In MDEV-25644 vers_check_update() sets vers_write to false in case it
returns false. It is ok for UPDATE but is not correct for ODKU is bulk
insert requires vers_write on next tuple.
The fix return vers_write value back when vers_check_update() and
related vers_insert_history_row() are done in ODKU.
Problem:
REPLACE DELAYED into a system-versioned table read an uninitialized
lex->vers_conditions.delete_history in TABLE::delete_row().
Delayed_insert has its own THD, and hence its own LEX, of which the
constructor copies only a few fields from the parser LEX.
vers_conditions was not copied, so it stayed uninitialized. It is read
when a REPLACE resolves a duplicate on a versioned table.
Fix:
Copy vers_conditions from the parser LEX in the Delayed_insert
constructor.
Remove the unscoped #pragma GCC diagnostic ignored
"-Wdeprecated-declarations" from include/violite.h and replace all
sprintf/vsprintf calls with snprintf/vsnprintf across the codebase.
Where possible, pass actual buffer sizes as function parameters
instead of using hardcoded constants or recomputing strlen().
Notable API changes:
- get_date(): added to_len parameter for buffer size
- nice_time(), end_timer() in client/mysql.cc: added buff_size
- generate_new_name(): added name_size parameter
- calc_md5(): added buffer_size parameter (fixes off-by-one)
- MD5_HASH_TO_STRING macro: added _size parameter
- Added MYSQL_UDF_MAX_RESULT_LENGTH constant in mysql_com.h
Also fixed a pre-existing bug in sql/rpl_mi.cc where the ellipsis
"..." was written to the wrong buffer (dbuff instead of buff).
Vendored code is excluded: extra/readline, extra/wolfssl,
wsrep-lib, libmariadb, storage/mroonga/vendor, zlib.
Prior to this change, AFTER UPDATE did not fire, if data was unchanged.
Now this is fixed. Also added a test to verify that trigger behavior for
on-duplicate-update is the same as normal update, in case data does not
change.
Problem:
=========
An assertion failure occurs in InnoDB during consecutive
ALTER TABLE operations using the COPY algorithm. The crash
happens during the table rename phase because the
source table (dict_table_t::n_ref_count) is non-zero, despite
the thread holding an exclusive Metadata Lock (MDL).
Reason:
========
When ALTER IGNORE TABLE is executed via the COPY algorithm,
it generates undo logs for every row inserted into the
intermediate table (e.g., #sql-alter-...). The background Purge
Thread, responsible for cleaning up these undo logs, attempts
to take an MDL on the table to prevent the table from
being dropped while in use.
Race condition:
==================
First ALTER: Creates #sql-alter-, copies data, and renames it to t1.
Purge Activation: The Purge thread picks up the undo logs from step 1.
It takes an MDL on the temporary name (#sql-alter-) and increments
the table's n_ref_count.
Identity Shift: InnoDB renames the physical table object to t1, but
the Purge thread still holds a reference to this object.
Second ALTER: Starts a new copy process. When it attempts to rename
the "new" t1 to a backup name, it checks if n_ref_count == 0.
Because the Purge thread is still "pinning" the object to
clean up logs from the first ALTER, the count is > 0,
triggering the assertion failure.
Solution:
========
ALTER IGNORE TABLE needs row-level undo logging to easily
roll back the last inserted row in case of duplicate key errors.
By discarding the last undo log record after inserting each row,
purge will not process any log records generated by
ALTER IGNORE TABLE, preventing unexpected access from the purge
subsystem during subsequent DDL operations.
Make skip_alter_undo (1-bit) to (2-bit enum)
to support different ALTER operation modes:
- NO_UNDO (0): Normal mode with standard undo logging
- SKIP_UNDO (1): ALTER mode that skips undo logging
- IGNORE_UNDO (2): ALTER IGNORE mode that rewrites undo blocks
trx_undo_report_row_operation(): Add ALTER IGNORE undo
rewriting logic. Store old undo record info before writing
new records for IGNORE_UNDO mode. Reset undo top_offset
to maintain only latest insert undo
row_ins_clust_index_entry_low(): Prevent ALTER IGNORE from
using bulk insert optimization. since it requires to write
undo log for each row operation that's incompatible with
existing bulk operation.
Reason:
======
During InnoDB DDL, statistics updation fails due to lock wait
timeout and calls push_warning_printf() to generate warnings
but then returns success, causing the SQL layer
to attempt calling set_ok_status() when the diagnostics area
is already set.
Solution:
=========
By temporarily setting abort_on_warning to false around operations
that prevents warning to error escalation and restore the original
setting after calling HA_EXTRA_END_ALTER_COPY for alter operation.
don't copy field default values and check constraints in
CREATE ... SELECT.
CREATE ... SELECT means a table is created from a *result set*
not from some other table.
For backward compatibility, though, let's keep copying constant
default values and the "compressed" attribute.
Caused by optimization done in 2e2b2a0469.
Cannot use lookup_handler in default branch of locate_dup_record() as
InnoDB update depends on positioned record and update is done in table
main handler.
The patch reverts some non-pure changes done by 2e2b2a0469 to
original logic from 72429cad. There was no long_unique_table condition
to init search on table->file, so we get into default branch with long
unique and table->file search uninitialized.
ha_rnd_init_with_error() on demand for HA_DUPLICATE_POS branch was
original logic as well.
More info: 2e2b2a0469 reverts 5e345281e3, but it seems to be OK as
MDEV-3888 test case passes. mysql-5.6.13 has the original code with
HA_WHOLE_KEY as well.
Timestamp-versioned row deletion was exposed to a collisional problem: if
current timestamp wasn't changed, then a sequence of row delete+insert could
get a duplication error. A row delete would find another conflicting history row
and return an error.
This is true both for REPLACE and DELETE statements, however in REPLACE, the
"optimized" path is usually taken, especially in the tests. There, delete+insert
is substituted for a single versioned row update. In the end, both paths end up
as ha_update_row + ha_write_row.
The solution is to handle a history collision somehow.
From the design perspective, the user shouldn't experience history rows loss,
unless there's a technical limitation.
To the contrary, trxid-based changes should never generate history for the same
transaction, see MDEV-15427.
If two operations on the same row happened too quickly, so that they happen at
the same timestamp, the history row shouldn't be lost. We can still write a
history row, though it'll have row_start == row_end.
We cannot store more than one such historical row, as this will violate the
unique constraint on row_end. So we will have to phisically delete the row if
the history row is already available.
In this commit:
1. Improve TABLE::delete_row to handle the history collision: if an update
results with a duplicate error, delete a row for real.
2. use TABLE::delete_row in a non-optimistic path of REPLACE, where the
system-versioned case now belongs entirely.
We had a protection against it, by allowing versioned delete if:
trx->id != table->vers_start_id()
For replace this check fails: replace calls ha_delete_row(record[2]), but
table->vers_start_id() returns the value from record[0], which is irrelevant.
The same problem hits Field::is_max, which may have checked the wrong record.
Fix:
* Refactor Field::is_max to optionally accept a pointer as an argument.
* Refactor vers_start_id and vers_end_id to always accept a pointer to the
record. there is a difference with is_max is that is_max accepts the pointer to
the
field data, rather than to the record.
Method val_int() would be too effortful to refactor to accept the argument, so
instead the value in record is fetched directly, like it is done in
Field_longlong.
See also MDEV-30046.
Idempotent write_row works same as REPLACE: if there is a duplicating
record in the table, then it will be deleted and re-inserted, with the
same update optimization.
The code in Rows:log_event::write_row was basically copy-pasted from
write_record.
What's done:
REPLACE operation was unified across replication and sql. It is now
representred as a Write_record class, that holds the whole state, and allows
re-using some resources in between the row writes.
Replace, IODKU and single insert implementations are split across different
methods, reluting in a much cleaner code.
The entry point is preserved as a single Write_record::write_record() call.
The implementation to call is chosen on the constructor stage.
This allowed several optimizations to be done:
1. The table key list is not iterated for every row. We find last unique key in
the order of checking once and preserve it across the rows. See last_uniq_key().
2. ib_handler::referenced_by_foreign_key acquires a global lock. This call was
done per row as well. Not all the table config that allows optimized replace is
folded into a single boolean field can_optimize. All the fields to check are
even stored in a single register on a 64-bit platform.
3. DUP_REPLACE and DUP_UPDATE cases now have one less level of indirection
4. modified_non_trans_tables is checked and set only when it's really needed.
5. Obsolete bitmap manipulations are removed.
Also:
* Unify replace initialization step across implementations:
add prepare_for_replace and finalize_replace
* alloca is removed in favor of mem_root allocation. This memory is reused
across the rows.
* An rpl-related callback is added to the replace branch, meaning that an extra
check is made per row replace even for the common case. It can be avoided with
templates if considered a problem.
Lots of different cases, SELECT, SELECT DEFAULT(),
UPDATE t SET x=DEFAULT, prepares statements,
opening of a table for the I_S, prelocking (so TL_WRITE),
insert with subquery (so SQLCOM_SELECT), etc.
Don't check NEXTVAL privileges in fix_fields() anymore, it cannot
possibly handle all the cases correctly. Make a special method
Item_func_nextval::check_access() for that and invoke it from
* fix_fields on explicit SELECT NEXTVAL()
(but not if NEXTVAL() is used in a DEFAULT clause)
* when DEFAULT bareword in used in, say, UPDATE t SET x=DEFAULT
(but not if DEFAULT() itself is used in a DEFAULT clause)
* in CREATE TABLE
* in ALTER TABLE ALGORITHM=INPLACE (that doesn't go CREATE TABLE path)
* on INSERT
helpers
* Virtual_column_info::check_access() to walk the item tree and invoke
Item::check_access()
* TABLE::check_sequence_privileges() to iterate default expressions
and invoke Virtual_column_info::check_access()
also, single-table UPDATE in prepared statements now associates
value items with fields just as multi-update already did, fixes the
case of PREPARE s "UPDATE t SET x=?"; EXECUTE s USING DEFAULT.
Get rid of need of matherialization for usual INSERT (cache results in
Item_cache* if needed)
- subqueries in VALUE do not see new records in the table we are
inserting to
- subqueries in RETIRNING prohibited to use the table we are inserting to
Problem:
========
- After commit cc8eefb0dc (MDEV-33087),
InnoDB does use bulk insert operation for ALTER TABLE.. ALGORITHM=COPY
and CREATE TABLE..SELECT as well. InnoDB fails to clear the bulk
buffer when it encounters error during CREATE..SELECT. Problem
is that while transaction cleanup, InnoDB fails to identify
the bulk insert for DDL operation.
Fix:
====
- Represent bulk_insert in trx by 2 bits. By doing that, InnoDB
can distinguish between TRX_DML_BULK, TRX_DDL_BULK. During DDL,
set bulk insert value for transaction to TRX_DDL_BULK.
- Introduce a parameter HA_EXTRA_ABORT_ALTER_COPY which rollbacks
only TRX_DDL_BULK transaction.
- bulk_insert_apply() happens for TRX_DDL_BULK transaction happens
only during HA_EXTRA_END_ALTER_COPY extra() call.
MDEV-35499 Errored-out CREATE-or-REPLACE-SELECT does not log DROP table into binlog
MDEV-35502 Failed at ROW-format binlogging CREATE-TABLE-SELECT should
not generate Incident event
When a CREATE TABLE .. SELECT errors while inserting data, a user
would expect that all changes are rolled back
and the table would not exist after executing the query.
However CREATE-TABLE-SELECT can face an error near the end of its execution
select_create::send_eof() so that the error was never checked which
led to various assert inside binlogging path that should not be
attended at all.
Specifically when binlog_commit() of ha_commit_one_phase() that
CREATE-TABLE-SELECT employs errored out because of a limited cache size
(binlog_commit may try writing to a transactional cache) the cache
was not flushed to binlog. The missed error check allowed further
execution down to trans_commit_implicit() in whose stack
DBUG_ASSERT(!(entry->using_trx_cache && !mngr->trx_cache.empty() &&
mngr->get_binlog_cache_log(TRUE)->error));
fired. In a non-debug build that table remains created/populated
inconsistently with binlog.
The fixes need and install the error checking in select_create::send_eof().
That prevents from any further execution when ha_commit_one_phase() fails
for any reason (typically due to binlog_commit()).
This commit also covers CREATE-or-REPLACE-SELECT that additionally had
a specific issue in that DROP TABLE was not logged the binary log, MDEV-35499.
See changes select_create::abort_result_set().
The current commit also corrects an unnecessary Incident event
logging when CREATE-TABLE-SELECT encounters a binloging issue, MDEV-35502.
The Incident was actually only harmful in this case as the table was
never going to be created, therefore replicated, in such a case.
In "normal" cases when the SELECT phase errors due to binlogging, an
internal incident flag gets reset inside select_create::abort_result_set().
A hunk in select_insert::prepare_eof() addresses a specific kind of
this issue that deals with incorrect computation of the binlog cache type.
Because of that in the OLD version execution was allowed to proceed along
ha_commit_trans()..binlog_commit() while a Pending event was not
flushed to the transactional cache. That might lead to the unnecessary
binlogged Incident despite the select_create::abort_result_set()
measures. However now with the corrected cache type any binlogging error
to flush the Pending event is covered according to the normal case.
non-transaction table, updates to the non-transactional table
NOTE the commit contains few tests overlapping with unfixed yet MDEV-36027.
Thanks to Brandon Nesterenko and Kristian Nielsen for thorough review,
and Kristian additionally for ideas to simplify the patch and some
code contribution.
disable the assert.
also, use the same check for check_that_all_fields_are_given_values()
as it's used in not_null_fields_have_null_values() - to avoid
issuing the same warning twice.
Problem was that in case of INSERT DELAYED thd->query() is
freed before we call trans_rollback where WSREP_DEBUG
could access thd->query() in wsrep_thd_query().
Fix is to reset thd->query() to NULL in delayed_insert
destructor after it is freed. There is already
null guard at wsrep_thd_query().
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
it's incorrect to zero out table->triggers->extra_null_bitmap
before a statement, because if insert uses an explicit field list
and omits a field that has no default value, the field should
get NULL implicitly. So extra_null_bitmap should have 1s for all
fields that have no defaults
* create extra_null_bitmap_init and initialize it as above
* copy extra_null_bitmap_init to extra_null_bitmap for inserts
* still zero out extra_null_bitmap for updates/deletes where
all fields definitely have a value
* make not_null_fields_have_null_values() to send
ER_NO_DEFAULT_FOR_FIELD for fields with no default and no value,
otherwise creation of a trigger with an empty body would change the
error message
system versioned table
For versioned table REPLACE first tries to insert a row, if it gets
duplicate key error and optimization is possible it does UPDATE +
INSERT history. If optimization is not possible it goes normal branch
for UPDATE to history and repeats the cycle of INSERT.
The failure was in normal branch when we tried UPDATE to history but
such history already exists from previous cycles. There is no such
failures in optimized branch because vers_insert_history_row() already
ignores duplicates.
The fix ignores duplicate errors for UPDATE to history and does DELETE
instead.
DELAYED with virtual columns
Segfault was cause by two different copies of same Field instance in
prepared delayed insert. One was made by
Delayed_insert::get_local_table() (see make_new_field()). That copy
went through parse_vcol_defs() and received new vcol_info->expr.
Another one was made by copy_keys_from_share() by this code:
/*
We are using only a prefix of the column as a key:
Create a new field for the key part that matches the index
*/
field= key_part->field=field->make_new_field(root, outparam, 0);
field->field_length= key_part->length;
So, key_part and table got different objects of same field and the
crash was because key_part->field->vcol_info->expr is NULL.
The fix does update_keypart_vcol_info() to update vcol_info->expr in
key_part->field.
Cleanup: memdup_vcol() is static inline instead of macro + check OOM.
The problems were that:
1) resources was freed "asimetric" normal execution in send_eof,
in case of error in destructor.
2) destructor was not called in case of SP for result objects.
(so if the last SP execution ended with error resorces was not
freeded on reinit before execution (cleanup() called before next
execution) and destructor also was not called due to lack of
delete call for the object)
Result cleanup() renamed to reset_for_next_ps_execution() to better
reflect function().
All result method revised and freeing resources made "symetric".
Destructor of result object called for SP.
Added skipped invalidation in case of error in insert.
Removed misleading naming of reset(thd) (could be mixed with
with reset()).
This problem occured for statements like `INSERT INTO t1 SELECT 1`,
which do not have tables in the SELECT part. In such scenarios
SELECT_LEX::insert_tables was not properly set at `setup_tables()`,
and this led to either incorrect execution or a crash
Reviewer: Oleksandr Byelkin <sanja@mariadb.com>
