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 aboutNDB
database objects for which mismatches have been detected between theNDB
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 timeNDB
performs mismatch detection; if the attempts fails due a permanent error, the object is added to thendb_sync_excluded_objects
table.ndb_sync_excluded_objects
: Shows information aboutNDB
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.