Let us make the test compatible with ./mtr --repeat
and convert variable_value to integer, so that comparisons like
16>9 will work as intended, instead of being compared as '16'<'9'.
The InnoDB table lookup in purge worker threads is a bottleneck that can
degrade a slow shutdown to utilize less than 2 threads. Let us fix that
bottleneck by constructing a local lookup table that does not require any
synchronization while the undo log records of the current batch
are being processed.
TRX_PURGE_TABLE_BUCKETS: The initial number of std::unordered_map
hash buckets used during a purge batch. This could avoid some
resizing and rehashing in trx_purge_attach_undo_recs().
purge_node_t::tables: A lookup table from table ID to an already
looked up and locked table. Replaces many fields.
trx_purge_attach_undo_recs(): Look up each table in the purge batch
only once.
trx_purge(): Close all tables and release MDL at the end of the batch.
trx_purge_table_open(), trx_purge_table_acquire(): Open a table in purge
and acquire a metadata lock on it. This replaces
dict_table_open_on_id<true>() and dict_acquire_mdl_shared().
purge_sys_t::close_and_reopen(): In case of an MDL conflict, close and
reopen all tables that are covered by the current purge batch.
It may be that some of the tables have been dropped meanwhile and can
be ignored. This replaces wait_SYS() and wait_FTS().
row_purge_parse_undo_rec(): Make purge_coordinator_task issue a
MDL warrant to any purge_worker_task which might need it
when innodb_purge_threads>1.
purge_node_t::end(): Clear the MDL warrant.
Reviewed by: Vladislav Lesin and Vladislav Vaintroub
- InnoDB fails to check the overflow buffer while applying
the operation to the table that was rebuilt. This is caused
by commit 3cef4f8f0f (MDEV-515).
In particular:
* @@debug
deprecated since 5.5.37
* sr_YU locale
deprecated since 10.0.11
* "engine_condition_pushdown" in the @@optimizer_switch
deprecated since 10.1.1
* @@date_format, @@datetime_format, @@time_format, @@max_tmp_tables
deprecated since 10.1.2
* @@wsrep_causal_reads
deprecated since 10.1.3
* "parser" in mroonga table comment
deprecated since 10.2.11
Before commit 6112853cda in MySQL 4.1.1
introduced the parameter innodb_file_per_table, all InnoDB data was
written to the InnoDB system tablespace (often named ibdata1).
A serious design problem is that once the system tablespace has grown to
some size, it cannot shrink even if the data inside it has been deleted.
There are also other design problems, such as the server hang MDEV-29930
that should only be possible when using innodb_file_per_table=0 and
innodb_undo_tablespaces=0 (storing both tables and undo logs in the
InnoDB system tablespace).
The parameter innodb_change_buffering was deprecated
in commit b5852ffbee.
Starting with commit baf276e6d4
(MDEV-19229) the number of innodb_undo_tablespaces can be increased,
so that the undo logs can be moved out of the system tablespace
of an existing installation.
If all these things (tables, undo logs, and the change buffer) are
removed from the InnoDB system tablespace, the only variable-size
data structure inside it is the InnoDB data dictionary.
DDL operations on .ibd files was optimized in
commit 86dc7b4d4c (MDEV-24626).
That should have removed any thinkable performance advantage of
using innodb_file_per_table=0.
Since there should be no benefit of setting innodb_file_per_table=0,
the parameter should be deprecated. Starting with MySQL 5.6 and
MariaDB Server 10.0, the default value is innodb_file_per_table=1.
row_log_table_apply_update(): Free the pcur.old_rec_buf before returning.
It may be allocated by btr_pcur_store_position() inside
btr_blob_log_check_t::check() and btr_store_big_rec_extern_fields().
This memory leak was introduced in
commit 2e814d4702 (MariaDB Server 10.2.2)
via mysql/mysql-server@ce0a1e85e2
(MySQL 5.7.5).
- InnoDB DDL results in `Duplicate entry' if concurrent DML throws
duplicate key error. The following scenario explains the problem
connection con1:
ALTER TABLE t1 FORCE;
connection con2:
INSERT INTO t1(pk, uk) VALUES (2, 2), (3, 2);
In connection con2, InnoDB throws the 'DUPLICATE KEY' error because
of unique index. Alter operation will throw the error when applying
the concurrent DML log.
- Inserting the duplicate key for unique index logs the insert
operation for online ALTER TABLE. When insertion fails,
transaction does rollback and it leads to logging of
delete operation for online ALTER TABLE.
While applying the insert log entries, alter operation
encounters 'DUPLICATE KEY' error.
- To avoid the above fake duplicate scenario, InnoDB should
not write any log for online ALTER TABLE before DML transaction
commit.
- User thread which does DML can apply the online log if
InnoDB ran out of online log and index is marked as completed.
Set online log error if apply phase encountered any error.
It can also clear all other indexes log, marks the newly
added indexes as corrupted.
- Removed the old online code which was a part of DML operations
commit_inplace_alter_table() : Does apply the online log
for the last batch of secondary index log and does frees
the log for the completed index.
trx_t::apply_online_log: Set to true while writing the undo
log if the modified table has active DDL
trx_t::apply_log(): Apply the DML changes to online DDL tables
dict_table_t::is_active_ddl(): Returns true if the table
has an active DDL
dict_index_t::online_log_make_dummy(): Assign dummy value
for clustered index online log to indicate the secondary
indexes are being rebuild.
dict_index_t::online_log_is_dummy(): Check whether the online
log has dummy value
ha_innobase_inplace_ctx::log_failure(): Handle the apply log
failure for online DDL transaction
row_log_mark_other_online_index_abort(): Clear out all other
online index log after encountering the error during
row_log_apply()
row_log_get_error(): Get the error happened during row_log_apply()
row_log_online_op(): Does apply the online log if index is
completed and ran out of memory. Returns false if apply log fails
UndorecApplier: Introduced a class to maintain the undo log
record, latched undo buffer page, parse the undo log record,
maintain the undo record type, info bits and update vector
UndorecApplier::get_old_rec(): Get the correct version of the
clustered index record that was modified by the current undo
log record
UndorecApplier::clear_undo_rec(): Clear the undo log related
information after applying the undo log record
UndorecApplier::log_update(): Handle the update, delete undo
log and apply it on online indexes
UndorecApplier::log_insert(): Handle the insert undo log
and apply it on online indexes
UndorecApplier::is_same(): Check whether the given roll pointer
is generated by the current undo log record information
trx_t::rollback_low(): Set apply_online_log for the transaction
after partially rollbacked transaction has any active DDL
prepare_inplace_alter_table_dict(): After allocating the online
log, InnoDB does create fulltext common tables. Fulltext index
doesn't allow the index to be online. So removed the dead
code of online log removal
Thanks to Marko Mäkelä for providing the initial prototype and
Matthias Leich for testing the issue patiently.
Occasionally, the test would fail with a result difference for
ddl_log_file_alter_table (0 instead of 1) due to some
nondeterminism in the test. Let us remove that nondeterminism.
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.
This is caused by commit 3cef4f8f0f
(MDEV-515). dict_table_t::clear() frees all the blob during
rollback of bulk insert.But online log tries to read the
freed blob while applying the log. It can be fixed if we
truncate the online log during rollback of bulk insert operation.
We implement an idea that was suggested by Michael 'Monty' Widenius
in October 2017: When InnoDB is inserting into an empty table or partition,
we can write a single undo log record TRX_UNDO_EMPTY, which will cause
ROLLBACK to clear the table.
For this to work, the insert into an empty table or partition must be
covered by an exclusive table lock that will be held until the transaction
has been committed or rolled back, or the INSERT operation has been
rolled back (and the table is empty again), in lock_table_x_unlock().
Clustered index records that are covered by the TRX_UNDO_EMPTY record
will carry DB_TRX_ID=0 and DB_ROLL_PTR=1<<55, and thus they cannot
be distinguished from what MDEV-12288 leaves behind after purging the
history of row-logged operations.
Concurrent non-locking reads must be adjusted: If the read view was
created before the INSERT into an empty table, then we must continue
to imagine that the table is empty, and not try to read any records.
If the read view was created after the INSERT was committed, then
all records must be visible normally. To implement this, we introduce
the field dict_table_t::bulk_trx_id.
This special handling only applies to the very first INSERT statement
of a transaction for the empty table or partition. If a subsequent
statement in the transaction is modifying the initially empty table again,
we must enable row-level undo logging, so that we will be able to
roll back to the start of the statement in case of an error (such as
duplicate key).
INSERT IGNORE will continue to use row-level logging and locking, because
implementing it would require the ability to roll back the latest row.
Since the undo log that we write only allows us to roll back the entire
statement, we cannot support INSERT IGNORE. We will introduce a
handler::extra() parameter HA_EXTRA_IGNORE_INSERT to indicate to storage
engines that INSERT IGNORE is being executed.
In many test cases, we add an extra record to the table, so that during
the 'interesting' part of the test, row-level locking and logging will
be used.
Replicas will continue to use row-level logging and locking until
MDEV-24622 has been addressed. Likewise, this optimization will be
disabled in Galera cluster until MDEV-24623 enables it.
dict_table_t::bulk_trx_id: The latest active or committed transaction
that initiated an insert into an empty table or partition.
Protected by exclusive table lock and a clustered index leaf page latch.
ins_node_t::bulk_insert: Whether bulk insert was initiated.
trx_t::mod_tables: Use C++11 style accessors (emplace instead of insert).
Unlike earlier, this collection will cover also temporary tables.
trx_mod_table_time_t: Add start_bulk_insert(), end_bulk_insert(),
is_bulk_insert(), was_bulk_insert().
trx_undo_report_row_operation(): Before accessing any undo log pages,
invoke trx->mod_tables.emplace() in order to determine whether undo
logging was disabled, or whether this is the first INSERT and we are
supposed to write a TRX_UNDO_EMPTY record.
row_ins_clust_index_entry_low(): If we are inserting into an empty
clustered index leaf page, set the ins_node_t::bulk_insert flag for
the subsequent trx_undo_report_row_operation() call.
lock_rec_insert_check_and_lock(), lock_prdt_insert_check_and_lock():
Remove the redundant parameter 'flags' that can be checked in the caller.
btr_cur_ins_lock_and_undo(): Simplify the logic. Correctly write
DB_TRX_ID,DB_ROLL_PTR after invoking trx_undo_report_row_operation().
trx_mark_sql_stat_end(), ha_innobase::extra(HA_EXTRA_IGNORE_INSERT),
ha_innobase::external_lock(): Invoke trx_t::end_bulk_insert() so that
the next statement will not be covered by table-level undo logging.
ReadView::changes_visible(trx_id_t) const: New accessor for the case
where the trx_id_t is not read from a potentially corrupted index page
but directly from the memory. In this case, we can skip a sanity check.
row_sel(), row_sel_try_search_shortcut(), row_search_mvcc():
row_sel_try_search_shortcut_for_mysql(),
row_merge_read_clustered_index(): Check dict_table_t::bulk_trx_id.
row_sel_clust_sees(): Replaces lock_clust_rec_cons_read_sees().
lock_sec_rec_cons_read_sees(): Replaced with lower-level code.
btr_root_page_init(): Refactored from btr_create().
dict_index_t::clear(), dict_table_t::clear(): Empty an index or table,
for the ROLLBACK of an INSERT operation.
ROW_T_EMPTY, ROW_OP_EMPTY: Note a concurrent ROLLBACK of an INSERT
into an empty table.
This is joint work with Thirunarayanan Balathandayuthapani,
who created a working prototype.
Thanks to Matthias Leich for extensive testing.
Problem:
========
Server fails to notify the engine by not setting the ADD_PK_INDEX and
DROP_PK_INDEX When there is a
i) Change in candidate for primary key.
ii) New candidate for primary key.
Fix:
====
Server sets the ADD_PK_INDEX and DROP_PK_INDEX while doing alter for the
above problematic case.
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.
- 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.
When MariaDB 10.1.0 introduced table options for encryption and
compression, it unnecessarily changed
ha_innobase::check_if_supported_inplace_alter() so that ALGORITHM=COPY
is forced when these parameters differ.
A better solution is to move the check to innobase_need_rebuild().
In that way, the ALGORITHM=INPLACE interface (yes, the syntax is
very misleading) can be used for rebuilding the table much more
efficiently, with merge sort, with no undo logging, and allowing
concurrent DML operations.
This bug is a regression caused by the code refactoring in
commit f5a833c3e0. It was not present
in any release of the MariaDB server. The bug affects table-rebuilding
ALTER TABLE when the source table is in ROW_FORMAT=REDUNDANT and
contains no virtual columns.
row_log_table_low_redundant(): Log virtual column data only if
virtual columns are present.
