MySQL NDB Cluster 7.5 Release Notes
MySQL NDB Cluster 7.5.3 is a new release of MySQL NDB Cluster 7.5,
based on MySQL Server 5.7 and including features in version 7.5 of
the NDB storage engine, as well as
fixing recently discovered bugs in previous NDB Cluster releases.
Obtaining MySQL NDB Cluster 7.5. MySQL NDB Cluster 7.5 source code and binaries can be obtained from https://dev.mysql.com/downloads/cluster/.
For an overview of changes made in MySQL NDB Cluster 7.5, see What is New in NDB Cluster 7.5.
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 5.7 through MySQL 5.7.13 (see Changes in MySQL 5.7.13 (2016-06-02, General Availability)).
Important Change:
It is now possible to set READ_BACKUP for an
existing table online using an SQL statement such as
ALTER
TABLE ... ALGORITHM=INPLACE,
COMMENT="NDB_TABLE=READ_BACKUP=1". See
Setting NDB Comment Options, for further
information about the READ_BACKUP option.
(Bug #80858, Bug #23001617)
References: See also: Bug #18435416.
Added three new tables to the
ndbinfo information database
to provide running information about locks and lock attempts in
an active MySQL NDB Cluster. These tables, with brief
descriptions, are listed here:
cluster_locks: Current
lock requests which are waiting for or holding locks; this
information can be useful when investigating stalls and
deadlocks. Analogous to
cluster_operations.
locks_per_fragment: Counts
of lock claim requests, and their outcomes per fragment, as
well as total time spent waiting for locks successfully and
unsuccessfully. Analogous to
operations_per_fragment
and memory_per_fragment.
server_locks: Subset of
cluster transactions—those running on the local
mysqld, showing a connection ID per
transaction. Analogous to
server_operations.
For more information, see ndbinfo: The NDB Cluster Information Database. (WL #7656)
The NDB storage engine now supports
generated columns (see
CREATE TABLE and Generated Columns) as well as
indexes on stored generated columns.
Indexes on virtual generated columns of NDB
tables are not supported.
ALTER
TABLE statements that add stored generated columns to
NDB tables cannot be performed online.
(WL #8188, WL #9048)
NDB Cluster APIs:
The scan lock takeover issued by
NdbScanOperation::lockCurrentTuple()
did not set the operation type for the takeover operation.
(Bug #23314028)
The ndbinfo
cpustat_1sec and
cpustat_20sec tables did not
provide any history information.
(Bug #23520271)
During shutdown, the mysqld process could
sometimes hang after logging NDB Util: Stop
... NDB Util: Wakeup.
(Bug #23343739)
References: See also: Bug #21098142.
During expansion or reduction of a hash table, allocating a new
overflow page in the DBACC kernel block
caused the data node to fail when it was out of index memory.
This could sometimes occur after a large table had increased or
decreased very rapidly in size.
(Bug #23304519)
References: This issue is a regression of: Bug #13436216.
When tracking time elapsed from sending a
SCAN_FRAGREQ signal to receiving a
corresponding SCAN_FRAGCONF, the assumption
was made in the DBTC kernel block that a
SCAN_FRAGCONF can occur only after sending a
SCAN_FRAGREQ or
SCAN_NEXTREQ signal, which is not always the
case: It is actually possible that a local query handler can,
immediately after sending a SCAN_FRAGCONF,
send an additional SCAN_FRAGCONF signal upon
reporting that the scan is closed. This problem is fixed by
ensuring that the timer value is initialized each time before
use.
(Bug #81907, Bug #23605817, Bug #23306695)
Table indexes were listed in the output of ndb_desc in a nondeterministic order that could vary between platforms. Now these indexes are ordered by ID in the output. (Bug #81763, Bug #23547742)
Following a restart of the cluster, the first attempt to read
from any of the ndbinfo
cpustat,
cpustat_50ms,
cpustat_1sec, or
cpustat_20sec tables generated
a warning to the effect that columns were missing from the
table. Subsequently, the thread_sleeping and
spin_time columns were found to be missing
from each of these tables.
(Bug #81681, Bug #23514557)
References: See also: Bug #23305078.
Using a ThreadConfig
parameter value with a trailing comma led to an assertion.
(Bug #81588, Bug #23344374)