MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0
The following table shows all Performance Schema tables relating
to the NDBCLUSTER storage engine.
Table 29.3 Performance Schema NDB Tables
| Table Name | Description | Introduced |
|---|---|---|
ndb_sync_excluded_objects |
NDB objects which cannot be synchronized | 8.0.21 |
ndb_sync_pending_objects |
NDB objects waiting for synchronization | 8.0.21 |
Beginning with NDB 8.0.16, automatic synchronization in
NDB attempts to detect and
synchronize automatically all mismatches in metadata between the
NDB Cluster's internal dictionary and the MySQL
Server's datadictionary. This is done by default in the
background at regular intervals as determined by the
ndb_metadata_check_interval
system variable, unless disabled using
ndb_metadata_check or
overridden by setting
ndb_metadata_sync. Prior to NDB
8.0.21, the only information readily accessible to users about
this process was in the form of logging messages and object
counts available (beginning with NDB 8.0.18) as the status
variables
Ndb_metadata_detected_count,
Ndb_metadata_synced_count, and
Ndb_metadata_excluded_count
(prior to NDB 8.0.22, this variable was named
Ndb_metadata_blacklist_size). Beginning with
NDB 8.0.21, more detailed information about the current state of
automatic synchronization is exposed by a MySQL server acting as
an SQL node in an NDB Cluster in these two Performance Schema
tables:
ndb_sync_pending_objects:
Displays information about NDB
database objects for which mismatches have been detected
between the NDB dictionary and the MySQL
data dictionary. When attempting to synchronize such
objects, NDB removes the object
from the queue awaiting synchronization, and from this
table, and tries to reconcile the mismatch. If
synchronization of the object fails due to a temporary
error, it is picked up and added back to the queue (and to
this table) the next time NDB performs
mismatch detection; if the attempts fails due a permanent
error, the object is added to the
ndb_sync_excluded_objects
table.
ndb_sync_excluded_objects:
Shows information about NDB
database objects for which automatic synchronization has
failed due to permanent errors resulting from mismatches
which cannot be reconciled without manual intervention;
these objects are blocklisted and not considered again for
mismatch detection until this has been done.
The ndb_sync_pending_objects and
ndb_sync_excluded_objects tables
are present only if MySQL has support enabled for the
NDBCLUSTER storage engine.
These tables are described in more detail in the following two sections.