MySQL Cluster NDB 7.2.5 is a new release of MySQL Cluster,
incorporating new features in the
NDBCLUSTER storage engine, and
fixing recently discovered bugs in previous MySQL Cluster NDB
Obtaining MySQL Cluster NDB 7.2. MySQL Cluster NDB 7.2 source code and binaries can be obtained from http://dev.mysql.com/downloads/cluster/.
This release also incorporates all bugfixes and changes made in previous MySQL Cluster releases, as well as all bugfixes and feature changes which were added in mainline MySQL 5.5 through MySQL 5.5.20 (see Changes in MySQL 5.5.20 (2012-01-10)).
Important Change: A number of changes have been made in the configuration of transporter send buffers.
The data node configuration parameter
is now deprecated, and thus subject to removal in a future
MySQL Cluster release.
ReservedSendBufferMemory has been
non-functional since it was introduced and remains so.
TotalSendBufferMemory now works correctly
with data nodes using ndbmtd.
A new data node configuration parameter
is introduced. Its purpose is to control how much additional
memory can be allocated to the send buffer over and above
that specified by
SendBufferMemory. The default setting
(0) allows up to 16MB to be allocated automatically.
(Bug #13633845, Bug #11760629, Bug #53053)
Important Change; Cluster Replication:
The master limited the number of operations per transaction to
10000 (based on
could result in a larger number of data-modification operations
in a single epoch than could be applied at one time, due to the
limit imposed on the slave by its (own) setting for
The fix for this issue is to allow a replication slave cluster
to exceed the configured value of
when necessary, so that it can apply all DML operations received
from the master in the same transaction.
Several instances in the NDB code affecting the operation of
multi-threaded data nodes, where
SendBufferMemory was associated with a
specific thread for an unnecessarily long time, have been
identified and fixed, by minimizing the time that any of these
buffers can be held exclusively by a given thread (send buffer
memory being critical to operation of the entire node).
LIKE ... ESCAPE on
NDB tables failed when pushed down
to the data nodes. Such queries are no longer pushed down,
regardless of the value of
(Bug #13604447, Bug #61064)
A data node crashed when more than 16G fixed-size memory was
DBTUP to one fragment (because
DBACC kernel block was not prepared to
accept values greater than 32 bits from it, leading to an
overflow). Now in such cases, the data node returns Error 889
Table fragment fixed data reference has reached
maximum possible value.... When this happens, you
can work around the problem by increasing the number of
partitions used by the table (such as by using the
MAXROWS option with
References: See also Bug #11747870, Bug #34348.
To avoid TCP transporter overload, an overload flag is kept in
the NDB kernel for each data node; this flag is used to abort
key requests if needed, yielding error 1218 Send
Buffers overloaded in NDB kernel in such cases.
Scans can also put significant pressure on transporters,
especially where scans with a high degree of parallelism are
executed in a configuration with relatively small send buffers.
However, in these cases, overload flags were not checked, which
could lead to node failures due to send buffer exhaustion. Now,
overload flags are checked by scans, and in cases where
returning sufficient rows to match the batch size
--ndb-batch-size server option)
would cause an overload, the number of rows is limited to what
can be accommodated by the send buffer.
See also Configuring MySQL Cluster Send Buffer Parameters. (Bug #13602508)
ndb_engine.so with only 2 API slots
available in the cluster configuration file,
memcached attempted to make a third
connection and crashed when this failed.
References: See also Bug #13608135.
A node failure and recovery while performing a scan on more than 32 partitions led to additional node failures during node takeover. (Bug #13528976)
option now causes ndb_mgmd to skip checking
for the configuration directory, and thus to skip creating it in
the event that it does not exist.
Conflict detection and resolution for statements updating a
given table could be employed only on the same server where the
table was created. When an
table is created by executing DDL on an SQL node, the binary log
setup portion of the processing for the
CREATE TABLE statement reads the
table's conflict detection function from the
ndb_replication table and sets up that function for the table.
However, when the created table was discovered by other SQL
nodes attached to the same MySQL Cluster due to schema
distribution, the conflict detection function was not correctly
set up. The same problem occurred when an
table was discovered as a result of selecting a database for the
first time (such as when executing a
USE statement), and when a table
was discovered as a result of scanning all files at server
Both of these issues were due to a dependency of the conflict
detection and resolution code on table objects, even in cases
where checking for such objects might not be appropriate. With
this fix, conflict detection and resolution for any
NDB table works whether the table
was created on the same SQL node, or on a different one.