Monthly Archives: September 2017

Oracle Sharding – Licensing

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This blog post covers how Oracle Sharding is licensed for On-premises and Oracle Cloud deployments.

Q: How is Oracle Sharding Licensed for On-premises?

A: For a sharded database (SDB) with 3 or fewer primary shards, Oracle Sharding is included with EE (includes Data Guard). No limit on number of standby shards.

For an SDB with more than 3 primary shards, in addition to EE, all shards must be licensed either for Active Data Guard, Oracle GoldenGate or RAC.

So if your licensing agreement covers EE and one of the HA options – Active Data Guard or Oracle GoldenGate or RAC, you can use Oracle Sharding at no additional cost.

Q: How is Oracle Sharding Licensed for Oracle Cloud (PaaS)?

A: With DBCS EE and DBCS EE-High Performance (HP), use is limited to three primary shards. (No limit on number of standby shards)

With DBCS EE-Extreme Performance (EP) and Exadata Cloud Service (ECS), there is no limit on the number of primary shards or standby shards.

Q: What is the Sharding BYOL model for Oracle Cloud (IaaS)?

A: For a sharded database (SDB) with 3 or fewer primary shards, Oracle Sharding is included with EE (includes Data Guard). No limit on number of standby shards. For the 3 primary shards, if Active Data Guard, Oracle GoldenGate or RAC are required for these shards, they ought to be licensed accordingly.

For an SDB with more than 3 primary shards, in addition to EE, all shards must be licensed either for Active Data Guard, Oracle GoldenGate or RAC.

Ref: Oracle Database Licensing Information User Manual, 12c Release 2 (12.2)

Can I build a scalable document store application with an Oracle Sharded Database?

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Yes, indeed! Starting with Oracle Database 12c Release 12.1.0.2, Oracle Database provides support for JSON. It can store, manage, and index JSON documents, and it enables rapid schemaless development. Oracle delivers the schemaless development paradigm that many developers want today, but without compromising on core enterprise capabilities. While many NoSQL systems are now recognizing the need for a tabular, structured format for accessing data, and some are even introducing SQL-like languages, Oracle Database delivers the full power of SQL to JSON document stores today, with its advanced SQL analytic capabilities and scalable parallel SQL infrastructure.

Unlike NoSQL databases, Oracle Database provides sophisticated SQL querying and reporting over JSON documents. This lets you integrate JSON and relational data, joining them in the same query. And because JSON features are integrated into Oracle Database 12c, all of its enterprise features for availability, security, scalability, and manageability are fully supported for JSON data. And now, with the advent of Oracle Sharding which naturally supports Oracle JSON, document-oriented databases can be built very easily. The following table illustrates how simple it is to build a system managed sharded table for a document store application.

CREATE SHARDED TABLE Customers
( CustId   VARCHAR2(60) NOT NULL,
CustProfile CLOB,
CONSTRAINT pk_customers PRIMARY KEY(CustId),
CONSTRAINT cons_json CHECK (CustProfile IS JSON)
)
PARTITION BY CONSISTENT HASH (CustId)
PARTITIONS AUTO
TABLESPACE SET tbs1 ;

The combination of Oracle JSON and Oracle Sharding renders data model flexibility, developer productivity plus the linear scalability of a sharded database.

I plan to do a detailed blog on using Oracle JSON with Oracle Sharding.

Cookbooks on Oracle Sharding

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In this blog, I will give you pointers on how to get started in deploying a sharded database (SDB), create a sample sharded schema and access the SDB with direct and proxy routing. I will also cover how to elastically scale an SDB.
Oracle Sharding provides the capability to automatically deploy the sharded database , which includes both the shards and the replicas.  For the replication, the SDB administrator can select either Data Guard or Active Data Guard or Oracle GoldenGate 12.3 while specifying the topology.
The SDB administrator defines the topology (regions, shard hosts, replication technology etc.) and invokes the DEPLOY command with declarative specification using the GDSCTL command-line interface.
The high-level steps of the deployment of a sharded database include the following:
a) Prerequisites:
• Create a Non-CDB database that hosts the shard catalog
• Install Oracle Database software on shard nodes
• Install shard director (GSM) software on shard director nodes
Note:  For production deployments, it is highly recommended to configure Data Guard for the shard catalog database. In Oracle Database 12.2.0.1 release, all shards and shard catalog must be Non-CDB databases.
b) Specify the topology layout using:
• CREATE SHARDCATALOG
• ADD GSM
• START GSM
• ADD CREDENTIAL (IF USING ‘CREATE SHARD’)
• ADD SHARDGROUP
• ADD INVITEDNOTE
• CREATE SHARD (OR ADD SHARD) (for each shard)
c) Run the “Deploy” command and add global service to access any shard in the SDB:
• DEPLOY
• ADD SERVICE
Oracle Sharding supports two deployment methods.
  1. The first method is with the “CREATE SHARD” command, where the creation of shards and the configuration of the replication setup are automatically done by the Oracle Sharding management tier. The “DEPLOY” command creates the shards. This is done via the DBMS_SCHEDULER package (executed on the shard catalog), which communicates with the scheduler agents on the remote shard hosts. Agents then invoke DBCA and NETCA to create the shards and the local listeners. Once the primary shards are created, the corresponding standby shards are built using the RMAN ‘duplicate’ command. After the primary and standby shards are built, the “DEPLOY” command configures the Data Guard Broker with Fast-Start Failover (FSFO) enabled. The FSFO observers are automatically started on the regional shard director.  If you plan to use CREATE SHARD method, use this cookbook.
  2. The second method is with the “ADD SHARD” command. Many customers have their own database creation standards and they may opt to deploy the SDB using their own pre-created databases. The ADD SHARD based deployment method supports this requirement by simply adding the shards, which are pre-built by the user. If the “ADD SHARD” command is used for deployment, the “DEPLOY” command handles the configuration of the Data Guard, Broker and Fast-start Failover. It also handles the scenario where the user has pre-configured Data Guard for the shard that is being added. You may also want to consider the “ADD SHARD” method, if you are using ASM, RAC or Oracle Restart at the shard-level. If you do plan to use “ADD SHARD” method, use this specific cookbook.
These cookbooks walk you through the entire lifecycle of a sharded database which include the following steps:
  • Creation of shard catalog and shard directors for system managed sharding
  • Specify the metadata and deploy the sharded database
  • Creation of table family using system managed sharding
  • Specify Sharding_Key for session based routing (using SQL*Plus)
  • Observe uniform data distribution by executing Read Write and Read Only workloads on the sharded database using a demo application (using UCP)
  • Execute cross-shard queries
  • Elastically scale the sharded database
Hope this helps in allowing you to get started in playing with Oracle Sharding.