latched the root page.
btr_page_get_parent(): Fetch a parent page that was already latched
in BTR_MODIFY_TREE, by invoking mtr_t::get_already_latched().
If needed, upgrade the root page U latch to X.
This avoids bloating mtr_t::m_memo as well as performing redundant
buf_pool.page_hash lookups. For non-QUICK CHECK TABLE as well as for
B-tree defragmentation, we will invoke btr_cur_search_to_nth_level().
btr_cur_search_to_nth_level(): This will only be used for non-leaf
(level>0) B-tree searches that were formerly named BTR_CONT_SEARCH_TREE
or BTR_CONT_MODIFY_TREE. In MDEV-29835, this function could be
removed altogether, or retained for the case of
CHECK TABLE without QUICK.
btr_cur_t::left_block: Remove. btr_pcur_move_backward_from_page()
can retrieve the left sibling from the end of mtr_t::m_memo.
btr_cur_t::open_leaf(): Some clean-up.
btr_cur_t::search_leaf(): Replaces btr_cur_search_to_nth_level()
for searches to level=0 (the leaf level). We will never release
parent page latches before acquiring leaf page latches. If we need to
temporarily release the level=1 page latch in the BTR_SEARCH_PREV or
BTR_MODIFY_PREV latch_mode, we will reposition the cursor on the
child node pointer so that we will land on the correct leaf page.
btr_cur_t::pessimistic_search_leaf(): Implement new BTR_MODIFY_TREE
latching logic in the case that page splits or merges will be needed.
The parent pages (and their siblings) should already be latched on
the first dive to the leaf and be present in mtr_t::m_memo; there
should be no need for BTR_CONT_MODIFY_TREE. This pre-latching almost
suffices; it must be revised in MDEV-29835 and work-arounds removed
for cases where mtr_t::get_already_latched() fails to find a block.
rtr_search_to_nth_level(): A SPATIAL INDEX version of
btr_search_to_nth_level() that can search to any level
(including the leaf level).
rtr_search_leaf(), rtr_insert_leaf(): Wrappers for
rtr_search_to_nth_level().
rtr_search(): Replaces rtr_pcur_open().
rtr_latch_leaves(): Replaces btr_cur_latch_leaves(). Note that unlike
in the B-tree code, there is no error handling in case the sibling
pages are corrupted.
rtr_cur_restore_position(): Remove an unused constant parameter.
btr_pcur_open_on_user_rec(): Remove the constant parameter
mode=PAGE_CUR_GE.
row_ins_clust_index_entry_low(): Use a new
mode=BTR_MODIFY_ROOT_AND_LEAF to gain access to the root page
when mode!=BTR_MODIFY_TREE, to write the PAGE_ROOT_AUTO_INC.
BTR_SEARCH_TREE, BTR_CONT_SEARCH_TREE: Remove.
BTR_CONT_MODIFY_TREE: Note that this is only used by
rtr_search_to_nth_level().
btr_pcur_optimistic_latch_leaves(): Replaces
btr_cur_optimistic_latch_leaves().
ibuf_delete_rec(): Acquire exclusive ibuf.index->lock in order
to avoid a deadlock with ibuf_insert_low(BTR_MODIFY_PREV).
btr_blob_log_check_t(): Acquire a U latch on the root page,
so that btr_page_alloc() in btr_store_big_rec_extern_fields()
will avoid a deadlock.
btr_store_big_rec_extern_fields(): Assert that the root page latch
is being held.
Tested by: Matthias Leich
Reviewed by: Vladislav Lesin
This also fixes part of MDEV-29835 Partial server freeze
which is caused by violations of the latching order that was
defined in https://dev.mysql.com/worklog/task/?id=6326
(WL#6326: InnoDB: fix index->lock contention). Unless the
current thread is holding an exclusive dict_index_t::lock,
it must acquire page latches in a strict parent-to-child,
left-to-right order. Not all cases are fixed yet. Failure to
follow the correct latching order will cause deadlocks of threads
due to lock order inversion.
As part of these changes, the BTR_MODIFY_TREE mode is modified
so that an Update latch (U a.k.a. SX) will be acquired on the
root page, and eXclusive latches (X) will be acquired on all pages
leading to the leaf page, as well as any left and right siblings
of the pages along the path. The test innodb.innodb_wl6326
will be removed, because at the time the DEBUG_SYNC point is hit,
the thread is actually holding several page latches that will be
blocking a concurrent SELECT statement.
We also remove double bookkeeping that was caused due to excessive
information hiding in mtr_t::m_memo. We simply let mtr_t::m_memo
store information of latched pages, and ensure that
mtr_memo_slot_t::object is never a null pointer.
The tree_blocks[] and tree_savepoints[] were redundant.
mtr_t::get_already_latched(): Look up a latched page in mtr_t::m_memo.
This avoids many redundant entries in mtr_t::m_memo, as well as
redundant calls to buf_page_get_gen() for blocks that had already
been looked up in a mini-transaction.
btr_get_latched_root(): Return a pointer to an already latched root page.
This replaces btr_root_block_get() in cases where the mini-transaction
has already latched the root page.
btr_page_get_parent(): Fetch a parent page that was already latched
in BTR_MODIFY_TREE, by invoking mtr_t::get_already_latched().
If needed, upgrade the root page U latch to X.
This avoids bloating mtr_t::m_memo as well as redundant
buf_pool.page_hash lookups. For non-QUICK CHECK TABLE as well as for
B-tree defragmentation, we will invoke btr_cur_search_to_nth_level().
btr_cur_search_to_nth_level(): This will only be used for non-leaf
(level>0) B-tree searches that were formerly named BTR_CONT_SEARCH_TREE
or BTR_CONT_MODIFY_TREE. In MDEV-29835, this function could be
removed altogether, or retained for the case of
CHECK TABLE without QUICK.
btr_cur_t::search_leaf(): Replaces btr_cur_search_to_nth_level()
for searches to level=0 (the leaf level).
btr_cur_t::pessimistic_search_leaf(): Implement the new
BTR_MODIFY_TREE latching logic in the case that page splits
or merges will be needed. The parent pages (and their siblings)
should already be latched on the first dive to the leaf and be
present in mtr_t::m_memo; there should be no need for
BTR_CONT_MODIFY_TREE. This pre-latching almost suffices;
MDEV-29835 will have to revise it and remove work-arounds where
mtr_t::get_already_latched() fails to find a block.
rtr_search_to_nth_level(): A SPATIAL INDEX version of
btr_search_to_nth_level() that can search to any level
(including the leaf level).
rtr_search_leaf(), rtr_insert_leaf(): Wrappers for
rtr_search_to_nth_level().
rtr_search(): Replaces rtr_pcur_open().
rtr_cur_restore_position(): Remove an unused constant parameter.
btr_pcur_open_on_user_rec(): Remove the constant parameter
mode=PAGE_CUR_GE.
btr_cur_latch_leaves(): Update a pre-existing mtr_t::m_memo entry
for the current leaf page.
row_ins_clust_index_entry_low(): Use a new
mode=BTR_MODIFY_ROOT_AND_LEAF to gain access to the root page
when mode!=BTR_MODIFY_TREE, to write the PAGE_ROOT_AUTO_INC.
btr_cur_t::open_leaf(): Some clean-up.
mtr_t::lock_register(): Register a page latch on a buffer-fixed block.
BTR_SEARCH_TREE, BTR_CONT_SEARCH_TREE: Remove.
BTR_CONT_MODIFY_TREE: Note that this is only used by
rtr_search_to_nth_level().
btr_pcur_optimistic_latch_leaves(): Replaces
btr_cur_optimistic_latch_leaves().
ibuf_delete_rec(): Acquire ibuf.index->lock.u_lock() in order
to avoid a deadlock with ibuf_insert_low(BTR_MODIFY_PREV).
Tested by: Matthias Leich
The purpose of the change buffer was to reduce random disk access,
which could be useful on rotational storage, but maybe less so on
solid-state storage.
When we wished to
(1) insert a record into a non-unique secondary index,
(2) delete-mark a secondary index record,
(3) delete a secondary index record as part of purge (but not ROLLBACK),
and the B-tree leaf page where the record belongs to is not in the buffer
pool, we inserted a record into the change buffer B-tree, indexed by
the page identifier. When the page was eventually read into the buffer
pool, we looked up the change buffer B-tree for any modifications to the
page, applied these upon the completion of the read operation. This
was called the insert buffer merge.
We remove the change buffer, because it has been the source of
various hard-to-reproduce corruption bugs, including those fixed in
commit 5b9ee8d819 and
commit 165564d3c3 but not limited to them.
A downgrade will fail with a clear message starting with
commit db14eb16f9 (MDEV-30106).
buf_page_t::state: Merge IBUF_EXIST to UNFIXED and
WRITE_FIX_IBUF to WRITE_FIX.
buf_pool_t::watch[]: Remove.
trx_t: Move isolation_level, check_foreigns, check_unique_secondary,
bulk_insert into the same bit-field. The only purpose of
trx_t::check_unique_secondary is to enable bulk insert into an
empty table. It no longer enables insert buffering for UNIQUE INDEX.
btr_cur_t::thr: Remove. This field was originally needed for change
buffering. Later, its use was extended to cover SPATIAL INDEX.
Much of the time, rtr_info::thr holds this field. When it does not,
we will add parameters to SPATIAL INDEX specific functions.
ibuf_upgrade_needed(): Check if the change buffer needs to be updated.
ibuf_upgrade(): Merge and upgrade the change buffer after all redo log
has been applied. Free any pages consumed by the change buffer, and
zero out the change buffer root page to mark the upgrade completed,
and to prevent a downgrade to an earlier version.
dict_load_tablespaces(): Renamed from
dict_check_tablespaces_and_store_max_id(). This needs to be invoked
before ibuf_upgrade().
btr_cur_open_at_rnd_pos(): Specialize for use in persistent statistics.
The change buffer merge does not need this function anymore.
btr_page_alloc(): Renamed from btr_page_alloc_low(). We no longer
allocate any change buffer pages.
btr_cur_open_at_rnd_pos(): Specialize for use in persistent statistics.
The change buffer merge does not need this function anymore.
row_search_index_entry(), btr_lift_page_up(): Add a parameter thr
for the SPATIAL INDEX case.
rtr_page_split_and_insert(): Specialized from btr_page_split_and_insert().
rtr_root_raise_and_insert(): Specialized from btr_root_raise_and_insert().
Note: The support for upgrading from the MySQL 3.23 or MySQL 4.0
change buffer format that predates the MySQL 4.1 introduction of
the option innodb_file_per_table was removed in MySQL 5.6.5
as part of mysql/mysql-server@69b6241a79
and MariaDB 10.0.11 as part of 1d0f70c2f8.
In the tests innodb.log_upgrade and innodb.log_corruption, we create
valid (upgraded) change buffer pages.
Tested by: Matthias Leich
btr_cur_t: Zero-initialize all fields in the default constructor.
btr_cur_t::index: Remove; it duplicated page_cur.index.
Many functions: Remove arguments that were duplicating
page_cur_t::index and page_cur_t::block.
page_cur_open_level(), btr_pcur_open_level(): Replaces
btr_cur_open_at_index_side() for dict_stats_analyze_index().
At the end, release all latches except the dict_index_t::lock
and the buf_page_t::lock on the requested page.
dict_stats_analyze_index(): Rely on mtr_t::rollback_to_savepoint()
to release all uninteresting page latches.
btr_search_guess_on_hash(): Simplify the logic, and invoke
mtr_t::rollback_to_savepoint().
We will use plain C++ std::vector<mtr_memo_slot_t> for mtr_t::m_memo.
In this way, we can avoid setting mtr_memo_slot_t::object to nullptr
and instead just remove garbage from m_memo.
mtr_t::rollback_to_savepoint(): Shrink the vector. We will be needing this
in dict_stats_analyze_index(), where we will release page latches and
only retain the index->lock in mtr_t::m_memo.
mtr_t::release_last_page(): Release the last acquired page latch.
Replaces btr_leaf_page_release().
mtr_t::release(const buf_block_t&): Release a single page latch.
Used in btr_pcur_move_backward_from_page().
mtr_t::memo_release(): Replaced with mtr_t::release().
mtr_t::upgrade_buffer_fix(): Acquire a latch for a buffer-fixed page.
This replaces the double bookkeeping in btr_cur_t::open_leaf().
Reviewed by: Vladislav Lesin
btr_cur_t::open_leaf(): Replaces btr_cur_open_at_index_side() for
most calls, except dict_stats_analyze_index(), which is the only
place where we need to open a page at the non-leaf level.
Use btr_block_get() for better error handling.
Also, use the enumeration type btr_latch_mode wherever possible.
Reviewed by: Vladislav Lesin
The approach to handling corruption that was chosen by Oracle in
commit 177d8b0c12
is not really useful. Not only did it actually fail to prevent InnoDB
from crashing, but it is making things worse by blocking attempts to
rescue data from or rebuild a partially readable table.
We will try to prevent crashes in a different way: by propagating
errors up the call stack. We will never mark the clustered index
persistently corrupted, so that data recovery may be attempted by
reading from the table, or by rebuilding the table.
This should also fix MDEV-13680 (crash on btr_page_alloc() failure);
it was extensively tested with innodb_file_per_table=0 and a
non-autoextend system tablespace.
We should now avoid crashes in many cases, such as when a page
cannot be read or allocated, or an inconsistency is detected when
attempting to update multiple pages. We will not crash on double-free,
such as on the recovery of DDL in system tablespace in case something
was corrupted.
Crashes on corrupted data are still possible. The fault injection mechanism
that is introduced in the subsequent commit may help catch more of them.
buf_page_import_corrupt_failure: Remove the fault injection, and instead
corrupt some pages using Perl code in the tests.
btr_cur_pessimistic_insert(): Always reserve extents (except for the
change buffer), in order to prevent a subsequent allocation failure.
btr_pcur_open_at_rnd_pos(): Merged to the only caller ibuf_merge_pages().
btr_assert_not_corrupted(), btr_corruption_report(): Remove.
Similar checks are already part of btr_block_get().
FSEG_MAGIC_N_BYTES: Replaces FSEG_MAGIC_N_VALUE.
dict_hdr_get(), trx_rsegf_get_new(), trx_undo_page_get(),
trx_undo_page_get_s_latched(): Replaced with error-checking calls.
trx_rseg_t::get(mtr_t*): Replaces trx_rsegf_get().
trx_rseg_header_create(): Let the caller update the TRX_SYS page if needed.
trx_sys_create_sys_pages(): Merged with trx_sysf_create().
dict_check_tablespaces_and_store_max_id(): Do not access
DICT_HDR_MAX_SPACE_ID, because it was already recovered in dict_boot().
Merge dict_check_sys_tables() with this function.
dir_pathname(): Replaces os_file_make_new_pathname().
row_undo_ins_remove_sec(): Do not modify the undo page by adding
a terminating NUL byte to the record.
btr_decryption_failed(): Report decryption failures
dict_set_corrupted_by_space(), dict_set_encrypted_by_space(),
dict_set_corrupted_index_cache_only(): Remove.
dict_set_corrupted(): Remove the constant parameter dict_locked=false.
Never flag the clustered index corrupted in SYS_INDEXES, because
that would deny further access to the table. It might be possible to
repair the table by executing ALTER TABLE or OPTIMIZE TABLE, in case
no B-tree leaf page is corrupted.
dict_table_skip_corrupt_index(), dict_table_next_uncorrupted_index(),
row_purge_skip_uncommitted_virtual_index(): Remove, and refactor
the callers to read dict_index_t::type only once.
dict_table_is_corrupted(): Remove.
dict_index_t::is_btree(): Determine if the index is a valid B-tree.
BUF_GET_NO_LATCH, BUF_EVICT_IF_IN_POOL: Remove.
UNIV_BTR_DEBUG: Remove. Any inconsistency will no longer trigger
assertion failures, but error codes being returned.
buf_corrupt_page_release(): Replaced with a direct call to
buf_pool.corrupted_evict().
fil_invalid_page_access_msg(): Never crash on an invalid read;
let the caller of buf_page_get_gen() decide.
btr_pcur_t::restore_position(): Propagate failure status to the caller
by returning CORRUPTED.
opt_search_plan_for_table(): Simplify the code.
row_purge_del_mark(), row_purge_upd_exist_or_extern_func(),
row_undo_ins_remove_sec_rec(), row_undo_mod_upd_del_sec(),
row_undo_mod_del_mark_sec(): Avoid mem_heap_create()/mem_heap_free()
when no secondary indexes exist.
row_undo_mod_upd_exist_sec(): Simplify the code.
row_upd_clust_step(), dict_load_table_one(): Return DB_TABLE_CORRUPT
if the clustered index (and therefore the table) is corrupted, similar
to what we do in row_insert_for_mysql().
fut_get_ptr(): Replace with buf_page_get_gen() calls.
buf_page_get_gen(): Return nullptr and *err=DB_CORRUPTION
if the page is marked as freed. For other modes than
BUF_GET_POSSIBLY_FREED or BUF_PEEK_IF_IN_POOL this will
trigger a debug assertion failure. For BUF_GET_POSSIBLY_FREED,
we will return nullptr for freed pages, so that the callers
can be simplified. The purge of transaction history will be
a new user of BUF_GET_POSSIBLY_FREED, to avoid crashes on
corrupted data.
buf_page_get_low(): Never crash on a corrupted page, but simply
return nullptr.
fseg_page_is_allocated(): Replaces fseg_page_is_free().
fts_drop_common_tables(): Return an error if the transaction
was rolled back.
fil_space_t::set_corrupted(): Report a tablespace as corrupted if
it was not reported already.
fil_space_t::io(): Invoke fil_space_t::set_corrupted() to report
out-of-bounds page access or other errors.
Clean up mtr_t::page_lock()
buf_page_get_low(): Validate the page identifier (to check for
recently read corrupted pages) after acquiring the page latch.
buf_page_t::read_complete(): Flag uninitialized (all-zero) pages
with DB_FAIL. Return DB_PAGE_CORRUPTED on page number mismatch.
mtr_t::defer_drop_ahi(): Renamed from mtr_defer_drop_ahi().
recv_sys_t::free_corrupted_page(): Only set_corrupt_fs()
if any log records exist for the page. We do not mind if read-ahead
produces corrupted (or all-zero) pages that were not actually needed
during recovery.
recv_recover_page(): Return whether the operation succeeded.
recv_sys_t::recover_low(): Simplify the logic. Check for recovery error.
Thanks to Matthias Leich for testing this extensively and to the
authors of https://rr-project.org for making it easy to diagnose
and fix any failures that were found during the testing.
The types btr_latch_mode and mtr_memo_type_t are partly derived from
rw_lock_type_t. Despite that, some code for converting between them
is using conditions instead of bitwise arithmetics.
Let us define btr_latch_mode in such a way that more conversions to
rw_lock_type_t are possible by bitwise and.
Some SPATIAL INDEX code that assumed !(BTR_MODIFY_TREE & BTR_MODIFY_LEAF)
was adjusted.
The function btr_pcur_close() is being invoked on local variables
even when no cleanup needs to be done. In particular, for B-tree
indexes (not SPATIAL INDEX), unless btr_pcur_store_position()
was invoked in the past, there is no need to invoke btr_pcur_close().
On purge and rollback, we will retain btr_pcur_close(&pcur)
because otherwise some ./mtr --suite=innodb_gis tests would leak memory.
This also fixes MDEV-20198: Instant ALTER TABLE is not crash safe
InnoDB dictionary recovery wrongly used the READ UNCOMMITTED isolation
level, causing some mismatch. For example, if a table was renamed or
replaced in a transaction, according to READ UNCOMMITTED the table might
not exist at all.
We implement READ COMMITTED isolation level for accessing the dictionary
tables SYS_TABLES, SYS_COLUMNS, SYS_INDEXES, SYS_FIELDS, SYS_VIRTUAL,
SYS_FOREIGN, SYS_FOREIGN_COLS. For most of these tables, no secondary
index exists. For the secondary indexes (on SYS_TABLES.ID,
SYS_FOREIGN.FOR_NAME, SYS_FOREIGN.REF_NAME), we will always look up
the primary key in the clustered index and check if the record actually
is a committed version.
dict_check_sys_tables(): Recover tablespaces also from delete-marked
committed records, so that if a matching .ibd file exists, it will
be removed by fil_delete_tablespace() when the committed delete-marked
SYS_INDEXES record of the clustered index is purged
in row_purge_remove_clust_if_poss_low().
fil_ibd_open(): Change the Boolean parameter "validate" to a ternary
one, to suppress error messages when the file might not exist.
It is possible that a .ibd file was deleted and the server shut down
before the SYS_INDEXES and SYS_TABLES records were purged. Hence, if
dict_check_sys_tables() finds a committed delete-marked record,
we must not complain if the tablespace file is not found.
On Windows, we msut treat ERROR_PATH_NOT_FOUND (directory not found)
in the same way as ERROR_FILE_NOT_FOUND. This fixes a few failures where
a previous test successfully executed DROP DATABASE (and deleted all
files and the directory), but a committed delete-marked SYS_TABLES
record had not been purged before server restart.
dict_getnext_system_low(): Do not filter out delete-marked records.
dict_startscan_system(), dict_getnext_system(): Do filter out
delete-marked records, for accessing the INFORMATION_SCHEMA tables.
dict_sys_tables_rec_read(): Return the DB_TRX_ID of the committed
version of the record. This is needed in dict_load_table_low().
dict_load_foreign_cols(), dict_load_foreign(): Add a parameter for
the current transaction identifier. In some DDL operations, the
FOREIGN KEY constraints are being loaded from the data dictionary
before the DDL transaction has been committed. For SYS_FOREIGN
and SYS_FOREIGN_COLS, we must implement the special case of
READ COMMITTED that the changes of the uncommitted current transaction
are visible.
dict_load_foreign(): Validate the table name. We could find a
SYS_FOREIGN.ID via a committed delete-marked secondary index record
that does not match the REF_NAME or FOR_NAME of the secondary index record.
dict_load_index_low(): Optionally take the table as a parameter,
so that table->def_trx_id can be updated in case of a
committed delete-marked SYS_INDEXES record corresponding
to DROP INDEX, but not corresponding to an index stub of ADD INDEX.
dict_load_indexes(): Do not update table->def_trx_id
in case of delete-marked records.
rec_is_metadata(), rec_offs_make_valid(), rec_get_offsets_func(),
row_build_low(): Relax some assertions. We may now have
!index->is_instant() even if a metadata record is present in the index.
Previously, the recovery of instant ADD/DROP COLUMN assumed
that READ UNCOMMITTED of the data dictionary will be performed.
Now, we will have a READ COMMITTED copy of the data dictionary
cache, and a READ UNCOMMITTED copy of the metadata record.
btr_page_reorganize_low(): Correctly update the FIL_PAGE_TYPE
when rolling back an instant ADD/DROP COLUMN operation.
row_rec_to_index_entry_impl(): Relax some assertions,
and disallow accessing "extra" fields. This fixes the recovery
of a crash during an instant ADD COLUMN after a successful
instant DROP COLUMN, in the test innodb.instant_alter_crash.
Tested by: Matthias Leich
Between btr_pcur_store_position() and btr_pcur_restore_position()
it is possible that purge empties a table and enlarges
index->n_core_fields and index->n_core_null_bytes.
Therefore, we must cache index->n_core_fields in
btr_pcur_t::old_n_core_fields so that btr_pcur_t::old_rec can be
parsed correctly.
Unfortunately, this is a huge change, because we will replace
"bool leaf" parameters with "ulint n_core"
(passing index->n_core_fields, or 0 for non-leaf pages).
For special cases where we know that index->is_instant() cannot hold,
we may also pass index->n_fields.
First part (row0mysql.cc) fixes ins_node_set_new_row() usage workflow
as it is designed to operate on empty row (see row_get_prebuilt_insert_row()
for example).
Second part (row0ins.cc) fixes duplicate key error in FTS_DOC_ID_INDEX
since history rows must not generate entries in that index. We detect
FTS_DOC_ID_INDEX by a number of attributes and skip it if the row is
historical.
Misc fixes:
row_build_index_entry_low() does not accept non-NULL tuple
for FTS index (subject assertion fails), assertion (index->type !=
DICT_FTS) adds code understanding.
Now as historical_row is copied in row_update_vers_insert() there is
no need to copy the row twice: ROW_COPY_POINTERS is used to build
historical_row initially.
dbug_print_rec() debug functions.
This was the last abuse of trx_sys.mutex, which is now exclusively
protecting trx_sys.trx_list.
This global acquisition was also potential scalability bottleneck for
oltp_read_write benchmark. Although it didn't expose itself as such due
to larger scalability issues.
Replaced trx_sys.mutex based synchronisation between ReadView creator
thread and purge coordinator thread performing latest view clone with
ReadView::m_mutex.
It also allowed to simplify tri-state view m_state down to boolean
m_open flag.
For performance reasons trx->read_view.close() is left as atomic relaxed
store, so that we don't have to waste resources for otherwise meaningless
mutex acquisition.
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).
Now that we will be invoking dtuple_get_n_ext() instead of
letting btr_push_update_extern_fields() update an already
calculated value, it is unnecessary to calculate the n_ext
upfront.
row_rec_to_index_entry(), row_rec_to_index_entry_low():
Remove the output parameter n_ext.
offset_t: this is a type which represents one record offset.
It's unsigned short int.
a lot of functions: replace ulint with offset_t
btr_pcur_restore_position_func(),
page_validate(),
row_ins_scan_sec_index_for_duplicate(),
row_upd_clust_rec_by_insert_inherit_func(),
row_vers_impl_x_locked_low(),
trx_undo_prev_version_build():
allocate record offsets on the stack instead of waiting for rec_get_offsets()
to allocate it from mem_heap_t. So, reducing memory allocations.
RECORD_OFFSET, INDEX_OFFSET:
now it's less convenient to store pointers in offset_t*
array. One pointer occupies now several offset_t. And those constant are start
indexes into array to places where to store pointer values
REC_OFFS_HEADER_SIZE: adjusted for the new reality
REC_OFFS_NORMAL_SIZE:
increase size from 100 to 300 which means less heap allocations.
And sizeof(offset_t[REC_OFFS_NORMAL_SIZE]) now is 600 bytes which
is smaller than previous 800 bytes.
REC_OFFS_SEC_INDEX_SIZE: adjusted for the new reality
rem0rec.h, rem0rec.ic, rem0rec.cc:
various arguments, return values and local variables types were changed to
fix numerous integer conversions issues.
enum field_type_t:
offset types concept was introduces which replaces old offset flags stuff.
Like in earlier version, 2 upper bits are used to store offset type.
And this enum represents those types.
REC_OFFS_SQL_NULL, REC_OFFS_MASK: removed
get_type(), set_type(), get_value(), combine():
these are convenience functions to work with offsets and it's types
rec_offs_base()[0]:
still uses an old scheme with flags REC_OFFS_COMPACT and REC_OFFS_EXTERNAL
rec_offs_base()[i]:
these have type offset_t now. Two upper bits contains type.
Problem:
=========
One of the purge thread access the corrupted page and tries to remove from
LRU list. In the mean time, other purge threads are waiting for same page
in buf_wait_for_read(). Assertion(buf_fix_count == 0) fails for the
purge thread which tries to remove the page from LRU list.
Solution:
========
- Set the page id as FIL_NULL to indicate the page is corrupted before
removing the block from LRU list. Acquire hash lock for the particular
page id and wait for the other threads to release buf_fix_count
for the block.
- Added the error check for btr_cur_open() in row_search_on_row_ref().
row_build_spatial_index_key(): Return early if the column is missing
in the table row tuple.
This is a regression that was introduced by
commit 0e5a4ac253.
