Adding virtual methods to class Schema:
make_item_func_replace()
make_item_func_substr()
make_item_func_trim()
This is a non-functional preparatory change for MDEV-27744.
Variant #2.
When Histogram::point_selectivity() sees that the point value of interest
falls into one bucket, it tries to guess whether the bucket has many
different (unpopular) values or a few popular values. (The number of
rows is fixed, as it's a Height-balanced histogram).
The basis for this guess is the "width" of the value range the bucket
covers. Buckets covering wider value ranges are assumed to contain
values with proportionally lower frequencies.
This is just a [brave] guesswork. For a very narrow bucket, it may
produce an estimate that's larger than total #rows in the bucket
or even in the whole table.
Remove the guesswork and replace it with basic logic: return
either the per-table average selectivity of col=const, or selectivity
of one bucket, whichever is lower.
Fix-up for commit 476b24d084
Author: Monty
Date: Thu Feb 16 14:19:33 2023 +0200
MDEV-20057 Distinct SUM on CROSS JOIN and grouped returns wrong result
which misses initializing of sorder->suffix_length.
In this commit the initialization is implemented by passing
MY_ZEROFILL flag to the allocation of SORT_FIELD elements
When using binlog_row_image=FULL with sequence table inserts, a
replica can deadlock because it treats full inserts in a sequence as DDL
statements by getting an exclusive lock on the sequence table. It
has been observed that with parallel replication, this exclusive
lock on the sequence table can lead to a deadlock where one
transaction has the exclusive lock and is waiting on a prior
transaction to commit, whereas this prior transaction is waiting on
the MDL lock.
This fix for this is on the master side, to raise FL_DDL
flag on the GTID of a full binlog_row_image write of a sequence table.
This forces the slave to execute the statement serially so a deadlock
cannot happen.
A test verifies the deadlock also to prove it happen on the OLD (pre-fixes)
slave.
OLD (buggy master) -replication-> NEW (fixed slave) is provided.
As the pre-fixes master's full row-image may represent both
SELECT NEXT VALUE and INSERT, the parallel slave pessimistically
waits for the prior transaction to have committed before to take on the
critical part of the second (like INSERT in the test) event execution.
The waiting exploits a parallel slave's retry mechanism which is
controlled by `@@global.slave_transaction_retries`.
Note that in order to avoid any persistent 'Deadlock found' 2013 error
in OLD -> NEW, `slave_transaction_retries` may need to be set to a
higher than the default value.
START-SLAVE is an effective work-around if this still happens.
The error was seen by a number of mtr tests being caused
by overdue initialization of rpl_parallel::LOCK_parallel_entry.
Specifically, SHOW-SLAVE-STATUS might find in
rpl_parallel::workers_idle() a gtid domain hash entry
already inserted whose mutex had not done
mysql_mutex_init().
Fixed with swapping the mutex init and the its entry's stack insertion.
Tested with a generous number of `mtr --repeat` of a few of the reported
to fail tests, incl rpl.parallel_backup.
When replicating MDL events for a table that uses system versioning
without primary keys, ensure that for data sets with duplicate
records, the updates to these records with duplicates are enacted on
the correct row. That is, there was a bug (reported in MDEV-30430)
such that the function to find the row to update would stop after
finding the first matching record. However, in the absence of
primary keys, the version of the record is needed to compare the row
to ensure we are updating the correct one.
The fix, therefore, updates the record comparison functionality to
use system version columns when there are no primary keys on the
table.
Reviewed By:
============
Andrei Elkin <andrei.elkin@mariadb.com>
Problem:
========
A master can segfault if it can't set up decryption for its binary
log during a binlog dump with Using_Gtid=Slave_Pos. If slave
connects using GTID mode, the master will call into
log.cc::get_gtid_list_event(), which iterate through binlog events
looking for a Gtid_list_log_event. On an encrypted binlog that the
master cannot decrypt, the first event will be a
START_ENCRYPTION_EVENT which will call into the following decryption branch
if (fdle->start_decryption((Start_encryption_log_event*) ev))
errormsg= ‘Could not set up decryption for binlog.’;
The event iteration however, does not stop in spite of this error.
The master will try to read the next event, but segfault while
trying to decrypt it because decryption failed to initialize.
Solution:
========
Break the event iteration if decryption cannot be set up.
Reviewed By:
============
Andrei Elkin <andrei.elkin@mariadb.com>
This bug could manifest itself at the first execution of prepared statement
created for queries using a materialized view defined as union. A crash
could happen for sure if the query contained a condition pushable into
the view and this condition was over the column defined via a complex string
expression requiring implicit conversion from one charset to another for
some of its sub-expressions. The bug could cause crashes when executing
PS for some other queries whose optimization needed building clones for
such expressions.
This bug was introduced in the patch for MDEV-29988 where the class
Item_direct_ref_to_item was added. The implementations of the virtual
methods get_copy() and build_clone() were invalid for the class and this
could cause crashes after the method build_clone() was called for
expressions containing objects of the Item_direct_ref_to_item type.
Approved by Sergei Golubchik <serg@mariadb.com>
Fixing buildbot failures on mariabackup.aria_log_dir_path_rel.
The problem was that directory_exists() was called with the
relative aria_log_dir_path value, while the current directory
in mariadb-backup is not necessarily equal to datadir when MTR is running.
Fix:
- Moving building the absolute path un level upper:
from the function copy_back_aria_logs() to the function copy_back().
- Passing the built absolute path to both directory_exists() and
copy_back_aria_logs() as a parameter.
This bug caused server crash when processing a multi-update statement that
used views if optimizer tracing was enabled.
The bug was introduced in the patch for MDEV-30539 that could incorrectly
detect the most top level selects of queries if views were used in them.
Approved by Oleksandr Byelkin <sanja@mariadb.com>
- `mariadb-backup --backup` was fixed to fetch the value of the
@@aria_log_dir_path server variable and copy aria_log* files
from @@aria_log_dir_path directory to the backup directory.
Absolute and relative (to --datadir) paths are supported.
Before this change aria_log* files were copied to the backup
only if they were in the default location in @@datadir.
- `mariadb-backup --copy-back` now understands a new my.cnf and command line
parameter --aria-log-dir-path.
`mariadb-backup --copy-back` in the main loop in copy_back()
(when copying back from the backup directory to --datadir)
was fixed to ignore all aria_log* files.
A new function copy_back_aria_logs() was added.
It consists of a separate loop copying back aria_log* files from
the backup directory to the directory specified in --aria-log-dir-path.
Absolute and relative (to --datadir) paths are supported.
If --aria-log-dir-path is not specified,
aria_log* files are copied to --datadir by default.
- The function is_absolute_path() was fixed to understand MTR style
paths on Windows with forward slashes, e.g.
--aria-log-dir-path=D:/Buildbot/amd64-windows/build/mysql-test/var/...
fp->field_length was unsigned and therefore the negative
condition around it.
Backport of cc182aca93 fixes it, however to correct the
consistent use of types pcf->Length needs to be unsigned
too.
At one point pcf->Precision is assigned from pcf->Length so
that's also unsigned.
GetTypeSize is assigned to length and has a length argument.
A -1 default value seemed dangerious to case, so at least 0
should assert if every hit.
Similar to 567b6812 continue to replace use of strcat() and
strcpy() with safer options strncat() and strncpy().
All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the BSD-new
license. I am contributing on behalf of my employer Amazon Web Services
do_shutdown_server(): After sending SIGKILL, invoke wait_until_dead().
Thanks to Sergei Golubchik for pointing out that the previous fix
does not actually work.
stored externally
row_merge_buf_add(): Has strict assert that fixed length mismatch
shouldn't happen while rebuilding the redundant row format table
btr_index_rec_validate(): Fixed size column can be stored externally.
So sum of inline stored length and external stored length of the
column should be equal to total column length
This issue happens when race condition happens when DDL
and fts optimize thread. DDL adds the new index to fts cache.
At the same time, fts optimize thread clears the cache
and reinitialize it. Take cache init lock before reinitializing
the cache. fts_sync_commit() should take dict_sys mutex
to avoid the deadlock with create index.
do_shutdown_server(): Call wait_until_dead() also when we are forcibly
killing the process (timeout=0). We have evidence that killing
the process may take some time and cause mystery failures in
crash recovery tests. For InnoDB, several failures were observed between
commit da094188f6 and
commit 0ee1082bd2
when no advisory file locking was being used by default.
Assertion `thd->mdl_context.is_lock_owner()` fires when a client is
disconnected, while transaction and and a table is opened through
`HANDLER` interface.
Reason for the assertion is that when a connection closes, its ongoing
transaction is eventually rolled back in
`Wsrep_client_state::bf_rollback()`. This method also releases explicit
which are expected to survive beyond the transaction lifetime.
This patch also removes calls to `mysql_ull_cleanup()`. User level
locks are not supported in combination with Galera, making these calls
unnecessary.
The glibc headers declare fallocate only if _GNU_SOURCE is defined.
Without this change, the probe fails with C compilers which do not
support implicit function declarations even if the system does in
fact support the fallocate function.
Upstream rocksdb does not need this because the probe is run with the
C++ compiler, and current g++ versions define _GNU_SOURCE
automatically.
This commit adds a new 'no-sni' option to socat which is required to
properly authenticate with newer socat versions (after version 1.7.4+).
This option is needed to disable the automatic use of the SNI feature
(Server Name Indication) since the SST script directly specifies the
commonname if necessary and automatic activation of the SNI feature
is unnecessary in such scenarios.
This bug could affect multi-update statements as well as single-table
update statements processed as multi-updates when the where condition
contained a range condition over a non-indexed varchar column. The
optimizer calculates selectivity of such range conditions using histograms.
For each range the buckets containing endpoints of the the range are
determined with a procedure that stores the values of the endpoints in the
space of the record buffer where values of the columns are usually stored.
For a range over a varchar column the value of a endpoint may exceed the
size of the buffer and in such case the value is stored with truncation.
This truncations cannot affect the result of the calculation of the range
selectivity as the calculation employes only the beginning of the value
string. However it can trigger generation of an unexpected error on this
truncation if an update statement is processed.
This patch prohibits truncation messages when selectivity of a range
condition is calculated for a non-indexed column.
Approved by Oleksandr Byelkin <sanja@mariadb.com>
This is a non-functional change.
simplifying the code logic:
- removing global variables ds_data and ds_meta
- passing these variables as parameters to functions instead
- adding helper classes: Datasink_free_list and Backup_datasinks
- moving some function accepting a ds_ctxt parameter
as methods to ds_ctxt.
If we are inside stored function or trigger we should not commit
or rollback current statement transaction.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
server has systemd support and calls sd_notify() to communicate
the status to systemd.
mariabackup links the whole server in, but it should not notify
systemd, because it's not started or managed by systemd.
- Adding a new argument "flag" to MY_COLLATION_HANDLER::strnncollsp_nchars()
and a flag MY_STRNNCOLLSP_NCHARS_EMULATE_TRIMMED_TRAILING_SPACES.
The flag defines if strnncollsp_nchars() should emulate trailing spaces
which were possibly trimmed earlier (e.g. in InnoDB CHAR compression).
This is important for NOPAD collations.
For example, with this input:
- str1= 'a ' (Latin letter a followed by one space)
- str2= 'a ' (Latin letter a followed by two spaces)
- nchars= 3
if the flag is given, strnncollsp_nchars() will virtually restore
one trailing space to str1 up to nchars (3) characters and compare two
strings as equal:
- str1= 'a ' (one extra trailing space emulated)
- str2= 'a ' (as is)
If the flag is not given, strnncollsp_nchars() does not add trailing
virtual spaces, so in case of a NOPAD collation, str1 will be compared
as less than str2 because it is shorter.
- Field_string::cmp_prefix() now passes the new flag.
Field_varstring::cmp_prefix() and Field_blob::cmp_prefix() do
not pass the new flag.
- The branch in cmp_whole_field() in storage/innobase/rem/rem0cmp.cc
(which handles the CHAR data type) now also passed the new flag.
- Fixing UCA collations to respect the new flag.
Other collations are possibly also affected, however
I had no success in making an SQL script demonstrating the problem.
Other collations will be extended to respect this flags in a separate
patch later.
- Changing the meaning of the last parameter of Field::cmp_prefix()
from "number of bytes" (internal length)
to "number of characters" (user visible length).
The code calling cmp_prefix() from handler.cc was wrong.
After this change, the call in handler.cc became correct.
The code calling cmp_prefix() from key_rec_cmp() in key.cc
was adjusted according to this change.
- Old strnncollsp_nchar() related tests in unittest/strings/strings-t.c
now pass the new flag.
A few new tests also were added, without the flag.
