MDEV-6218 Wrong result of CHAR_LENGTH(non-BMP-character) with 3-byte utf8
- Moving get_text() as a method to Lex_input_stream.
- Moving the unescaping part into a separate function,
this piece of code will later go to /strings most likely.
- Removing Lex_input_string::yytoklen, as it's not needed any more.
XID cache is now based on lock-free hash.
Also fixed lf_hash_destroy() to call alloc destructor.
Note that previous implementation had race condition when thread was accessing
XA owned by different thread. This new implementation doesn't fix it either.
Review fixes:
- Coding style
- Fix bad .result file
- Fix test to be tolerant of different timing.
- Fix test to give better info in case of unexpected timing.
Parallel replication (in 10.0 / "conservative" mode) relies on binlog group
commits to group transactions that can be safely run in parallel on the
slave. The --binlog-commit-wait-count and --binlog-commit-wait-usec options
exist to increase the number of commits per group. But in case of conflicts
between transactions, this can cause unnecessary delay and reduced througput,
especially on a slave where commit order is fixed.
This patch adds a heuristics to reduce this problem. When transaction T1 goes
to commit, it will first wait for N transactions to queue up for a group
commit. However, if we detect that another transaction T2 is waiting for a row
lock held by T1, then we will skip the wait and let T1 commit immediately,
releasing locks and let T2 continue.
On a slave, this avoids the unfortunate situation where T1 is waiting for T2
to join the group commit, but T2 is waiting for T1 to release locks, causing
no work to be done for the duration of the --binlog-commit-wait-usec timeout.
(The heuristic seems reasonable on the master as well, so it is enabled for
all transactions, not just replication transactions).
Merge from Percona Server enforced use of a specific storage engine
authored by Stewart Smith.
Modified to be session variable and modifiable only by SUPER. Use
similar implementation as default_storage_engine.
fixed embedded server tests
MDEV-7009: SET STATEMENT min_examined_row_limit has no effect
MDEV-6948:SET STATEMENT gtid_domain_id = ... FOR has no effect (same for gtid_seq_no and server_id)
old values of SET STATENENT variables now saved in its own Query_arena and restored later
MASTER_GTID_WAIT function needs some status to evaluate its use.
master_gtid_wait_count indicates how many times the function is called.
master_gtid_wait_time indicates how much time in microseconds occurred
waiting (or timing out)
master_gtid_timeouts indicates how many time times this function timed
out rather than all successful gtids events being available.
INFORMATION_SCHEMA.SYSTEM_VARIABLES.DEFAULT_VALUE had broken values on
big endian.
Default value is internally stored as longlong, while I_S references it's
pointer (longlong *) according to variable type (e.g. int, my_bool, etc). This
works well on little endian, but on big endian we always get 0 for such
variables.
Added a SESSION-only system variable "wsrep_dirty_reads" to allow SELECT
queries to pass even when the node is not prepared to accept queries
(wsrep_ready=OFF). Added a test case.
Added a SESSION-only system variable "wsrep_dirty_reads" to allow SELECT
queries to pass even when the node is not prepared to accept queries
(wsrep_ready=OFF). Added a test case.
Added a SESSION-only system variable "wsrep_dirty_reads" to allow SELECT
queries to pass even when the node is not prepared to accept queries
(wsrep_ready=OFF). Added a test case.
The code in binlog group commit around wait_for_commit that controls commit
order, did the wakeup of subsequent commits early, as soon as a following
transaction is put into the group commit queue, but before any such commit has
actually taken place. This causes problems with too early wakeup of
transactions that need to wait for prior to commit, but do not take part in
the binlog group commit for one reason or the other.
This patch solves the problem, by moving the wakeup to happen only after the
binlog group commit is completed.
This requires a new solution to ensure that transactions that arrive later
than the leader are still able to participate in group commit. This patch
introduces a flag wait_for_commit::commit_started. When this is set, a waiter
can queue up itself in the group commit queue.
This way, effectively the wait_for_prior_commit() is skipped only for
transactions that participate in group commit, so that skipping the wait is
safe. Other transactions still wait as needed for correctness.
The method subselect_union_engine::no_rows() must take
into account the fact that now unit->fake_select_lex is
NULL for for select_union_direct objects.
