* Log rows in online_alter_binlog.
* Table online data is replicated within dedicated binlog file
* Cached data is written on commit.
* Versioning is fully supported.
* Works both wit and without binlog enabled.
* For now savepoints setup is forbidden while ONLINE ALTER goes on.
Extra support is required. We can simply log the SAVEPOINT query events
and replicate them together with row events. But it's not implemented
for now.
* Cache flipping:
We want to care for the possible bottleneck in the online alter binlog
reading/writing in advance.
IO_CACHE does not provide anything better that sequential access,
besides, only a single write is mutex-protected, which is not suitable,
since we should write a transaction atomically.
To solve this, a special layer on top Event_log is implemented.
There are two IO_CACHE files underneath: one for reading, and one for
writing.
Once the read cache is empty, an exclusive lock is acquired (we can wait
for a currently active transaction finish writing), and flip() is emitted,
i.e. the write cache is reopened for read, and the read cache is emptied,
and reopened for writing.
This reminds a buffer flip that happens in accelerated graphics
(DirectX/OpenGL/etc).
Cache_flip_event_log is considered non-blocking for a single reader and a
single writer in this sense, with the only lock held by reader during flip.
An alternative approach by implementing a fair concurrent circular buffer
is described in MDEV-24676.
* Cache managers:
We have two cache sinks: statement and transactional.
It is important that the changes are first cached per-statement and
per-transaction.
If a statement fails, then only statement data is rolled back. The
transaction moves along, however.
Turns out, there's no guarantee that TABLE well persist in
thd->open_tables to the transaction commit moment.
If an error occurs, tables from statement are purged.
Therefore, we can't store te caches in TABLE. Ideally, it should be
handlerton, but we cut the corner and store it in THD in a list.
This patch adds for "--ps-protocol" second execution
of queries "SELECT".
Also in this patch it is added ability to disable/enable
(--disable_ps2_protocol/--enable_ps2_protocol) second
execution for "--ps-prototocol" in testcases.
ANALYZE FORMAT=JSON output now includes table.r_engine_stats which
has the engine statistics. Only non-zero members are printed.
Internally: EXPLAIN data structures Explain_table_acccess and
Explain_update now have handler* handler_for_stats pointer.
It is used to read statistics from handler_for_stats->handler_stats.
The following applies only to 10.9+, backport doesn't use it:
Explain data structures exist after the tables are closed. We avoid
walking invalid pointers using this:
- SQL layer calls Explain_query::notify_tables_are_closed() before
closing tables.
- After that call, printing of JSON output is disabled. Non-JSON output
can be printed but we don't access handler_for_stats when doing that.
The new statistics is enabled by adding the "engine", "innodb" or "full"
option to --log-slow-verbosity
Example output:
# Pages_accessed: 184 Pages_read: 95 Pages_updated: 0 Old_rows_read: 1
# Pages_read_time: 17.0204 Engine_time: 248.1297
Page_read_time is time doing physical reads inside a storage engine.
(Writes cannot be tracked as these are usually done in the background).
Engine_time is the time spent inside the storage engine for the full
duration of the read/write/update calls. It uses the same code as
'analyze statement' for calculating the time spent.
The engine statistics is done with a generic interface that should be
easy for any engine to use. It can also easily be extended to provide
even more statistics.
Currently only InnoDB has counters for Pages_% and Undo_% status.
Engine_time works for all engines.
Implementation details:
class ha_handler_stats holds all engine stats. This class is included
in handler and THD classes.
While a query is running, all statistics is updated in the handler. In
close_thread_tables() the statistics is added to the THD.
handler::handler_stats is a pointer to where statistics should be
collected. This is set to point to handler::active_handler_stats if
stats are requested. If not, it is set to 0.
handler_stats has also an element, 'active' that is 1 if stats are
requested. This is to allow engines to avoid doing any 'if's while
updating the statistics.
Cloned or partition tables have the pointer set to the base table if
status are requested.
There is a small performance impact when using --log-slow-verbosity=engine:
- All engine calls in 'select' will be timed.
- IO calls for InnoDB reads will be timed.
- Incrementation of counters are done on local variables and accesses
are inline, so these should have very little impact.
- Statistics has to be reset for each statement for the THD and each
used handler. This is only 40 bytes, which should be neglectable.
- For partition tables we have to loop over all partitions to update
the handler_status as part of table_init(). Can be optimized in the
future to only do this is log-slow-verbosity changes. For this to work
we have to update handler_status for all opened partitions and
also for all partitions opened in the future.
Other things:
- Added options 'engine' and 'full' to log-slow-verbosity.
- Some of the new files in the test suite comes from Percona server, which
has similar status information.
- buf_page_optimistic_get(): Do not increment any counter, since we are
only validating a pointer, not performing any buf_pool.page_hash lookup.
- Added THD argument to save_explain_data_intern().
- Switched arguments for save_explain_.*_data() to have
always THD first (generates better code as other functions also have THD
first).
* removed universal suppression of everything "Event Schedule" everywhere
* added suppressions in tests as needed
* moved events test to the events suite
* renamed -master.opt -> .opt
* added standard test header
* verified in the test that the error, indeed, was written into the log
* removed useless suppressions
* removed ER_EVENTS_NO_ACL, replaced with ER_OPTION_PREVENTS_STATEMENT
* fixed error message to say exactly what option disabled event scheduler
instead of "this or that or that, you figure it out"
* also fixed old message for SET event_scheduler=
(it was also non-translatable)
* changed to use sql_print_error() when an error is not sent to the user
* removed duplicate hard-coded error message
The reason for the MDEV reported failures is that the tests are enabling
encryption for Aria but not providing any encryption keys.
Fixed by checking if encryption keys exists before creating the table.
Other things:
- maria.encrypt_wrong-key changed as we now get the error on CREATE
instead during insert.
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.
- 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.
EXPLAIN EXTENDED for an UPDATE/DELETE/INSERT/REPLACE statement did not
produce the warning containing the text representation of the query
obtained after the optimization phase. Such warning was produced for
SELECT statements, but not for DML statements.
The patch fixes this defect of EXPLAIN EXTENDED for DML statements.
mtr uses group suffix, but some existing inc and test files use
server_id for expect files. This patch aims to fix that.
For spider:
With this change we will not have to maintain a separate version of
restart_mysqld.inc for spider, that duplicates code, just because
spider tests use different names for expect files, and shutdown_mysqld
requires magical names for them.
With this change spider tests will also be able to use other features
provided by restart_mysqld.inc without code duplication, like the
parameter $restart_parameters (see e.g. the testcase mdev_29904.test
in commit ef1161e5d4f).
Tests run after this change: default, spider, rocksdb, galera, using
the following command
mtr --parallel=auto --force --max-test-fail=0 --skip-core-file
mtr --suite spider,spider/*,spider/*/* \
--skip-test="spider/oracle.*|.*/t\..*" --parallel=auto --big-test \
--force --max-test-fail=0 --skip-core-file
mtr --suite galera --parallel=auto
mtr --suite rocksdb --parallel=auto
Created tests for "delete" based on update_use_source.test
For the update_use_source.test tests, data recovery in the table has been changed
from a rollback transaction to a complete delete and re-insert of the data with
optimize table. Cases are now being checked on three engines.
Added tests for update/delete with LooseScan and DuplicateWeedout optimization strategies
Added tests for engine MEMORY on delete and update
Added tests for multi-update with JSON_TABLE
Added tests for multi-update and multi-delete for engine Connect
