MySQL NDB Cluster 7.2 Release Notes
Important Change: A number of changes have been made in the configuration of transporter send buffers.
The data node configuration parameter
ReservedSendBufferMemory
is now deprecated, and thus subject to removal in a future
MySQL NDB Cluster release.
ReservedSendBufferMemory has been
non-functional since it was introduced and remains so.
TotalSendBufferMemory now works correctly
with data nodes using ndbmtd.
SendBufferMemory can
now over-allocate into
SharedGlobalMemory
for ndbmtd data nodes (only).
A new data node configuration parameter
ExtraSendBufferMemory
is introduced. Its purpose is to control how much additional
memory can be allocated to the send buffer over and above
that specified by TotalSendBufferMemory
or SendBufferMemory. The default setting
(0) allows up to 16MB to be allocated automatically.
(Bug #13633845, Bug #11760629, Bug #53053)
Setting insert_id had no effect
on the auto-increment counter for
NDB tables.
(Bug #13731134)
A data node crashed when more than 16G fixed-size memory was
allocated by DBTUP to one fragment (because
the 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
CREATE TABLE).
(Bug #13637411)
References: See also: Bug #11747870, Bug #34348.
Several instances in the NDB code affecting the operation of
multithreaded 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).
(Bug #13618181)
A very large value for
BackupWriteSize, as
compared to
BackupMaxWriteSize,
BackupDataBufferSize, or
BackupLogBufferSize,
could cause a local checkpoint or backup to hang.
(Bug #13613344)
Queries using 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
engine_condition_pushdown.
(Bug #13604447, Bug #61064)
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 NDB Cluster Send Buffer Parameters. (Bug #13602508)
A SELECT from an
NDB table using
LIKE with a multibyte column (such as
utf8) did not return the correct result when
engine_condition_pushdown was
enabled.
(Bug #13579318, Bug #64039)
References: See also: Bug #13608135.
memcached started with the
ndb_engine.so plugin failed to start if the
ndbmemcache database was missing.
(Bug #13567414)
When starting memcached using
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.
(Bug #13559728)
A node failure and recovery while performing a scan on more than 32 partitions led to additional node failures during node takeover. (Bug #13528976)
The
--skip-config-cache
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.
(Bug #13428853)