MySQL Cluster 8.0.20 has been released
Posted by: Balasubramanian Kandasamy
Date: April 27, 2020 10:42AM
Date: April 27, 2020 10:42AM
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 8.0.20 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.
The release notes are available from
http://dev.mysql.com/doc/relnotes/mysql-cluster/8.0/en/index.html
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 8.0.20 (2020-04-27, General Availability)
MySQL NDB Cluster 8.0.20 is a new release of NDB 8.0, based
on MySQL Server 8.0 and including features in version 8.0 of
the NDB storage engine, as well as fixing recently discovered
bugs in previous NDB Cluster releases.
Obtaining NDB Cluster 8.0. NDB Cluster 8.0 source code and
binaries can be obtained from
https://dev.mysql.com/downloads/cluster/.
For an overview of changes made in NDB Cluster 8.0, see What
is New in NDB Cluster
(https://dev.mysql.com/doc/refman/8.0/en/mysql-cluster-what-is-new.html).
This release also incorporates all bug fixes and changes made
in previous NDB Cluster releases, as well as all bug fixes
and feature changes which were added in mainline MySQL 8.0
through MySQL 8.0.20 (see Changes in MySQL 8.0.20 (2020-04-27, General Availability)
(https://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-20.html)).
* Functionality Added or Changed
* Bugs Fixed
Functionality Added or Changed
* Important Change: It is now possible to divide a backup
into slices and to restore these in parallel using two
new options implemented for the ndb_restore utility,
making it possible to employ multiple instances of
ndb_restore to restore subsets of roughly the same size
of the backup in parallel, which should help to reduce
the length of time required to restore an NDB Cluster
from backup.
The --num-slices options determines the number of slices
into which the backup should be divided; --slice-id
provides the ID of the slice (0 to 1 less than the number
of slices) to be restored by ndb_restore.
Up to 1024 slices are supported.
For more information, see the descriptions of the
--num-slices and --slice-id options. (Bug #30383937)
* Important Change: To increase the rate at which update
operations can be processed, NDB now supports and by
default makes use of multiple transporters per node
group. By default, the number of transporters used by
each node group in the cluster is equal to the number of
the number of local data management (LDM) threads. While
this number should be optimal for most use cases, it can
be adjusted by setting the value of the
NodeGroupTransporters data node configuration parameter
which is introduced in this release. The maximum is the
greater of the number of LDM threads or the number of TC
threads, up to an overall maximum of 32 transporters.
See Multiple Transporters
(https://dev.mysql.com/doc/refman/8.0/en/mysql-cluster-ndbd-definition.html#mysql-cluster-multiple-transporters),
for additional information.
* NDB Client Programs: Two options are added for the
ndb_blob_tool utility, to enable it to detect missing
blob parts for which inline parts exist, and to replace
these with placeholder blob parts (consisting of space
characters) of the correct length. To check whether there
are missing blob parts, use the ndb_blob_tool
--check-missing option. To replace with placeholders any
blob parts which are missing, use the program's
--add-missing option, also added in this release. (Bug
#28583971)
* NDB Client Programs: Removed a dependency from the
ndb_waiter and ndb_show_tables utility programs on the
NDBT library. This library, used in NDB development for
testing, is not required for normal use. The visible
effect for users from this change is that these programs
no longer print NDBT_ProgramExit - status following
completion of a run. Applications that depend upon this
behavior should be updated to reflect this change when
upgrading to this release.
* MySQL NDB ClusterJ: A few Java APIs used by ClusterJ are
now deprecated in recent Java versions. These adjustments
have been made to ClusterJ:
+ Replaced all Class.newInstance() calls with
Class.getDeclaredConstructor().newInstance() calls.
Also updated the exception handling and the test
cases wherever required.
+ All the Number classes' constructors that
instantiate an object from a String or a primitive
type are deprecated. Replaced all such deprecated
instantiation calls with the corresponding valueOf()
method calls.
+ The Proxy.getProxyClass() is now deprecated. The
DomainTypeHandlerImpl class now directly creates a
new instance using the Proxy.newProxyInstance()
method; all references to the Proxy class and its
constructors are removed from the
DomainTypeHandlerImpl class. SessionFactoryImpl
class now uses the interfaces underlying the proxy
object to identify the domain class rather than
using the Proxy class. Also updated
DomainTypeHandlerFactoryTest.
+ The finalize() method is now deprecated. This patch
does not change the overriding finalize() methods,
but just suppresses the warnings on them. This
deprecation will be handled separately in a later
patch.
+ Updated the CMake configuration to treat deprecation
warnings as errors when compiling ClusterJ.
(Bug #29931625)
* MySQL NDB ClusterJ: The minimum Java version ClusterJ
supports for MySQL NDB Cluster 8.0 is now Java 8. (Bug
#29931625)
* MySQL NDB ClusterJ: The unused antlr3 plugin has been
removed from the ClusterJ pom file. (Bug #29931625)
* NDB now supports versioning for ndbinfo tables, and
maintains the current definitions for its tables
internally. At startup, NDB compares its supported
ndbinfo version with the version stored in the data
dictionary. If the versions differ, NDB drops any old
ndbinfo tables and recreates them using the current
definitions.
* Many outer joins and semijoins which previously could not
be pushed down to the data nodes can now pushed (see
Engine Condition Pushdown Optimization
(https://dev.mysql.com/doc/refman/8.0/en/condition-pushdown-optimization.html)).
Outer joins which can now be pushed include those which
meet the following conditions:
+ There are no unpushed conditions on this table
+ There are no unpushed conditions on other tables in
the same join nest, or in upper join nests on which
it depends
+ All other tables in the same join nest, or in upper
join nests on which it depends are also pushed
A semijoin using an index scan can now be pushed if it
meets the the conditions just noted for a pushed outer
join, and it uses the firstMatch strategy.
References: See also: Bug #28728603, Bug #28672214, Bug
#29296615, Bug #29232744, Bug #29161281, Bug #28728007.
* A new and simplified interface is implemented for
enabling and configuring adaptive CPU spin. The
SpinMethod data node parameter, added in this release,
provides the following four settings:
+ StaticSpinning: Disables adaptive spinning; uses the
static spinning employed in previous NDB Cluster
releases
+ CostBasedSpinning: Enables adaptive spinning using a
cost-based model
+ LatencyOptimisedSpinning: Enables adaptive spinning
optimized for latency
+ DatabaseMachineSpinning: Enables adaptive spinning
optimized for machines hosting databases, where each
thread has its own CPU
Each of these settings causes the data node to use a set
of predetermined values, as needed, for one or more of
the spin parameters listed here:
+ SchedulerSpinTimer: The data node configuration
parameter of this name.
+ EnableAdaptiveSpinning: Enables or disables adaptive
spinning; cannot be set directly in the cluster
configuration file, but can be controlled directly
using DUMP 104004
+ SetAllowedSpinOverhead: CPU time to allow to gain
latency; cannot be set directly in the config.ini
file, but possible to change directly, using DUMP
104002
The presets available from SpinMethod should cover most
use cases, but you can fine-tune the adaptive spin
behavior using the SchedulerSpinTimer data node
configuration parameter and the DUMP commands just
listed, as well as additional DUMP commands in the
ndb_mgm cluster management client; see the description of
SchedulerSpinTimer for a complete listing.
NDB 8.0.20 also adds a new TCP configuration parameter
TcpSpinTime which sets the time to spin for a given TCP
connection. This can be used to enable adaptive spinning
for any such connections between data nodes, management
nodes, and SQL or API nodes.
The ndb_top tool is also enhanced to provide spin time
information per thread; this is displayed in green in the
terminal window.
For more information, see the descriptions of the
SpinMethod and TcpSpinTime configuration parameters, the
DUMP commands listed or indicated previously, and the
documentation for ndb_top.
Bugs Fixed
* Important Change: When lower_case_table_names was set to
0, issuing a query in which the lettercase of any foreign
key names differed from the case with which they were
created led to an unplanned shutdown of the cluster. This
was due to the fact that mysqld treats foreign key names
as case insensitive, even on case-sensitive file systems,
whereas the manner in which the NDB dictionary stored
foreign key names depended on the value of
lower_case_table_names, such that, when this was set to
0, during lookup, NDB expected the lettercase of any
foreign key names to match that with which they were
created. Foreign key names which differed in lettercase
could then not be found in the NDB dictionary, even
though it could be found in the MySQL data dictionary,
leading to the previously described issue in NDBCLUSTER.
This issue did not happen when lower_case_table_names was
set to 1 or 2.
The problem is fixed by making foreign key names case
insensitive and removing the dependency on
lower_case_table_names. This means that the following two
items are now always true:
1. Foreign key names are now stored using the same
lettercase with which they are created, without
regard to the value of lower_case_table_names.
2. Lookups for foreign key names by NDB are now always
case insensitive.
(Bug #30512043)
* Packaging: Removed an unnecessary dependency on Perl from
the mysql-cluster-community-server-minimal RPM package.
(Bug #30677589)
* Packaging: NDB did not compile successfully on Ubuntu
16.04 with GCC 5.4 due to the use of isnan() rather than
std::isnan(). (Bug #30396292)
References: This issue is a regression of: Bug #30338980.
* OS X: Removed the variable SCHEMA_UUID_VALUE_LENGTH which
was used only once in the NDB sources, and which caused
compilation warnings when building on Mac OSX. The
variable has been replaced with UUID_LENGTH. (Bug
#30622139)
* MySQL NDB ClusterJ: When a Date value was read from a NDB
cluster, ClusterJ sometimes extracted the wrong year
value from the row. It was because the Utility class,
when unpacking the Date value, wrongly extracted some
extra bits for the year. This patch makes ClusterJ only
extract the required bits. (Bug #30600320)
* MySQL NDB ClusterJ: When the cluster's
NdbOperation::AbortOption type had the value of
AO_IgnoreOnError, when there was a read error, ClusterJ
took that as the row was missing and returned null
instead of an exception. This was because with
AO_IgnoreOnErro, the execute() method always returns a
success code after each transaction, and ClusterJ is
supposed to check for any errors in any of the individual
operations; however, read operations were not checked by
ClusterJ in the case. With this patch, read operations
are now checked for errors after query executions, so
that a reading error is reported as such. (Bug #30076276)
* The fix for a previous issue in the MySQL Optimizer
adversely affected engine condition pushdown for the NDB
storage engine. (Bug #303756135)
References: This issue is a regression of: Bug #97552,
Bug #30520749.
* When restoring signed auto-increment columns, ndb_restore
incorrectly handled negative values when determining the
maximum value included in the data. (Bug #30928710)
* Formerly (prior to NDB 7.6.4) an SPJ worker instance was
activated for each fragment of the root table of the
pushed join, but in NDB 7.6 and later, a single worker is
activated for each data node and is responsible for all
fragments on that data node.
Before this change was made, it was sufficient for each
such worker to scan a fragment with parallelism equal to
1 for all SPJ workers to keep all local data manager
threads busy. When the number of workers was reduced as
result of the change, the minimum parallelism should have
been increased to equal the number of fragments per
worker to maintain the degree of parallelism.
This fix ensures that this is now done. (Bug #30639503)
* The ndb_metadata_sync system variable is set to true to
trigger synchronization of metadata between the MySQL
data dictionary and the NDB dictionary; when
synchronization is complete, the variable is
automatically reset to false to indicate that this has
been done. One scenario involving the detection of a
schema not present in the MySQL data dictionary but in
use by the NDB Dictionary sometimes led to
ndb_metadata_sync being reset before all tables belonging
to this schema were successfully synchronized. (Bug
#30627292)
* When using shared user and grants, all ALTER USER
statements were distributed as snapshots, whether they
contained plaintext passwords or not.
In addition, SHOW CREATE USER did not include resource
limits (such as MAX_QUERIES_PER_HOUR) that were set to
zero, which meant that these were not distributed among
SQL nodes. (Bug #30600321)
* Two buffers used for logging in QMGR were of insufficient
size. (Bug #30598737)
References: See also: Bug #30593511.
* Removed extraneous debugging output relating to SPJ from
the node out logs. (Bug #30572315)
* When performing an initial restart of an NDB Cluster,
each MySQL Server attached to it as an SQL node
recognizes the restart, reinstalls the ndb_schema table
from the data dictionary, and then clears all NDB schema
definitions created prior to the restart. Because the
data dictionary was cleared only after ndb_schema is
reinstalled, installation sometimes failed due to
ndb_schema having the same table ID as one of the tables
from before the restart was performed. This issue is
fixed by ensuring that the data dictionary is cleared
before the ndb_schema table is reinstalled. (Bug
#30488610)
* When the optimizer decides to presort a table into a
temporary table, before later tables are joined, the
table to be sorted should not be part of a pushed join.
Although logic was present in the abstract query plan
interface to detect such query plans, that this did not
detect correctly all situations using filesort into
temporary table. This is changed to check whether a
filesort descriptor has been set up; if so, the table
content is sorted into a temporary file as its first step
of accessing the table, which greatly simplifies
interpretation of the structure of the join. We now also
detect when the table to be sorted is a part of a pushed
join, which should prevent future regressions in this
interface. (Bug #30338585)
* When a node ID allocation request failed with NotMaster
temporary errors, the node ID allocation was always
retried immediately, without regard to the cause of the
error. This caused a very high rate of retries, whose
effects could be observed as an excessive number of Alloc
node id for node nnn failed log messages (on the order of
15,000 messages per second). (Bug #30293495)
* For NDB tables having no explicit primary key,
NdbReceiverBuffer could be allocated with too small a
size. This was due to the fact that the attribute bitmap
sent to NDB from the data nodes always includes the
primary key. The extra space required for hidden primary
keys is now taken into consideration in such cases. (Bug
#30183466)
* When translating an NDB table created using .frm files in
a previous version of NDB Cluster and storing it as a
table object in the MySQL data dictionary, it was
possible for the table object to be committed even when a
mismatch had been detected between the table indexes in
the MySQL data dictionary and those for the same table's
representation the NDB dictionary. This issue did not
occur for tables created in NDB 8.0, where it is not
necessary to upgrade the table metadata in this fashion.
This problem is fixed by making sure that all such
comparisons are actually performed before the table
object is committed, regardless of whether the
originating table was created with or without the use of
.frm files to store its metadata. (Bug #29783638)
* NDB sometimes made the assumption that the list of nodes
containing index statistics was ordered, but this list is
not always ordered in the same way on all nodes. This
meant that in some cases NDB ignored a request to update
index statistics, which could result in stale data in the
index statistics tables. (Bug #3044482)
* An error raised when obtaining cluster metadata caused a
memory leak. (Bug #97737, Bug #30575163)
On Behalf of MySQL Release Engineering team,
Balasubramanian Kandasamy
Subject
Views
Written By
Posted
Sorry, you can't reply to this topic. It has been closed.
Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.