Problem:
=======
ALTER TABLE in InnoDB fails to detect duplicate entries
for the unique index when the character set or collation of
an indexed column is changed in such a way that the character
encoding is compatible with the old table definition.
In this case, any secondary indexes on the changed columns
would be rebuilt (DROP INDEX, ADD INDEX).
Solution:
========
During ALTER TABLE, InnoDB keeps track of columns whose collation
changed, and will fill in the correct metadata when sorting the
index records, or applying changes from concurrent DML.
This metadata will be allocated in the dict_index_t::heap of
the being-created secondary indexes.
The fix was developed by Thirunarayanan Balathandayuthapani
and simplified by me.
In commit 1bd681c8b3 (MDEV-25506 part 3)
we introduced a "fake instant timeout" when a transaction would wait
for a table or record lock while holding dict_sys.latch. This prevented
a deadlock of the server but could cause bogus errors for operations
on the InnoDB persistent statistics tables.
A better fix is to ensure that whenever a transaction is being
executed in the InnoDB internal SQL parser (which will for now
require dict_sys.latch to be held), it will already have acquired
all locks that could be required for the execution. So, we will
acquire the following locks upfront, before acquiring dict_sys.latch:
(1) MDL on the affected user table (acquired by the SQL layer)
(2) If applicable (not for RENAME TABLE): InnoDB table lock
(3) If persistent statistics are going to be modified:
(3.a) MDL_SHARED on mysql.innodb_table_stats, mysql.innodb_index_stats
(3.b) exclusive table locks on the statistics tables
(4) Exclusive table locks on the InnoDB data dictionary tables
(not needed in ANALYZE TABLE and the like)
Note: Acquiring exclusive locks on the statistics tables may cause
more locking conflicts between concurrent DDL operations.
Notably, RENAME TABLE will lock the statistics tables
even if no persistent statistics are enabled for the table.
DROP DATABASE will only acquire locks on statistics tables if
persistent statistics are enabled for the tables on which the
SQL layer is invoking ha_innobase::delete_table().
For any "garbage collection" in innodb_drop_database(), a timeout
while acquiring locks on the statistics tables will result in any
statistics not being deleted for any tables that the SQL layer
did not know about.
If innodb_defragment=ON, information may be written to the statistics
tables even for tables for which InnoDB persistent statistics are
disabled. But, DROP TABLE will no longer attempt to delete that
information if persistent statistics are not enabled for the table.
This change should also fix the hangs related to InnoDB persistent
statistics and STATS_AUTO_RECALC (MDEV-15020) as well as
a bug that running ALTER TABLE on the statistics tables
concurrently with running ALTER TABLE on InnoDB tables could
cause trouble.
lock_rec_enqueue_waiting(), lock_table_enqueue_waiting():
Do not issue a fake instant timeout error when the transaction
is holding dict_sys.latch. Instead, assert that the dict_sys.latch
is never being held here.
lock_sys_tables(): A new function to acquire exclusive locks on all
dictionary tables, in case DROP TABLE or similar operation is
being executed. Locking non-hard-coded tables is optional to avoid
a crash in row_merge_drop_temp_indexes(). The SYS_VIRTUAL table was
introduced in MySQL 5.7 and MariaDB Server 10.2. Normally, we require
all these dictionary tables to exist before executing any DDL, but
the function row_merge_drop_temp_indexes() is an exception.
When upgrading from MariaDB Server 10.1 or MySQL 5.6 or earlier,
the table SYS_VIRTUAL would not exist at this point.
ha_innobase::commit_inplace_alter_table(): Invoke
log_write_up_to() while not holding dict_sys.latch.
dict_sys_t::remove(), dict_table_close(): No longer try to
drop index stubs that were left behind by aborted online ADD INDEX.
Such indexes should be dropped from the InnoDB data dictionary by
row_merge_drop_indexes() as part of the failed DDL operation.
Stubs for aborted indexes may only be left behind in the
data dictionary cache.
dict_stats_fetch_from_ps(): Use a normal read-only transaction.
ha_innobase::delete_table(), ha_innobase::truncate(), fts_lock_table():
While waiting for purge to stop using the table,
do not hold dict_sys.latch.
ha_innobase::delete_table(): Implement a work-around for the rollback
of ALTER TABLE...ADD PARTITION. MDL_EXCLUSIVE would not be held if
ALTER TABLE hits lock_wait_timeout while trying to upgrade the MDL
due to a conflicting LOCK TABLES, such as in the first ALTER TABLE
in the test case of Bug#53676 in parts.partition_special_innodb.
Therefore, we must explicitly stop purge, because it would not be
stopped by MDL.
dict_stats_func(), btr_defragment_chunk(): Allocate a THD so that
we can acquire MDL on the InnoDB persistent statistics tables.
mysqltest_embedded: Invoke ha_pre_shutdown() before free_used_memory()
in order to avoid ASAN heap-use-after-free related to acquire_thd().
trx_t::dict_operation_lock_mode: Changed the type to bool.
row_mysql_lock_data_dictionary(), row_mysql_unlock_data_dictionary():
Implemented as macros.
rollback_inplace_alter_table(): Apply an infinite timeout to lock waits.
innodb_thd_increment_pending_ops(): Wrapper for
thd_increment_pending_ops(). Never attempt async operation for
InnoDB background threads, such as the trx_t::commit() in
dict_stats_process_entry_from_recalc_pool().
lock_sys_t::cancel(trx_t*): Make dictionary transactions immune to KILL.
lock_wait(): Make dictionary transactions immune to KILL, and to
lock wait timeout when waiting for locks on dictionary tables.
parts.partition_special_innodb: Use lock_wait_timeout=0 to instantly
get ER_LOCK_WAIT_TIMEOUT.
main.mdl: Filter out MDL on InnoDB persistent statistics tables
Reviewed by: Thirunarayanan Balathandayuthapani
Back in 2006 or 2007, when MySQL AB and Innobase Oy existed as
separately controlled entities (Innobase had been acquired by
Oracle Corporation), MySQL 5.1 introduced a storage engine plugin
interface and Oracle made use of it by distributing a separate
InnoDB Plugin, which would contain some more bug fixes and
improvements, compared to the version of InnoDB that was statically
linked with the mysqld server that was distributed by MySQL AB.
The built-in InnoDB would export global symbols, which would clash
with the symbols of the dynamic InnoDB Plugin (which was supposed
to override the built-in one when present).
The solution to this problem was to declare all global symbols with
UNIV_INTERN, so that they would get the GCC function attribute that
specifies hidden visibility.
Later, in MariaDB Server, something based on Percona XtraDB (a fork of
MySQL InnoDB) became the statically linked implementation, and something
closer to MySQL InnoDB was available as a dynamic plugin. Starting with
version 10.2, MariaDB Server includes only one InnoDB implementation,
and hence any reason to have the UNIV_INTERN definition was lost.
btr_get_size_and_reserved(): Move to the same compilation unit with
the only caller.
innodb_set_buf_pool_size(): Remove. Modify innobase_buffer_pool_size
directly.
fil_crypt_calculate_checksum(): Merge to the only caller.
ha_innobase::innobase_reset_autoinc(): Merge to the only caller.
thd_query_start_micro(): Remove. Call thd_start_utime() directly.
Make DDL operations that involve FULLTEXT INDEX atomic.
In particular, we must drop the internal FTS_ tables in the same
DDL transaction with ALTER TABLE.
Remove all references to fts_drop_orphaned_tables().
row_merge_drop_temp_indexes(): Drop also the internal FTS_ tables
that are associated with index stubs that were created in
prepare_inplace_alter_table_dict() for
CREATE FULLTEXT INDEX before the server was killed.
fts_clear_all(): Remove the fts_drop_tables() call. It has to be
executed before the transaction is committed!
dict_load_indexes(): Do not load any metadata for index stubs
that had been created by prepare_inplace_alter_table_dict()
fts_create_one_common_table(), fts_create_common_tables(),
fts_create_one_index_table(), fts_create_index_tables():
Remove redundant error handling. The tables will be dropped
just fine by dict_drop_index_tree().
commit_try_norebuild(): Also drop the FTS_ tables when dropping
FULLTEXT INDEX.
The changes to the test case innodb_fts.crash_recovery has been
extensively tested. The non-debug server will be killed while
the 3 ALTER TABLE are in any phase of execution. With the debug
server, DEBUG_SYNC should make the test deterministic.
InnoDB used to support at most one CREATE TABLE or DROP TABLE
per transaction. This caused complications for DDL operations on
partitioned tables (where each partition is treated as a separate
table by InnoDB) and FULLTEXT INDEX (where each index is maintained
in a number of internal InnoDB tables).
dict_drop_index_tree(): Extend the MDEV-24589 logic and treat
the purge or rollback of SYS_INDEXES records of clustered indexes
specially: by dropping the tablespace if it exists. This is the only
form of recovery that we will need.
trx_undo_ddl_type: Document the DDL undo log record types better.
trx_t::dict_operation: Change the type to bool.
trx_t::ddl: Remove.
trx_t::table_id, trx_undo_t::table_id: Remove.
dict_build_table_def_step(): Remove trx_t::table_id logging.
dict_table_close_and_drop(), row_merge_drop_table(): Remove.
row_merge_lock_table(): Merged to the only callers, which can
call lock_table_for_trx() directly.
fts_aux_table_t, fts_aux_id, fts_space_set_t: Remove.
fts_drop_orphaned_tables(): Remove.
row_merge_rename_index_to_drop(): Remove. Thanks to MDEV-24589,
we can simply delete the to-be-dropped indexes from SYS_INDEXES,
while still being able to roll back the operation.
ha_innobase_inplace_ctx: Make a few data members const.
Preallocate trx.
prepare_inplace_alter_table_dict(): Simplify the logic. Let the
normal rollback take care of some cleanup.
row_undo_ins_remove_clust_rec(): Simplify the parsing of SYS_COLUMNS.
trx_rollback_active(): Remove the special DROP TABLE logic.
trx_undo_mem_create_at_db_start(), trx_undo_reuse_cached():
Always write TRX_UNDO_TABLE_ID as 0.
Problem:
========
InnoDB fails to clean the index stub if it fails to add the
virtual index which contains new virtual column. But it clears
the newly virtual column from index in clear_added_indexes()
during inplace_alter_table. On commit, InnoDB evicts and
reload the table. In case of rollback, it doesn't happen.
InnoDB clears the ABORTED index while opening the table
or doing the DDL. In the mean time, InnoDB can access
the dropped virtual index columns while creating prebuilt
or rollback of concurrent DML.
Solution:
==========
(1) InnoDB should maintain newly added virtual column while
rollbacking the newly added virtual index.
(2) InnoDB must not defer the index removal
if the alter table is executed with LOCK=EXCLUSIVE.
(3) For LOCK=SHARED, InnoDB should check whether the table
has any other transaction lock other than alter transaction
before deferring the index stub.
Replaced has_new_v_col with dict_add_vcol_info in dict_index_t to
indicate whether the index has any new virtual column.
dict_index_t::has_new_v_col(): Returns whether the index has
newly added virtual column, it doesn't say which columns are
newly added virtual column
ha_innobase_inplace_ctx::is_new_vcol(): Return whether the
given column is added as a part of the current alter.
ha_innobase_inplace_ctx::clean_new_vcol_index(): Copy the newly
added virtual column to new_vcol_info in dict_index_t. Replace
the column in the index fields with virtual column stored
in new_vcol_info.
dict_index_t::assign_new_v_col(): Store the number of virtual
column added in index as a part of alter table.
dict_index_t::get_n_new_vcol(): Get the number of newly added
virtual column
dict_index_t::assign_drop_v_col(): Allocate the memory for
adding new virtual column in new_vcol_info.
dict_index_t::add_drop_v_col(): Add the newly added virtual
column in new_vcol_info.
dict_table_t::has_lock_for_other_trx(): Whether the table has
any other transaction lock than given transaction.
row_merge_drop_indexes(): Add parameter alter_trx and check
whether the table has any other lock than alter transaction.
fil_delete_tablespace(): Remove the unused parameter drop_ahi,
and add the parameter if_exists=false. We want to suppress
error messages if we know that the tablespace has been discarded.
dict_table_rename_in_cache(): Pass the new parameter to
fil_delete_tablespace(), that is, do not complain about
missing tablespace if the tablespace has been discarded.
row_make_new_pathname(): Declare as static.
row_drop_table_for_mysql(): Tolerate !table->data_dir_path
when the tablespace has been discarded.
row_rename_table_for_mysql(): Skip part of the RENAME TABLE
when fil_space_get_first_path() returns NULL.
Simplify the logging of ALTER TABLE operations, by making use of the
TRX_UNDO_RENAME_TABLE undo log record that was introduced in
commit 0bc36758ba.
commit_try_rebuild(): Invoke row_rename_table_for_mysql() and
actually rename the files before committing the transaction.
fil_mtr_rename_log(), commit_cache_rebuild(),
log_append_on_checkpoint(), row_merge_rename_tables_dict(): Remove.
mtr_buf_copy_t, log_t::append_on_checkpoint: Remove.
row_rename_table_for_mysql(): If !use_fk, ignore missing foreign
keys. Remove a call to dict_table_rename_in_cache(), because
trx_rollback_to_savepoint() should invoke the function if needed.
During native table rebuild or index creation, InnoDB used to skip
redo logging and write MLOG_INDEX_LOAD records to inform crash recovery
and Mariabackup of the gaps in redo log. This is fragile and prohibits
some optimizations, such as skipping the doublewrite buffer for
newly (re)initialized pages (MDEV-19738).
row_merge_write_redo(): Remove. We do not write MLOG_INDEX_LOAD
records any more. Instead, we write full redo log.
FlushObserver: Remove.
fseg_free_page_func(): Remove the parameter log. Redo logging
cannot be disabled.
fil_space_t::redo_skipped_count: Remove.
We cannot remove buf_block_t::skip_flush_check, because PageBulk
will temporarily generate invalid B-tree pages in the buffer pool.
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.
Some I/O functions and macros that are declared in os0file.h used to
return a Boolean status code (nonzero on success). In MySQL 5.7, they
were changed to return dberr_t instead. Alas, in MariaDB Server 10.2,
some uses of functions were not adjusted to the changed return value.
Until MDEV-19231, the valid values of dberr_t were always nonzero.
This means that some code that was incorrectly checking for a zero
return value from the functions would never detect a failure.
After MDEV-19231, some tests for ALTER ONLINE TABLE would fail with
cmake -DPLUGIN_PERFSCHEMA=NO. It turned out that the wrappers
pfs_os_file_read_no_error_handling_int_fd_func() and
pfs_os_file_write_int_fd_func() were wrongly returning
bool instead of dberr_t. Also the callers of these functions were
wrongly expecting bool (nonzero on success) instead of dberr_t.
This mistake had been made when the addition of these functions was
merged from MySQL 5.6.36 and 5.7.18 into MariaDB Server 10.2.7.
This fix also reverts commit 40becbc3c7
which attempted to work around the problem.
The record MLOG_INDEX_LOAD is supposed to be written to indicate that
some page modifications bypassed redo logging, and that redo logging
is now re-enabled. It was not written for fulltext indexes during
ALTER TABLE.
row_merge_write_redo(): Declare globally. Assert that the index
is neither a spatial nor fulltext index.
recv_mlog_index_load(): Observe a MLOG_INDEX_LOAD operation.
recv_parse_log_recs(): Handle MLOG_INDEX_LOAD also in multi-record
mini-transactions. Because of this omission, we should keep writing
MLOG_INDEX_LOAD in single-record mini-transactions, because older
versions of Mariabackup would fail.
row_fts_merge_insert(): Write MLOG_INDEX_LOAD for the auxiliary
tables of fulltext indexes.
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.
NULL values when there is no DEFAULT
Copy and inplace algorithm works similarly for
NULL to NOT NULL conversion for the following cases:
(1) strict sql mode - Should give error.
(2) non-strict sql mode - Should give warnings alone
(3) alter ignore table command. - Should give warnings alone.
commit 2dbeebdb16 accidentally changed
ALTER_COLUMN_OPTION and ALTER_COLUMN_STORAGE_TYPE to be separate flags.
InnoDB and Mroonga are only checking for the latter;
the example storage engine is checking for the former only.
The impact of this bug should be incorrect operation of Mroonga when
the column options GROONGA_TYPE, FLAGS are changed.
InnoDB does not define any column options, only table options,
so the flag ALTER_COLUMN_OPTION should never have been set.
Also, remove the unused flag ALTER_DROP_HISTORICAL.
- Allow NOT NULL constraint to replace the NULL value in the row with
explicit or implicit default value.
- If the default value is non-const value then inplace alter won't
support it.
- ALTER IGNORE will ignore the error if the concurrent DML contains
NULL value.
file IO, rather than int.
On Windows, it is suboptimal to depend on C runtime, as it has limited
number of file descriptors. This change eliminates
os_file_read_no_error_handling_int_fd(), os_file_write_int_fd(),
OS_FILE_FROM_FD() macro.
Rollback attempted to dereference DB_ROLL_PTR=0, which cannot possibly
be a valid undo log pointer. A safer canonical value would be
roll_ptr_t(1) << ROLL_PTR_INSERT_FLAG_POS
which is what was chosen in MDEV-12288, corresponding to reset_trx_id.
No deterministic test case for the bug was found. The simplest test
cases may be related to MDEV-11415, which suppresses undo logging for
ALGORITHM=COPY operations. In those operations, in the spirit of
MDEV-12288, we should actually have written reset_trx_id instead of
using the transaction identifier of the current transaction
(and a bogus value of DB_ROLL_PTR=0). However, thanks to MySQL Bug#28432
which I had fixed in MySQL 5.6.8 as part of WL#6255, access to the
rebuilt table by earlier-started transactions should actually have been
refused with ER_TABLE_DEF_CHANGED.
reset_trx_id: Move the definition to data0type.cc and the declaration
to data0type.h.
btr_cur_ins_lock_and_undo(): When undo logging is disabled, use the
safe value that corresponds to reset_trx_id.
btr_cur_optimistic_insert(): Validate the DB_TRX_ID,DB_ROLL_PTR before
inserting into a clustered index leaf page.
ins_node_t::sys_buf[]: Replaces row_id_buf and trx_id_buf and some
heap usage.
row_ins_alloc_sys_fields(): Init ins_node_t::sys_buf[] to reset_trx_id.
row_ins_buf(): Only if undo logging is enabled, copy trx->id
to node->sys_buf. Otherwise, rely on the initialization in
row_ins_alloc_sys_fields().
row_purge_reset_trx_id(): Invoke mlog_write_string() with reset_trx_id
directly. (No functional change.)
trx_undo_page_report_modify(): Assert that the DB_ROLL_PTR is not 0.
trx_undo_get_undo_rec_low(): Assert that the roll_ptr is valid before
trying to dereference it.
dict_index_t::is_primary(): Check if the index is the primary key.
PageConverter::adjust_cluster_record(): Fix
MDEV-15249 Crash in MVCC read after IMPORT TABLESPACE
by resetting the system fields to reset_trx_id instead of writing
the current transaction ID (which will be committed at the
end of the IMPORT TABLESPACE) and DB_ROLL_PTR=0.
This can partially be viewed as a follow-up fix of MDEV-12288,
because IMPORT should already then have written
DB_TRX_ID=0 and DB_ROLL_PTR=1<<55 to prevent unnecessary
DB_TRX_ID lookups in subsequent accesses to the table.
remove remnants of 10.0 bugfix, incorrectly merged into 10.2
Using col_names[i] was obviously, wrong, must've been col_names[ifield->col_no].
incorrect column name resulted in innodb having index unique_id2(id1),
while the server thought it's unique_id2(id4).
But col_names[ifield->col_no] is wrong too, because `table` has non-renamed
columns, so the correct column name is always dict_table_get_col_name(table, ifield->col_no)
Reverted incorrect changes done on MDEV-7367 and MDEV-9469. Fixes properly
also related bugs:
MDEV-13668: InnoDB unnecessarily rebuilds table when renaming a column and adding index
MDEV-9469: 'Incorrect key file' on ALTER TABLE
MDEV-9548: Alter table (renaming and adding index) fails with "Incorrect key file for table"
MDEV-10535: ALTER TABLE causes standalone/wsrep cluster crash
MDEV-13640: ALTER TABLE CHANGE and ADD INDEX on auto_increment column fails with "Incorrect key file for table..."
Root cause for all these bugs is the fact that MariaDB .frm file
can contain virtual columns but InnoDB dictionary does not and
previous fixes were incorrect or unnecessarily forced table
rebuilt. In index creation key_part->fieldnr can be bigger than
number of columns in InnoDB data dictionary. We need to skip not
stored fields when calculating correct column number for InnoDB
data dictionary.
dict_table_get_col_name_for_mysql
Remove
innobase_match_index_columns
Revert incorrect change done on MDEV-7367
innobase_need_rebuild
Remove unnecessary rebuild force when column is renamed.
innobase_create_index_field_def
Calculate InnoDB column number correctly and remove
unnecessary column name set.
innobase_create_index_def, innobase_create_key_defs
Remove unneeded fields parameter. Revert unneeded memset.
prepare_inplace_alter_table_dict
Remove unneeded col_names parameter
index_field_t
Remove unneeded col_name member.
row_merge_create_index
Remove unneeded col_names parameter and resolution.
Effected tests:
innodb-alter-table : Add test case for MDEV-13668
innodb-alter : Remove MDEV-13668, MDEV-9469 FIXMEs
and restore original tests
innodb-wl5980-alter : Remove MDEV-13668, MDEV-9469 FIXMEs
and restore original tests
For InnoDB tables, adding, dropping and reordering columns has
required a rebuild of the table and all its indexes. Since MySQL 5.6
(and MariaDB 10.0) this has been supported online (LOCK=NONE), allowing
concurrent modification of the tables.
This work revises the InnoDB ROW_FORMAT=REDUNDANT, ROW_FORMAT=COMPACT
and ROW_FORMAT=DYNAMIC so that columns can be appended instantaneously,
with only minor changes performed to the table structure. The counter
innodb_instant_alter_column in INFORMATION_SCHEMA.GLOBAL_STATUS
is incremented whenever a table rebuild operation is converted into
an instant ADD COLUMN operation.
ROW_FORMAT=COMPRESSED tables will not support instant ADD COLUMN.
Some usability limitations will be addressed in subsequent work:
MDEV-13134 Introduce ALTER TABLE attributes ALGORITHM=NOCOPY
and ALGORITHM=INSTANT
MDEV-14016 Allow instant ADD COLUMN, ADD INDEX, LOCK=NONE
The format of the clustered index (PRIMARY KEY) is changed as follows:
(1) The FIL_PAGE_TYPE of the root page will be FIL_PAGE_TYPE_INSTANT,
and a new field PAGE_INSTANT will contain the original number of fields
in the clustered index ('core' fields).
If instant ADD COLUMN has not been used or the table becomes empty,
or the very first instant ADD COLUMN operation is rolled back,
the fields PAGE_INSTANT and FIL_PAGE_TYPE will be reset
to 0 and FIL_PAGE_INDEX.
(2) A special 'default row' record is inserted into the leftmost leaf,
between the page infimum and the first user record. This record is
distinguished by the REC_INFO_MIN_REC_FLAG, and it is otherwise in the
same format as records that contain values for the instantly added
columns. This 'default row' always has the same number of fields as
the clustered index according to the table definition. The values of
'core' fields are to be ignored. For other fields, the 'default row'
will contain the default values as they were during the ALTER TABLE
statement. (If the column default values are changed later, those
values will only be stored in the .frm file. The 'default row' will
contain the original evaluated values, which must be the same for
every row.) The 'default row' must be completely hidden from
higher-level access routines. Assertions have been added to ensure
that no 'default row' is ever present in the adaptive hash index
or in locked records. The 'default row' is never delete-marked.
(3) In clustered index leaf page records, the number of fields must
reside between the number of 'core' fields (dict_index_t::n_core_fields
introduced in this work) and dict_index_t::n_fields. If the number
of fields is less than dict_index_t::n_fields, the missing fields
are replaced with the column value of the 'default row'.
Note: The number of fields in the record may shrink if some of the
last instantly added columns are updated to the value that is
in the 'default row'. The function btr_cur_trim() implements this
'compression' on update and rollback; dtuple::trim() implements it
on insert.
(4) In ROW_FORMAT=COMPACT and ROW_FORMAT=DYNAMIC records, the new
status value REC_STATUS_COLUMNS_ADDED will indicate the presence of
a new record header that will encode n_fields-n_core_fields-1 in
1 or 2 bytes. (In ROW_FORMAT=REDUNDANT records, the record header
always explicitly encodes the number of fields.)
We introduce the undo log record type TRX_UNDO_INSERT_DEFAULT for
covering the insert of the 'default row' record when instant ADD COLUMN
is used for the first time. Subsequent instant ADD COLUMN can use
TRX_UNDO_UPD_EXIST_REC.
This is joint work with Vin Chen (陈福荣) from Tencent. The design
that was discussed in April 2017 would not have allowed import or
export of data files, because instead of the 'default row' it would
have introduced a data dictionary table. The test
rpl.rpl_alter_instant is exactly as contributed in pull request #408.
The test innodb.instant_alter is based on a contributed test.
The redo log record format changes for ROW_FORMAT=DYNAMIC and
ROW_FORMAT=COMPACT are as contributed. (With this change present,
crash recovery from MariaDB 10.3.1 will fail in spectacular ways!)
Also the semantics of higher-level redo log records that modify the
PAGE_INSTANT field is changed. The redo log format version identifier
was already changed to LOG_HEADER_FORMAT_CURRENT=103 in MariaDB 10.3.1.
Everything else has been rewritten by me. Thanks to Elena Stepanova,
the code has been tested extensively.
When rolling back an instant ADD COLUMN operation, we must empty the
PAGE_FREE list after deleting or shortening the 'default row' record,
by calling either btr_page_empty() or btr_page_reorganize(). We must
know the size of each entry in the PAGE_FREE list. If rollback left a
freed copy of the 'default row' in the PAGE_FREE list, we would be
unable to determine its size (if it is in ROW_FORMAT=COMPACT or
ROW_FORMAT=DYNAMIC) because it would contain more fields than the
rolled-back definition of the clustered index.
UNIV_SQL_DEFAULT: A new special constant that designates an instantly
added column that is not present in the clustered index record.
len_is_stored(): Check if a length is an actual length. There are
two magic length values: UNIV_SQL_DEFAULT, UNIV_SQL_NULL.
dict_col_t::def_val: The 'default row' value of the column. If the
column is not added instantly, def_val.len will be UNIV_SQL_DEFAULT.
dict_col_t: Add the accessors is_virtual(), is_nullable(), is_instant(),
instant_value().
dict_col_t::remove_instant(): Remove the 'instant ADD' status of
a column.
dict_col_t::name(const dict_table_t& table): Replaces
dict_table_get_col_name().
dict_index_t::n_core_fields: The original number of fields.
For secondary indexes and if instant ADD COLUMN has not been used,
this will be equal to dict_index_t::n_fields.
dict_index_t::n_core_null_bytes: Number of bytes needed to
represent the null flags; usually equal to UT_BITS_IN_BYTES(n_nullable).
dict_index_t::NO_CORE_NULL_BYTES: Magic value signalling that
n_core_null_bytes was not initialized yet from the clustered index
root page.
dict_index_t: Add the accessors is_instant(), is_clust(),
get_n_nullable(), instant_field_value().
dict_index_t::instant_add_field(): Adjust clustered index metadata
for instant ADD COLUMN.
dict_index_t::remove_instant(): Remove the 'instant ADD' status
of a clustered index when the table becomes empty, or the very first
instant ADD COLUMN operation is rolled back.
dict_table_t: Add the accessors is_instant(), is_temporary(),
supports_instant().
dict_table_t::instant_add_column(): Adjust metadata for
instant ADD COLUMN.
dict_table_t::rollback_instant(): Adjust metadata on the rollback
of instant ADD COLUMN.
prepare_inplace_alter_table_dict(): First create the ctx->new_table,
and only then decide if the table really needs to be rebuilt.
We must split the creation of table or index metadata from the
creation of the dictionary table records and the creation of
the data. In this way, we can transform a table-rebuilding operation
into an instant ADD COLUMN operation. Dictionary objects will only
be added to cache when table rebuilding or index creation is needed.
The ctx->instant_table will never be added to cache.
dict_table_t::add_to_cache(): Modified and renamed from
dict_table_add_to_cache(). Do not modify the table metadata.
Let the callers invoke dict_table_add_system_columns() and if needed,
set can_be_evicted.
dict_create_sys_tables_tuple(), dict_create_table_step(): Omit the
system columns (which will now exist in the dict_table_t object
already at this point).
dict_create_table_step(): Expect the callers to invoke
dict_table_add_system_columns().
pars_create_table(): Before creating the table creation execution
graph, invoke dict_table_add_system_columns().
row_create_table_for_mysql(): Expect all callers to invoke
dict_table_add_system_columns().
create_index_dict(): Replaces row_merge_create_index_graph().
innodb_update_n_cols(): Renamed from innobase_update_n_virtual().
Call my_error() if an error occurs.
btr_cur_instant_init(), btr_cur_instant_init_low(),
btr_cur_instant_root_init():
Load additional metadata from the clustered index and set
dict_index_t::n_core_null_bytes. This is invoked
when table metadata is first loaded into the data dictionary.
dict_boot(): Initialize n_core_null_bytes for the four hard-coded
dictionary tables.
dict_create_index_step(): Initialize n_core_null_bytes. This is
executed as part of CREATE TABLE.
dict_index_build_internal_clust(): Initialize n_core_null_bytes to
NO_CORE_NULL_BYTES if table->supports_instant().
row_create_index_for_mysql(): Initialize n_core_null_bytes for
CREATE TEMPORARY TABLE.
commit_cache_norebuild(): Call the code to rename or enlarge columns
in the cache only if instant ADD COLUMN is not being used.
(Instant ADD COLUMN would copy all column metadata from
instant_table to old_table, including the names and lengths.)
PAGE_INSTANT: A new 13-bit field for storing dict_index_t::n_core_fields.
This is repurposing the 16-bit field PAGE_DIRECTION, of which only the
least significant 3 bits were used. The original byte containing
PAGE_DIRECTION will be accessible via the new constant PAGE_DIRECTION_B.
page_get_instant(), page_set_instant(): Accessors for the PAGE_INSTANT.
page_ptr_get_direction(), page_get_direction(),
page_ptr_set_direction(): Accessors for PAGE_DIRECTION.
page_direction_reset(): Reset PAGE_DIRECTION, PAGE_N_DIRECTION.
page_direction_increment(): Increment PAGE_N_DIRECTION
and set PAGE_DIRECTION.
rec_get_offsets(): Use the 'leaf' parameter for non-debug purposes,
and assume that heap_no is always set.
Initialize all dict_index_t::n_fields for ROW_FORMAT=REDUNDANT records,
even if the record contains fewer fields.
rec_offs_make_valid(): Add the parameter 'leaf'.
rec_copy_prefix_to_dtuple(): Assert that the tuple is only built
on the core fields. Instant ADD COLUMN only applies to the
clustered index, and we should never build a search key that has
more than the PRIMARY KEY and possibly DB_TRX_ID,DB_ROLL_PTR.
All these columns are always present.
dict_index_build_data_tuple(): Remove assertions that would be
duplicated in rec_copy_prefix_to_dtuple().
rec_init_offsets(): Support ROW_FORMAT=REDUNDANT records whose
number of fields is between n_core_fields and n_fields.
cmp_rec_rec_with_match(): Implement the comparison between two
MIN_REC_FLAG records.
trx_t::in_rollback: Make the field available in non-debug builds.
trx_start_for_ddl_low(): Remove dangerous error-tolerance.
A dictionary transaction must be flagged as such before it has generated
any undo log records. This is because trx_undo_assign_undo() will mark
the transaction as a dictionary transaction in the undo log header
right before the very first undo log record is being written.
btr_index_rec_validate(): Account for instant ADD COLUMN
row_undo_ins_remove_clust_rec(): On the rollback of an insert into
SYS_COLUMNS, revert instant ADD COLUMN in the cache by removing the
last column from the table and the clustered index.
row_search_on_row_ref(), row_undo_mod_parse_undo_rec(), row_undo_mod(),
trx_undo_update_rec_get_update(): Handle the 'default row'
as a special case.
dtuple_t::trim(index): Omit a redundant suffix of an index tuple right
before insert or update. After instant ADD COLUMN, if the last fields
of a clustered index tuple match the 'default row', there is no
need to store them. While trimming the entry, we must hold a page latch,
so that the table cannot be emptied and the 'default row' be deleted.
btr_cur_optimistic_update(), btr_cur_pessimistic_update(),
row_upd_clust_rec_by_insert(), row_ins_clust_index_entry_low():
Invoke dtuple_t::trim() if needed.
row_ins_clust_index_entry(): Restore dtuple_t::n_fields after calling
row_ins_clust_index_entry_low().
rec_get_converted_size(), rec_get_converted_size_comp(): Allow the number
of fields to be between n_core_fields and n_fields. Do not support
infimum,supremum. They are never supposed to be stored in dtuple_t,
because page creation nowadays uses a lower-level method for initializing
them.
rec_convert_dtuple_to_rec_comp(): Assign the status bits based on the
number of fields.
btr_cur_trim(): In an update, trim the index entry as needed. For the
'default row', handle rollback specially. For user records, omit
fields that match the 'default row'.
btr_cur_optimistic_delete_func(), btr_cur_pessimistic_delete():
Skip locking and adaptive hash index for the 'default row'.
row_log_table_apply_convert_mrec(): Replace 'default row' values if needed.
In the temporary file that is applied by row_log_table_apply(),
we must identify whether the records contain the extra header for
instantly added columns. For now, we will allocate an additional byte
for this for ROW_T_INSERT and ROW_T_UPDATE records when the source table
has been subject to instant ADD COLUMN. The ROW_T_DELETE records are
fine, as they will be converted and will only contain 'core' columns
(PRIMARY KEY and some system columns) that are converted from dtuple_t.
rec_get_converted_size_temp(), rec_init_offsets_temp(),
rec_convert_dtuple_to_temp(): Add the parameter 'status'.
REC_INFO_DEFAULT_ROW = REC_INFO_MIN_REC_FLAG | REC_STATUS_COLUMNS_ADDED:
An info_bits constant for distinguishing the 'default row' record.
rec_comp_status_t: An enum of the status bit values.
rec_leaf_format: An enum that replaces the bool parameter of
rec_init_offsets_comp_ordinary().
This should also fix the MariaDB 10.2.2 bug
MDEV-13826 CREATE FULLTEXT INDEX on encrypted table fails.
MDEV-12634 FIXME: Modify innodb-index-online, innodb-table-online
so that they will write and read merge sort files. InnoDB 5.7
introduced some optimizations to avoid using the files for small tables.
Many collation test results have been adjusted for MDEV-10191.
…porary file
Fixed by removing writing key version to start of every block that
was encrypted. Instead we will use single key version from log_sys
crypt info.
After this MDEV also blocks writen to row log are encrypted and blocks
read from row log aren decrypted if encryption is configured for the
table.
innodb_status_variables[], struct srv_stats_t
Added status variables for merge block and row log block
encryption and decryption amounts.
Removed ROW_MERGE_RESERVE_SIZE define.
row_merge_fts_doc_tokenize
Remove ROW_MERGE_RESERVE_SIZE
row_log_t
Add index, crypt_tail, crypt_head to be used in case of
encryption.
row_log_online_op, row_log_table_close_func
Before writing a block encrypt it if encryption is enabled
row_log_table_apply_ops, row_log_apply_ops
After reading a block decrypt it if encryption is enabled
row_log_allocate
Allocate temporary buffers crypt_head and crypt_tail
if needed.
row_log_free
Free temporary buffers crypt_head and crypt_tail if they
exist.
row_merge_encrypt_buf, row_merge_decrypt_buf
Removed.
row_merge_buf_create, row_merge_buf_write
Remove ROW_MERGE_RESERVE_SIZE
row_merge_build_indexes
Allocate temporary buffer used in decryption and encryption
if needed.
log_tmp_blocks_crypt, log_tmp_block_encrypt, log_temp_block_decrypt
New functions used in block encryption and decryption
log_tmp_is_encrypted
New function to check is encryption enabled.
Added test case innodb-rowlog to force creating a row log and
verify that operations are done using introduced status
variables.
row_merge_read_clustered_index(): The row->fields[] could point
to a record in the clustered index page of the source table, or
to an old version of the record that was constructed in row_heap.
If the row->fields[] points to the clustered index page, then
we were modifying buffer pool data without holding appropriate
block->lock and without appropriate redo logging. The intention
was to modify a copy of the data, not the source file page,
because concurrent readers would still very much need the original
values of the DB_TRX_ID,DB_ROLL_PTR for their multi-versioning.
Either way, it is simplest to not write anything at all, and to
make row->fields[] point to the constant reset_trx_id.
When MySQL 5.7 introduced fulltext parser plugins to InnoDB,
it hard-coded the plugin name "ngram" to mean something special.
Because -fsanitize=undefined was issuing warnings for the
assignment in row_merge_create_index() that the value is out of
range for Boolean, we remove this code that was not intended to
be used in MariaDB 10.2.
fts_check_token(): Remove the special logic for N-gram tokens.
Define my_thread_id as an unsigned type, to avoid mismatch with
ulonglong. Change some parameters to this type.
Use size_t in a few more places.
Declare many flag constants as unsigned to avoid sign mismatch
when shifting bits or applying the unary ~ operator.
When applying the unary ~ operator to enum constants, explictly
cast the result to an unsigned type, because enum constants can
be treated as signed.
In InnoDB, change the source code line number parameters from
ulint to unsigned type. Also, make some InnoDB functions return
a narrower type (unsigned or uint32_t instead of ulint;
bool instead of ibool).
