MySQL Cluster 7.6.3 dmr has been released
Piotr Obrzut <[email protected]> Wed, 5 Jul 2017 13:04:40 +0200
| Newsgroups | gmane.comp.db.mysql.announce,gmane.comp.db.mysql.general,gmane.comp.db.mysql.packagers |
|---|---|
| Message-ID | <[email protected]> |
Dear MySQL Users,
MySQL Cluster is the distributed, shared-nothing variant of MySQL.
This storage engine provides:
- In-Memory storage - Real-time performance (with optional
checkpointing to disk)
- Transparent Auto-Sharding - Read & write scalability
- Active-Active/Multi-Master geographic replication
- 99.999% High Availability with no single point of failure
and on-line maintenance
- NoSQL and SQL APIs (including C++, Java, http, Memcached
and JavaScript/Node.js)
MySQL Cluster 7.6.3 dmr, has been released and can be downloaded from
http://www.mysql.com/downloads/cluster/
where you will also find Quick Start guides to help you get your
first MySQL Cluster database up and running.
MySQL Cluster 7.6.3 dmr is also available from our repository for Linux
platforms, go here for details:
http://dev.mysql.com/downloads/repo/
MySQL Cluster enables users to meet the database challenges of next
generation web, cloud, and communications services with uncompromising
scalability, uptime and agility.
More details can be found at
http://www.mysql.com/products/cluster/
Enjoy !
Changes in MySQL NDB Cluster 7.6.3 (5.7.18-ndb-7.6.3) (2017-07-03,
Development Milestone 3)
MySQL NDB Cluster 7.6.3 is a new release of NDB 7.6, based on
MySQL Server 5.7 and including features in version 7.6 of the
NDB storage engine, as well as fixing recently discovered
bugs in previous NDB Cluster releases.
Obtaining NDB Cluster 7.6. NDB Cluster 7.6 source code and
binaries can be obtained from
http://dev.mysql.com/downloads/cluster/.
For an overview of changes made in NDB Cluster 7.6, see What
is New in NDB Cluster 7.6
(http://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-what-is-new-7-6.html).
This release also incorporates all bugfixes and changes made
in previous NDB Cluster releases, as well as all bugfixes and
feature changes which were added in mainline MySQL 5.7
through MySQL 5.7.18 (see Changes in MySQL 5.7.18
(2017-04-10, General Availability)
(http://dev.mysql.com/doc/relnotes/mysql/5.7/en/news-5-7-18.html)).
* Packaging Notes
* Functionality Added or Changed
* Bugs Fixed
Packaging Notes
* mysqladmin was added to Docker/Minimal packages because
it is needed by InnoDB Cluster. (Bug #25998285)
Functionality Added or Changed
* NDB Replication: Added the --ndb-log-update-minimal
option for logging by mysqld. This option causes only
primary key values to be written in the before image, and
only changed columns in the after image. (Bug #24438868)
* In some critical situations such as data node failure, it
was possible for the volume of log messages produced to
cause file system and other issues, which compounded the
problem, due to the fact that these messages were logged
synchronously using stdout. To keep this from happening,
log messages from worker threads now use a log buffer
instead, which is non-blocking, and thus much less likely
to cause interference with other processes under such
conditions. (Bug #24748843)
* Added the --diff-default option for ndb_config. This
option causes the program to print only those parameters
having values that differ from their defaults. (Bug
#85831, Bug #25844166)
* Added the ndb_top program on unix-based platforms. This
utility shows CPU load and usage information for an NDB
data node, with periodic updates (each second, by
default). The display is in text or color ASCII graph
format; both formats can be displayed at the same time.
It is also possible to disable color output for the
graph.
ndb_top connects to an NDB Cluster SQL node---that is, a
MySQL Server---and for this reason must be able to
connect as a MySQL user having the SELECT privilege on
tables in the ndbinfo database.
ndb_top is not currently available for Windows platforms.
For more information, see ndb_top --- View CPU usage
information for NDB threads
(http://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-programs-ndb-top.html).
Bugs Fixed
* Packaging: Two missing dependencies were added to the apt
packages:
+ The data node package requires
libclass-methodmaker-perl
+ The auto-installer requires python-paramiko
(Bug #85679, Bug #25799465)
* NDB Disk Data: If the tablespace for a disk table had
been fully consumed when a node failed, and table rows
were deleted and inserted---or updated with shrinking or
expanding disk column values---while the node was
unavailable, a subsequent restart could fail with error
1601 Out of extents, tablespace full. We prevent this
from happening by reserving 4 percent of the tablespace
for use during node starts. (Bug #25923125)
* NDB Replication: Added a check to stop an NDB replication
slave when configuration as a multi-threaded slave is
detected (for example, if slave_parallel_workers is set
to a nonzero value). (Bug #21074209)
* NDB Cluster APIs: The implementation method
NdbDictionary::NdbTableImpl::getColumn(), used from many
places in the NDB API where a column is referenced by
name, has been made more efficient. This method used a
linear search of an array of columns to find the correct
column object, which could be inefficient for tables with
many columns, and was detected as a significant use of
CPU in customer applications. (Ideally, users should
perform name-to-column object mapping, and then use
column IDs or objects in method calls, but in practice
this is not always done.) A less costly hash index
implementation, used previously for the name lookup, is
reinstated for tables having relatively many columns. (A
linear search continues to be used for tables having
fewer columns, where the difference in performance is
neglible.) (Bug #24829435)
* NDB Cluster APIs: NDB error 631 is reclassified as the
(temporary) node recovery error Scan take over error,
restart scan transaction. This was previously exposed to
applications as an internal (and permanent) error which
provided no description. (Bug #86401, Bug #26116231)
* MySQL NDB ClusterJ: The JTie and NDB JTie tests were
skipped when the unit tests for ClusterJ were being run.
(Bug #26088583)
* Backup .log files contained log entries for one or more
extra fragments, due to an issue with filtering out
changes logged by other nodes in the same node group.
This resulted in a larger .log file and thus use of more
resources than necessary; it could also cause problems
when restoring, since backups from different nodes could
interfere with one another while the log was being
applied. (Bug #25891014)
* Memory exhaustion during fragment creation led to an
unplanned shutdown of the cluster. This issue could be
triggered by the addition of unique keys to a large
number of columns at the same time. (Bug #25851801)
* When making the final write to a redo log file, it is
expected that the next log file is already opened for
writes, but this was not always the case with a slow
disk, leading to node failure. Now in such cases NDB
waits for the next file to be opened properly before
attempting to write to it. (Bug #25806659)
* Data node threads can be bound to a single CPU or a set
of CPUs, a set of CPUs being represented internally by
NDB as a SparseBitmask. When attempting to lock to a set
of CPUs, CPU usage was excessive due to the fact that the
routine performing the locks used the
mt_thr_config.cpp::do_bind() method, which looks for bits
that are set over the entire theoretical range of the
SparseBitmask (2^32-2, or 4294967294). This is fixed by
using SparseBitmask::getBitNo(), which can be used to
iterate over only those bits that are actually set,
instead. (Bug #25799506)
* Setting NoOfFragmentLogParts such that there were more
than 4 redo log parts per local data manager led to
resource exhaustion and subsequent multiple data node
failures. Since this is an invalid configuration, a check
has been added to detect a configuration with more than 4
redo log parts per LDM, and reject it as invalid. (Bug
#25333414)
* In certain cases, a failed ALTER TABLE ... ADD UNIQUE KEY
statement could lead to SQL node failure. (Bug #24444878)
References: This issue is a regression of: Bug #23089566.
* Error 240 is raised when there is a mismatch between
foreign key trigger columns and the values supplied to
them during trigger execution, but had no error message
indicating the source of the problem. (Bug #23141739)
References: See also: Bug #23068914, Bug #85857.
* If the number of LDM blocks was not evenly divisible by
the number of TC/SPJ blocks, SPJ requests were not
equally distributed over the available SPJ instances. Now
a round-robin distribution is used to distribute SPJ
requests across all available SPJ instances more
effectively.
As part of this work, a number of unused member variables
have been removed from the class Dbtc. (Bug #22627519)
* ALTER TABLE .. MAX_ROWS=0 can now be performed only by
using a copying ALTER TABLE statement. Resetting MAX_ROWS
to 0 can no longer be performed using ALGORITHM=INPLACE.
(Bug #21960004)
* During a system restart, when a node failed due to having
missed sending heartbeats, all other nodes reported only
that another node had failed without any additional
information. Now in such cases, the fact that heartbeats
were missed and the ID of the node that failed to send
heartbeats is reported in both the error log and the data
node log. (Bug #21576576)
* Due to a previous issue with unclear separation between
the optimize and execute phases when a query involved a
GROUP BY, the join-pushable evaluator was not sure
whether its optimized query execution plan was in fact
pushable. For this reason, such grouped joins were always
considered not pushable. It has been determined that the
separation issue has been resolved by work already done
in MySQL 5.6, and so we now remove this limitation. (Bug
#86623, Bug #26239591)
* When deleting all rows from a table immediately followed
by DROP TABLE, it was possible that the shrinking of the
DBACC hash index was not ready prior to the drop. This
shrinking is a per-fragment operation that does not check
the state of the table. When a table is dropped, DBACC
releases resources, during which the description of the
fragment size and page directory is not consistent; this
could lead to reads of stale pages, and undefined
behavior.
Inserting a great many rows followed by dropping the
table should also have had such effects due to expansion
of the hash index.
To fix this problem we make sure, when a fragment is
about to be released, that there are no pending expansion
or shrinkage operations on this fragment. (Bug #86449,
Bug #26138592)
* Some error messages still referred to IndexMemory,
although that parameter has been deprecated. (Bug #86385,
Bug #26107514)
* The internal function execute_signals() in mt.cpp read
three section pointers from the signal even when none was
passed to it. This was mostly harmless, although
unneeded. When the signal read was the last one on the
last page in the job buffer, and the next page in memory
was not mapped or otherwise accessible, ndbmtd failed
with an error. To keep this from occurring, this function
now only reads section pointers that are actually passed
to it. (Bug #86354, Bug #26092639)
* There was at most one attempt in Dbacc to remove hash
index pages freed when a table was dropped. This meant
that, for large partitions (32 pages or more) there were
always some pages lost. Now all hash index pages are
freed when table using them is dropped. (Bug #86247, Bug
#26030894)
* When a query on an NDB table failed due to a foreign key
constraint violation, no useful information about the
foreign key was shown in the error message, which
contained only the text Unknown error code. (Bug #86241,
Bug #26029485, Bug #16371292)
References: See also: Bug #16275684.
* The ndb_show_tables program --unqualified option did not
work correctly when set to 0 (false); this should disable
the option and so cause fully qualified table and index
names to be printed in the output. (Bug #86017, Bug
#25923164)
* When an NDB table with foreign key constraints is
created, its indexes are created first, and then, during
foreign key creation, these indexes are loaded into the
NDB dictionary cache. When a CREATE TABLE statement
failed due to an issue relating to foreign keys, the
indexes already in the cache were not invalidated. This
meant that any subsequent CREATE TABLE with any indexes
having the same names as those in the failed statement
produced inconsistent results. Now, in such cases, any
indexes named in the failed CREATE TABLE are immediately
invalidated from the cache. (Bug #85917, Bug #25882950)
* During a local checkpoint, the record size is obtained
from the DBTUP kernel block. This record size remained in
use until the LCP scan was completed, which made it
possible for DBTUP to update the maximum record size on
commit of an ALTER TABLE that added a column to the
table, and which could lead to node failure during the
LCP. Now the record size is fetched at a point where
updating it does not lead to this condition. (Bug #85858,
Bug #25860002)
* Attempting to execute ALTER TABLE ... ADD FOREIGN KEY
when the key to be added had the name of an existing
foreign key on the same table failed with the wrong error
message. (Bug #85857, Bug #23068914)
* The node internal scheduler (in mt.cpp) collects
statistics about its own progress and any outstanding
work it is performing. One such statistic is the number
of outstanding send bytes, collected in
send_buffer::m_node_total_send_buffer_size. This
information may later be used by the send thread
scheduler, which uses it as a metric to tune its own send
performance versus latency.
In order to reduce lock contention on the internal send
buffers, they are split into two thr_send_buffer parts,
m_buffer and m_sending, each protected by its own mutex,
and their combined size repesented by
m_node_total_send_buffer_size.
Investigation of the code revealed that there was no
consistency as to which mutex was used to update
m_node_total_send_buffer_size, with the result that there
was no consurrency protection for this value. To avoid
this, m_node_total_send_buffer_size is replaced with two
values, m_buffered_size and m_sending_size, which keep
separate track of the sizes of the two buffers. These
counters are updated under the protection of two
different mutexes protecting each buffer individually,
and are now added together to obtain the total size.
With concurrency control established, updates of the
partial counts should now be correct, so that their
combined value no longer accumulates errors over time.
(Bug #85687, Bug #25800933)
* Enabled the use of short or packed short TRANSID_AI
signals for sending results from DBSPJ back to the client
API. (Bug #85545, Bug #25750355)
References: See also: Bug #85525, Bug #25741170.
* The maximum BatchByteSize as sent in SCANREQ signals was
not always set correctly to reflect a limited byte size
available in the client result buffers. The result buffer
size calculation has been modified such that the
effective batch byte size accurately reflects the maximum
that may be returned by data nodes to prevent a possible
overflow of the result buffers. (Bug #85411, Bug
#25703113)
* When compiling the NDB kernel with gcc version 6.0.0 or
later, it is now built using -flifetime-dse=1. (Bug
#85381, Bug #25690926)
On Behalf of the MySQL RE Team
Piotr Obrzut
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