In MariaDB, we have a confusing problem where:
* The transaction_isolation option can be set in a configuration file, but it cannot be set dynamically.
* The tx_isolation system variable can be set dynamically, but it cannot be set in a configuration file.
Therefore, we have two different names for the same thing in different contexts. This is needlessly confusing, and it complicates the documentation. The same thing applys for transaction_read_only.
MySQL 5.7 solved this problem by making them into system variables. https://dev.mysql.com/doc/relnotes/mysql/5.7/en/news-5-7-20.html
This commit takes a similar approach by adding new system variables and marking the original ones as deprecated. This commit also resolves some legacy problems related to SET STATEMENT and transaction_isolation.
row_check_index(): Treat secondary indexes of temporary tables as if
SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED
is in effect. That is, only consider the delete-mark and nothing else.
ha_innobase::check(): Do not enable READ UNCOMMITTED isolation level
for temporary tables, because it would report index count mismatch
for secondary indexes.
row_check_index(): Ignore EXTENDED for temporary tables, because
the tables are private to the current connection and there will be
no purge of committed transaction history.
Let us introduce the parameter innodb_read_only_compressed
that is ON by default, making any ROW_FORMAT=COMPRESSED tables
read-only.
I developed the ROW_FORMAT=COMPRESSED format based on
Heikki Tuuri's rough design between 2005 and 2008. It might
have been a good idea back then, but no proper benchmarks were
ever run to validate the design or the implementation.
The format has been more or less obsolete for years.
It limits innodb_page_size to 16384 bytes (the default),
and instant ALTER TABLE is not supported.
This is the first step towards deprecating and removing
write support for ROW_FORMAT=COMPRESSED tables.
- multi_range_read_info_const now uses the new records_in_range interface
- Added handler::avg_io_cost()
- Don't calculate avg_io_cost() in get_sweep_read_cost if avg_io_cost is
not 1.0. In this case we trust the avg_io_cost() from the handler.
- Changed test_quick_select to use TIME_FOR_COMPARE instead of
TIME_FOR_COMPARE_IDX to align this with the rest of the code.
- Fixed bug when using test_if_cheaper_ordering where we didn't use
keyread if index was changed
- Fixed a bug where we didn't use index only read when using order-by-index
- Added keyread_time() to HEAP.
The default keyread_time() was optimized for blocks and not suitable for
HEAP. The effect was the HEAP prefered table scans over ranges for btree
indexes.
- Fixed get_sweep_read_cost() for HEAP tables
- Ensure that range and ref have same cost for simple ranges
Added a small cost (MULTI_RANGE_READ_SETUP_COST) to ranges to ensure
we favior ref for range for simple queries.
- Fixed that matching_candidates_in_table() uses same number of records
as the rest of the optimizer
- Added avg_io_cost() to JT_EQ_REF cost. This helps calculate the cost for
HEAP and temporary tables better. A few tests changed because of this.
- heap::read_time() and heap::keyread_time() adjusted to not add +1.
This was to ensure that handler::keyread_time() doesn't give
higher cost for heap tables than for normal tables. One effect of
this is that heap and derived tables stored in heap will prefer
key access as this is now regarded as cheap.
- Changed cost for index read in sql_select.cc to match
multi_range_read_info_const(). All index cost calculation is now
done trough one function.
- 'ref' will now use quick_cost for keys if it exists. This is done
so that for '=' ranges, 'ref' is prefered over 'range'.
- scan_time() now takes avg_io_costs() into account
- get_delayed_table_estimates() uses block_size and avg_io_cost()
- Removed default argument to test_if_order_by_key(); simplifies code
InnoDB does not allow FOREIGN KEY constraints to exist for TEMPORARY TABLE.
InnoDB introduced a dedicated tablespace for temporary tables, and actually
stopped creating persistent metadata and data for temporary tables.
row_table_add_foreign_constraints(): Do not create a persistent
transaction.
dict_create_foreign_constraints_low(): Add the persistent transaction to
the update the foreign key relation in dictionary.
dict_create_foreign_constraints_low(): Remove a duplicated check for
partitioned tables.
The parameter --innodb-sync-debug, which is disabled by default,
aims to find potential deadlocks in InnoDB.
When the parameter is enabled, lots of tests failed. Most of these
failures were due to bogus diagnostics. But, as part of this fix,
we are also fixing a bug in error handling code and removing dead
code, and fixing cases where an uninitialized mutex was being
locked and unlocked.
dict_create_foreign_constraints_low(): Remove an extraneous
mutex_exit() call that could cause corruption in an error handling
path. Also, do not unnecessarily acquire dict_foreign_err_mutex.
Its only purpose is to control concurrent access to
dict_foreign_err_file.
row_ins_foreign_trx_print(): Replace a redundant condition with a
debug assertion.
srv_dict_tmpfile, srv_dict_tmpfile_mutex: Remove. The
temporary file is never being written to or read from.
log_free_check(): Allow SYNC_FTS_CACHE (fts_cache_t::lock)
to be held.
ha_innobase::inplace_alter_table(), row_merge_insert_index_tuples():
Assert that no unexpected latches are being held.
sync_latch_meta_init(): Properly initialize dict_operation_lock_key
at SYNC_DICT_OPERATION. dict_sys->mutex is SYNC_DICT, and
the now-removed SRV_DICT_TMPFILE was wrongly registered at
SYNC_DICT_OPERATION.
buf_block_init(): Correctly register buf_block_t::debug_latch.
It was previously misleadingly reported as LATCH_ID_DICT_FOREIGN_ERR.
latch_level_t: Correct the relative latching order of
SYNC_IBUF_PESS_INSERT_MUTEX,SYNC_INDEX_TREE and
SYNC_FILE_FORMAT_TAG,SYNC_DICT_OPERATION to avoid bogus failures.
row_drop_table_for_mysql(): Avoid accessing btr_defragment_mutex
if the defragmentation thread has not been started. This is the
case during fts_drop_orphaned_tables() in recv_recovery_rollback_active().
fil_space_destroy_crypt_data(): Avoid acquiring fil_crypt_threads_mutex
when it is uninitialized. We may have created crypt_data before the
mutex was created, and the mutex creation would be skipped if
InnoDB startup failed or --innodb-read-only was specified.
On Windows, when tmpdir is not writable, there are only messages
like this:
2017-07-05 14:04:25 3860 [ERROR] InnoDB: Unable to create temporary file; errno: 0
On other platforms, there would be two messages for each failure:
2017-07-05 17:23:02 140436573771648 [ERROR] mysqld: Can't create/write to file '/dev/null/nonexistent/ibaajU4U' (Errcode: 20 "Not a directory")
2017-07-05 17:23:02 140436573771648 [ERROR] InnoDB: Unable to create temporary file; errno: 20
This is a regression caused by
commit bb60a832ede139d24a2470a1b1217d30799d726e
srv_shutdown_all_bg_threads(): If os_thread_count indicates that
no threads are running, do not bother checking thread status.
This avoids a crash when InnoDB startup is aborted before
os_aio_init() has been invoked. (os_aio_all_slots_free() would
dereference AIO::s_reads even though it is NULL.)
The InnoDB temporary tablespace is only usable if innodb_read_only=OFF.
It is useless to create the tablespace in read-only mode, because
CREATE TEMPORARY TABLE is disallowed if innodb_read_only, and nothing
can we written to the temporary tablespace if no temporary tables
can be created.
1. Special mode to search in error logs: if SEARCH_RANGE is not set,
the file is considered an error log and the search is performed
since the last CURRENT_TEST: line
2. Number of matches is printed too. "FOUND 5 /foo/ in bar".
Use greedy .* at the end of the pattern if number of matches
isn't stable. If nothing is found it's still "NOT FOUND",
not "FOUND 0".
3. SEARCH_ABORT specifies the prefix of the output.
Can be "NOT FOUND" or "FOUND" as before,
but also "FOUND 5 " if needed.
MySQL 5.7 allows temporary tables to be created in ROW_FORMAT=COMPRESSED.
The usefulness of this is questionable. WL#7899 in MySQL 8.0.0
prevents the creation of such compressed tables, so that all InnoDB
temporary tables will be located inside the predefined
InnoDB temporary tablespace.
Pick up and adjust some tests from MySQL 5.7 and 8.0.
dict_tf_to_fsp_flags(): Remove the parameter is_temp.
fsp_flags_init(): Remove the parameter is_temporary.
row_mysql_drop_temp_tables(): Remove. There cannot be any temporary
tables in InnoDB. (This never removed #sql* tables in the datadir
which were created by DDL.)
dict_table_t::dir_path_of_temp_table: Remove.
create_table_info_t::m_temp_path: Remove.
create_table_info_t::create_options_are_invalid(): Do not allow
ROW_FORMAT=COMPRESSED or KEY_BLOCK_SIZE for temporary tables.
create_table_info_t::innobase_table_flags(): Do not unnecessarily
prevent CREATE TEMPORARY TABLE with SPATIAL INDEX.
(MySQL 5.7 does allow this.)
fil_space_belongs_in_lru(): The only FIL_TYPE_TEMPORARY tablespace
is never subjected to closing least-recently-used files.
