8 Globally Distributed Database

This chapter provides information about the Globally Distributed Database metrics.

A distributed database is a method of partitioning data to distribute the computational and storage workload. This is achieved using a technology called database sharding, in which segments of a data set or a shard is distributed across lots of databases on lots of different computers. All the shards together make up a single logical database, called a distributed database. For more information, see Oracle Globally Distributed Database Overview in Oracle Globally Distributed Database.

Shard Director

This section provides information about the metric categories available for the Shard Director target.

Shard Director is a Global Service Manager, which supports the routing of connections based on data location.

Global Service Performance

This section provides information on the metrics in the Global Service Performance category.

Target Version Evaluation and Collection Frequency
12c and later Every 15 minutes
Metric Name Description Unit
Average Response Time Elapsed time per user call. Milliseconds
CPU IO Violations Count of CPU IO threshold violations. None
CPU Load CPU utilization Percentage
Calls Per Second Number of logins, parses, or execute calls per second during the sample period. None
Collected Region Name of the GSM region. None
Latency Network latency between database region and GSM region. Milliseconds
Latency Region Name of the GSM region for which latency is computed. None
Master Global Master GSM None
Region Master Regional Master GSM None
Runtime Load Balance Percentage of workload for runtime load balancing purposes. None
Session Count Current session count over the past 30 seconds. None

Load

This section provides information on the metrics in the Load category.

Target Version Evaluation and Collection Frequency
12c and later Every 5 minutes
Metric Name Description Unit
Connections Established (per min) Count of connections established per minute. None
Connections Refused (per min) Count of connections refused per minute. None

General Status

This section provides information on the metrics in the General Status category.

Target Version Evaluation and Collection Frequency
12c and later Every 5 minutes
Metric Name Description Unit
Host GSM host None
Port GSM port None
Region Region name None
Region Master Regional master GSM None
Start Date GSM start time Date
TNSPING Response Time Response time of TNSPING test from GDS home to GSM server. Milliseconds
TNSPING Status Status of TNSPING test from GDS home to GSM server. Status (0 or 1)

Chunk Performance

The metric in this category reports the chunk-level performance.

Note that this metric is disabled by default and you can enable it in the Oracle Enterprise Manager console or using a Monitoring template.

Target Version Evaluation and Collection Frequency
12c and later Every 15 minutes
Metric Name Description Unit
Throughput (calls/sec) Number of calls per second in a chunk. Operations per second

Response

The metric in this category reports the status of the Globally Distributed Database.

Target Version Evaluation and Collection Frequency
12c and later Event-driven
Metric Name Description Unit
Status Status of the Globally Distributed Database. None

Service Distribution

The metrics in this category report the service distribution details.

Target Version Evaluation and Collection Frequency
12c and later Every 5 minutes
Metric Name Description Unit
Calls per second distribution (Instance:::Database:::Region) Number of calls distribution per service per shard database per region. Operations per second
Region Name Name of the region. None
Response time distribution (Instance:::Database:::Region) Response time distribution per service per shard database per region. Milliseconds

Service Status

The metrics in this category report the service status details.

Target Version Evaluation and Collection Frequency
12c and later Every 5 minutes
Metric Name Description Unit
Preferred Database(s) Preferred list of instances where the service should run. If the role is specified to a service, then all role matching instances are preferred. None
Running Database(s) Instances where the service is running. None
Status Status of the global service based on running and preferred instances.
  • If the service is running on all preferred instances, then its status is Up.
  • If the service is running on some of the preferred instances, then its status is Up with Warning.
  • If the service is not running on any of the preferred instances, then its status is Down.
 None

Shard Chunk Size (GB)

The metric in this category reports the size of a chunk per shard.

Note that this metric is disabled by default and you can enable it in the Oracle Enterprise Manager console or using a Monitoring template.

Target Version Evaluation and Collection Frequency
12c and later Every 15 minutes
Metric Name Description Unit
Chunk Size (GB) Size of a chunk per shard. GB

Shard Global Service Performance

The metrics in this category report the shard global service performance details.

Note that this metric is disabled by default and you can enable it in the Oracle Enterprise Manager console or using a Monitoring template.

Target Version Evaluation and Collection Frequency
12c and later Every 15 minutes
Metric Name Description Unit
Average Active Sessions Ratio of the DB time to wall clock time. None
Service Time (m/s) Average time spent per user call. Milliseconds
Throughput (calls/sec) Number of user calls per second. Operations per second

Shard Replication Units Summary

The metrics in this category provide a summary of the replication units in an Oracle Globally Distributed Database. Replication units in an Oracle Globally Distributed Database are created by Raft replication and distributed automatically to handle chunk assignment, chunk movement, workload distribution, and balancing upon scaling (addition or removal of shards), which includes planned or unplanned shard availability changes.

Target Version Evaluation and Collection Frequency
23ai and later Every 15 minutes
Metric Name Description Unit
Replication Unit Number Number of the replication unit. None
Shard DB Number Number of the shard that contains the replication unit. None
Replication Unit Leader Shard DB Number Number of the shard that leads the replication process. None
Replication Unit Role Role of the shard for this replication unit:
  • 1 = leader
  • 2 = follower
  • 3 = candidate
 None

Data Source

SELECT rp.ru_number AS RU_NUMBER,
       rp.db_number AS SHARD_DB_NUMBER,
       rp.role AS RU_ROLE_IN_SHARD,       
       ru.leaderid  As RU_LEADER_ID
FROM    
       gsmadmin_internal.ru_peers rp,    
       gsmadmin_internal.replication_unit ru
WHERE  
       rp.ru_number = ru.ru_number
ORDER BY    
       rp.ru_number

Shard Size (GB)

The metrics in this category report the allocated size of the shard.

Note that this metric is disabled by default and you can enable it in the Oracle Enterprise Manager console or using a Monitoring template.

Target Version Evaluation and Collection Frequency
12c and later Every 15 minutes
Metric Name Description Unit
Number of Chunks Change Rate Rate of change in the number of chunks per shard during metric collection. Percentage
Data Size Change Rate Rate of change in data size per shard during metric collection. Percentage
Data Size (GB) Size of a shard. GB
Number of Chunks Number of chunks per shard. None
Number of Tablespaces Number of tablespaces per shard. None

Shard Status Details

The metrics in this category report shard status details.

Target Version Evaluation and Collection Frequency
12c and later Every 15 minutes
Metric Name Description Unit
Connect String Shard database connect string used in the Shard Director (GSM) configuration. None
Convert State Displays shard database role change possibility. None
DDL Error Displays DDL error in GSM operations, if any. None
DDL Number DDL operation number in GSM. None
Data Guard Broker ID Data guard broker ID shared across the primary and standby databases. None
Database Status Status of the shard database in GSM. None
Database Type Shard database type. For example, RAC or Non-RAC. None
Database Up Status of the shard database in Oracle Enterprise Manager. None
Deployment Status Deployment status of the shard database from the GSM. For example, Deployed or Pending. None
Host Shard database host. None
Is Primary Shard database role. None
Oracle Home Oracle home path for the shard database. None
Region Name Region in which the shard database is deployed. None
Shardgroup Name Name of the shardgroup to which the shard database belongs. None
Shardspace Name Name of the shardspace to which the shard database belongs. None

Shard Tablespace Summary

The metrics in this category report the shard tablespace summary.

Note that this metric is disabled by default and you can enable it in the Oracle Enterprise Manager console or using a Monitoring template.

Target Version Evaluation and Collection Frequency
12c and later Every 15 minutes
Metric Name Description Unit
Tablespace Set Name Tablespace set name. None
Chunk Number ID of the chunk. None
Shardspace ID ID of the shardspace. None

Unique Keys Count

The metrics in this category report the details of the unique sharding keys per shard.

Note that this metric is disabled by default and you can enable it in the Oracle Enterprise Manager console or using a Monitoring template.

Target Version Evaluation and Collection Frequency
12c and later Every 1 hour
Metric Name Description Unit
Number of Unique Keys Change Rate Rate of change of the number of unique keys per shard during metric collection. Percentage
Unique Keys Count Number of unique sharding keys present in the shard. None