Patch fixes two bugs:
1) BEGIN_TIMESTAMP of MYSQL.TRANSACTION_REGISTY is '0-0-0' on replication record insertion
2) BEGIN_TIMESTAMP equals COMMMIT_TIMESTAMP in MYSQL.TRANSACTION_REGISTRY
Fixed by calling THD::set_time() at appropriate places
Changing columns WITH/WITHOUT SYSTEM VERSIONING doens't require to read data at
all. Thus it should be an instant operation.
Patch also fixes a bug when ALTER_COLUMN_UNVERSIONED wasn't passed to InnoDB
to change its internal structures.
change_field_versioning_try(): apply WITH/WITHOUT SYSTEM VERSIONING
change in SYS_COLUMNS for one field.
change_fields_versioning_try(): apply WITH/WITHOUT SYSTEM VERSIONING
change in SYS_COLUMNS for every changed field in a table.
change_fields_versioning_cache(): update cache for versioning property
of columns.
MDEV-16100 FOR SYSTEM_TIME erroneously resolves string user variables as transaction IDs
Problem:
Vers_history_point::resolve_unit() tested item->result_type() before
item->fix_fields() was called.
- Item_func_get_user_var::result_type() returned REAL_RESULT by default.
This caused MDEV-16100.
- Item_func_sp::result_type() crashed on assert.
This caused MDEV-16094
Changes:
1. Adding item->fix_fields() into Vers_history_point::resolve_unit()
before using data type specific properties of the history point
expression.
2. Adding a new virtual method Type_handler::Vers_history_point_resolve_unit()
3. Implementing type-specific
Type_handler_xxx::Type_handler::Vers_history_point_resolve_unit()
in the way to:
a. resolve temporal and general purpose string types to TIMESTAMP
b. resolve BIT and general purpose INT types to TRANSACTION
c. disallow use of non-relevant data type expressions in FOR SYSTEM_TIME
Note, DOUBLE and DECIMAL data types are disallowed intentionally.
- DOUBLE does not have enough precision to hold huge BIGINT UNSIGNED values
- DECIMAL rounds on conversion to INT
Both lack of precision and rounding might potentionally lead to
very unpredictable results when a wrong transaction ID would be chosen.
If one really wants dangerous use of DOUBLE and DECIMAL, explicit CAST
can be used:
FOR SYSTEM_TIME AS OF CAST(double_or_decimal AS UNSIGNED)
QQ: perhaps DECIMAL(N,0) could still be allowed.
4. Adding a new virtual method Item::type_handler_for_system_time(),
to make HEX hybrids and bit literals work as TRANSACTION rather
than TIMESTAMP.
5. sql_yacc.yy: replacing the rule temporal_literal to "TIMESTAMP TEXT_STRING".
Other temporal literals now resolve to TIMESTAMP through the new
Type_handler methods. No special grammar needed. This removed
a few shift/resolve conflicts.
(TIMESTAMP related conflicts in "history_point:" will be removed separately)
6. Removing the "timestamp_only" parameter from
vers_select_conds_t::resolve_units() and Vers_history_point::resolve_unit().
It was a hint telling that a table did not have any TRANSACTION-aware
system time columns, so it's OK to resolve to TIMESTAMP in case of uncertainty.
In the new reduction it works as follows:
- the decision between TIMESTAMP and TRANSACTION is first made
based only on the expression data type only
- then, in case if the expression resolved to TRANSACTION, the table
is checked if TRANSACTION-aware columns really exist.
This way is safer against possible ALTER TABLE statements changing
ROW START and ROW END columns from "BIGINT UNSIGNED" to "TIMESTAMP(x)"
or the other way around.
Store transaction start time in thd->transaction.start_time.
THD::transaction_time() wraps over transaction.start_time taking into
account current status of BEGIN.
Vers SQL: TRT fix getting TRX_ID by COMMIT_TS
Fixed wrong assumption that records are ordered by COMMIT_TS.
This is anyway a quick hack until tempesta-tech#314 is done.
See also FIXME and TODO in TR_table::query(MYSQL_TIME, bool).
Test: SEES case for trx_id.test [closes#456]
MDEV-11415 Remove excessive undo logging during ALTER TABLE…ALGORITHM=COPY
Move a test from innodb.rename_table_debug to innodb.alter_copy.
ha_innobase::extra(HA_EXTRA_BEGIN_ALTER_COPY): Register id-versioned
tables so that mysql.transaction_registry will be updated, even for
empty tables that are subjected to ALTER TABLE…ALGORITHM=COPY.
and the system_versioning_transaction_registry variable.
The user enables transaction registry by specifying BIGINT for
row_start/row_end columns.
check mysql.transaction_registry structure on the first open,
not on startup. Avoid warnings unless transaction_registry
is actually used.
Many related changes.
Note that AS OF condition must always be pushed down to physical tables,
it cannot be applied to a derived or a view. Thus:
* no versioning for internal temporary tables, they can never store
historical data.
* remove special versioning code from mysql_derived_prepare and
remove ER_VERS_DERIVED_PROHIBITED - derived can have no historical
data and cannot be prohibited for system versioning related reasons.
* do not expand select list for derived/views with sys vers fields,
derived/views can never have historical data.
* remove special invisiblity rules for sys vers fields, they are no
longer needed after the previous change
* remove system_versioning_hide, it lost the meaning after the
previous change.
* remove ER_VERS_SYSTEM_TIME_CLASH, it's no "clash", the inner
AS OF clause always wins.
* non-versioned fields in a historical query
reword the warning text, downgrade to note, don't
replace values with NULLs
